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Radiotherapy (RT) is an integral component of treatment for prostate cancer. Intensity-modulated radiotherapy (IMRT) has been proposed as a method of external beam RT that delivers adequate radiation to the tumor volume, minimizing the radiation dose to surrounding normal tissues and structures.
For localized prostate cancer, 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 recommend adjuvant RT to patients with adverse pathologic findings at the time of prostatectomy and salvage RT for patients with prostate-specific antigen (PSA) or local recurrence after prostatectomy in the absence of metastatic disease.
Conventional (2-Dimensional) External Beam Radiotherapy
Most early trials used 2-dimensional treatment planning based on flat images and radiation beams with cross-sections of uniform intensity that were sequentially aimed at the tumor along 2 or 3 intersecting axes. Collectively, these methods are termed conventional or 2-dimensional external beam radiotherapy. Methods to plan and deliver RT have evolved in ways that permit more precise targeting of tumors with complex geometries.
Three-Dimensional Conformal Radiation
Treatment planning evolved by using 3-dimensional images, usually from computed tomography (CT) scans, to delineate the boundaries of the tumor and discriminate tumor tissue from adjacent normal tissue and nearby organs at risk for radiation damage. Computer algorithms were developed to estimate cumulative radiation doses delivered to each volume of interest by summing the contribution from each shaped beam. Methods also were 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. Collectively, these methods are termed 3-dimensional conformal radiotherapy (3D-CRT).
IMRT, which uses computer software and CT and magnetic resonance imaging images, offers better conformality than 3D-CRT, because IMRT modulates the intensity of the overlapping radiation beams projected on the target and uses multiple-shaped treatment fields. IMRT uses a device (a multileaf collimator) which, coupled to a computer algorithm, 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 of the tumor and surrounding tissues and organs at risk, computer software optimizes the location, shape, and intensities of the beam’s ports, to achieve the treatment plan’s goals.
Increased conformality permits escalated tumor doses without increasing normal tissue toxicity and thus may 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 help avoid underdosing and decrease overdosing.
Because most tumors move as patients breathe, dosimetry with stationary targets may not accurately reflect doses delivered within target volumes and adjacent tissues in patients. Furthermore, treatment planning and delivery are more complex, time-consuming, and labor-intensive for IMRT than for 3D-CRT. Thus, clinical studies must test whether IMRT improves tumor control or reduces acute and late toxicities when compared to 3D-CRT.
Methodologic Issues in IMRT research
Multiple-dose planning studies have generated 3D-CRT and IMRT treatment plans from the same scans, and then compared predicted dose distributions within the target and adjacent organs at risk. Results of such studies have shown that IMRT improves on 3D-CRT with respect to conformality to, and dose homogeneity within, the target. Dosimetry using stationary targets generally confirms these predictions. Thus, radiation oncologists hypothesized that IMRT may improve treatment outcomes compared with those of 3D-CRT. However, these types of studies offer indirect evidence for IMRT treatment benefit, and it is difficult to relate dosing study results to actual effects on health outcomes.
Comparative studies of radiation-induced adverse effects from IMRT versus alternative radiation delivery are probably the most important evidence in establishing the benefit of IMRT. Such studies would answer whether the theoretic benefit of IMRT in sparing normal tissue translates into real health outcomes. Single-arm series of IMRT can give some insights into the potential for benefit, particularly if an adverse effect that is expected to occur at high rates is shown to decrease by a large amount. Studies of treatment benefit are also important to establish that IMRT is at least as good as other types of delivery, but in the absence of such comparative trials, it is likely that benefit from IMRT is at least as good as with other types of delivery.
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 received marketing clearance through the FDA 510(k) process. Intensity modulators include the Innocure Intensity Modulating Radiation Therapy Compensators (Innocure) and decimal tissue compensator (Southeastern Radiation Products) FDA product code: IXI. Intensity modulators may be added to standard linear accelerators to deliver IMRT when used with proper treatment planning systems.
Radiotherapy treatment planning systems have also received FDA 510(k) marketing clearance. They include the Prowess Panther (Prowess), TiGRT (LinaTech), Ray Dose (Ray Search Laboratories), 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 to receive FDA 510(k) clearance is the Varian IMRT system (Varian Medical Systems). FDA product code: IYE.
Note: IMRT of the breast and lung is considered separately in another policy.
Intensity-modulated radiotherapy (IMRT) may be considered medically necessary in the treatment of localized prostate cancer (see Policy Guidelines).
IMRT may be considered medically necessary after radical prostatectomy as:
IMRT is considered investigational for the treatment of prostate cancer when the above criteria are not met.
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-T2a, a Gleason score of 6 or less, and prostate-specific antigen (PSA) level less than 10 ng/mL.
NCCN has recommended doses up to 81.0 Gy for patients with intermediate- and high-risk cancers, defined as: intermediate risk: stage T2b-T2c or Gleason score of 7 or PSA levels between 10 ng/mL and 20 ng/mL; and high risk: stage T3a or Gleason score of 8 to 10 or PSA level greater than 20 ng/mL (based on Eade et al, 2007; Zelefsky et al, 2008, and Xu et al, 2011).
Post Prostatectomy: Radiotherapy as Adjuvant or Salvage Therapy
Adjuvant therapy is the use of radiotherapy after prostatectomy in patients at a higher risk of recurrence (before recurrence). In the adjuvant setting, adverse pathologic findings at prostatectomy include positive surgical margins, seminal vesicle invasion, extraprostatic extension, and Gleason scores of 8 to 10.
Salvage therapy is the use of radiotherapy to the prostate bed and possibly to surrounding tissues, including lymph nodes, in a patient with locoregional recurrence after surgery. In the salvage setting, biochemical recurrence is a detectable or rising PSA level of 0.2 ng/mL or higher after surgery, with a confirmatory test level of 0.2 ng/mL or higher.
American Urological Association and American Society for Radiation Oncology (2013) guidelines recommend a minimum dose of 64 to 65 Gy in the post-prostatectomy setting.
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. Published randomized controlled trials (RCTs) have failed to demonstrate superiority of hypofractionation in definitive radiotherapy for prostate cancer, either for efficacy or late toxicity. Ongoing phase 3 noninferiority trials may provide insight.
NCCN guidelines state that because, in the treatment of prostate cancer, moderately hypofractionated intensity-modulated radiotherapy (IMRT) regimens (2.4-4 Gy per fraction over 4-6 weeks) have been tested in RCTs and efficacy and toxicity have been found similar to conventionally fractionated IMRT, hypofractionation may 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 in close proximity to organs at risk and 3-dimensional conformal radiotherapy planning is not able to 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
Radiation Dose Volume (1.8 - 2.0 Gy/fx) 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 Nervous/Mental Conditions, 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 Medically Necessary, “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 HISTORY1/19/2009: 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 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.
SOURCE(S)Blue Cross Blue Shield Association policy # 8.01.47
CODE REFERENCEThis 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.