Intensity-Modulated Radiotherapy (IMRT): Abdomen, Pelvis and Chest

POLICY NUMBER

A.8.01.49

DESCRIPTION

Radiotherapy may be an integral component of the treatment of cancers of the abdomen, pelvis, and chest. Intensity-modulated radiotherapy (IMRT) has been proposed as a method that allows adequate radiation to the tumor while minimizing the radiation dose to surrounding normal tissues and critical structures.

Radiotherapy Techniques

Radiation therapy may be administered externally (ie, a beam of radiation is directed into the body) or internally (ie, a radioactive source is placed inside the body, near a tumor). External radiotherapy (RT) techniques include "conventional" or 2-dimensional (2D) RT, 3-dimensional (3D) conformal RT, and intensity-modulated radiation therapy (IMRT).

Conventional External-Beam RadiotherapyMethods to plan and deliver radiotherapy (RT) have evolved in ways that permit more precise targeting of tumors with complex geometries. Conventional 2D treatment planning utilizes X-ray films to guide and position radiation beams. Bony landmarks visualized on X-ray are used to locate a tumor and direct the radiation beams. The radiation is typically of uniform intensity.

Three-Dimensional Conformal RadiotherapyRadiation treatment planning has evolved to use 3-dimensional images, usually from computed tomography (CT) scans, to more precisely delineate the boundaries of the tumor and to discriminate tumor tissue from adjacent normal tissue and nearby organs at risk for radiation damage. Three-dimensional conformal RT (3D-CRT) involves initially scanning the patient in the position that will be used for the radiation treatment. The tumor target and surrounding normal organs are then outlined in 3D on the scan. Computer software assists in determining the orientation of radiation beams and the amount of radiation the tumor and normal tissues receive to ensure coverage of the entire tumor in order to minimize radiation exposure for at risk normal tissue and nearby organs. Other imaging techniques and devices such as multileaf collimators may be used to "shape" the radiation beams. Methods have also been developed to position the patient and the radiation portal reproducibly for each fraction and immobilize the patient, thus maintaining consistent beam axes across treatment sessions.

Intensity-Modulated RadiotherapyIntensity-modulated radiotherapy is the more recent development in external radiation. Treatment planning and delivery are more complex, time consuming, and labor-intensive for IMRT than for 3D-CRT. Similar to 3D-CRT, the tumor and surrounding normal organs are outlined in 3D by a scan and multiple radiation beams are positioned around the patient for radiation delivery. In IMRT, radiation beams are divided into a grid-like pattern, separating a single beam into many smaller "beamlets." Specialized computer software allows for "inverse" treatment planning. The radiation oncologist delineates the target on each slice of a CT scan and specifies the target’s prescribed radiation dose, acceptable limits of dose heterogeneity within the target volume, adjacent normal tissue volumes to avoid, and acceptable dose limits within the normal tissues. Based on these parameters and a digitally reconstructed radiographic image of the tumor, surrounding tissues, and organs at risk, computer software optimizes the location, shape, and intensities of the beam ports to achieve the treatment plan’s goals.

Increased conformality may permit escalated tumor doses without increasing normal tissue toxicity and is proposed to improve local tumor control, with decreased exposure to surrounding, normal tissues, potentially reducing acute and late radiation toxicities. Better dose homogeneity within the target may also improve local tumor control by avoiding underdosing within the tumor and may decrease toxicity by avoiding overdosing.

Other advanced techniques may further improve RT treatment by improving dose distribution. These techniques are considered variations of IMRT. Volumetric modulated arc therapy delivers radiation from a continuous rotation of the radiation source. The principal advantage of volumetric modulated arc therapy is greater efficiency in treatment delivery time, reducing radiation exposure and improving target radiation delivery due to less patient motion. Image-guided RT involves the incorporation of imaging before and/or during treatment to more precisely deliver RT to the target volume.

In general, IMRT systems include intensity modulators, which control, block, or filter the intensity of radiation; and RT planning systems, which plan the radiation dose to be delivered.

A number of intensity modulators have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. Intensity modulators include the Innocure Intensity Modulating Radiation Therapy Compensators (Innocure), cleared in 2006, and the decimal tissue compensator (Southeastern Radiation Products), cleared in 2004. FDA product code: IXI. Intensity modulators may be added to standard linear accelerators to deliver IMRT when used with proper treatment planning systems.

Radiotherapy planning systems have also been cleared for marketing by the FDA through the 510(k) process. They include the FOCUS Radiation Treatment Planning System (Computerized Medical Systems) in 2002, Prowess Panther™ (Prowess) in 2003, TiGRT (LinaTech) in 2009, the RayDose (RaySearch Laboratories) in 2008, and the Eclipse Treatment Planning System (Varian Medical Systems) in 2017. FDA product code: MUJ.

Fully integrated IMRT systems also are available. These devices are customizable and support all stages of IMRT delivery, including planning, treatment delivery, and health record management. Varian Medical Systems has several 510(k) marketing clearances for high-energy linear accelerator systems that can be used to deliver precision radiotherapy such as IMRT. FDA product code: IYE.

Related medical policies are Intensity-Modulated Radiotherapy (IMRT): Prostate ,  Intensity Modulated Radiotherapy (IMRT): Breast and Lung , and Intensity-Modulated Radiotherapy (IMRT): Cancer of the Head and Neck or Thyroid . 

POLICY

Intensity-modulated radiotherapy may be considered medically necessary as an approach to delivering radiotherapy for individuals with cancer of the anus and anal canal.

