ModifiedUnitedHealthcarePolicy 2026T0132MM

Proton Beam Radiation Therapy

Clinical coverage policy for proton beam radiation therapy (PBT/PBRT) for UnitedHealthcare Commercial and Individual Exchange plans, addressing indications, documentation, and coding for individuals 19 years and older.

Policy Summary

PayerUnitedHealthcare

PolicyProton Beam Radiation Therapy

Policy CodePolicy 2026T0132MM

Change TypeMaterial coverage updates and additions

Effective DateMar 1, 2026

Next Review DateN/A

Key ActionProvide comparative treatment plans and documentation showing photon techniques cannot adequately spare surrounding normal tissue when requesting authorization or exceptions for PBT.

SourceLink

POLICY UPDATE CHANGES

Primary head and neck cancers are added as a proven indication for definitive PBT when tumors are near critical structures or have intracranial extension or perineural invasion and documentation shows photon techniques cannot spare normal tissue.

Primary central nervous system tumors (e.g., brain or spinal cord) are added as a proven indication for definitive PBT when tumors are near critical structures and documentation shows photon techniques cannot spare normal tissue.

Primary mediastinal tumors (e.g., thymomas, mediastinal lymphomas, thoracic sarcomas) are added to the list of proven indications for definitive PBT.

Reirradiation is added as a proven indication when prior radiation was to the same anatomic site and documentation shows photon techniques cannot spare normal tissue.

The HCC indication was broadened/replaced to 'primary liver malignancies, such as hepatocellular carcinoma and intrahepatic cancer (localized, unresectable) in the curative setting' with the same documentation requirement regarding inability to spare normal tissue using standard techniques.

Exception evaluation criteria changed: replaced requirement for comparison of treatment plans among PBT, IMRT, and SBRT with a requirement to compare PBT and photon-based radiation therapy (such as IMRT or SBRT) for the individual.

Updated Medical Records Documentation Used for Reviews to add history of prior radiation and documentation comparing plans when required for exceptions.

19+Policy applies to individuals age

Related Billing Codes

CPT-77522-PROTON-BEAM-THERAPY-TECHNICAL-SINGLE-PORT

CPT 77522: Proton Beam Radiation Therapy, Technical Component

CPT-77387-IMAGE-GUIDANCE-RADIATION-THERAPY-TARGETING

CPT 77387: Image Guidance for Radiation Therapy Targeting

CPT-77338-MLC-DESIGN-CONSTRUCTION-IMRT

CPT 77338: MLC Design and Construction for IMRT

CPT-77523-PROTON-BEAM-RADIATION-THERAPY-TECHNICAL-INTERMEDIATE

CPT 77523: Proton Beam Radiation Therapy, Technical Component, Intermediate

CPT-77525-COMPLEX-PROTON-BEAM-RADIATION-THERAPY-TECHNICAL

CPT 77525: Complex Proton Beam Radiation Therapy, Technical Component

CPT-77520-PROTON-BEAM-RADIATION-TECHNICAL-SIMPLE-TECHNIQUE

CPT 77520: Proton Beam Radiation Therapy, Technical Component (Simple)

CPT-77301-INTENSITY-MODULATED-RADIOTHERAPY-IMRT-DELIVERY

CPT 77301: Intensity Modulated Radiotherapy (IMRT) Delivery

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MultipleCovered indications listed

77520-77525Proton delivery CPT codes listed

MultipleSystematic reviews cited

Low–Very LowEvidence quality for several GI/esophageal

Coverage Criteria for Proton Beam Therapy

Prostate Cancer stance

Proton beam radiation therapy (PBT) and intensity-modulated radiation therapy (IMRT) are considered clinically equivalent options for treating localized prostate cancer. Coverage and medical necessity determinations for PBT in prostate cancer will be made in accordance with the member-specific benefit plan terms. The following statements summarize evidence, guideline positions, and coverage implications for prostate cancer:

PBT and IMRT are considered clinically equivalent for localized prostate cancer; PBT is a treatment option but has not been shown to be superior to other radiation modalities in cancer control or toxicity profile.

