Coverage Policy Manual
Policy #: 2011078
Category: Surgery
Initiated: December 2011
Last Review: October 2018
  Microwave Ablation of Tumors

Description:
Microwave ablation (MWA) is a technique to destroy tumors and soft tissue by using microwave energy to create thermal coagulation and localized tissue necrosis. MWA is used to treat tumors considered to be inoperable or not amenable to resection or to treat patients ineligible for surgery due to age, presence of comorbidities, or poor general health. MWA may be performed as an open procedure, laparoscopically, percutaneously or thoracoscopically under image guidance (e.g., ultrasound, computed tomography [CT] or magnetic resonance imaging [MRI]) with sedation, or local or general anesthesia. This technique may also be referred to as microwave coagulation therapy.
 
Microwave ablation (MWA) is a technique in which the use of microwave energy induces an ultra-high speed, 915 MHz or 2450 MHz (2.45GHz), alternating electric field which causes water molecule rotation and the creation of heat. This results in thermal coagulation and localized tissue necrosis. In MWA, a single microwave antenna or multiple antennas connected to a generator are inserted directly into the tumor or tissue to be ablated; energy from the antennas generates friction and heat. The local heat coagulates the tissue adjacent to the probe, resulting in a small, approximately 2-3 cm elliptical area (5 x 3 cm) of tissue ablation. In tumors greater than 2 cm in diameter, 2-3 antennas may be used simultaneously to increase the targeted area of MWA and shorten operative time. Multiple antennas may also be used simultaneously to ablate multiple tumors. Tissue ablation occurs quickly, within 1 minute after a pulse of energy, and multiple pulses may be delivered within a treatment session depending on the size of the tumor. The cells killed by MWA are typically not removed but are gradually replaced by fibrosis and scar tissue. If there is local recurrence, it occurs at the edges. Treatment may be repeated as needed. MWA may be used to: 1) control local tumor growth and prevent recurrence; 2) palliate symptoms; and 3) extend survival duration.
 
Complications from MWA are usually considered mild and may include pain and fever. Other potential complications associated with MWA include those caused by heat damage to normal tissue adjacent to the tumor (e.g., intestinal damage during MWA of the kidney or liver), structural damage along the probe track (e.g., pneumothorax as a consequence of procedures on the lung), liver enzyme elevation, liver abscess, ascites, pleural effusion, diaphragm injury or secondary tumors if cells seed during probe removal. MWA should be avoided in pregnant patients since potential risks to the patient and/or fetus have not been established and in patients with implanted electronic devices such as implantable pacemakers that may be adversely affected by microwave power output.
 
MWA is an ablative technique similar to radiofrequency or cryosurgical ablation. However, MWA has some potential hypothetical advantages over radiofrequency or cryosurgical ablation. In MWA, the heating process is active, which produces higher temperatures than the passive heating of radiofrequency ablation and should allow for more complete thermal ablation in a shorter period of time. The higher temperatures reached with MWA (over 100° C) can overcome the “heat sink” effect in which tissue cooling occurs from nearby blood flow in large vessels potentially resulting in incomplete tumor ablation. MWA does not rely on the conduction of electricity for heating, and therefore, does not have electrical current flow through patients and does not require grounding pads be used during the procedure since there is no risk of skin burns. Additionally, MWA does not produce electric noise, which allows ultrasound guidance to occur during the procedure without interference, unlike radiofrequency ablation. Finally, MWA can be completed in less time than radiofrequency ablation since multiple antennas can be used simultaneously.
 
MWA was first used percutaneously in 1986 as an adjunct to liver biopsy. Since that time, MWA has been used for ablation of tumors and tissue for the treatment of many conditions including: hepatocellular carcinoma, colorectal cancer metastatic to the liver, renal cell carcinoma, renal hamartoma, adrenal malignant carcinoma, non-small cell lung cancer, intrahepatic primary cholangiocarcinoma, secondary splenomegaly and hypersplenism, abdominal tumors and other tumors not amenable to resection. Well-established local or systemic treatment alternatives are available for each of these malignancies. The hypothesized advantages of MWA for these cancers include improved local control and those common to any minimally invasive procedure (e.g., preserving normal organ tissue, decreasing morbidity, decreasing length of hospitalization).
 
Hepatic Tumors. Hepatic tumors can arise either as primary liver cancer (hepatocellular cancer) or by metastasis to the liver from other primary cancer sites. Local therapy for hepatic metastasis may be indicated when there is no extrahepatic disease, which rarely occurs for patients with primary cancers other than colorectal carcinoma or certain neuroendocrine malignancies. At present, surgical resection with adequate margins or liver transplantation constitutes the only treatments available with demonstrated curative potential. Partial liver resection, hepatectomy, is considered the gold standard. However, the majority of hepatic tumors are unresectable at diagnosis, due either to their anatomic location, size, number of lesions, or underlying liver reserve.
 
Various locoregional therapies for unresectable liver tumors have been investigated including: microwave coagulation, radiofrequency ablation, cryosurgical ablation (cryosurgery), laser ablation, trans-hepatic artery embolization/chemoembolization (TACE), percutaneous ethanol injection, and radioembolization (Yttrium-90 microspheres).
 
MWA has been investigated as a treatment for unresectable hepatic tumors, both as primary treatment, palliative treatment and as a bridge to liver transplant. In the latter setting, it is hoped that MWA will reduce the incidence of tumor progression while awaiting transplantation and thus maintain a patient’s candidacy for liver transplant during the wait time for a donor organ.
 
Renal Cell Carcinoma. Radical nephrectomy remains the principal treatment of renal cell carcinoma, however, partial nephrectomy or nephron-sparing surgery has been shown to be as effective as radical nephrectomy, with comparable long-term recurrence-free survival rates, in a select group of patients. Prognosis drops precipitously if the tumor extends outside the kidney capsule, since chemotherapy is relatively ineffective against metastatic renal cell carcinoma. Alternative therapies such as MWA are of interest in patients with small renal tumors when preservation of renal function is necessary (e.g., in patients with marginal renal function, a solitary kidney, bilateral tumors) and in patients with comorbidities that would render them unfit for surgery. Another consideration would be in patients at high risk of developing additional renal cancers (as in von Hippel-Lindau disease).
 
Regulatory Status
There are several devices cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process for MWA. Covidien’s (a subsidiary of Tyco Healthcare) Evident Microwave Ablation System has 510(k) clearance for soft tissue ablation, including partial or complete ablation of non-resectable liver tumors. The following devices have 510(k) clearance for MWA of (unspecified) soft tissue:
  •  BSD Medical Corporation’s MicroThermX® Microwave Ablation System (MTX-180);
  •  Valleylab’s (a subsidiary of Covidien) VivaWave® Microwave Ablation System;
  •  Vivant’s (acquired by Valleylab in 2005) Tri-Loop™ Microwave Ablation Probe;
  •  MicroSurgeon Microwave Soft Tissue Ablation Device;
  •  Microsulis Medical’s (now part of AngioDynamics) Acculis® Accu2i; and
  •  NeuWave Medical’s Certus 140™
 
These devices are considered substantially equivalent to previously FDA-approved radiofrequency and MWA devices.
 
This policy does not address MWA for the treatment of splenomegaly or ulcers or as a surgical coagulation tool.
 
There are no specific CPT codes for this procedure. The unlisted CPT code for the anatomic area should be reported such as code 19499 for unlisted procedure, breast, code 47399 for unlisted procedure, liver, or code 53899 for unlisted procedure, urinary system (for renal tumors).
 
