Comparison of Local Medicare Guidance and Medicare Advantage Plans for Stereotactic Radiosurgery for Brain Metastases

Abstract

Purpose

Medicare Advantage operates under a capitated payment model, where Medicare Advantage Organizations (MAOs) must provide services that meet or exceed Medicare Parts A and B standards, ensuring actuarial equivalence. MAOs are mandated to base their coverage determinations on medical necessity, aligning with Medicare's national and local coverage determinations (LCD) policies.

Methods and Materials

This study evaluates coverage policies for stereotactic radiosurgery (SRS) for brain metastases (BM) across our institution's local LCD and various MAOs, including Cigna, Aetna, UnitedHealthcare, Humana, and Anthem. The CMS LCD L39553 (CMS) serves as the benchmark, deeming SRS medically necessary for new BM and repeat BM therapy if the patient has each of the following: good performance status (Karnofsky Performance Status ≥70 or Eastern Cooperative Oncology Group Performance Status 0-2), absence of leptomeningeal metastases, and no primary diagnosis of lymphoma, germ cell tumor, or small cell carcinoma. For repeat BM, CMS also requires stable extracranial disease and a life expectancy over 6 months. Additionally, SRS may be indicated for relapses in previously irradiated cranial fields to minimize normal tissue injury. Five MAO policies were reviewed, revealing alignment with LCD criteria in several areas but also presenting additional, sometimes more restrictive, requirements.

Results

For new BM, all MAOs required good performance status, with most also considering histology and absence of leptomeningeal metastases. Some MAOs introduced criteria like systemic therapy options, lesion number/volume, and BM size. For repeat BM, most MAOs required stable extracranial disease and occasionally considered life expectancy. Additional criteria included the number of BM over a year and postoperative SRS guidelines for lesion size and number.

Conclusions

Despite general concordance, the added criteria by MAOs could impose more stringent requirements than CMS, potentially resulting in coverage denials. It is important that MAO policies remain consistent with evidence-based guidelines to avoid disparities that could impact patient treatments.

Introduction

Medicare Advantage Organizations (MAOs) receive capitated payments from the Centers for Medicare & Medicaid Services (CMS) to provide Medicare Parts A and B benefits under the Medicare Advantage framework, with the requirement that coverage be equivalent to or exceed original Medicare benefits.^1,2 By regulation, MAOs must not employ more restrictive determinations of medical necessity than those established by national and local coverage determinations (NCDs/LCDs).^1,2 In 2024, 32.8 million people (54% of the eligible Medicare population) were enrolled in Medicare Advantage plans, accounting for $462 billion (54%) of Medicare spending.³ Given the impact of Medicare spending on the United States population, evaluation of existing coverage requirements and potential disparities is warranted.

Stereotactic radiosurgery (SRS) is a targeted, high-dose radiation therapy technique widely employed to treat brain metastases (BM), which occur in 10% to 30% of adults with cancer.⁴ Multispecialty guidelines recognize SRS alone or in combination with other modalities as a viable treatment option for BM in many circumstances and the preferred approach for some patients, due to both efficacy and preservation of neurocognition.⁴ Currently, no NCD exists for SRS. For our institution, the local CMS LCD L39553 provides coverage guidelines that MAOs are expected to follow or surpass when approving SRS for BM.⁵ However, it is not uncommon for MAOs to adopt additional criteria often based on factors such as lesion number, lesion size, performance status, histology, extracranial disease burden, and life expectancy, potentially resulting in coverage policies that are more restrictive than the original LCD.6, 7, 8, 9, 10

This analysis compares the CMS LCD L39553 with the publicly available SRS coverage policies of 5 major Medicare Advantage insurers including Aetna, Cigna, UnitedHealthcare (UHC), Humana, and Anthem Blue Cross Blue Shield, to highlight discrepancies that may affect patient access to SRS. By delineating these similarities and differences, we aim to clarify potential risks of coverage denials for patients who might otherwise qualify under CMS guidelines.6, 7, 8, 9, 10

Methods and Materials

Data collection

We identified and analyzed CMS LCD L39553 for BM management via SRS and compared it with policies from major Medicare Advantage providers. Policies from local MAOs were gathered, including Aetna's eviCore, UHC's Medicare Advantage policy, Humana's guidelines, Anthem Blue Cross Blue Shield's policy, and Cigna's eviCore guidelines.6, 7, 8, 9, 10 This study covers SRS criteria for both new and repeat BM therapy and includes specific factors such as patient performance status, lesion count, systemic therapy options, leptomeningeal disease (LMD) status, extracranial disease status, life expectancy, and histological categorization.

