Subject:
Radiation Therapy for Thymoma and Thymic Cancer
Description:
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IMPORTANT NOTE:
The purpose of this policy is to provide general information applicable to the administration of health benefits that Horizon Blue Cross Blue Shield of New Jersey and Horizon Healthcare of New Jersey, Inc. (collectively “Horizon BCBSNJ”) insures or administers. If the member’s contract benefits differ from the medical policy, the contract prevails. Although a service, supply or procedure may be medically necessary, it may be subject to limitations and/or exclusions under a member’s benefit plan. If a service, supply or procedure is not covered and the member proceeds to obtain the service, supply or procedure, the member may be responsible for the cost. Decisions regarding treatment and treatment plans are the responsibility of the physician. This policy is not intended to direct the course of clinical care a physician provides to a member, and it does not replace a physician’s independent professional clinical judgment or duty to exercise special knowledge and skill in the treatment of Horizon BCBSNJ members. Horizon BCBSNJ is not responsible for, does not provide, and does not hold itself out as a provider of medical care. The physician remains responsible for the quality and type of health care services provided to a Horizon BCBSNJ member.
Horizon BCBSNJ medical policies do not constitute medical advice, authorization, certification, approval, explanation of benefits, offer of coverage, contract or guarantee of payment.
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Over the past several decades, methods to plan and deliver radiation therapy have evolved in ways that permit more precise targeting of tumors with complex geometries. Earlier methods involved two-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. These methods were collectively termed conventional external beam radiation therapy (EBRT).
Subsequent enhancement evolved using 3-dimensional images, usually from computed tomography (CT) scans, to delineate the tumor, its boundaries with adjacent normal tissue, and organs at risk for radiation damage. Radiation oncologists used these images, displayed from a "beam's-eye-view", to shape each of several beams (e.g., with compensators, blocks, or wedges) to conform to the patient's tumor geometry perpendicular to the beam's axis. Computer algorithms were developed to estimate cumulative radiation dose 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 immobilize the patient, thus maintaining consistent beam axes across treatment sessions. However, "forward" planning used a trial and error process to select treatment parameters (the number of beams and the intensity, shape, and incident axis of each beam). The planner/radiotherapist modified one or more parameters and recalculated dose distributions, if analysis predicted underdosing for part of the tumor or overdosing of nearby normal tissue. Furthermore, since beams had uniform cross-sectional intensity wherever they bypassed shaping devices, it was difficult to match certain geometries (e.g., concave surfaces). Collectively, these methods are termed 3-dimensional conformal radiation therapy (3D-CRT).
Other methods were subsequently developed to permit beam delivery with non-uniform cross-sectional intensity. This often relies on a device (multi-leaf collimator, MLC) situated between the beam source and patient that moves along an arc around the patient. As it moves, a computer varies aperture size independently and continuously for each leaf. Thus, MLCs divide beams into narrow "beamlets", with intensities that range from zero to 100% of the incident beam. Beams may remain on as MLCs move around the patient (dynamic MLC), or they may be off during movement and turned on once the MLC reaches prespecified positions ("step and shoot" technique). Another method of delivering radiation beam uses a small radiation portal emitting a single narrow beam that moves spirally around the patient, with intensity varying as it moved. This method, also known as tomotherapy or helical tomotherapy, is described as the use of a linear accelerator inside a large "donut" that spirals around the body while the patient laid on the table during treatment. Each method (MLC-based or tomotherapy) is coupled to a computer algorithm for "inverse" treatment planning. The planner/radiotherapist delineates the target on each slice of a CT scan, and specifies that 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 and surrounding tissues and organs at risk, computer software optimizes the location and shape of beam ports, and beam and beamlet intensities, to achieve the treatment plan's goals. Collectively, these methods are termed intensity-modulated radiation therapy (IMRT).
According to ECRI Institute, there are two different approaches to image-guided radiation therapy that are in current use: pre-treatment imaging and real-time guidance. IMRT is an example of a method that uses pre-treatment imaging to prepare a treatment plan. In contrast, real-time guidance utilizes real-time imaging (at the time of treatment) to guide treatment. It provides real-time, online images of the radiation target area from a computed tomography (CT) scanner before, during, and after therapy. Patient positioning, radiation field alignment, and collimator positioning can be verified and adjusted before and during irradiation. This approach should, in theory, provide more accurate radiation delivery than conventional IMRT. Organ motion, day-to-day variations in tumor position, and differences in patient positioning in each treatment session could be taken into account with real-time imaging.