According to a 2012 American Medical Association publication (Clinical Examples in Radiology, Vol. 8, Issue 3; Summer 2012), “microwave is part of the radiofrequency spectrum, and simply uses a different part of the radiofrequency spectrum to develop heat energy to destroy abnormal tissue.” Therefore, they instruct that microwave ablation should be reported using the CPT codes for radiofrequency ablation – 32998 (pulmonary), 47382 (liver), and 50592 (renal).
 
RELATED POLICIES:
  •  2003062 - Cryosurgical Ablation of Breast Tumors, Benign and Malignant
  •  2003063 - Cryosurgical Ablation of Pancreatic Cancer
  •  2003002 - Cryosurgical Ablation of Prostate Cancer
  •  2000041 - Cryosurgical Ablation of Renal Tumors
  •  2008006 - Transcatheter Arterial Chemoembolization (TACE) to Treat Primary or Metastatic Liver Malignancies
  •  1997255 - Hepatic Tumors, Ablative Procedures (Percutaneous Ethanol Injections, Acetic Acid Injections, and Interstitial Laser Photocoagulation)
  •  2012062 - Radiofrequency Ablation of Primary or Metastatic Liver Tumors
  •  2006014 - Microwave Thermotherapy for Breast Cancer
  •  2003061 - Brachytherapy, Radioembolization of Primary & Metastatic Tumors of the Liver with Therapeutic Microspheres   

Policy/
Coverage:
Microwave ablation of primary and metastatic tumors does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes.
 
For members with contracts without primary coverage criteria, microwave ablation of primary and metastatic tumors is considered investigational.  Investigational services are specific contract exclusions in most member benefit certificates of coverage.
 

Rationale:
The policy was developed with a literature search of the MEDLINE database through October 2011. The findings of the literature search are summarized below with select studies.
 
Literature Review
Hepatocellular Carcinoma
The literature search identified many publications on studies of microwave ablation (MWA) for hepatocellular carcinoma, primarily small case series and retrospective reviews conducted in China and Japan. Only two studies were indexed in the PubMed database as randomized clinical trials (Shibata, 2002) (Taniai, 2006). No randomized controlled trials (RCTs) comparing the use of MWA for hepatocellular carcinoma to the gold standard of surgical resection were identified. The following summarizes 2 systematic reviews (Ong, 2009) (Bertot, 2011) and select studies reporting on 25 or more patients. All of the studies demonstrated that the technique of MWA provided good tumor ablation (87-100% ablation of targeted tumors) with low procedural complication rates. Associated morbidity and mortality, as well as overall survival and disease-free survival rates with MWA are similar to radiofrequency ablation, which would be an appropriate comparator in patients with tumors not amenable to surgical resection. However, only one RCT comparing MWA directly to radiofrequency ablation was identified (Shibata, 2002).  
 
In 2009, Ong and colleagues conducted a systematic review of studies on MWA for primary and secondary liver tumors (Ong, 2009). Based on the results from 25 clinical studies reporting outcomes on MWA, the authors concluded MWA is an effective and safe technique for liver tumor ablation with low complication rates and survival rates comparable to hepatic resection. However, rates of local recurrence after MWA were noted to be higher than hepatic resection. In most studies, hepatocellular carcinoma recurrence rates were approximately 10% but were also noted to be as high as 50%, which the authors indicated can be addressed with further ablation. Survival rates in the studies on MWA for hepatocellular carcinoma were as high as 92% at 3 years and 72% at 5 years, which was noted to be comparable to radiofrequency ablation and percutaneous ethanol injections. Pain and fever were the most frequently reported complications, but complications increased when there were more tumors, larger tumors, and more microwave antennas used. Ong and colleagues concluded MWA is a promising treatment option for the treatment of liver tumors but should be reserved for patients not amenable to hepatic resection. The authors also noted further randomized clinical trials are warranted to compare MWA to other ablation procedures. Bertot and colleagues conducted a systematic review in 2011 of ablation techniques for primary and secondary liver tumors (Bertot, 2011). This review included 2 studies using MWA totaling 1,185 patients (Lu, 2005) (Liang, 2009). The pooled mortality rate for MWA was 0.23% (95% confidence interval [CI], 0.0–0.58%). Major complication rates were 4.6% for MWA (calculated by using a random effects model since there was significant heterogeneity). The authors concluded percutaneous ablation techniques, including MWA, are safe and have acceptable complication rates for the treatment of liver tumors.
 
In 2002, Shibata and colleagues reported on 72 consecutive patients with 94 small hepatocellular carcinoma nodules randomized by sealed envelopes to receive either percutaneous MWA or radiofrequency ablation performed by a single surgeon (Shibata, 2002). No significant differences were identified between the 2 treatment group characteristics, e.g., sex, age, nodule size, Child-Pugh cirrhosis class and number of nodules. In the radiofrequency ablation group, complete therapeutic effect was seen in 46 (96%) of 48 nodules (mean size 2.3 cm, range of 1.0-3.7) versus 41 (89%) of 46 nodules (mean size 2.2 cm, range 0.9-3.4) treated with percutaneous MWA (p=0.26). Treatment outcomes were not significantly different between the percutaneous MWA and radiofrequency ablation groups in the rates of untreated disease during a follow-up range of 6-27 months (8 of 46 nodules vs. 4 of 48 nodules, respectively), and major complication rates (4 vs. 1, respectively). Major complications included one case of segmental hepatic infarction in the radiofrequency ablation group. In the MWA group, major complications included one case of each of the following: liver abscess, cholangitis with intrahepatic bile duct dilatation, subcutaneous abscess with skin burn and subcapsular hematoma. Life-threatening complications were not experienced. The number of treatment sessions required per nodule in the radiofrequency ablation group was significantly lower than in the percutaneous MWA group (1.1 vs. 2.4; p<0.001). However, treatment time per session was significantly shorter in the MWA group (33 minutes ± 11) than the radiofrequency ablation group (53 minutes ± 16).
 
Taniai and colleagues, in 2006, reported on 30 patients with multiple hepatocellular carcinoma tumors who underwent reduction hepatectomy with postoperative transcatheter arterial embolization (Taniai, 2006). Prior to surgery, patients were randomly assigned to receive no intraoperative adjuvant therapy (n=15) or intraoperative adjuvant therapy with either MWA (n=10) or radiofrequency ablation (n=5) of satellite lesions. No significant differences in characteristics were identified between the two treatment groups of no intraoperative adjuvant therapy vs. intraoperative adjuvant therapy, e.g., sex, age, nodule size (maximum tumor size 42.7 mm ± 23.5 vs. 37.8 mm ± 16, respectively), Child-Pugh cirrhosis class and number of nodules. Cumulative survival rates at 3 and 5 years were not significantly different in the group that did not receive intraoperative adjuvant therapy (35.0% and 0%, respectively) versus the intraoperative adjuvant therapy group (35.7% and 7.7%, respectively). A-fetoprotein, number of tumors, maximum tumor size and clinical stage, but not intraoperative adjuvant therapy, were identified as independent prognostic survival factors.
 
