Microwave Tumor Ablation

POLICY NUMBER

A.7.01.133

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. Microwave ablation is used to treat tumors not amenable to resection and to treat patients ineligible for surgery due to age, comorbidities, or poor general health. Microwave ablation may be performed as an open procedure, laparoscopically, percutaneously, or thoracoscopically under image guidance (e.g., ultrasound, computed tomography, or magnetic resonance imaging) with sedation, or local or general anesthesia. This technique is also referred to as microwave coagulation therapy.

Microwave Ablation

Microwave ablation (MWA) uses microwave energy to induce an ultra-high-speed, 915 MHz or 2 450 MHz (2.45 GHz), alternating electric field, which causes water molecule rotation and creates 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, 2 to 3 cm elliptical area of tissue ablation. In tumors greater than 2 cm in diameter, 2 to 3 antennas may be used simultaneously to increase the targeted area of MWA and shorten the 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 tumor size. The cells killed by MWA are typically not removed, but are gradually replaced by fibrosis and scar tissue. If there is a local recurrence, it occurs at the margins. Treatment may be repeated as needed. Microwave ablation may be used for the following purposes: 1) to control local tumor growth and prevent recurrence; 2) to palliate symptoms; and 3) to prolong survival.

Microwave ablation is similar to radiofrequency (RFA) and cryosurgical ablation. However, MWA has potential advantages over radiofrequency and 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 less 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. Microwave ablation does not rely on the conduction of electricity for heating, and therefore, does not flow electrical current through patients and does not require grounding pads because there is no risk of skin burns. Additionally, MWA does not produce electric noise, which allows ultrasound guidance during the procedure without interference, unlike radiofrequency ablation. Finally, MWA can take 20% to 30% less time than radiofrequency ablation because multiple antennas can be used simultaneously for multiple ablations. There is no comparable RFA system with the capacity to drive multiple electrically dependent electrodes.

Adverse EventsComplications from MWA may include pain and fever. Other 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. Microwave ablation should be avoided in pregnant women because potential risks to the patient and/or fetus have not been established, and in patients with implanted electronic devices (eg, implantable pacemakers) that may be adversely affected by microwave power output.

ApplicationsMicrowave ablation was first used percutaneously in 1986 as an adjunct to liver biopsy. Since then, MWA has been used to ablate tumors and tissue to treat many conditions including hepatocellular carcinoma, breast cancer, 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 potential advantages of MWA for these cancers include improved local control and other advantages common to any minimally invasive procedure (e.g., preserving normal organ tissue, decreasing morbidity, shortening length of hospitalization). Microwave ablation also has been investigated as a treatment for unresectable hepatic tumors, as both primary and palliative treatment, and as a bridge to liver transplant. In the latter setting, MWA is being assessed to determine whether it can reduce the incidence of tumor progression while awaiting transplantation and thus maintain a patient’s candidacy while awaiting a liver transplant.

Multiple MWA devices have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. These devices are indicated for soft tissue ablation, including partial or complete ablation of non-resectable liver tumors. Some devices are specifically cleared for use in open surgical ablation, percutaneous ablation, or laparoscopic procedures. The table below is a summary of selected MWA devices cleared by the FDA.

The FDA used determinations of substantial equivalence to existing radiofrequency and MWA devices to clear these devices.

This policy does not address MWA for the treatment of splenomegaly or ulcers, for cardiac applications, or as a surgical coagulation tool.

Selected Microwave Ablation Devices Cleared by the FDA

Related medical policies are –

• Cryosurgical Ablation of Primary or Metastatic Liver Tumors

• Radiofrequency Ablation of Primary or Metastatic Liver Tumors

• Cryosurgical Ablation of Miscellaneous Solid Tumors Other Than Liver, Prostate, or Dermatologic Tumors

• Radiofrequency Ablation of Miscellaneous Solid Tumors Excluding Liver Tumors

• Transcatheter Arterial Chemoembolization (TACE) to Treat Primary or Metastatic Liver Malignancies

• Radioembolization for Primary and Metastatic Tumors of the Liver

POLICY

Microwave ablation of primary or metastatic hepatic tumors may be considered medically necessary under the following conditions:

• The tumor is unresectable due to location of lesion[s] and/or comorbid conditions.

• A single tumor of ≤5 cm or up to 3 nodules ≤3 cm each.

Microwave ablation of primary or metastatic lung tumors may be considered medically necessary under the following conditions:

• The tumor is unresectable due to location of lesion and/or comorbid conditions.

• A single tumor of ≤3 cm.

Microwave ablation of more than a single primary or metastatic tumor in the lung is considered investigational.

Microwave ablation of primary or metastatic tumors other than liver or lung is considered investigational.

POLICY EXCEPTIONS

Federal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Mental Health Disorders, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:

1. consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and

2. appropriate with regard to standards of good medical practice; and

3. not solely for the convenience of the Member, his or her Provider; and

4. the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.

For the definition of medical necessity, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.

POLICY HISTORY

03/22/2012: Approved by Medical Policy Advisory Committee.

04/16/2013: Added the following ICD-9 procedure codes to the Code Reference section: 50.23, 50.24, 50.25, 50.29, 55.32, 55.33, 55.34, and 55.39.

01/22/2014: Policy reviewed; no changes.

12/05/2014: Policy reviewed; description updated regarding devices. Policy statement unchanged.

08/31/2015: Medical policy revised to add ICD-10 codes.

05/31/2016: Policy number A.7.01.133 added. Investigative definition updated in Policy Guidelines section.

07/07/2016: Policy description updated. Policy statement unchanged.

10/19/2017: Policy description updated to remove information on hepatic tumors and renal cell carcinoma. Policy statement unchanged.

10/01/2018: Code Reference section updated to add new ICD-10 procedure codes 0F500ZF, 0F503ZF, 0F504ZF, 0F510ZF, 0F513ZF, 0F520ZF, 0F523ZF, and 0F524ZF.

11/09/2018: Policy description updated. Policy statement unchanged.

02/01/2021: Policy description updated regarding devices. Added medically necessary policy statements for liver and lung tumors meeting the listed conditions. Added statement that microwave ablation of more than a single primary or metastatic tumor in the lung is considered investigational. Revised investigational statement to state that microwave ablation of primary or metastatic tumors other than liver or lung is considered investigational. Policy Guidelines updated to define medically necessary. Code Reference section updated to move CPT codes 32999 and 47399 from investigational to medically necessary and add ICD-10 diagnosis codes C22.0, C22.2, C22.3, C22.4, C22.7, C22.8, C22.9, C7B.02, C78.7, and D37.6. Removed ICD-10 procedure codes from the policy.

01/17/2022: Policy description updated regarding devices. First medically necessary statement updated to change "A single tumor of ≤5 cm or up to 3 nodules <3 cm each" to "A single tumor of ≤5 cm or up to 3 nodules ≤3 cm each."

12/14/2022: Policy description updated regarding devices. Policy statements unchanged.

11/15/2023: Policy reviewed; no changes.

01/14/2025: Policy description updated regarding devices. Policy statements unchanged.

SOURCE(S)

Blue Cross Blue Shield Association policy # 7.01.133

CODE REFERENCE

This may not be a comprehensive list of procedure codes applicable to this policy.

The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.

Medically Necessary Codes

Investigational Codes

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