Intensity-Modulated Radiotherapy (IMRT): Prostate

POLICY NUMBER

L.8.01.415

DESCRIPTION

Radiotherapy (RT) is an integral component of prostate cancer treatment. Intensity-modulated radiotherapy (IMRT) has been proposed as a method of external-beam radiotherapy that delivers adequate radiation to the tumor volume while minimizing the radiation dose to surrounding normal tissues and structures.

Prostate cancer is the second leading cause of cancer-related death among men in the U.S. According to the most recent incidence data available from 2020, there were 201,082 reported new cases of prostate cancer among men in the United States. From 2016 to 2020, localized, regional, distant, and unknown stage prostate cancer accounted for 69.9%, 13.4%, 7.9%, 8.8% of new cases, respectively. In 2020, the incidence of prostate cancer was highest for men 70 to 74 years of age and Black men. White (non-Hispanic) men had lower percentages of distant (7.7%) and unstaged prostate cancer (7.2%) than did any other race/ethnicity. With regard to survival for distant stage disease, 5-year survival was highest among Asian-Pacific islanders (45.4%), followed by Hispanic (38.8%), Black (34.9%), American Indian/Alaska Native (32.6%), and White (32.5%) men. Five-year survival for all stages combined was higher for Black men as compared to White or Hispanic men.

Prostate Cancer Treatment

For localized prostate cancer, radiotherapy (RT) is an accepted option for primary (definitive) treatment. Other options include surgery (radical prostatectomy), hormonal treatment, or active surveillance.

In the postoperative setting, RT to the prostate bed is an accepted procedure for patients with an increased risk of local recurrence, based on 3 randomized controlled trials that showed a significant increase in biochemical recurrence-free survival. Professional society guidelines have recommended adjuvant RT to patients with adverse pathologic findings at the time of prostatectomy and salvage RT for patients with prostate-specific antigen recurrence or local recurrence after prostatectomy in the absence of metastatic disease.

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 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 Radiotherapy

IMRT 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 computed tomography 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 radiotherapy 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 RayDose (RaySearch Laboratories) in 2008, and the eIMRT Calculator (Standard Imaging). 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.

Note: Intensity-Modulated Radiotherapy: Breast and Lung is considered separately in another policy.

POLICY

Intensity-modulated radiotherapy (IMRT) may be considered medicallynecessary in the treatment of localized prostate cancer (see Policy Guidelines).

IMRT may be considered medically necessary after radical prostatectomy as:

• Adjuvant therapy when there are adverse pathologic findings at prostatectomy or with a persistently detectable prostate-specific antigen level after prostatectomy (see Policy Guidelines)

• Salvage therapy when there is evidence of biochemical or local recurrence when there is no evidence of distant metastatic disease (see Policy Guidelines).

IMRT is considered investigational for the treatment of prostate cancer when the above criteria are not met.

POLICY EXCEPTIONS

None 

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.

Localized Prostate Cancer: Radiotherapy as Definitive Treatment

Localized prostate cancer can be defined as cancer confined to the prostate gland T1-T2N0-NXM0 or as locally advanced cancer. Locally advanced cancer is confined to adjacent structures and includes T3a-T3bN0-NXM0. The presence of tumor invasion beyond extracapsular extension or other than seminal vesicles, or with evidence of regional lymph node involvement, in the absence of distant metastases T4N0-N1M0, does not necessarily preclude definitive therapy.

The National Comprehensive Cancer Network (NCCN) has recommended a dose of 75.6 to 79.2 gray (Gy) in conventional fractions (with or without seminal vesicles) for patients with low-risk cancers (based on findings from Kuban et al, 2008). Low-risk features in localized prostate cancer are defined as stage T1 to T2a, Grade Group 1 (Gleason score of 6 or less), and a prostate-specific antigen (PSA) level less than 10 ng/mL.

The NCCN has recommended doses up to 81.0 Gy for patients with intermediate- and high-risk cancers, defined as: intermediate risk: stage T2b to T2c or Grade Group 2 (Gleason score of 7), or PSA levels between 10 ng/mL and 20 ng/mL; and high-risk: stage T3a, or Grade Group 4 or 5 (Gleason score of 8 to 10), or PSA level greater than 20 ng/mL (based on Eade et al, 2007; and Xu et al, 2011).

Post Prostatectomy: Radiotherapy as Adjuvant or Salvage Therapy

Radiotherapy (RT) after prostatectomy is used as adjuvant therapy in individuals at a higher risk of recurrence. In the adjuvant setting, adverse pathologic findings at prostatectomy include positive surgical margins, seminal vesicle invasion, and extraprostatic extension.