Policy:
(NOTE: This policy only applies to adult members. It does not apply to pediatric members.
For Medicare Advantage, please refer to the Medicare Coverage Section below for coverage guidance.)
- External beam photon radiation therapy
- External beam photon radiation therapy is considered medically necessary for the following:
- Stage I thymoma following resection with microscopic positive margins or gross residual disease
- Stage I thymic carcinoma
- Stage II to IVA thymoma or thymic carcinoma
- Unresectable or medically inoperable thymoma or thymic carcinoma
- Isolated local recurrence in the setting of no additional sites of distant metastatic disease
- Palliation
- Fractionation
- Resectable disease with thymic histology or microscopic positive margins
- Up to 27 fractions is considered medically necessary
- Unresectable or gross residual disease
- 30 to 35 fractions are considered medically necessary
- Isolated local recurrence felt to be curative
- 30 to 35 fractions are considered medically necessary
- Palliation
- Up to 15 fractions is considered medically necessary
- Techniques
- External beam photon radiation therapy with three-dimensional conformal radiation therapy (3DCRT) is considered medically necessary.
- Intensity-Modulated Radiation Therapy (IMRT) is not considered medically necessary.
Medicare Coverage:
There is no National Coverage Determination (NCD) or Local Coverage Determination (LCD) for jurisdiction JL for External beam photon radiation therapy (EBRT) for Thymoma and Thymic Cancer. Therefore, Medicare Advantage Products will follow the Horizon BCBSNJ Medical Policy for Radiation Treatment of for Thymoma and Thymic Cancer using (EBRT).
Novitas Solutions, Inc, the Local Medicare Carrier for jurisdiction JL, has issued a determination for Intensity-Modulated Radiation Therapy (IMRT). Medicare Advantage Products will follow LCD L36711 for Intensity Modulated Radiation Therapy (IMRT). For additional information and eligibility, refer to Local Coverage Determination (LCD): Intensity Modulated Radiation Therapy (IMRT) (L36711). Available at: https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=36711&ver=18&name=314*1&UpdatePeriod=749&bc=AAAAEAAAAAAAAA%3d%3d&.
Per Billing and Coding Article: Intensity Modulated Radiation Therapy (IMRT) (A56725), IMRT for Thymoma and Thymic Cancer is noncovered. For additional information, refer to Local Coverage Article:Billing and Coding: Intensity Modulated Radiation Therapy (IMRT) (A56725). Available at: https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=36711&ver=18&name=314*1&UpdatePeriod=749&bc=AAAAEAAAAAAAAA%3d%3d&.
[RATIONALE: For individuals with thymic malignancies, surgery with total thymectomy with en bloc removal of contiguous and noncontiguous disease is the treatment of choice. The use of radiation therapy following surgical resection is guided by the stage and degree of resection. The radiation treatment volume includes the tumor or the tumor bed plus a margin (Komaki and Gomez, 2013). As the rate of lymph node involvement is low, elective nodal irradiation is not routinely utilized (Komaki and Gomez, 2013).
For individuals with Stage I disease who undergo a complete resection, adjuvant radiation therapy is not recommended (Komaki and Gomez, 2013; Zhang et al., 1999). A randomized trial evaluating the use of postoperative radiation therapy in patients with Stage I thymoma found no significant difference in survival for those who received surgery alone versus surgery and radiation therapy (Zhang et al., 1999). The 10 year survival rate with surgery alone was > 90% (Zhang et al., 1999).
