BlueCross BlueShield of Tennessee Medical Policy Manual

Intensity-Modulated Radiotherapy (IMRT) of the Breast and Lung

DESCRIPTION

Intensity-modulated radiotherapy (IMRT) has been proposed as a method of radiotherapy that allows adequate dosing to the tumor while minimizing the radiation dose to surrounding normal tissues and critical structures; especially the heart in left-sided breast cancer.  IMRT, which uses computer software, CT images and magnetic resonance imaging (MRI), offers better conformality than 3-dimensional conformal radiation therapy (3D-CRT), as it is able to modulate the intensity of the overlapping radiation beams projected on the target and to use multiple-shaped treatment fields.  The radiation oncologist delineates the target on each slice of a CT scan and specifies the target’s prescribed radiation dose, 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 and surrounding tissues and organs at risk, computer software optimizes the location, shape and intensities of the beams to achieve the treatment plan’s goals.  Increased conformality may permit 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 improve local tumor control by avoiding underdosing within the tumor and may decrease toxicity by avoiding overdosing.

For the treatment of breast cancer, IMRT appears to produce clinical outcomes comparable with that of 3-dimensional conformal radiation therapy (3D-CRT).  Dosimetry studies have demonstrated that IMRT reduces inhomogeneity of radiation dose, thus potentially providing a mechanism for reduced skin toxicity compared with 2-dimensional radiotherapy (2D-RT).  IMRT has not demonstrated improvements in health outcomes for partial-breast irradiation or chest wall irradiation in post-mastectomy breast cancer cases.

For the treatment of lung cancer, IMRT appears to produce clinical outcomes comparable with that of 3D-CRT.  Dosimetry studies report that IMRT can reduce radiation exposure to critical surrounding structures, especially in large lung cancer.

BCBST uses MCG Care Guidelines for all other uses of IMRT - Intensity Modulated Radiation Therapy (IMRT) ACG: A-0455)

POLICY

MEDICAL APPROPRIATENESS

IMPORTANT REMINDERS

ADDITIONAL INFORMATION 

Studies on IMRT for partial-breast irradiation are limited and have not demonstrated improvements in health outcomes.  No studies have reported on health outcomes after IMRT for chest wall irradiation in post-mastectomy cases. 

SOURCES

BlueCross BlueShield Association. Evidence Positioning System. (7:2018). Intensity-modulated radiotherapy of the breast and lung. (8.01.46). Retrieved February 27, 2019 from https://www.evidencepositioningsystem.com/.  (27 articles and/or guidelines reviewed)

Livi, L., Meattini, I., Marrazzo, L., Simontacchi, G., Pallotta, S., Saieva, C., et al. (2015). Accelerated partial breast irradiation using intensity-modulated radiotherapy versus whole breast irradiation: 5-year survival analysis of a phase 3 randomised controlled trial. European Journal of Cancer, 51 (4), 451-463. Abstract retrieved June 27, 2016 from PubMed database.

National Comprehensive Cancer Network. (2018, October). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Small cell lung cancer. V1.2019. Retrieved February 27, 2019 from the National Comprehensive Cancer Network.

National Comprehensive Cancer Network. (2019, February). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Breast cancer.V4.2018. Retrieved February 27, 2019 from the National Comprehensive Cancer Network.

National Comprehensive Cancer Network. (2019, January). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Non-small cell lung cancer.V3.2019. Retrieved February 27, 2019 from the National Comprehensive Cancer Network.

Winifred S. Hayes, Inc. Medical Technology Directory. (2018, October; last search updated October 2018). Accelerated partial breast irradiation for breast cancer using conformal and intensity-modulated radiation therapy.  Retrieved February 27, 2019 from www.Hayesinc.com/subscribers. (50 articles and/or guidelines reviewed)

ORIGINAL EFFECTIVE DATE:  11/18/2015

MOST RECENT REVIEW DATE:  3/28/2019

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