Use of RT as salvage therapy included treating the prostate bed and possibly surrounding tissues, including lymph nodes, in an individual with locoregional recurrence after surgery. In the salvage setting, biochemical recurrence is defined as a detectable or rising PSA level of 0.2 ng/mL or more after surgery, with a confirmatory test level of 0.2 ng/mL or higher.

American Urological Association and American Society for Radiation Oncology (2019) guidelines recommend a minimum dose of 64 to 65 Gy in the post-prostatectomy setting.

Fractionation

In the treatment of prostate cancer, conventional radiotherapy applies total doses in excess of 74 Gy over the course of up to 9 weeks, whereas hypofractionated radiotherapy involves daily doses greater than 2 Gy and has an overall shorter treatment time.

The NCCN guidelines state that in the treatment of prostate cancer, moderately hypofractionated image-guided intensity-modulated radiotherapy (IMRT) regimens (2.4 to 4 Gy per fraction over 4 to 6 weeks) have been tested in randomized trials, and their efficacy has been similar or non-inferior to conventionally fractionated IMRT, with 1 trial showing fewer treatment failures with a moderately fractionated regimen. Toxicity was similar between moderately hypofractionated and conventional regimens in some but not all of the trials. Overall, the panel believes that hypofractionated IMRT techniques, which are more convenient for individuals, can be considered as an alternative to conventionally fractionated regimens when clinically indicated.

Radiation Tolerance of Normal Tissue

Organs at risk are defined as normal tissues whose radiation sensitivity may significantly influence treatment planning and/or prescribed radiation dose. Organs at risk may be particularly vulnerable to clinically important complications from radiation toxicity.

IMRT should be considered when a tumor is near organs at risk, and 3-dimensional conformal radiotherapy planning does not meet dose-volume constraints for normal tissue tolerance.

The tables below outline radiation doses that are generally considered tolerance thresholds for these normal structures in the pelvis.

Radiation Tolerance Doses for Normal Tissues of the Pelvis

NP: not provided; TD: tolerance dose 

Radiation Dose Volume (1.8 to 2.0 Gray per Fraction) for Normal Tissues of the Pelvis

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

1/19/2009: Policy added.

5/15/09: Policy reviewed, no changes.

12/28/2009: Added prior Approval for FEP members effective January 1, 2010.

07/16/2010: Policy Exceptions section revised to state that as of July 1, 2010, prior approval is no longer required for outpatient IMRT provided for the treatment of prostate cancer for FEP members.

08/17/2010: Added CPT code 77338 to the Covered Codes table.

04/26/2012: Policy reviewed; no changes.

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

07/18/2014: Policy title changed from "Intensity-Modulated Radiation Therapy (IMRT) of the Prostate" to "Intensity-Modulated Radiotherapy of the Prostate." Policy description updated. Medically necessary policy statement revised to change "radiation therapy" to "radiotherapy." Added policy statement: IMRT is considered investigational for the treatment of prostate cancer when the above criteria are not met. Policy guidelines updated regarding localized prostate cancer.

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 section updated to add medically necessary and investigative definitions.

05/26/2016: Policy number A.8.01.47 added. Removed deleted CPT codes 77418 and 0073T from the Code Reference section.

08/11/2016: Policy description updated regarding radiotherapy in the postoperative setting. Medically necessary statement for localized prostate cancer updated to remove radiation dose constraints for definitive therapy, with policy guidelines providing additional details on dose for low-risk versus intermediate- to high-risk prostate cancer. Added policy statement that IMRT may be considered medically necessary after radical prostatectomy with certain criteria. Policy Guidelines updated regarding radiotherapy in the postoperative setting, fractionation, and radiation tolerance of normal tissue.

08/11/2017: Policy description updated regarding technologic development and IMRT methods. Policy statements unchanged.

08/14/2018: Policy description updated. Policy statements unchanged.

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

08/20/2020: Policy description updated regarding radiotherapy techniques. Policy statements unchanged. Policy Guidelines updated regarding fractionation and radiation tolerance doses for normal tissues of the pelvis.

12/03/2021: 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 new data for prostate cancer. Policy statements unchanged. Policy Guidelines updated to change "patients" to "individuals."

08/15/2023: Policy description updated regarding new data for prostate cancer. Policy statements unchanged. Policy statements unchanged.

01/15/2025: Policy updated to change the medical policy number from "A.8.01.47" to "L.8.01.415." Policy description updated regarding new data for prostate cancer. Policy statements unchanged. Policy Guidelines updated regarding current NCCN recommendations.

SOURCE(S)

Blue Cross Blue Shield Association policy # 8.01.47

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.