In April 2011, Simo and colleagues retrospectively compared laparoscopic MWA (13 patients with 15 tumors) to radiofrequency ablation (22 patients with 27 tumors) performed by a single surgeon for the treatment of hepatocellular carcinoma. (7) No significant differences were identified between the two treatment group characteristics except for sex (54% vs. 86% male, respectively). Average tumor size was 2.31 cm in the MWA group versus 2.53 cm in the radiofrequency ablation group. The authors reported average tumor ablation volumes were not significantly different at 28.99 cm for MWA and 23.43 cm for radiofrequency ablation. In the MWA group, at a mean follow-up of 7 months, disease-free survival was 54%, with 2 patients having received liver transplants, 31% having disease progression and 15% deceased. The radiofrequency ablation group was followed for a longer period of time at a mean of 19 months. This group experienced 50% survival without evidence of disease, with 4 patients having received liver transplants, 9% having disease progression, 36% deceased, and 5% lost to follow-up. Operative times were shorter in the MWA group (112 ± 40 vs. 149 ± 35 minutes).
 
In 2011, Zhou and colleagues prospectively evaluated percutaneous MWA for hepatocellular carcinoma in 215 patients with tumors equal to or less than 60 mm (median size 29 mm) in a single center, Phase II study (Zhou, 2011). The authors reported technical effectiveness in all patients. Overall survival rates at 1, 2, 3, 4 and 5 years were 94%, 82.9%, 66%, 54.1% and 44.4%, respectively, and median survival time was 40 months (range 4 to 106 months). Complications related to the procedure included 3 cases of pleural effusion and one case of bile duct injury. In another prospective study by Zhou et al. in 2009, percutaneous MWA was performed on 124 patients with 144 hepatocellular carcinoma lesions and 28 patients with 35 lesions of hepatic metastases (Zhou, 2009). Included in this total of 152 patients were 59 patients with 61 lesions (mean size 27 mm) located less than 5 mm from the gastrointestinal tract and 93 patients with 126 lesions (mean size 24 mm) located more than 5 mm from the gastrointestinal tract. For lesions less than 5 mm from the gastrointestinal tract, the temperatures of the margins were monitored closely during ablation and to prevent thermal injury, ethanol injections were placed into marginal tumor tissue in 33 lesions that were protruding or in contact with the gastrointestinal tract. No procedural complications were noted; however, tumor seeding occurred in 3 patients. Complete ablation was achieved in 47 of 53 lesions (88.7%) in the group with tumors near the gastrointestinal tract and in 116 of the other 126 lesions (92.1%) as confirmed by imaging during the follow-up period ranging from 3-32 months. Local tumor progression occurred in 16 tumors during 1-9 months’ follow-up. Separate treatment outcomes for hepatocellular tumors and hepatic metastasis were not provided.
 
Lu and colleagues, in 2005, reported on a retrospective comparison of 102 patients with hepatocellular carcinoma treated with either percutaneous MWA (49 patients with 98 nodules, mean size 2.5 cm) or radiofrequency ablation (53 patients with 72 nodules, mean size 2.6 cm) (Lu, 2005). Patient follow-up was 25.1 months in the MWA group and 24.8 months in the radiofrequency ablation group. Complete ablation was not significantly different in the treatment groups and was achieved in 93 of 98 tumors (94.9%) in the MWA group and in 67 of 72 tumors (93.1%) in the radiofrequency ablation group. However, complete ablation rates increased in tumors less than or up to 3 cm in size to 98.6% (73 of 74) in the MWA group and 98% (50 of 51) in the radiofrequency ablation group. In tumors greater than 3 cm, complete ablation rates decreased to 83.3% (20 of 24) in the MWA group and 81% (17 of 21) in the radiofrequency ablation group. There were also no significant differences found in the MWA group versus the radiofrequency ablation group in rates of local tumor recurrence (11.8% vs. 20.9%, respectively), major complications (8.2% vs. 5.7%, respectively) or disease-free survival at 1, 2 and 3 years (45.9%, 26.9% and 26.9% vs. 37.2%, 20.7%, and 15.5%, respectively).
 
In 2009, Liang et al. reported on a retrospective review of complications experienced with percutaneous MWA for the treatment of 1,928 malignant liver tumors in 1,136 patients at a single institution (Liang, 2009). Each patient received an average of 1.8 treatment sessions for a total of 3,697 treatment sessions. Thirty patients (2.6%) experienced major complications, which included 5 cases of liver abscess and empyema, 2 bile duct injuries, 2 colon perforations, 5 tumor seedings, 12 pleural effusions requiring thoracentesis, 1 hemorrhage requiring arterial embolization, and 3 skin burns requiring resection for a total of 30 (2.6%) patient complications. Two deaths occurred within 30 days after MWA in patients with Child class B uncompensated cirrhosis. One patient (age 78) had multi-organ failure and died 14 days after treatment and another patient (age 83) had respiratory and cardiac failure and died 14 days after treatment. Minor complications included fever (83.4%), pain (80.1%), asymptomatic pleural effusion (10.4%), thickening of the gallbladder wall (2.8%), and arterioportal shunt (0.3%), small stricture of the bile duct (0.4%) and skin burn requiring no treatment (1.6%). A significantly higher rate of major complications and more ablation sessions were experienced when a noncooled-shaft antenna was used during the period of 1994 to 2005 (n=583) than when newer technology, cooled-shaft antennas were used beginning in 2005 (n=583).
 
Hepatic Metastasis from Primary Cancers from Other Sites
The literature search identified several small studies on MWA for hepatic metastases and 3 systematic reviews (Ong, 2009) (Bertot, 2011) (Pathak, 2011). In the Ong review described above, local recurrence rates for liver metastases after treatment with MWA averaged approximately 15% but varied between 0 and 50% in the 7 studies reviewed that addressed liver metastases. As noted above, Ong and colleagues concluded MWA is a promising treatment option for the treatment of liver tumors but should be reserved for patients not amenable to hepatic resection. Bertot and colleagues conducted a systematic review described above (Bertot, 2011). In 2011, Pathak and colleagues also conducted a systematic review of ablation techniques for colorectal liver metastases, which included 13 studies on MWA totaling 406 patients with a minimum of 1-year follow-up (Pathak, 2011). Mean survival rates were 73%, 30% and 16% and ranged from 40–91.4%, 0–57% and 14–32% at 1-, 3- and 5-years’ follow-up, all respectively. Minor and major complication rates were considered acceptable and ranged from 6.7–90.5% and 0–19%, respectively. Local recurrence rates ranged from 2-14%. The authors acknowledged limitations in the available studies but concluded survival rates for MWA are more favorable than for palliative chemotherapy alone.
 
Only one RCT comparing the use of MWA for hepatic metastases to the gold standard of surgical resection was identified. In 2000, Shibata et al. reported on a trial of 30 patients with hepatic metastases from colorectal cancer randomly assigned without stratification to treatment with either MWA after laparotomy (n=14) or hepatectomy (n=16) (Shibata, 2000). The study began with 40 patients, but 10 patients were excluded because the researchers discovered intraoperatively that these patients did not meet study criteria due to having extensive metastasis or equal to or greater than 10 tumors. The treatment groups of MWA vs. hepatectomy were not significantly different in age (mean age 61 in both groups) number of tumors (mean 4.1 vs. 3.0, respectively) or tumor size (mean 27 mm vs. 34 mm, respectively). The authors reported no significant differences in survival rates following MWA or hepatectomy (27 months vs. 25 months, respectively) and mean disease-free survival (11.3 vs. 13.3 months, respectively). However, intraoperative blood loss was significantly lower and no blood transfusions were required in the MWA group whereas 6 patients in the hepatectomy group required blood transfusions. Complications in the microwave group consisted of one hepatic abscess and one bile duct fistula. In the hepatectomy group, complications were one intestinal obstruction, one bile duct fistula and one wound infection.
 