High-quality comparative evidence is limited and mixed: several systematic reviews, large database observational studies, and technology assessments report that PBT is relatively safe and yields oncologic outcomes broadly comparable to photon EBRT or brachytherapy, but randomized evidence demonstrating clear superiority is lacking.

Some observational studies (for example, national database analyses) have reported improved overall survival for selected subgroups treated with PBT compared with photon EBRT; however, these findings are subject to confounding and selection bias and are not confirmed by randomized trials.

Population-based cohort studies have identified greater gastrointestinal (GI) toxicity with PBT compared with IMRT in some analyses, while other studies have reported similar or mixed toxicity profiles; the evidence on comparative late toxicities remains inconclusive.

Major guideline positions: - The American Urological Association (AUA) and ASTRO guideline (2022) conditionally recommends proton therapy as a treatment option for clinically localized prostate cancer but notes it has not been demonstrated to be superior to other radiation modalities in outcomes or toxicity. - The NCCN recognizes both photon RT and proton beam RT as appropriate forms of external-beam RT for prostate cancer and indicates current evidence suggests comparable outcomes in toxicity, quality of life, and tumor control.

Technology assessments (e.g., Hayes, ECRI) conclude that while PBT provides favorable disease control and appears relatively safe, the available studies are generally low quality or nonrandomized and do not establish a clear advantage over standard photon approaches; additional well-designed comparative trials are needed.

Ongoing clinical trials are in progress to compare proton therapy with photon approaches (examples: NCT01617161, NCT00969111, NCT03561220); coverage decisions may be influenced by emerging trial results over time.

Operational coverage implication: medical necessity for PBT in prostate cancer will be determined per the member's benefit plan; when PBT is requested, documentation should support selection of modality (for example, clinical rationale, comorbidities, prior pelvic irradiation, or anatomical considerations) and, when available, comparison of treatment plans (PBT vs photon-based RT) demonstrating expected dosimetric or clinical advantage for the individual.

Where plan documents limit coverage to modalities proven superior by evidence, PBT may be considered equivalent but not preferential; conversely, where benefit plans list PBT as a covered treatment option, it should be authorized when medical necessity criteria and plan-specific requirements are met.

Provider Actions, Prior Authorization, and Documentation

Prior Authorization

Prior Authorization to Confirm Guideline-Concordant Indication

Prior authorization is required to confirm that proton beam therapy (PBT) is being requested for a guideline-concordant indication and that PBT is necessary for the individual member. Prior authorization reviews should confirm tumor site, indication, and that guideline-recommended criteria are met (for example: ocular melanoma, base of skull tumors such as chordoma/chondrosarcoma, unresectable primary liver malignancies in the curative setting when photon techniques cannot meet constraints, mediastinal lymphomas where OAR sparing is critical, and reirradiation scenarios).

Confirm tumor site and guideline-concordant indication at prior authorization; reference applicable society guideline(s).
For requests citing guideline support (ASTRO, NCCN, ILROG, ARS, AUA/ASCO/ASTRO), include the guideline name and relevant excerpt or rationale.
Payer will evaluate medical necessity consistent with member-specific benefit plan.

Prior Authorization

Prior Authorization for PBT

Prior authorization for PBT should verify that: the indication is listed as proven/medically necessary in this policy or that an exception review is requested with required supporting documentation; photon alternatives (including advanced photon techniques) have been considered and cannot meet normal tissue constraints when that is the rationale for PBT; and that appropriate technology and expertise are available at the treating center.

Procedure and Diagnosis Codes

Proton delivery CPT CodesCPT

77520	Proton treatment delivery; simple, without compensation
77522	Proton treatment delivery; simple, with compensation
77523	Proton treatment delivery; intermediate
77525	Proton treatment delivery; complex
77301	Intensity modulated radiotherapy plan, including dose-volume histograms for target and critical structure partial tolerance specifications
77338	Multi-leaf collimator (MLC) device(s) for intensity modulated radiation therapy (IMRT), design and construction per IMRT plan
77387	Guidance for localization of target volume for delivery of radiation treatment, includes intrafraction tracking, when performed

Diagnosis/ICD-10 Codes (partial list)ICD-10

C11.0	Malignant neoplasm of superior wall of nasopharynx
C22.0	Liver cell carcinoma
C31.0	Malignant neoplasm of nasal cavity
C69.0	Malignant neoplasm of conjunctiva
C61	Malignant neoplasm of prostate
Q28.2	Arteriovenous malformation of cerebral vessels

Minimum study size exclusions in cited meta-analysis

Meta-analysis exclusion criterionStudies with fewer than 10 individuals were excluded from the cited meta-analysis.

