Medical Policy


Subject: Neutron Beam Radiotherapy
Document #: THER-RAD.00008 Publish Date:    02/28/2018
Status: Reviewed Last Review Date:    01/25/2018


This document addresses neutron beam radiation therapy. Radiobiologic principles suggest that neutron beam radiotherapy (NBT) is associated with a higher linear energy transfer (LET) compared with conventional photon or electrons resulting in a high radiation biological effect (RBE). Certain tumors seem to be more susceptible to the cytotoxic effects of neutrons, including salivary gland tumors. NBT or neutron beam radiation therapy is not to be confused with boron neutron capture therapy (BNCT) for cancer, which is not addressed within this document.

Position Statement

Investigational and Not Medically Necessary:

Neutron beam radiotherapy is considered investigational and not medically necessary for all indications.


The high RBE effect of neutron radiation therapy occurs because the neutron remains at the target site longer so that double-strand breaks of the deoxyribonucleic acid (DNA) molecule are possible. This greatly reduces the ability of a cancer cell to repair itself and is more likely to lead to cell death. Since neutron radiation therapy is so effective, the required treatments are about one third that of traditional radiation treatments. However, neutron radiation therapy carries a high risk of irradiation to adjacent normal tissue.

Huber and colleagues (2001) compared radiotherapy with neutrons, photons, and a photon/neutron mixed beam in participants with advanced adenoid cystic carcinoma (n=75). Local control, survival, distant failure and complications were analyzed. Follow-up ranged from 1 to 160 months (median, 51 months), and the surviving individuals had a minimum follow-up of 3 years at the time of analysis. The actuarial 5-year local control was 75% for neutrons and 32% for both mixed beam and photons (p=0.015, log-rank). In spite of better local control in the neutron therapy group, there were no significant differences in survival across the groups. Acute toxicity was similar in all 3 radiotherapy groups, although severe late grade 3 and 4 toxicity was significantly more prevalent with neutrons (19%) than with mixed beam (10%) and photons (4%) (p>0.1). While neutron therapy did show improved local control, this did not translate into an improvement in overall survival. In addition, neutron therapy had significant associated toxicities as compared to other treatments.

There have been a few retrospective analyses done evaluating the safety and effectiveness of neutron therapy in salivary gland neoplasms. Local control and toxicity rates were consistent with previously reported outcomes. These studies lack comparison with other treatments (Douglas, 2003; Stannard, 2013).

Maucort-Boulch and colleagues (2010) reported a meta-analysis that included four randomized controlled trials (RCTs; total n=316) evaluating neutron therapy alone, neutron therapy with photon therapy, and photon therapy alone for treatment of glioblastoma. Follow-up at 12 months showed a 7% increase in mortality (range, 5% to 20% increase) and at 24 months, a 6% increase in mortality (range, 3% to 15% increase) in neutron therapy compared with photon therapy. This meta-analysis showed that neutron therapy did not improve survival rate. 

While several past studies have reported that neutron therapy is more effective than photon therapy in the treatment of salivary gland tumors, Spratt and colleagues (2014) note that much of the data supporting superior local control (LC) in neutron therapy versus photon radiotherapy (RT) is more than 20 years old and there have been many advances in oncological treatment since that time. The researchers reviewed the records of 27 individuals with primary unresectable salivary gland cancer treated with photon RT between 2000 and 2009. These results were compared to results reported in a 1993 randomized controlled trial comparing neutron and photon therapy. The 2- and 5-year LC for photon therapy compared to historical neutron therapy outcomes were similar (65%, 55% versus 67%, 56%, respectively). Importantly, the current study data showed lower rates of toxicity in comparison to the historical neutron therapy data. While there are limitations associated with comparing current and historical data, the study supports that alternative treatments exist with comparable control and survival outcomes with lower related toxicities.

The Head and Neck Cancer guideline developed by the National Comprehensive Cancer Network® (NCCN®) Clinical Practice Guidelines in Oncology (2017) removed the recommendation for neutron beam radiotherapy as both a definitive radiation therapy option and a postoperative treatment option for salivary gland tumors in 2015. NCCN noted concern that any potential disease control advantages are offset by the toxicity of neutron therapy. As concerns about toxicity increased, the number of centers offering this treatment in the United States (U.S.) has decreased. At this time, there is only one treatment center in the U.S. (Pfster, 2015).