In 2011, Lorentzen and colleagues reported on a retrospective review of percutaneous or open MWA in 39 patients with 125 liver metastases from the primary sites of colorectal cancer (n=31), breast cancer (n=6), carcinioid tumor (n=1) and gastrointestinal stromal tumor (n=1) (Lorentzen, 2011). Complete ablation was achieved in 100% of tumors (median size of 1.5 cm) with one treatment session in 34 patients, 2 sessions for 4 patients and 3 sessions for one patient. One case of liver abscess, which resolved after percutaneous drainage, was the only major complication reported. Four minor complications included one incidence of ascites and 3 complaints of puncture site pain. Upon median follow-up of 11 months, local tumor progression was seen in 12 of 125 tumors (9.6%) in 10 of the 39 patients (26%).
 
In a prospective, single institution Phase II study in 2010, Martin et al. reported on 100 patients treated with 270 open or laparoscopic MWAs for hepatocellular carcinoma (n=17) and liver metastases from the primary sites of colorectal (n=50), carcinoid (n=11) and other cancers (n=22 and included cholangiocarcinoma, metastatic breast, renal cell carcinoma, bladder, carcinoid, melanoma, and sarcoma) (Martin, 2010). Median tumor size was 3.0 cm. Thirty-eight patients were treated with MWA alone, 53 patients had MWA with concomitant hepatic resection while another 9 patients had MWA concomitant with other organ resection. Only 2 patients had incomplete ablations after the procedure. No bleeding complications were experienced, but 2 cases of hepatic abscess and 2 cases of hepatic insufficiency occurred. At median follow-up of 36 months, 5 patients were found to have incomplete ablations and only 2 patients (2%) had local tumor recurrence while 37 patients (37%) developed recurrence at other nonablated sites.
 
Primary Renal Tumors
No RCTs comparing the use of MWA for renal tumors to the gold standard of nephron-sparing surgical resection or other treatment options were identified. Several small case studies on renal tumors were identified. In 2011, Muto and colleagues reported complete tumor coagulation necrosis in 10 patients treated with laparoscopic MWA for clear cell renal carcinoma with a median tumor size of 2.75 cm (Muto, 2011). Depending on tumor size, the microwave antennas were used 1 to 3 times for a mean application time of 14.1 minutes. No complications were reported during or after the procedure. Bai et al. in 2010, reported complete laparoscopic MWA in 17 of 18 clear cell renal carcinoma tumors with a mean tumor size of 2.8 cm (Bai, 2010). In this study, evidence of disease progression was not found in any of the patients followed up for a median of 20 months including the patient with an incomplete ablation who was followed for 31 months. Complications reported were mild (18.2%), and renal function did not significantly deteriorate. However, in a 2011 study of 10 patients with solid-enhancing renal tumors (median size of 3.65 cm), treated with laparoscopic (n=7) or percutaneous (n=3) MWA, Castle and colleagues reported tumor recurrence was seen in 3 of 8 tumors upon mean follow-up time of 17.9 months (Castle, 2011).  Since tumor size was larger in this study, mean ablation time was 21 minutes. Additionally, 20% of patients experienced intraoperative complications while 40% experienced postoperative complications including, perinephric hematoma, splenic capsular tear, pleuritic chest pain, skin burn, fever, hematuria, genitofemoral neuralgia and urinoma.
 
One study by Guan and colleagues, in 2010, reported on the safety of retroperitoneoscopic MWA for renal hamartoma (Guan, 2010). In this case series report, 15 of 16 patients had complete tumor ablation. Disease recurrence was not found in all 16 patients at a median follow-up of 16 months.
 
Other Tumors or Conditions
No RCTs on the use of MWA for other tumors or conditions were identified. Case studies and retrospective reviews on MWA for adrenal carcinoma, (18) intrahepatic primary cholangiocarcinoma, (Yu, 2011) lung tumors (He, 2006) (Vogl, 2011) (Carrafiello, 2011) and other non-oncologic conditions (i.e., bleeding peptic ulcers, esophageal varices, and secondary hypersplenism) were identified. A review of ablation techniques for breast cancer found only 0-8% of breast tumors were completely ablated with MWA (Zhao, 2010). The authors noted the studies identified for the review were mostly feasibility and pilot studies conducted in research settings.
 
Ongoing Clinical Trials
A November 12, 2011 search of clinical trials in online site ClinicalTrials.gov identified one randomized trial on MWA. In this Phase III, prospective RCT, MWA will be compared to radiofrequency ablation in the treatment of unresectable hepatocellular carcinoma no more than 6 cm in diameter (NCT01340105). Patients may only have up to 3 nodules that are amenable to ablation and do not have any major vascular or bile duct invasion. Patients with resectable tumors may be included in the study if local ablation is preferred. The trial began in April 2011 in Hong Kong, China and expects to recruit 92 patients.
 
Summary
In summary, based on review of the published data (which consists largely of small case series and limited randomized trials) and expert opinion, there is insufficient evidence to permit conclusions concerning the comparative effectiveness of microwave ablation (MWA) to other ablative techniques on health outcomes. Studies show MWA results in a wide range of complete tissue ablation (from 50-100%) depending on tumor size with complete ablation common and nearing 100% with smaller tumors (e.g., ≤3 cm). Recurrence of tumors at ablated sites is very low. However, recurrence of tumors at nonablated sites is common and may be due to the nature of the disease state (e.g., in hepatocellular carcinoma). Intraoperative and postoperative minor and major complications are low, especially in cases where tumors are smaller and more accessible. While some earlier studies found MWA required more treatment sessions to achieve adequate ablation, more recent studies using newer MWA technology that deliver larger ablation zones with cooled-shaft antennas have demonstrated shorter ablation times and fewer complications. While MWA has theoretical advantages over radiofrequency ablation, studies on the use of MWA with larger numbers of patients and longer follow-up are needed to adequately assess health outcomes. Patient selection criteria and rationale for using MWA over other established techniques such as surgical resection or radiofrequency ablation are needed. Results of the ongoing Phase III trial comparing MWA to radiofrequency ablation will provide additional information in determining the role of MWA in the treatment of hepatocellular carcinoma. Information from additional future studies may indicate a role for MWA for the treatment of tumors for control of local tumor growth, palliation of symptoms, and extended survival durations in tumors that are not amenable to resection or in patients who are not surgical candidates. However, in total, the current available evidence is insufficient to permit conclusions on net health outcomes of MWA of tumors.
 
Practice Guidelines and Position Statements
The National Comprehensive Cancer Network (NCCN) guidelines on hepatobiliary cancers lists MWA (along with radiofrequency ablation, cryoablation and percutaneous alcohol injection) as a treatment option for hepatocellular carcinoma tumors in patients who are not candidates for potential curative treatments (e.g., resection and transplantation). The guidelines indicate hepatocellular carcinoma tumors should be equal to or less than 3 centimeters and accessible by percutaneous, laparoscopic or open approaches. Hepatocellular carcinoma tumors between 3-5 centimeters may also be treated with ablation when used in combination with arterial embolization. Additionally, the tumor location must be accessible to permit ablation of the tumor and tumor margins without ablating major vessels, bile ducts, the diaphragm or other abdominal organs. However, there are only 2 reviews cited in the guideline on ablative techniques to support these recommendations that are not specific to MWA [category 2A].
 
