Intensity-Modulated Radiotherapy (IMRT): Breast and Lung

POLICY NUMBER

A.8.01.46

DESCRIPTION

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

For certain stages of many cancers, including breast and lung, randomized controlled trials have shown that postoperative radiotherapy (RT) improves outcomes for operable patients. Adding radiation to chemotherapy also improves outcomes for those with inoperable lung tumors that have not metastasized beyond regional lymph nodes.

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 (3D-CRT), and intensity-modulated radiation therapy (IMRT).

Conventional External-Beam RadiotherapyMethods to plan and deliver 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 3D 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 (MLCs) 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 to 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.

Investigators are exploring an active breathing control device combined with moderately deep inspiration breath-holding techniques to improve conformality and dose distributions during IMRT for breast cancer. Techniques presently being studied with other tumors (eg, lung cancer) either gate beam delivery to the patient’s respiratory movement or continuously monitor tumor (by in-room imaging) or marker (internal or surface) positions to aim radiation more accurately at the target. The impact of these techniques on the outcomes of 3D-CRT or IMRT for breast cancer is unknown. However, it appears likely that respiratory motion alters the dose distributions actually delivered while treating patients from those predicted by plans based on static CT scans, or measured by dosimetry using stationary (nonbreathing) targets.

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 Prowess Panther (Prowess) in 2003, TiGRT (LinaTech) in 2009, the Ray Dose (RaySearch Laboratories) in 2008, and the Accuray Precision Treatment Planning System in 2021 (Accuray Incorporated). 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. One such device cleared for marketing by the FDA through the 510(k) process is the Varian® IMRT system (Varian Medical Systems). FDA product code: IYE.

POLICY

Intensity-modulated radiotherapy (IMRT) may be considered medically necessary as a technique to deliver whole-breast irradiation in individuals receiving treatment for left-sided breast cancer after breast-conserving surgery when all the following conditions have been met:

• Significant cardiac radiation exposure cannot be avoided using alternative radiotherapy, and

• IMRT dosimetry demonstrates significantly reduced cardiac target volume radiation exposure. (See Policy Guidelines.)

Intensity-modulated radiotherapy (IMRT) may be considered medically necessary in individuals with large breasts when treatment planning with 3D conformal radiotherapy results in hot spots (focal regions with dose variation greater than 10% of target) and the hot spots can be avoided with IMRT. (See Policy Guidelines.)

Intensity-modulated radiotherapy (IMRT) of the breast is considered investigational as a technique of partial-breast irradiation after breast-conserving surgery.

Intensity-modulated radiotherapy (IMRT) of the chest wall is considered investigational as a technique of post-mastectomy irradiation.

Intensity-modulated radiotherapy (IMRT) may be considered medically necessary as a technique to deliver radiotherapy in individuals with lung cancer when all of the following conditions are met:

• Radiotherapy is being given with curative intent,

• 3D conformal radiotherapy will expose >35% of normal lung tissue to more than a 20 Gy dose-volume (V20), and

• IMRT dosimetry demonstrates reduction in the V20 to at least 10% below the V20 that is achieved with the 3D plan (e.g. from 40% down to 30% or lower).

Intensity-modulated radiotherapy (IMRT) is considered investigational as a technique to deliver radiotherapy in individuals receiving palliative treatment for lung cancer.

IMRT is investigational for the treatment of breast or lung cancer for all indications not meeting the criteria above.

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 these normal structures of the chest and abdomen. Dosimetry plans may be used to demonstrate that radiation by 3-dimensional conformal radiotherapy (3D-CRT) would exceed tolerance doses to structures at risk.

Radiation Tolerance Doses for Normal Tissues of the Chest

Compiled from: (1) Morgan MA, Ten Taken RK, Lawrence TS. Essentials of radiation therapy. In DeVita, Hellman, and Rosenberg, Cancer: Principles & Practice of Oncology. Philadelphia: Lippincott Williams and Wilkins; 2019; and (2) Kehwar TS, Sharma SC. Use of normal tissue tolerance doses into linear quadratic equation to estimate normal tissue complication probability. Available at: http://www.rooj.com/Radiation%20Tissue%20Tolerance.htm . Accessed May 23, 2025.NP: not provided; TD: tolerance dose.^aTD 5/5 is the average dose that results in a 5% complication risk within 5 years.^bTD 50/5 is the average dose that results in a 50% complication risk within 5 years.