Neutron beam therapy is a specialized form of external beam radiation therapy. It is often used to treat inoperable tumors or tumors that are radioresistant, meaning that they are very resistant to conventional X-ray radiation therapy. Neutrons have a greater biologic impact on cells than other types of radiation. Used carefully, this added impact may be advantageous in certain situations.


Fast neutron beam therapy: A type of external radiation treatment in which neutral charge subatomic particles (neutrons) are precisely targeted to a specific tissue mass by using a sophisticated stereotactic planning and delivery system; an interventional radiologist performs this therapy at a treatment facility equipped with a superconducting accelerator (cyclotron); pretreatment planning usually involves computed tomography (CT) to locate and determine the tumor volume prior to radiation therapy.

Glioblastoma: A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord. Glioblastoma usually occurs in adults and affects the brain more often than the spinal cord. Glioblastoma is also called grade IV astrocytoma, glioblastoma multiforme and GBM.

Unresectable: Unable to be removed with surgery.


The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When Services are Investigational and Not Medically Necessary:




High energy neutron radiation treatment delivery; 1 or more isocenter(s) with coplanar or non-coplanar geometry with blocking and/or wedge, and/or compensator(s)



ICD-10 Procedure



Beam radiation of central and peripheral nervous system using neutrons [includes codes D0005ZZ, D0015ZZ, D0065ZZ, D0075ZZ]


Beam radiation of lymphatic and hematologic system, using neutrons [includes codes D7005ZZ, D7015ZZ, D7025ZZ, D7035ZZ, D7045ZZ, D7055ZZ, D7065ZZ, D7075ZZ, D7085ZZ]


Beam radiation of eye using neutrons


Beam radiation of ear/nose/hypopharynx/mouth/tongue using neutrons [includes codes D9005ZZ, D9015ZZ, D9035ZZ, D9045ZZ, D9055ZZ]


Beam radiation of salivary glands using neutrons


Beam radiation of sinuses/palate/larynx/pharynx using neutrons [includes codes D9075ZZ, D9085ZZ, D9095ZZ, D90B5ZZ, D90D5ZZ, D90F5ZZ]


Beam radiation of respiratory system using neutrons [includes codes DB005ZZ, DB015ZZ, DB025ZZ, DB055ZZ, DB065ZZ, DB075ZZ, DB085ZZ]


Beam radiation of gastrointestinal system using neutrons [includes codes DD005ZZ, DD015ZZ, DD025ZZ, DD035ZZ, DD045ZZ, DD055ZZ, DD075ZZ]


Beam radiation of hepatobiliary system and pancreas using neutrons [includes codes DF005ZZ, DF015ZZ, DF025ZZ, DF035ZZ]


Beam radiation of endocrine system using neutrons [includes codes DG005ZZ, DG015ZZ, DG025ZZ, DG045ZZ, DG055ZZ]


Beam radiation of skin using neutrons [by body area, includes codes DH025ZZ, DH035ZZ, DH045ZZ, DH065ZZ, DH075ZZ, DH085ZZ, DH095ZZ, DH0B5ZZ]


Beam radiation of breast using neutrons [includes codes DM005ZZ, DM015ZZ]


Beam radiation of musculoskeletal system using neutrons [includes codes DP005ZZ, DP025ZZ, DP035ZZ, DP045ZZ, DP055ZZ, DP065ZZ, DP075ZZ, DP085ZZ, DP095ZZ, DP0B5ZZ, DP0C5ZZ]


Beam radiation of urinary system using neutrons [includes codes DT005ZZ, DT015ZZ, DT025ZZ, DT035ZZ]


Beam radiation of ovary/cervix/uterus using neutrons [includes codes DU005ZZ, DU015ZZ, DU025ZZ]


Beam radiation of prostate/testis using neutrons [includes codes DV005ZZ, DV015ZZ]


Beam radiation of anatomic regions using neutrons [includes codes DW015ZZ, DW025ZZ, DW035ZZ, DW045ZZ, DW055ZZ, DW065ZZ]



ICD-10 Diagnosis



All diagnoses


Peer Reviewed Publications:

  1. Douglas JG, Koh WJ, Austin-Seymour M, Laramore GE. Treatment of salivary gland neoplasms with fast neutron radiotherapy. Arch Otolaryngol Head Neck Surg. 2003; 129(9):944-948.
  2. Huber PE, Debus J, Latz D, et al. Radiotherapy for advanced adenoid cystic carcinoma: neutrons, photons or mixed beam?  Radiother Oncol. 2001; 59(2):161-167.
  3. Maucort-Boulch D, Baron MH, Pommier P, et al. Rationale for carbon ion therapy in high-grade glioma based on a review and a meta-analysis of neutron beam trials. Cancer Radiother. 2010; 14(1):34-41.
  4. Pfster DG, Spencer S, Brizel DM, et al. Head and Neck Cancers, Version 1.2015. J Natl Compr Canc Netw. 2015; 13(7):847-855
  5. Spratt DE, Salgado LR, Riaz N, et al. Results of photon radiotherapy for unresectable salivary gland tumors: is neutron radiotherapy's local control superior? Radiol Oncol. 2014; 48(1):56-61.
  6. Stannard C, Vernimmen F, Carrara H, et al. Malignant salivary gland tumours: can fast neutron therapy results point the way to carbon ion therapy? Radiother Oncol. 2013; 109(2):262-268.

Government Agency, Medical Society, and Other Authoritative Publications:

  1. National Cancer Institute (NCI). Salivary Gland Cancer Treatment (PDQ). Updated December 21, 2016. Available at: Accessed on December 11, 2017.
  2. NCCN Clinical Practice Guidelines in Oncology® (NCCN). © 2017 National Comprehensive Cancer Network, Inc. For additional information visit the NCCN website: Accessed on December 11, 2017.
Websites for Additional Information
  1. American Cancer Society (ACS). Radiation Therapy for Salivary Gland Cancer. Revised September 28, 2017. Available at: Accessed on December 11, 2017.
  2. American Society of Clinical Oncology (ASCO). Salivary Gland Cancer Treatment. Updated November 2016. Available at: Accessed on December 11, 2017.

Neutron Beam Radiotherapy
Salivary Gland Tumors

Document History






Medical Policy & Technology Assessment Committee (MPTAC) review.



Hematology/Oncology Subcommittee review. References and Websites sections updated.



MPTAC review.



Hematology/Oncology Subcommittee review. The document header wording updated from “Current Effective Date” to “Publish Date.” Rationale, References and Websites sections updated. Updated Coding section with 01/01/2018 CPT changes to remove 77422 deleted 12/31/2017.



MPTAC review.



Hematology/Oncology Subcommittee review. Rationale, References and Websites sections updated.



MPTAC review.



Hematology/Oncology Subcommittee review. Changed the document number from RAD.00047 to THER-RAD.00008. Removed the medically necessary indications for the treatment of salivary gland tumors. Updated investigational and not medically necessary statement to include all indications. Rationale, Coding and References sections updated. Removed ICD-9 codes from Coding section.



MPTAC review.



Hematology/Oncology Subcommittee review. Rationale and Reference sections updated.



MPTAC review.



Hematology/Oncology Subcommittee review. Rationale and Reference sections updated.



MPTAC review.



Hematology/Oncology Subcommittee review. Rationale, Definition and Reference sections updated.



MPTAC review.



Hematology/Oncology Subcommittee review. Rationale and References updated.



MPTAC review.



Hematology/Oncology Subcommittee review. Rationale and References updated.



MPTAC review.



Hematology/Oncology Subcommittee review. References updated.



MPTAC review.



Hematology/Oncology Subcommittee review. References were updated.



MPTAC review.



Hematology/Oncology Subcommittee review. The phrase “investigational/not medically necessary” was clarified to read “investigational and not medically necessary.” References were updated.



MPTAC review. References and coding were updated. 



MPTAC review. Description was reworded for clarity based on input from outside consultant. 



MPTAC review. Revision based on Pre-merger Anthem and Pre-merger WellPoint Harmonization.

Pre-Merger Organizations

Last Review Date

Document Number



Anthem, Inc.



No prior document

WellPoint Health Networks, Inc.



Neutron Beam Radiotherapy