In the NCCN guidelines on neuroendocrine tumors, MWA is listed as one treatment option (along with radiofrequency ablation or cryoablation) for liver metastases as hepatic regional therapy in carcinoid tumors and pancreatic endocrine (islet cell) tumors when there is unresectable disease and/or distant metastases. These guidelines note, currently, there are limited prospective data and no randomized clinical trials on ablative therapies (including MWA), and data on these ablative techniques are emerging. Additionally, the 2 articles cited in the guideline on ablative techniques are not specific to MWA [category 2A].
 
The National Institute for Health and Clinical Excellence (NICE) published guidance on MWA for the Treatment of Metastases in the Liver in May 2007. This guidance indicates “Current evidence on microwave ablation for the treatment of liver metastases raises no major safety concerns. The evidence on efficacy is inadequate in quantity and quality. Therefore this procedure should only be used with special arrangements for clinical governance, consent and audit or research.”  
 
The American College of Chest Physicians (ACCP) evidence-based guidelines on the treatment of non-small cell lung cancer note that insufficient data are available on ablative therapies including MWA of tumors (Scott, 2007).
 
2012 Update:
Liu and colleagues (2012) published the results of a study conducted on eighty (80) HCC patients with the maximum tumor measuring between 3 and 8 cm were treated using MWA. Of these patients, 57 had initial HCC, while 23 had recurrent HCC. Fifty-two patients had a main tumor measuring 3-5 cm, and 28 had a main tumor measuring 5-8 cm. Local tumor control, complications, long-term survival, and prognostic factors were analyzed.
 
Complete ablation after the initial treatment was achieved in 70 of 80 (87.5%) patients. Local recurrence developed in 16 of the 72 (22.2%) successfully treated patients.  Major complications occurred in 7.5% patients. No procedure-related mortality was observed. The 1, 2, 3, and 5 year overall survival rates after the initial ablation were 81.1, 68.2, 56.5, and 34.6%, with a median survival of 56 months.  Percutaneous MWA is effective and safe for treating larger HCC tumors. The local tumor control and long-term survival are acceptable.
 
Qi, et al. (2012) published the results of a study done to evaluate the feasibility, safety and efficacy of ultrasound-guided microwave (MW) ablation for abdominal wall metastatic tumors.  Over a 3-year period,  a total of 11 patients with 23 abdominal wall nodules (diameter 2.59 cm ± 1.11 cm, range 1.3 cm to 5.0 cm) were treated with MW ablation. Treatment outcome was observed by contrast-enhanced ultrasound and magnetic resonance imaging (MRI) or computed tomography (CT) during follow-up.  MW ablation was well tolerated by all patients. Major complications included mild pain (54.5%), post-ablation fever (100%) and abdominal wall edema (25%). All 23 tumors (100%) in this group were completely ablated.   On follow-up (median of 13 months [range 1 to 32 mo], no residual tumor or local recurrence was observed.  The ablation zone was well defined on contrast-enhanced imaging (contrast-enhanced CT, MRI and/or contrast-enhanced ultrasound) and gradually shrank with time.  The authors concluded that ultrasound-guided MW ablation may be a feasible, safe and effective treatment for abdominal wall metastatic tumors in selected patients.
 
Lu and colleagues (2012) published the results of a 3-year, retrospective analyses conducted on 69 patients who underwent computed tomography (CT)-guided percutaneous MWA of pulmonary malignancies. All patients were deemed medically inoperable. The correlation of tumor sizes and local progression after ablation was analyzed and the survival rates within 3 years post surgery were compared between non-small-cell lung cancer and pulmonary metastases groups also.
 
Pneumothorax was the most frequent complication and occurred in 24.64% patients after ablation. Neither needle track implantation was found nor did patient death occur in these patients within 30 days. The 1-, 2-, and 3-year overall survival rates were 66.7%, 44.9% and 24.6%, respectively. The overall survival rates for NSCLC patients in 1 year, 2 years, and 3 years were 75.0%, 54.2%, and 29.2%, respectively. The overall survival rates for pulmonary metastatic tumor patients in 1 year, 2 years, and 3 years were 47.6%, 23.8%, and 14.3%, respectively. The recurrence-free survival rates for NSCLC patients in 1 year, 2 years, and 3 years were 72.9%, 50.0%, and 27.1%, respectively. The mortality rates for pulmonary metastatic tumor patients in 1 year, 2 years, and 3 years were 47.6%, 19.0%, and 14.3%, respectively.  Conclusion was that percutaneous microwave coagulation therapy could be beneficial for the improvement of inoperable pulmonary malignancies treatment.
 
Li and colleagues (2012) published a study conducted from May 2005 to June 2008 to prospectively evaluate the safety and effectiveness of percutaneous microwave (MW) ablation for liver cancer adjacent to the diaphragm.  A comparison of was done between the study group and a control group (hepatic lesions not adjacent to the diaphragm).  The study group included 89 patients with 96 hepatic lesions adjacent to the diaphragm (the shortest distance from the lesion margin to the diaphragm less than 5 mm), who underwent ultrasound (US)-guided percutaneous MW ablation. The control group included 100 patients with 127 hepatic lesions not adjacent to the diaphragm (the shortest distance from the lesion to the diaphragm and the first or second branch of the hepatic vessels more than 10 mm), who underwent US-guided percutaneous MW ablation.  During the ablation the temperature of marginal ablation tissue proximal to the diaphragm was monitored and controlled at 50°-60°C for more than 10 min in the study group.
A total of 91 of 96 tumors (94.8%) in the study group and 123 of 127 tumors (96.9%) in the control group achieved complete ablation (P > 0.05). Local tumor progression was found in 18 of 96 tumors (18.8%) in the study group and 21 of 127 tumors (16.5%) in the control group during follow-up after MW ablation (P > 0.05).  No major complications occurred in either group.  The authors concluded that under strict temperature monitoring, percutaneous MW ablation is safe and can achieve a high complete ablation rate for the treatment of hepatic tumors adjacent to the diaphragm.
 
Guam and colleagues (2012) reported the results of a prospective randomized comparison of intermediate-term outcomes of patients with small renal tumors who were treated with partial nephrectomy (PN) or microwave (MW) ablation.  Of 102 selected patients with solitary small renal tumors who had prospectively completed at least 2 years of follow-up since December 2004, randomized, 54 had either open (19) or laparoscopic (35) PN and 48 had laparoscopic (28) or open (20) microwave ablation.  The comparison included: patient and tumor characteristics, surgical data, complications, histologic and oncologic data, and functional data of the two approaches.
Patients in the MW ablation group and PN group matched for age, sex, American Society of Anesthesiologists score, body mass index, and tumor size and were respectively followed for median 32 and 36 months.  Surgical and hospitalization times were comparable in both groups. Estimated blood loss, complication rates, and decline of postoperative renal function were significantly less in the microwave ablation group (P = 0.0002, P = 0.0187, and P = 0.0092, respectively).  The decrease in estimated glomerular filtration rate at the last available follow-up was similar in both groups (P = 1.0000). There were no disease-specific deaths. Kaplan-Meier estimates of overall local recurrence-free survival at 3 years were 91.3% for microwave ablation and 96.0% for PN (P = 0.5414); the respective numbers for renal cell carcinomas were 90.4 and 96.6% (P = 0.4650).  This intermediate analysis showed that MW ablation provides favorable results compared to PN. However, longer term data are still needed.
 
Ongoing Clincial Trials:
  •  NCT00892255 – “Microwave Ablation of Resectable Liver Tumors”; estimated enrollment of 50 and completion date of April 2015.  This study will evaluate the treatment effect of MWA in liver tumors. Patients undergoing planned surgical removal of liver tumors will have the tumors intra-operatively treated with MWA. The histological changes will be evaluated upon removal of the specimen.
 