Language and study-type exclusionsNon-English publications, case reports, letters, abstracts, and duplicate-data studies were excluded.

Reirradiation exclusionReirradiation studies were excluded from the analyzed population in the chondrosarcoma meta-analysis.

BED threshold

BED threshold for 1-year LCBED > 75.2 GyE was associated with higher 1-year local control (95.7% vs 84.6%; p = 0.029).

Study contextFinding reported in a multicenter hypofractionated PBT registry analysis (Parzen et al., 2021) of HCC/ICC patients.

Definitions and Abbreviations

Base of Skull Tumors

Anatomic definitionLesions arising in the anatomically complex region at the base of the skull, including the anterior cranial fossa, clivus, petrous bone, middle cranial fossa, cavernous sinus, and infratemporal fossa.

Critical structuresRegion houses essential endocrine, neurological, and vascular components relevant to treatment planning (eg, cranial nerves, pituitary/hypothalamic structures).

Common tumor typesIncludes chordomas and chondrosarcomas as commonly occurring skull-base tumors cited in the literature.

Central Nervous System Tumors

DefinitionTumors originating in the central nervous system, including brainstem glioma, craniopharyngioma, medulloblastoma, and meningioma.

SourceDefinition aligns with the National Cancer Institute (NCI) terminology cited in the policy.

Background, Evidence Summaries, and Indication-Specific Evidence

inv-10: Evidence summaries by indication (no explicit coverage criteria in this part)

Evidence summaries and guideline positions by indication (duplicated here for evidence context)

Ophthalmic indications (AMD, choroidal hemangioma): Systematic reviews and RCTs show limited or uncertain benefit of RT/PBT for neovascular AMD; studies are heterogeneous and often predate anti-VEGF therapy. For choroidal hemangioma, comparative retrospective data suggest similar functional outcomes for PDT and PBT for tumors ≤ 3 mm; PBT may be preferred for > 3 mm.tumor thickness > 3 mm may favor PBT

Evidence quality low; further large-scale studies needed.

Bladder cancer (muscle-invasive): Small series report acceptable short-term OS/PFS and low severe GI/GU toxicity with PBT as part of trimodal therapy, but data are limited and follow-up short; guideline-based bladder-preserving therapy recommends conventional EBRT plus chemotherapy as standard.tumor size ≥ 5 cm and multiplicity associated with progression in one series

PBT not specifically addressed in major guidelines as standard.

Revision History and Policy Changes

2026-03-01policy_revisionLatest

Revised list of proven/medically necessary indications: added primary head and neck cancers, primary central nervous system tumors, primary mediastinal tumors, and explicit reirradiation criteria; replaced prior HCC wording with a broader 'primary liver malignancies' statement; updated exception evaluation criteria to require comparison of PBT and photon-based treatment plans for the individual.

2026-03-01administrative_update

Updated Medical Records Documentation Used for Reviews to add prior radiation history and plan-comparison documentation elements; archived previous policy version 2026T0132LL.

Policy Summary

PayerUnitedHealthcare

PolicyProton Beam Radiation Therapy

Policy CodePolicy 2026T0132MM

Change TypeMaterial coverage updates and additions

Effective DateMar 1, 2026

Next Review DateN/A

Key ActionProvide comparative treatment plans and documentation showing photon techniques cannot adequately spare surrounding normal tissue when requesting authorization or exceptions for PBT.