The role of role of postoperative radiation therapy in the management of thymoma is controversial. There are studies indicating a benefit to postoperative radiation therapy while other studies have not shown a clear advantage. In an analysis of 2001 patients from the National Cancer Database, Jackson and colleagues (2017) found that postoperative radiation therapy was associated with improved overall survival in patients with Masaoka-Koga Stage IIB thymoma, Stage III thymoma, and positive margins. A SEER analysis of 1334 patients with thymic malignancies found adjuvant radiation therapy did not improve overall survival (OS) for patients with Stage I or IIA disease but was associated with increased survival for those with Stage III or IV disease (Fernandes et al., 2010). In an analysis of 1263 Stage II and III thymoma patients from the International Thymic Malignancy Interest Group database who underwent complete resection, postoperative radiation therapy was associated with improved 10 year overall survival compared with surgery alone (86% vs. 79%, p = 0.002) (Rimner et al., 2016). A retrospective review of 146 patients with Stage I-IVa thymic carcinoma or Stage III or IV thymoma found that patients with Stage III disease had improved OS with radiation therapy combined with surgical resection and chemotherapy compared to single modality therapy (Modh et al., 2016). In contrast, Ruffini et al. (1997) observed decreased survival in Stage III thymoma patients who received postoperative radiation therapy following complete resection.
Neoadjuvant chemoradiation has been evaluated in locally advanced thymoma. In a single arm prospective trial of 22 patients with locally advanced thymoma or thymic carcinoma, 77% of patients were able to undergo a complete resection after receiving neoadjuvant chemoradiation therapy (Korst et al., 2014). This prospective study was able to demonstrate that neoadjuvant chemoradiation therapy is feasible with acceptable toxicity for patients with locally advanced thymic tumors (Korst et al., 2014).
Radiation therapy combined with chemotherapy is recommended for patients with unresectable or medically inoperable thymic malignancies. Wang and colleagues (2016) conducted a retrospective review of 42 patients with thymoma with unresectable Stage III or Stage IV (limited to an adjacent pleural implant or lymph node) disease. The median dose of radiation was 60 Gy (34 to 70 Gy). This study found combined chemoradiation therapy resulted in a higher overall response rate (ORR) (87.5% vs. 43.8%, p = 0.009) and an increased 5 year OS (61.9% vs. 30%, p = 0.01) compared to radiation therapy alone.
There is no published literature that describes a definitive clinical benefit to IMRT in thymic malignancies compared to 3DCRT. The available literature is primarily retrospective reviews which tend to combine 3DCRT and IMRT together. For example, Fan and colleagues (2013) found a non-statistically significant trend towards improved survival with 3DCRT or IMRT when compared with conventional radiation therapy techniques (100% vs. 86.9%, p = 0.12).
There is no clear dose-response relationship in the treatment of thymoma. Kundel and colleagues (2007) found improved OS when doses of 45 Gy or higher were utilized for patients with thymoma who received adjuvant radiation therapy. When Fan et al. (2013) examined the outcomes for patients who received ≤50 Gy vs. > 50 Gy, there was no difference in difference in 5 year or 10 year OS with higher doses of radiation (65% vs. 58.2%, p = 0.7). Similarly, in 128 thymoma patients who received radiation therapy, the 5 year local control rate was comparable in patients who received ≤ 50 Gy and those who received > 50 Gy (Zhu et al, 2004).
As patients with thymoma have a long life expectancy, it is important to evaluate potential long term sequelae of treatment. The available literature has not demonstrated an increased rate of cardiac morbidity or an increased incidence of secondary malignancies in thymoma patients who receive radiation therapy. Fernandes and colleagues (2010) utilized the SEER database to analyze long term outcomes and complications for 1334 patients with thymoma who received radiation therapy. There was no difference in the 24 year rate of cardiac mortality for those patients who received surgery alone when compared to those who received surgery and radiation therapy (11.8% vs. 17.4%, p = 0.83). There was no difference in the incidence of all secondary malignancies (11.7% vs. 12.4%, p = 0.70) and thoracic secondary malignancies (3.4% vs. 4.3%, p = 0.31) for patients treated with surgery alone versus those who received radiation.
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Horizon BCBSNJ Medical Policy Development Process:
This Horizon BCBSNJ Medical Policy (the “Medical Policy”) has been developed by Horizon BCBSNJ’s Medical Policy Committee (the “Committee”) consistent with generally accepted standards of medical practice, and reflects Horizon BCBSNJ’s view of the subject health care services, supplies or procedures, and in what circumstances they are deemed to be medically necessary or experimental/ investigational in nature. This Medical Policy also considers whether and to what degree the subject health care services, supplies or procedures are clinically appropriate, in terms of type, frequency, extent, site and duration and if they are considered effective for the illnesses, injuries or diseases discussed. Where relevant, this Medical Policy considers whether the subject health care services, supplies or procedures are being requested primarily for the convenience of the covered person or the health care provider. It may also consider whether the services, supplies or procedures are more costly than an alternative service or sequence of services, supplies or procedures that are at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of the relevant illness, injury or disease. In reaching its conclusion regarding what it considers to be the generally accepted standards of medical practice, the Committee reviews and considers the following: all credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, physician and health care provider specialty society recommendations, the views of physicians and health care providers practicing in relevant clinical areas (including, but not limited to, the prevailing opinion within the appropriate specialty) and any other relevant factor as determined by applicable State and Federal laws and regulations.