  •  NCT00922181 – “Single-probe Microwave Ablation of Metastatic Liver Cancer is Highly Variable and Irreproducible”; completed. Results not published. The aim of this study was to evaluate the variability and reproducibility of single-probe MWA versus radiofrequency ablation (RFA) of metastatic liver tumors smaller than 3 cm in patients without underlying liver disease.
 
  •  NCT01340105 - Microwave Versus Radiofrequency Ablation for Hepatocellular Carcinoma: a Prospective Randomized Control Trial; estimated enrollment of 92 and completion date of April 2016.
 
  •  NCT01563679 – “Prospective Analysis of Percutaneous Ablations for Cancer Treatment”; estimated enrollment of 500 and completion date of December 2015.  This is a study involving patients with cancer who are referred by their treating physician for percutaneous locoregional therapies.   Patient's clinical and radiology findings, pathology findings, survival, treatment responses, and complications after their locoregional therapy will be studied.
 
 2013 Update
In 2013, Ding et al. also reported on a retrospective comparison of 113 patients treated with MWA for 131 HCC tumors and 85 patients treated with radiofrequency ablation (RFA) for 98 HCC tumors. (Ding, 2013a).  Rates of complete ablation, local recurrence, disease-free and cumulative survival (at 1, 2, 3, and 4 years), and major complications were not significantly different between groups. In another 2013 study by Ding et al., complications were retrospectively compared between 556 patients treated with MWA for 1,090 tumors (491 HCC, 18 cholangiocarcinoma, and 47 liver metastases) and 323 patients treated with RFA for 562 liver tumors.   (279 HCC, 6 cholangiocarcinoma, and 38 liver metastases) (Ding, 2013b) Rates of death (2 of 556 MWA and 1 of 323 RFA patients), major complications and minor complications did not differ significantly between MWA and RFA groups.
 
In 2013, Liu et al. reported on 35 patients treated with MWA for 62 tumors and 54 patients treated with RFA for 70 tumors from liver metastases (Liu, 2013).  Ablation was complete in 88.6% (117 of 132) of tumors and was not significantly different between tumor types: 86.2% for metastatic colorectal cancer (56/65) and 91% for other metastatic disease 61/67). Nor was there a significant difference between MWA and RFA in the complete ablation rate. Tumors 3.0 cm or less were completely ablated significantly more often than tumors greater than 3.0 cm (93.5 vs. 66.7%, p=0.001).
 
No RCTs on the use of MWA for other tumors or conditions were identified. Case studies and retrospective reviews on MWA for adrenal carcinoma (Li, 2011), metastatic bone tumors (Pusceddu, 2013), intrahepatic primary cholangiocarcinoma (Yu, 2011), benign thyroid tumors (Yue, 2013), and other non-oncologic conditions (i.e., bleeding peptic ulcers, esophageal varices, secondary hypersplenism) were identified.
 
The National Comprehensive Cancer Network (NCCN) guidelines on hepatobiliary cancers lists MWA (along with radiofrequency ablation, cryoablation, and percutaneous alcohol injection) as a treatment option for hepatocellular carcinoma tumors in patients who are not candidates for potential curative treatments (e.g., resection and transplantation) and do not have large-volume extrahepatic disease (NCCN, V.2.2013).  Ablation should only be considered when tumors are accessible by percutaneous, laparoscopic or open approaches.  The guidelines indicate hepatocellular carcinoma tumors equal to or less than 3 centimeters may be curatively treated with ablation alone. Hepatocellular carcinoma tumors between 3-5 centimeters may also be treated with ablation to prolong survival when used in combination with arterial embolization. Additionally, the tumor location must be accessible to permit ablation of the tumor and tumor margins without ablating major vessels, bile ducts, the diaphragm or other abdominal organs. However, there are only 2 reviews cited in the guideline on ablative techniques to support these recommendations, but these reviews are not specific to MWA [category 2A].  
 
2014 Update
A literature search conducted through September 2014 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
A 2013 Cochrane review (Bala, 2013) identified only 1 RCT on ablation for liver metastasis, Shibata et al (Shibata, 2000), (described below). The reviewers found insufficient evidence to determine any benefits of MWA for liver metastasis over surgical resection.
 
Primary Renal Tumors
In a 2014 systematic review and meta-analysis, Katsanos et al compared thermal ablation (MWA and RFA) to surgical nephrectomy for small renal tumors (mean size 2.5 cm) (Katsanos, 2014). Included in the analysis were 1 randomized study on MWA30 (described below) and 5 cohort studies on RFA with a total of 587 patients. In the ablation group, the complication rates and renal function decline were significantly lower than in the nephrectomy group (p=0.04 and p=0.03, respectively). The local recurrence rate was 3.6% in both groups (risk ratio: 0.92, 95% CI: 0.4 to 2.14, p=0.79) and disease-free survival up to five years was not significantly different between groups (hazard ratio: 1.04, 95% CI: 0.48 to 2.24, p=0.92).
 
Martin and colleagues reported on a meta-analysis of MWA versus cryoablation for small renal tumors in 2013 (Martin, 2013). Included in the analysis were 7 MWA studies (n=164) and 44 cryoablation studies (n=2989). The studies were prospective or retrospective, nonrandomized, noncomparative studies. The mean follow-up duration was shorter for MWA than cryoablation (17.86 months vs 30.22 months, p= 0.07). While the mean tumor size was significantly larger in the MWA studies than the cryoablation studies (2.58 cm vs 3.13 cm, respectively, p=0.04), local tumor progression (4.07% vs 2.53%, respectively; p=0.46), and progression to metastatic disease (0.8% vs 0%, respectively; p=0.12) were not significantly different.
  
2016 Update
A literature search conducted through September 2016 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Hepatocellular Carcinoma
Chinnaratha and colleagues published a meta-analysis of randomized controlled trials (RCTs) and observational studies that compared the effectiveness and safety of radiofrequency ablation (RFA) to MWA in patients with primary hepatocellular carcinoma (HCC) (Chinnaratha, 2016).  MEDLINE, EMBASE, and Cochrane Central databases were searched between January 1980 and May 2014 for human studies comparing the 2 technologies. The primary outcome was the risk of local tumor progression (LTP); secondary outcomes were complete ablation, overall survival (OS), and major adverse events. Odds ratios (ORs) were combined across studies using a random-effects model. Ten studies (2 prospective, 8 retrospective) were included. The overall LTP rate was 14% (176/1298). There was no difference in LTP rates between RFA and MWA (OR=1.01; 95% CI, 0.67 to 1.50; p=0.9). The complete ablation rate, 1- and 3- year OS, and major adverse events were similar between the 2 modalities (p>0.05 for all). Subgroup analysis showed LTP rates were lower with MWA for treatment of larger tumors (OR=1.88; 95% CI, 1.10 to 3.23; p=0.02). No significant publication bias was detected nor was inter-study heterogeneity (I2<50%, p>0.1) observed for any measured outcomes.
 