SourceLink

On This Page

If PBT is requested for a listed proven indication, submit clinical documentation demonstrating criteria are met (see Required Clinical Documentation callout).
If PBT is requested for an unlisted diagnosis, submit an exception request with dosimetric plan comparison (see Exception Requests Require Plan Comparisons).
When PBT is requested for mediastinal disease, reirradiation, or thoracic curative intent, include specific prior treatment and dose information.

Prior Authorization

Prior Authorization Recommended for Curative Thoracic PBT

Prior authorization is recommended (and may be required by benefit terms) when PBT is requested for curative-intent thoracic radiation (e.g., NSCLC, esophageal cancer) to confirm that advanced photon options (IMRT/VMAT) have been evaluated and that PBT offers a clear dosimetric or clinical advantage to limit normal tissue toxicity.

Provide dosimetric comparisons showing PBT reduces dose to critical thoracic OARs (heart, lung, esophagus) compared with IMRT/VMAT when claiming superiority.
Include tumor stage, planned concurrent chemotherapy, motion management, and simulation details per NCCN recommendations.

Prior Authorization

Exception Requests Require Plan Comparisons

Exception requests for diagnoses not listed as proven require a comparison of treatment plans and supportive justification. An exception evaluation must include documentation that photon-based techniques cannot achieve adequate sparing of normal tissues and must include a dosimetric comparison of the individual's PBT plan versus appropriate photon-based plans (eg, IMRT, VMAT, or SBRT).

Required: side-by-side dose-volume histogram (DVH) comparisons for PBT and the best-available photon plan(s).
Required: clear statement that photon techniques cannot meet organ-at-risk (OAR) constraints and why (anatomic proximity, prior dose overlap, or other technical limitations).
Requests lacking plan comparison may be denied as insufficient for exception review.

Documentation Required

Documentation Affects Coverage

Coverage determination depends on the member-specific benefit plan and applicable laws. Medical records may be requested and the absence of required documentation can lead to denial even if clinical criteria appear met on initial review.

Benefit coverage is not guaranteed by prior authorization and remains subject to plan terms and legal mandates.
Failure to provide requested medical records, prior radiation details, or plan comparisons can result in denial of coverage.

Denial Risk

AVM Intervention vs Conservative Management

Randomized evidence shows interventional treatments for unruptured intracranial AVMs (including endovascular, surgical, or RT interventions) were associated with worse functional outcomes compared with conservative management in at least one high-quality RCT. This evidence should inform decision-making when PBT is proposed for intracranial AVMs.

When PBT is requested for intracranial AVMs, include explanation of why intervention is favored over conservative management for the specific individual.
Highlight any factors that made the patient ineligible for conservative management or that indicate a higher-than-usual rupture or morbidity risk.

Documentation Required

Patient Eligibility Boundary Signals

Prior authorization reviewers should note patient eligibility boundary signals—clinical and trial exclusion criteria that often define populations unlikely to benefit or raise safety concerns (for example: vascular invasion, very high AFP, Child-Pugh C cirrhosis, high MELD scores, bilirubin >3 mg/dL, or other contraindications described in pivotal trials).

If member meets common exclusion thresholds from key trials, include rationale for why PBT is still appropriate or provide alternative recommendations.
For mediastinal lymphoma and reirradiation cases, document prior treatment availability and selection rationale given limited PBT access.

Denial Risk

Risk for Unproven Indications

Requests for PBT for indications classified as 'Unproven' or with limited evidence carry a higher risk for denial if submitted without robust supporting data. Use caution when requesting PBT for indications where evidence is limited, inconsistent, or primarily from small nonrandomized studies.

Provide high-quality supportive data (prospective trials, larger comparative series) when available; otherwise, expect careful scrutiny and potential denial.
Consider enrolling the patient in a clinical trial when evidence is limited.

Denial Risk

Combined PBT+IMRT Not Supported

There is no evidence supporting the combined use of PBT and IMRT in a single treatment plan. Requests proposing combined PBT+IMRT should include a clear rationale and will be subject to review; absence of supporting evidence may result in nonapproval.

Combined PBT+IMRT plans are unsupported by current literature and may be denied as not medically necessary.
If a combined approach is proposed, submit peer-reviewed evidence or strong clinical rationale specific to the patient.