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Index:
Radiation Therapy for Thymoma and Thymic Cancer
Radiation Treatment of Thymoma and Thymic Cancer
Thymoma, Radiation Treatment for
Thymic Cancer, Radiation Treatment for
References:
1. Fan C, Feng Q, Chen Y, et al. Postoperative radiotherapy for completely resected Masaoka stage III thymoma: a retrospective study of 65 cases from a single institution. Radiat Oncol. 2013 Aug 13;8:199.
2. Fernandes AT, Shinohara ET, Guo M, et al. The role of radiation therapy in malignant thymoma: A Surveillance, Epidemiology, and End Results database analysis. J Thorac Oncol. 2010 Sep;5(9):1454-1460.
3. Jackson MW, Palma DA, Camidge DR, et al. The impact of postoperative radiotherapy for thymoma and thymic carcinoma. J Thorac Oncol. 2017 Apr;12(4):734-744.
4. Komaki R and Gomez DR. Radiotherapy for thymic carcinoma: Adjuvant, inductive, and definitive. Front Oncol. 2014 Jan;3:330.
5. Korst RJ, Bezjak A, Blackmon S, et al. Neoadjuvant chemoradiotherapy for locally advanced thymic tumors: A phase II, multi-institutional clinical trial. J Thorac Cardiovasc Surg. 2014 Jan;147(1):36-46.e1.
6. Kundel Y, Yelling A, Popovtzer A, et al. Adjuvant radiotherapy for thymic epithelial tumor: Treatment results and prognostic factors. Am J Clin Oncol. 2007 Aug;30(4):389-394.
7. Modh A, Rimner A, Allen PK, et al. Treatment modalities and outcomes in patients with advanced invasive thymoma or thymic carcinoma. Am J Clin Oncol. 2016 Apr;39(2):120-125.
8. Rimner A, Yao X, Huang J, et al. Postoperative radiation therapy is associated with longer overall survival in completely resected stage II and III thymoma--an analysis of the International Thymic Malignancies Interest Group retrospective database. J Thorac Oncol. 2016 Oct;11(10):1785-1992.
9. Ruffini E, Mancuso M, Oliaro A, et al. Recurrence of thymoma: Analysis of clinicopathologic features, treatment, and outcome. J Thorac Cardiovasc Surg. 1997 Jan;113(1):55–63.
10. Wang C-L, Gao L-T, Lv C-X, et al. Outcome of nonsurgical treatment for locally advanced thymic tumors. J Thorac Dis. 2016 Apr;8(4):705-710.
11. Willmann J and Rimner A. The expanding role of radiation therapy for thymic malignancies. J Thorac Dis. 2018 Aug;10(Suppl 21):S2555-S2564.
12. Zhang H, Lu N, Wang M, et al. Postoperative radiotherapy for stage I thymoma: A prospective randomized trial in 29 cases. Chin Med J (Engl). 1999 Feb;112(2):136-138.
13. Zhu G, He S, Fu X, et al. Radiotherapy and prognostic factors for thymoma: A retrospective study of 175 patients. Int J Radiat Oncol Biol Phys. 2004 Nov 15;60(4):1113–1119.
Codes:
(The list of codes is not intended to be all-inclusive and is included below for informational purposes only. Inclusion or exclusion of a procedure, diagnosis, drug or device code(s) does not constitute or imply authorization, certification, approval, offer of coverage or guarantee of payment.)
CPT*
HCPCS
* CPT only copyright 2020 American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association.
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Medical policies can be highly technical and are designed for use by the Horizon BCBSNJ professional staff in making coverage determinations. Members referring to this policy should discuss it with their treating physician, and should refer to their specific benefit plan for the terms, conditions, limitations and exclusions of their coverage.
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