Abdelaziz and colleagues reported a prospective study that evaluated the efficacy and safety of MWA and transarterial chemoembolization (TACE) for large tumors (5-7 cm) and assessed their effects on local tumor progression and survival\l " (Abdelaziz, 2015). Sixty-four patients with large lesions were divided into 2 groups treated by MWA or by TACE. Both groups were comparable in demographic and ultrasonographic tumor features. MWA completely ablated 75% of cases in fewer sessions, with a lower incidence of tumor recurrence (p=0.02), development of de novo lesions (p=0.03), occurrence of posttreatment ascites (p=0.003), and had higher OS rates (p=0.04) than TACE. Mean OS in the MWA group was 22 months and 14 months in the TACE group. Actuarial probabilities of survival at 12 and 18 months were 78% and 68%, respectively, in the MWA group and 52% and 29%, respectively, in the TACE group.
 
Vogl and colleagues published a retrospective comparative study in 2015\l " (Vogl, 2015). It enrolled 53 patients with 68 liver lesions due to HCC. MWA was performed in 36 patients and RFA in 32 patients. There were no differences between groups on complete response immediately following treatment or for progression-free survival at 12 month or OS at 3 years. In 2013, Ding and colleagues retrospectively compared 113 patients treated with MWA for 131 HCC tumors and 85 patients treated with RFA for 98 HCC tumors. \l " Rates of complete ablation, local recurrence, disease-free (DFS) and cumulative survival (at 1, 2, 3, and 4 years), and major complications did not differ significantly between groups.
 
Lung Cancer
In 2015, Acksteiner and Steinke reported a retrospective study that evaluated the safety, effectiveness, and follow-up imaging of MWA in 10 patients (age range, ³75 years) with early-stage non-small-cell lung cancer (NSCLC) (Acksteiner, 2015).  Follow-up with CT and 18-fluorodeoxyglucose-positron emission tomography (FDG-PET) extended for 30 months (median, 12 months). No periprocedural deaths or major complications were reported. Seven patients were disease-free. Three patients showed growth of the treated lesions, 1 patient died (age 90) due to unknown cause 18 months postsurgery. One patient still living presented with local progression and disseminated metastatic disease at 12 months. One patient showed increasing soft tissue mass at the ablation site 15 months posttreatment, but 3 consecutive core biopsies over 2 months failed to confirm tumor recurrence.
 
A 2015 observational study evaluated the clinical efficacy and utility of percutaneous microwave ablation therapy (PMAT) for lung cancer without surgical treatment (Sun, 2015). Thirty-nine lesions in 29 patients with peripheral lung cancer were treated by PMAT under local anesthesia. Treatments were completed in 29 patients. Average surgical time was 8 minutes (range, 5-12 minutes). Eight, 14, 4, and 3 patients achieved complete remission, partial remission, stable status, and progression, respectively, for an effectiveness rate of 76%. Complications included 5, 2, and 15 cases of pneumothorax, pleural effusion, and fever, respectively. No complications from needle track insertion were observed. Mean progression-free survival was 15 months. One- and 2-year OS rates were 91% and 83%, respectively.
 
2017 Update
A literature search conducted through August 2017 did not reveal any new information that would prompt a change in the coverage statement.
 
2018 Update
A literature search was conducted through September 2018.  There was no new information identified that would prompt a change in the coverage statement.  

CPT/HCPCS:
19499Unlisted procedure, breast
32998Ablation therapy for reduction or eradication of 1 or more pulmonary tumor(s) including pleura or chest wall when involved by tumor extension, percutaneous, including imaging guidance when performed, unilateral; radiofrequency
47380Ablation, open, of 1 or more liver tumor(s); radiofrequency
47382Ablation, 1 or more liver tumor(s), percutaneous, radiofrequency
47399Unlisted procedure, liver
50592Ablation, 1 or more renal tumor(s), percutaneous, unilateral, radiofrequency
53899Unlisted procedure, urinary system
60699Unlisted procedure, endocrine system
76940Ultrasound guidance for, and monitoring of, parenchymal tissue ablation
77013Computed tomography guidance for, and monitoring of, parenchymal tissue ablation
77022Magnetic resonance guidance for, and monitoring of, parenchymal tissue ablation

References: Abdelaziz AO, Nabeel MM, Elbaz TM, et al.(2015) Microwave ablation versus transarterial chemoembolization in large hepatocellular carcinoma: prospective analysis. Scand J Gastroenterol. Apr 2015;50(4):479-484. PMID 25592058

Acksteiner C, Steinke K.(2015) Percutaneous microwave ablation for early-stage non-small cell lung cancer (NSCLC) in the elderly: a promising outlook. J Med Imaging Radiat Oncol. Feb 2015;59(1):82-90. PMID 25335916

Bai J, Hu Z, Guan W et al.(2010) Initial experience with retroperitoneoscopic microwave ablation of clinical T(1a) renal tumors. J Endourol 2010; 24(12):2017-22.

Bala MM, Riemsma RP, Wolff R, et al.(2013) Microwave coagulation for liver metastases. Cochrane Database Syst Rev. 2013;10:CD010163. PMID 24122576

Bertot LC, Sato M, Tateishi R et al.(2011) Mortality and complication rates of percutaneous ablative techniques for the treatment of liver tumors: a systematic review. Eur Radiol 2011; 21(12):2584-96.

Carrafiello G, Mangini M, Fontana F et al.(2011) Complications of microwave and radiofrequency lung ablation: personal experience and review of the literature. Radiol Med 2011 [Epub ahead of print].

Castle SM, Salas N, Leveillee RJ.(2011) Initial experience using microwave ablation therapy for renal tumor treatment: 18-month follow-up. Urology 2011; 77(4):792-7.

Chinnaratha MA, Chuang MA, Fraser RJ, et al.(2016) Percutaneous thermal ablation for primary hepatocellular carcinoma: A systematic review and meta-analysis. J Gastroenterol Hepatol. Feb 2016;31(2):294-301. PMID 26114968

Ding J, Jing X, Liu J et al.(2013) Comparison of two different thermal techniques for the treatment of hepatocellular carcinoma. Eur J Radiol 2013a; 82(9):1379-84.

Ding J, Jing X, Liu J et al.(2013) Complications of thermal ablation of hepatic tumours: comparison ofradiofrequency and microwave ablative techniques. Clin Radiol 2013(b); 68(6):608-15.

Guan W, Bai J, Hu Z et al.(2010) Retroperitoneoscopic microwave ablation of renal hamartoma: middle-term results. J Huazhong Univ Sci Technolog Med Sci 2010; 30(5):669-71.

Guan W, Bai J, Liu J, et al.(2012) Microwave ablation versus partial nephrectomy for small renal tumors: intermediate-term results. J Surg Oncol. 2012 Sep 1;106(3):316-21.

He W, Hu XD, Wu DF et al.(2006) Ultrasonography-guided percutaneous microwave ablation of peripheral lung cancer. Clin Imaging 2006; 30(4):234-41.

Katsanos K, Mailli L, Krokidis M, et al.(2014) Systematic review and meta-analysis of thermal ablation versus surgical nephrectomy for small renal tumours. Cardiovasc Intervent Radiol. Apr 2014;37(2):427-437. PMID 24482030

Li M, Yu XL, Liang P, et al.(2012) Percutaneous microwave ablation for liver cancer adjacent to the diaphragm. nt J Hyperthermia. 2012;28(3):218-26.

Li X, Fan W, Zhang L et al.(2011) CT-guided percutaneous microwave ablation of adrenal malignant carcinoma: Preliminary results. Cancer 2011; 117(22):5182-8.

Liang P, Wang Y, Yu X et al.(2009) Malignant liver tumors: treatment with percutaneous microwave ablation--complications among cohort of 1136 patients. Radiology 2009; 251(3):933-40.