Denial Risk

Lack of Documentation Showing Photon Techniques Cannot Spare Normal Tissue

When the clinical rationale for PBT is that photon techniques cannot adequately spare surrounding normal tissue, prior authorization must include documentation demonstrating attempts to optimize photon plans and dosimetric comparisons showing photon techniques (including IMRT/VMAT/VMAT-based approaches) cannot meet OAR constraints.

Submit representative photon plan(s) (eg, IMRT/VMAT) used for comparison and why they fail to meet constraints.
Describe technical or anatomic reasons (eg, overlapping prior radiation, proximity to critical structures) that prevent photon-based sparing.

Documentation Required

Medical Records Requirement

Medical records and specific clinical documentation may be required to assess whether the member meets coverage criteria. Documentation does not guarantee coverage; lack of requested records can result in denial. Refer to the Medical Records Documentation Used for Reviews guideline for additional details.

Medical records often requested include history and physical, pathology reports, imaging, prior radiation records (doses, fields), and prior treatment summaries.
Provide complete records at the time of prior authorization when possible to avoid delays or denials.

Documentation Required

Clinical Justification and Tumor Localization

Clinical justification must clearly document tumor type, exact anatomic location (eg, skull base region, orbit, cavernous sinus, intracranial extension, perineural invasion), intent of therapy (definitive/curative, palliative, reirradiation), and the specific clinical reason PBT is preferred over photon therapy.

Include tumor histology, stage, size, laterality, and proximity to critical structures.
State anticipated survival or cure intent when relevant (eg, long-term survival where late toxicity avoidance is critical).

Documentation Required

Required Clinical Documentation

Required clinical documentation for prior authorization and coverage review should demonstrate diagnosis, stage, tumor location, underlying organ function where relevant (eg, liver function for HCC/ICC), prior therapies, and that photon techniques cannot achieve required sparing when claimed.

Diagnosis and histologic confirmation (pathology report).
Staging studies and imaging demonstrating tumor extent and relation to OARs.
Prior treatment history including surgery, systemic therapy, and prior radiation with dose and field overlap details.
Relevant organ function tests (eg, Child-Pugh, MELD, AFP for liver cases).

Documentation Required

Supportive Trial Documentation Elements

When relying on prospective clinical trial data to support PBT for an individual, include trial-specific elements: histologic confirmation, stage, prior surgery status, radiation dose/fractionation, and follow-up outcomes (LC, PFS, OS), as applicable. Prospective trial details strengthen exception requests and coverage justification.

Provide trial identifier (eg, NCT number), inclusion/exclusion criteria, and how the patient matches trial eligibility.
Include meaningful endpoints and comparative dosimetric or toxicity results from the trial.

Documentation Required

Documentation for Lung Cancer PBT

For lung cancer PBT requests, document the specific lung cancer indication (eg, NSCLC stage), rationale for PBT (need to spare normal lung, heart, esophagus; reirradiation; or to permit dose escalation), and reference applicable guideline recommendations and ongoing trials when available.

Include tumor stage, planned systemic therapy, motion management strategy, simulation imaging (4DCT/PET-CT), and expected dose/fractionation.
Provide dosimetric comparisons versus IMRT/3D-CRT and cite relevant ongoing phase 3 trials if used to support the request.

Step Therapy

Step for Non-Listed Indications

For diagnoses not specifically listed as proven in this policy, the prior authorization pathway requires a stepwise justification: attempt or evaluation with advanced photon techniques (IMRT/VMAT/SBRT) and, if those cannot meet constraints, submission of dosimetric comparisons and clinical rationale for PBT.

Document attempts to meet OAR constraints with optimized photon plans before proceeding to PBT.
If photon plans were not attempted due to prior radiation overlap or other clear technical reasons, provide prior radiation records and explanation.

Step Therapy

Step from Photon RT to PBT

When guideline recommendations indicate PBT is reasonable only when photon RT cannot adequately spare surrounding tissue, prior authorization should require demonstration (via dosimetric comparison or documented optimization attempts) that photon RT is insufficient before approving PBT.