When dosimetric planning with standard 3-D conformal radiotherapy predicts that the radiation dose to an adjacent organ would result in unacceptable normal tissue toxicity (see Policy Guidelines), intensity-modulated radiotherapy (IMRT) may be considered medically necessary for the treatment of cancer of the abdomen and pelvis, including but not limited to:

• stomach (gastric);

• hepatobiliary tract;

• pancreas;

• esophageal cancer;

• rectal locations; or

• gynecologic tumors (to include cervical, endometrial, and vulvar cancers).

Intensity-modulated radiotherapy (IMRT) would be considered investigational for all other uses in the abdomen and pelvis.

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.

The table below outlines radiation doses generally considered tolerance thresholds for normal structures in the abdomen, pelvis, and chest. Dosimetry plans may be reviewed to demonstrate that radiation by 3-dimensional conformal radiotherapy (3D-CRT) would exceed tolerance doses to structures at risk.

Radiation Tolerance Doses forNormal Tissues of the Abdomen, Pelvis, and Chest

^aTD 5/5, the average dose that results in a 5% complication risk within 5 years.^bTD 50/5, the average dose that results in a 50% complication risk within 5 years.NP: not providedTD: tolerance dose

For IMRT to provide outcomes superior to 3D-CRT, there must be a clinically meaningful decrease in the radiation exposure to normal structures with IMRT compared with 3D-CRT. There is no standardized definition for a clinically meaningful decrease in radiation dose. In principle, a clinically meaningful decrease would signify a significant reduction in anticipated complications of radiation exposure. To document a clinically meaningful reduction in dose, dosimetry planning studies should demonstrate a significant decrease in the maximum dose of radiation delivered per unit of tissue, and/or a significant decrease in the volume of normal tissue exposed to potentially toxic radiation doses. While radiation tolerance dose levels for normal tissues are well-established, the decrease in the volume of tissue exposed that is needed to provide a clinically meaningful benefit has not been standardized. Therefore, precise parameters for a clinically meaningful decrease cannot be provided.

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:

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

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

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

D.  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

5/20/2009: Policy added.

7/16/2009: Approved by Medical Policy Advisory Committee (MPAC).

08/12/2010: Policy description updated to add links to related medical policies. Policy statement revised to state that IMRT may be considered medically necessary as an approach to delivering radiation therapy for patients with squamous cell cancer of the anus/anal canal, effective 05/13/2010.  IMRT remains investigational for other locations in the abdomen and pelvis. The definition of investigative service added to the policy guidelines. Coding information removed from the policy guidelines; this information is provided in the Code Reference section. FEP verbiage added to the Policy Exceptions section. All codes moved from non-covered to covered. Added CPT code 77338 and ICD-9 codes 154.2 and 154.3.

04/10/2013: Policy statement revised to state that IMRT may be considered medically necessary for the treatment of cancer of the abdomen and pelvis when dosimetric planning with standard 3-D conformal radiation predicts that the radiation dose to an adjacent organ would result in unacceptable normal tissue toxicity. IMRT remains investigational for all other uses in the abdomen and pelvis. Policy guidelines updated regarding radiation tolerance doses for normal tissues of the abdomen and pelvis.

03/13/2014: Policy reviewed; no changes.

12/31/2014: Added the following new 2015 CPT codes to the Code Reference section: 77385 and 77386. Added the following HCPCS codes to the Code Reference section: G6015, G6016.

01/27/2015: Policy description updated regarding radiation techniques. Policy statements updated to change "radiation therapy"to "radiotherapy." Removed "squamous cell" from the first medically necessary policy statement. It previously stated: Intensity modulated radiation therapy may be considered medically necessary as an approach to delivering radiation therapy for patients with squamous cell cancer of the anus/anal canal.

08/28/2015: Medical policy revised to add ICD-10 codes.

05/26/2016: Policy number A.8.01.49 added. Policy Guidelines updated to add medically necessary and investigative definitions. Removed deleted CPT codes 77418 and 0073T from the Code Reference section.

10/12/2016: Policy description updated regarding advanced techniques and IMRT methods. Second medically necessary policy statement updated to change "radiation" to "radiotherapy." Title of table in Policy Guidelines updated to add "of the Abdomen and Pelvis."

08/14/2017: Policy description updated regarding devices. Policy statements unchanged. Policy Guidelines updated regarding radiation tolerance doses.

11/28/2017: Code Reference section updated to add ICD-10 diagnosis code C21.8.

08/15/2018: Policy description updated regarding radiotherapy treatment planning systems. Policy statements unchanged.

08/21/2019: Policy reviewed; no changes.

08/21/2020: Policy description updated regarding radiotherapy techniques. Policy statements unchanged. Policy Guidelines updated regarding radiation tolerance doses for normal tissues of the abdomen and pelvis.

04/29/2022: Policy title changed from "Intensity-Modulated Radiation Therapy (IMRT) Abdomen and Pelvis" to "Intensity-Modulated Radiotherapy: Abdomen and Pelvis." Policy description updated. Medically necessary statement regarding dosimetric planning with standard 3-D conformal radiotherapy updated to add esophageal cancer as an indication. Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity."

08/24/2022: Policy title changed from "Intensity-Modulated Radiotherapy: Abdomen and Pelvis" to "Intensity-Modulated Radiotherapy: Abdomen, Pelvis and Chest." Policy reviewed. Policy statements unchanged. Policy Guidelines updated to include the chest.

08/15/2023: Policy description updated. Policy statement updated to change "patients" to "individuals."

08/15/2024: Policy reviewed; no changes.

09/15/2025: Policy reviewed; no changes.

SOURCE(S)

Blue Cross & Blue Shield Association Policy # 8.01.49

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.

Covered Codes

CPT copyright American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association.