Liu Y, Li S, Wan X et al.(2013) Efficacy and safety of thermal ablation in patients with liver metastases. Eur J Gastroenterol Hepatol 2013; 25(4):442-6.

Liu Y, Zheng Y, Li S, et al.(2012) Percutaneous microwave ablation of larger hepatocellular carcinoma. Clin Radiol. 2012 Jul 3. [Epub ahead of print].

Lorentzen T, Skjoldbye BO, Nolsoe CP.(2011) Microwave Ablation of Liver Metastases Guided by Contrast-Enhanced Ultrasound: Experience with 125 Metastases in 39 Patients. Ultraschall Med 2011; 32(5):492-96.

Loveman E, Jones J, Clegg AJ, et al.(2014) The clinical effectiveness and cost-effectiveness of ablative therapies in the management of liver metastases: systematic review and economic evaluation. Health Technol Assess. Jan 2014;18(7):vii-viii, 1-283. PMID 24484609

Lu MD, Xu HX, Xie XY et al.(2005) Percutaneous microwave and radiofrequency ablation for hepatocellular carcinoma: a retrospective comparative study. J Gastroenterol 2005; 40(11):1054-60.

Lu Q, Cao W, Huang L, et al.(2012) CT-guided percutaneous microwave ablation of pulmonary malignancies: Results in 69 cases. World J Surg Oncol. 2012 May 7;10:80.

Martin J, Athreya S.(2013) Meta-analysis of cryoablation versus microwave ablation for small renal masses: is there a difference in outcome? Diagn Interv Radiol. Nov-Dec 2013;19(6):501-507. PMID 24084196

Martin RC, Scoggins CR, McMasters KM.(2010) Safety and efficacy of microwave ablation of hepatic tumors: a prospective review of a 5-year experience. Ann Surg Oncol 2010; 17(1):171-8.

Muto G, Castelli E, Migliari R et al.(2011) Laparoscopic microwave ablation and enucleation of small renal masses: preliminary experience. Eur Urol 2011; 60(1):173-6.

National Comprehensive Cancer Network (NCCN).(2011) Hepatobiliary Cancers (V.1.2012). . Available online at: http://www.nccn.org/professionals/physician_gls/pdf/hepatobiliary.pdf. Last accessed October 2011.

National Comprehensive Cancer Network (NCCN).(2011) Neuroendocrine Tumors (V.1.2011). Available online at: http://www.nccn.org/professionals/physician_gls/pdf/neuroendocrine.pdf. Last accessed October 24, 2011.

National Institute for Clinical Excellence (NICE).(2011) Microwave Ablation for the Treatment of Metastases in the Liver. 2011. Available online at: http://guidance.nice.org.uk/IPG406. Last accessed October 2011.

NCT00892255.(2012) Microwave Ablation of Resectable Liver Tumors. www.cilnicaltrials.gov. Last accessed 10/29/2012.

NCT00922181.(2012) Single-probe Microwave Ablation of Metastatic Liver Cancer is Highly Variable and Irreproducible. www.clinicaltrials.gov. Last accessed 10/29/2012.

NCT01340105.(2012) Microwave Versus Radiofrequency Ablation for Hepatocellular Carcinoma: a Prospective Randomized Control Trial. www.clinicaltrials.gov. Last accessed 10/29/20

NCT01563679.(2012) Prospective Analysis of Percutaneous Ablations for Cancer Treatment. www.clinicaltrials.gov. Last accessed 10/29/20

Ong SL, Gravante G, Metcalfe MS et al.(2009) Efficacy and safety of microwave ablation for primary and secondary liver malignancies: a systematic review. Eur J Gastroenterol Hepatol 2009; 21(6):599-605.

Pathak S, Jones R, Tang JM et al.(2011) Ablative therapies for colorectal liver metastases: a systematic review. Colorectal Dis 2011; 13(9):e252-65.

Pusceddu C, Sotgia B, Fele RM et al.(2013) Treatment of bone metastases with microwave thermal ablation. J Vasc Interv Radiol 2013; 24(2):229-33.

Qi C, Yu XL, Liang P, et al.(2012) Ultrasound-guided microwave ablation for abdominal wall metastatic tumors: a preliminary study. World J Gastroenterol. 2012 Jun 21;18(23):3008-14.

Scott WJ, Howington J, Feigenberg S et al.(2007) Treatment of non-small cell lung cancer stage I and stage II: ACCP evidence-based clinical practice guidelines (2nd edition). Chest 2007; 132(3 Suppl):234S-42S.

Shibata T, Iimuro Y, Yamamoto Y et al.(2002) Small hepatocellular carcinoma: comparison of radio-frequency ablation and percutaneous microwave coagulation therapy. Radiology 2002; 223(2):331-7.

Shibata T, Niinobu T, Ogata N et al.(2000) Microwave coagulation therapy for multiple hepatic metastases from colorectal carcinoma. Cancer 2000; 89(2):276-84.

Shibata T, Niinobu T, Ogata N, et al.(2000) Microwave coagulation therapy for multiple hepatic metastases from colorectal carcinoma. Cancer. Jul 15 2000;89(2):276-284. PMID 10918156

Simo KA, Sereika SE, Newton KN et al.(2011) Laparoscopic-assisted microwave ablation for hepatocellular carcinoma: Safety and efficacy in comparison with radiofrequency ablation. J Surg Oncol 2011; 104(7):822-9.

Sun YH, Song PY, Guo Y, et al.(2015) Computed tomography-guided percutaneous microwave ablation therapy for lung cancer. Genet Mol Res. 2015;14(2):4858-4864. PMID 25966260

Taniai N, Yoshida H, Mamada Y et al.(2006) Is intraoperative adjuvant therapy effective for satellite lesions in patients undergoing reduction surgery for advanced hepatocellular carcinoma? Hepatogastroenterology 2006; 53(68):258-61.

Vogl TJ, Farshid P, Naguib NN, et al.(2015) Ablation therapy of hepatocellular carcinoma: a comparative study between radiofrequency and microwave ablation. Abdom Imaging. Aug 2015;40(6):1829-1837. PMID 25601438

Vogl TJ, Naguib NN, Gruber-Rouh T et al.(2011) Microwave ablation therapy: clinical utility in treatment of pulmonary metastases. Radiology 2011; 261(2):643-51.

Yu MA, Liang P, Yu XL et al.(2011) Sonography-guided percutaneous microwave ablation of intrahepatic primary cholangiocarcinoma. Eur J Radiol 2011; 80(2):548-52.

Yue W, Wang S, Wang B et al.(2013) Ultrasound guided percutaneous microwave ablation of benign thyroid nodules: Safety and imaging follow-up in 222 patients. Eur J Radiol 2013; 82(1):e11-6.

Zhao Z, Wu F.(2010) Minimally-invasive thermal ablation of early-stage breast cancer: a systemic review. Eur J Surg Oncol 2010; 36(12):1149-55.

Zhou P, Liang P, Dong B et al.(2011) Long-term results of a phase II clinical trial of superantigen therapy with staphylococcal enterotoxin C after microwave ablation in hepatocellular carcinoma. Int J Hyperthermia 2011; 27(2):132-9.

Zhou P, Liang P, Yu X et al.(2009) Percutaneous microwave ablation of liver cancer adjacent to the gastrointestinal tract. J Gastrointest Surg 2009; 13(2):318-24.


Group specific policy will supersede this policy when applicable. This policy does not apply to the Wal-Mart Associates Group Health Plan participants or to the Tyson Group Health Plan participants.
CPT Codes Copyright © 2019 American Medical Association.