Provide the best-available photon plan(s) and show comparative DVHs to substantiate claim.
Include technical notes on why photon planning was limited (eg, OAR proximity, prior dose constraints, or inability to escalate tumor dose).

Step Therapy

Step Therapy Considerations for Bladder Preservation

For muscle-invasive bladder cancer undergoing bladder-preserving trimodality therapy, guidelines recommend conventional EBRT plus chemotherapy as standard; PBT is not specifically addressed in major bladder-preservation guidelines and should generally not be considered first-line unless a strong, documented dosimetric or clinical rationale exists.

If PBT is proposed as part of trimodality bladder-preserving therapy, include rationale comparing conventional pelvic photon EBRT vs PBT and show benefit in sparing bowel, bone marrow, or other OARs.
Expect careful review and documentation that PBT provides meaningful advantage over standard EBRT plus chemotherapy.

Clinical implicationDose escalation to BED > 75.2 GyE correlated with improved short-term local control in hypofractionated liver PBT series.

Typical prescription dose (PSRS)

Most common single-fraction PSRS dose15 Gy was the most common single-fraction prescription reported in the single-fraction PSRS series.

Source series sizeThe large single-institution PSRS series included 248 patients with 254 AVMs (1991–2010).

Associated outcomeAt median follow-up of 35 months, obliteration rate was 64.6% with a median time to obliteration of 31 months.

Liver PBT dose protocols

Example protocol — GI protocol77.0 GyE in 35 fractions (gastrointestinal protocol).

Example protocol — hilar protocol72.6 GyE in 22 fractions (hilar protocol).

Example protocol — standard protocol66.0 GyE in 10 fractions (standard protocol).

Biologically effective dose (BED) threshold

BED threshold for improved outcomesMedian BED delivered across hypofractionated early-stage NSCLC studies was 105.6 Gy (RBE); outcomes were better with BED ≥ 105.6 Gy (RBE).

Reported benefitsHigher BED (≥105.6 Gy RBE) was associated with improved OS, cancer-specific survival, disease-free survival, and local control in pooled analyses.

Toxicity trade-offLate grade ≥2 toxicities were nearly three times more frequent in the higher-dose group; rib fractures were notably more common.

Relevance to coverageCNS tumors are listed as proven indications when tumors are near critical structures and photon techniques cannot spare normal tissue.

Definitive Therapy

DefinitionRadiation treatments given with curative intent (NCCN; NCI definition of curative therapy).

Clinical implicationPolicy distinguishes definitive (curative) therapy from palliative indications when defining covered uses of PBT.

Documentation requirementDefinitive therapy indications generally require documentation that photon techniques cannot achieve necessary normal-tissue sparing.

Head and Neck Cancer

DefinitionCancers originating in tissues of the head and neck region (nasal cavity, sinuses, lips, mouth, salivary glands, throat, larynx), typically squamous cell carcinomas.

Common subtypes referencedOropharynx, nasopharynx, paranasal sinus, salivary gland, and mucosal melanoma appear in guideline and evidence summaries.

Coverage nuancePolicy covers primary head and neck cancers when tumors are near critical structures or have intracranial extension/perineural invasion and photon techniques cannot spare normal tissue.

PSRS

Acronym meaningPSRS = Proton beam stereotactic radiosurgery, a high-dose, stereotactic proton technique typically used for cerebral AVMs; often single-fraction.

Typical useEmployed for cerebral arteriovenous malformations where high-precision, high-dose delivery is required to achieve obliteration.

Example dose contextSingle-fraction PSRS series commonly reported prescription doses such as 15 Gy in the large institutional series.

OAR

DefinitionOAR = Organ at risk — critical normal structures (eg, optic nerves, brainstem, cochleae) for which dose sparing is clinically important.

Clinical roleIdentification and dose constraints for OARs drive dosimetric comparisons and are central to prior-authorization rationale for PBT vs photon techniques.

Guideline supportASTRO, NCCN, and ACR/ARS emphasize OAR sparing when considering PBT for high-conformality indications.