The following is an example of clinical guidelines that may be used with IMRT in left-sided breast lesions:

• The target volume coverage results in cardiac radiation exposure that is expected to be greater than or equal to 25 Gy to 10 cm³ or more of the heart (V25 ≥10 cm³) with 3D conformal RT, despite the use of a complex positioning device (eg, Vac-Lok), and

• With the use of IMRT, there is a reduction in the absolute heart volume receiving 25 Gy or more by at least 20% (eg, volume predicted to receive 25 Gy by 3D-CRT is 20 cm³, and the volume predicted by IMRT is ≤16 cm³).

The following are examples of criteria to define large breast size when using IMRT to avoid hot spots, as derived from randomized studies:

• Donovan and colleagues enrolled individuals with a "higher than average risk of late radiotherapy-adverse effects," which included individuals having larger breasts. The authors state that while breast size is not particularly good at identifying women with dose inhomogeneity falling outside current International Commission on Radiation Units and Measurements guidelines, they excluded women with small breasts (less than or equal to 500 cm³), who generally have fairly good dosimetry with standard 2D compensators.

• In the trial by Pignol and colleagues, which reported that the use of IMRT significantly reduced the proportion of individuals experiencing moist desquamation, breast size was categorized as small, medium or large by cup size. Multivariate analysis found that smaller breast size was significantly associated with a decreased risk of moist desquamation (p<0.001).

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

7/23/2007: Policy added.

11/15/2007: Policy approved by MPAC.

5/11/2009: Policy reviewed, no changes. 

08/17/2010: Policy description unchanged. Policy statement regarding IMRT as a technique to deliver wholebreast irradiation in patients receiving treatment for breast cancer after breast-conserving surgery was changed from investigational to not medically necessary. IMRT as a technique of partial breast irradiation after breast-conserving surgery remains investigational. Policy statement regarding use of IMRT in lung cancer was changed from investigational to not medically necessary. FEP verbiage added to the Policy Exceptions sections. Added new CPT code 77338 to the Code Reference section.

12/30/2010: Policy reviewed; no changes.

04/26/2012: Policy description updated regarding treatment techniques. Added policy statement to indicate that chest wall IMRT postmastectomy is investigational. Added policy statement to indicate that whole breast IMRT may be medically necessary in large-sized breasts. Changed policy statements regarding whole breast and lung IMRT from not medically necessary to medically necessary if certain conditions are met. Policy statement on partial breast IMRT remains investigational. Added statement to indicate that IMRT of the chest wall is considered investigational as a technique of postmastectomy irradiation. Policy guidelines updated regarding patient selection criteria. The Code Reference section was changed from non-covered to covered; added ICD-9 codes 162.3 - 162.9, 174.0 - 174.9, 175.0 - 175.9 as covered diagnoses.

08/09/2013: Policy reviewed; no changes.

07/18/2014: Policy title changed from "Intensity Modulated Radiation Therapy (IMRT) of the Breast and Lung" to "Intensity-Modulated Radiotherapy of the Breast and Lung." Policy description and statement updated to change "radiation therapy" to "radiotherapy" throughout policy. Added policy statement: IMRT is not medically necessary for the treatment of breast or lung cancer for all indications not meeting the criteria above.

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

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

09/16/2015: Policy description updated regarding IMRT systems. Policy statements unchanged. Policy Guidelines updated to add medically necessary and investigative definitions.

05/26/2016: Policy number A.8.01.46 added. Removed deleted CPT codes 0073T and 77418 from the Code Reference section.

09/23/2016: Policy description updated regarding radiation techniques. Policy statements unchanged.

08/11/2017: Policy description updated. Medically necessary policy statements updated to change "3-D conformal" to "3-D conformal radiotherapy." Policy Guidelines updated regarding radiation tolerance doses for normal tissues of the chest and abdomen.

08/14/2018: First medically necessary policy statement updated to change "radiation techniques" to "radiotherapy."

08/16/2019: Policy reviewed; no changes.

08/19/2020: Policy description updated regarding radiotherapy techniques. Policy statements unchanged. Policy Guidelines updated regarding radiation tolerance doses for normal tissues of the chest.

12/02/2021: Policy description updated. Policy statements unchanged. Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity."

08/24/2022: Policy description updated regarding radiotherapy planning systems. Policy statements and Policy Guidelines updated to change "patients" to "individuals."

08/14/2023: Policy reviewed. Policy statements updated to change "patients" to "individuals" and "not medically necessary" to "investigational." Policy Guidelines updated.

08/15/2024: Policy description updated regarding radiotherapy planning systems. Policy statements unchanged. Policy Guidelines updated.

09/15/2025: Policy reviewed. Policy statements unchanged. Policy Guidelines updated.

10/01/2025: Code Reference section updated to add new ICD-10 diagnosis codes C50.A0, C50.A1, and C50.A2.

SOURCE(S)

Blue Cross Blue Shield Association Policy # 8.01.46

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.