PSRS (alternate entry)

PSRS (alternate wording)Proton beam stereotactic radiosurgery — single- or multi-fraction high-precision proton stereotactic treatments used for cerebral arteriovenous malformations.

Clinical outcomesSeries report variable obliteration rates and a risk of posttreatment hemorrhage until obliteration is achieved.

Fractionation examplesBoth single-fraction (eg, 15 Gy) and multi-fraction (eg, 16 Gy in 2 fractions) PSRS approaches are described in the literature.

Hypofractionated PBT

DefinitionHypofractionated PBT = Regimen delivering higher per-fraction proton doses over fewer sessions, often used for liver tumors (HCC/ICC) with dose-escalation intent.

BED relevanceHypofractionated regimens frequently report BED calculations (eg, Parzen et al. reported median BED 80.5 GyE).

Clinical intentUsed to maximize local control with acceptable toxicity in localized, unresectable liver malignancies.

Advanced photon techniques

DefinitionAdvanced photon techniques include IMRT and VMAT, which provide conformal dose delivery and are recommended alternatives to 3D-CRT for many thoracic and mediastinal indications.

Comparative rolePolicy emphasizes dosimetric comparisons between advanced photon techniques and PBT to justify proton use when OAR sparing cannot be achieved with photons.

Guideline citationARS and NCCN guidance recommend IMRT or PBT over 3D-CRT for select thymic and mediastinal malignancies to reduce cardiac and pulmonary dose.

Reirradiation

DefinitionReirradiation = Delivering a second course of radiation to a target previously irradiated, requiring individualized planning considering prior dose, overlap, and time interval.

Evidence contextSystematic reviews report feasible local control but nontrivial late grade 3 toxicity rates (up to 37%) with charged-particle reirradiation in selected series.

Documentation needPolicy requires documentation of prior radiation dose, overlap, and rationale when requesting PBT for reirradiation.

neovascular age-related macular degeneration (AMD)

DefinitionNeovascular age-related macular degeneration (AMD) = subtype of AMD with choroidal neovascularization; RCTs and systematic reviews show uncertain benefit for RT/PBT.

Evidence noteMultiple trials and reviews (including Zambarakji et al.) found no consistent visual benefit and notable radiation-related adverse events.

Policy stanceRadiotherapy for neovascular AMD is not considered a proven beneficial therapy; further research is not prioritized until newer therapies are evaluated in trials.

trimodal bladder-preserving therapy

DefinitionTrimodal bladder-preserving therapy = maximal transurethral resection of bladder tumor followed by chemotherapy and external beam radiation; some series include PBT as boost/component.

Evidence contextRetrospective PBT series (Takaoka et al.) report acceptable short-term outcomes but are limited by heterogeneity and follow-up duration.

Selection factorsTumor size and multiplicity (eg, ≥5 cm) were associated with progression in some series; selection for PBT should be individualized.

Hypofractionated PBT (alternate)

DefinitionHypofractionated PBT (alternate) = PBT delivered with fraction sizes of at least 3 Gy (RBE) per fraction, as defined in early-stage NSCLC hypofractionation studies.

Typical BEDMedian BED reported in pooled early-stage NSCLC studies was 105.6 Gy (RBE).

Clinical noteHigher BED regimens were associated with improved outcomes but with increased late toxicity risk.

PSPT

DefinitionPSPT = Passive scattering proton therapy, a delivery technique contrasted with IMRT in randomized trials for NSCLC.

Trial contextA single-center randomized trial compared PSPT with IMRT with concurrent chemotherapy for inoperable NSCLC, showing evolving outcomes with experience.

Dosimetric findingPSPT exposed less lung tissue to low doses but more lung tissue to ≥20 Gy RBE compared with IMRT in that trial.

PBT / PBRT

DefinitionPBT / PBRT = Proton beam radiation therapy (proton beam radiotherapy): charged-particle external beam radiation using protons to concentrate dose in tumor and spare normal tissue.

Clinical implicationUsed across multiple disease sites where OAR sparing and conformal delivery may reduce late toxicities compared with photons, per dosimetric and some clinical studies.

Evidence caveatFor many adult solid tumors, comparative phase 3 data are limited; policy decisions rely on a mix of trials, systematic reviews, and expert guidance.

Central nervous system tumor (term entry)

TermCentral nervous system tumor — referenced NCI definition in policy references.

SourceNational Cancer Institute dictionary cited in references for term definitions.

UsageUsed throughout policy to categorize CNS indications for PBT coverage considerations.

Curative therapy (term entry)

TermCurative therapy — NCI definition referenced in policy references.

Policy relevanceDistinguishes definitive (curative) indications for which PBT may be proven/medically necessary from palliative uses.

DocumentationCurative-intent treatments require justification and, when applicable, demonstration that photon techniques cannot meet OAR constraints.

Proton beam therapy delivers radiation using charged particles that produce a more confined dose distribution compared with photons, enabling potential sparing of adjacent organs at risk. The policy bases coverage distinctions on the strength of clinical evidence and guideline recommendations: PBT is covered for specified indications where comparative or guideline‑supported benefits are established or where photon techniques cannot meet dose constraints; for many other adult indications, evidence of clinical superiority is limited or lacking.

Breast cancer (adjuvant/postmastectomy/partial): Systematic reviews suggest PBT may reduce cardiac and some toxicities and provide favorable dosimetry, especially for regional nodal irradiation; evidence is low quality with no RCTs directly comparing PBT to photon RT.mean heart dose ≤ 1 Gy cited as potential PBT advantage

Higher-quality RCTs with longer follow-up required.

Esophageal cancer: Meta-analyses indicate PBT reduces OAR doses and certain toxicities and may improve some survival endpoints versus photon therapy, but evidence is heterogeneous and mostly retrospective; prospective RCTs are needed.

Caution warranted; further RCTs recommended.

inv-13: Coverage-relevant evidence summaries

Summary of coverage-relevant clinical evidence and guideline positions from the extracted sections

NSCLC evidence: Single-center retrospective series reported higher delivered doses with PBT and lower rates of severe pneumonitis and esophagitis compared with historical photon cohorts, but follow-up was short and no phase 3 trials were available at time of review.

Supports potential toxicity benefit but limited by study design and follow-up.

Systematic review conclusion for lung: Systematic reviews found encouraging local control and survival ranges for PBT in mainly stage I NSCLC but no phase 3 trials; concluded charged particle therapy should be considered experimental until stronger data are available.

Evidence gap: no phase 3 RCTs at time of review.

Vestibular schwannoma evidence: Meta-analysis reported high tumor control (~95%) with PBRT but low hearing preservation (~40.6%) and no clear advantage in functional outcomes compared with standard radiosurgery techniques.

High tumor control but functional outcomes not superior.

Pancreatic cancer evidence: Robust clinical evidence is lacking for PBT in pancreatic cancer; larger prospective studies are warranted.

Insufficient evidence to establish routine effectiveness.

inv-12: Evidence and uncertainty

Evidence synthesis signals

Dosimetric benefit: Multiple systematic reviews and studies report consistent dosimetric advantages of PBT (reduced OAR dose) across several tumor sites, which informs coverage decisions when photon techniques cannot meet constraints.

Documented in multiple evidence syntheses.

Evidence quality and uncertainty: Clinical outcome data are heterogeneous and generally limited in quality, with retrospective series and small prospective cohorts predominating; randomized data are limited or ongoing, affecting certainty of comparative effectiveness.

Low-to-very-low quality evidence for many GI and thoracic indications.

Implication for coverage: Because of these evidence limitations, coverage decisions emphasize documented dosimetric or clinical advantage over advanced photon techniques, multidisciplinary review, and, when applicable, enrollment in clinical trials.

Policy requires plan comparisons and supporting documentation for exceptions and non-listed indications.

Because the policy lists proven indications explicitly, the absence of a diagnosis from that list implies it is not considered a proven indication. Exceptions to this rule require that providers submit a comparative dosimetric evaluation showing that photon-based techniques (eg, IMRT/VMAT or SBRT) cannot adequately spare normal tissues and that PBT is expected to provide a clinically meaningful advantage for the individual case.