Comparative analysis

CMS LCD L39553 permits SRS coverage for patients with new BM if they have a good performance status (Karnofsky Performance Status [KPS] ≥ 70 or Eastern Cooperative Oncology Group Performance Status [ECOG], 0-2), do not have LMD, and do not have a primary diagnosis of lymphoma, germ cell tumor, or small cell carcinoma.⁵ For new BM, CMS LCD L39553 does not restrict the usage of SRS based on the number of BM, life expectancy, size of lesions, or extracranial disease status.⁵ For repeat BM therapy, criteria extend to the stability of extracranial disease for more than 2 months and a life expectancy threshold of >6 months.⁵ For repeat BM therapy, CMS LCD L39553 does not restrict the usage of SRS based on the number of developing lesions in 12 months.⁵

LCD L39553 also outlines general circumstances under which SRS is not considered reasonable and necessary; for instance, when no functional improvement is expected, the patient's performance status is very poor (KPS <40 or ECOG >3), or life expectancy is limited by widespread disease.⁵ These overarching limitations form the baseline medical necessity criteria under Medicare, beyond the specific BM indications described above. Coverage determinations from the MAOs were compared against this baseline, focusing on any additional or modified criteria.

Results

The coverage criteria for new and repeat BM, and repeat BM only, for each of the 5 MAO policies is detailed in Table 1, Table 2, respectively. For new BM, every MAO agrees that patients should have a good performance status (KPS ≥70 or ECOG 0-2) and, in most cases, no leptomeningeal metastases (LMD). Four of the 5 MAOs (Aetna, Cigna, UHC, Humana) also exclude certain histologies, such as lymphoma, germ cell tumors, and small cell carcinoma, closely paralleling the CMS LCD.6, 7, 8^,10 Anthem is the only policy that does not explicitly mention histology exclusions for new BM.⁹

Table 1.

New and repeat brain metastasis treatment criteria

	New and repeat brain metastasis treatment
Policy	Lesion	Performance status	Histology	Leptomeningeal disease	Number/volume of lesions	Extracranial disease status
Medicare LCD L39553	Primary/secondary of brain, meninges, or adjacent bones.	KPS ≥ 70, ECOG 0-2	No lymphoma, GCT, SCLC	No	Unspecified	Unspecified
UnitedHealthcare	Primary/secondary of brain, meninges, or adjacent bones	KPS ≥ 70, ECOG 0-2	No lymphoma, GCT, SCLC	No	≤ 10 lesions / 15 cc	Unspecified
Anthem, Blue Cross	Brain metastases	KPS ≥ 70, ECOG 0-2	Unspecified	Unspecified	Unspecified	Newly diagnosed, stable disease, have reasonable systemic options
Cigna	Brain metastases	KPS ≥ 70, ECOG 0-2	No lymphoma, GCT, SCLC	No	≤ 10 lesions	Good control or systemic options
Aetna	Brain metastases	KPS ≥ 70, ECOG 0-2	No lymphoma, GCT, SCLC	No	≤ 10 lesions	Good control or systemic options
Humana	Referred to Medicare guidelines, < 5 cm, extracranial disease stable or remission

Abbreviations: ECOG = Eastern Cooperative Oncology Group; GCT = germ cell tumor; KPS = Karnofsky Performance Status; SCLC = small cell lung cancer.

Summarizes coverage requirements across Medicare LCD L39553 and 5 Medicare Advantage Organizations for initial treatment of brain metastases. Key parameters include lesion type, performance status, histology, presence of leptomeningeal disease, lesion number/volume, and extracranial disease status.

Table 2.

Repeat brain metastasis treatment criteria

	Repeat brain metastasis treatment only
Policy	Extracranial disease	Life expectancy	Number/volume of lesions in 12 mo
Medicare LCD L39553	Stable > 2 mo	> 6 mo	Unspecified
UnitedHealthcare	Stable > 2 mo	> 6 mo	≤ 13 over 12 mo
Anthem, Blue Cross	Unspecified	Unspecified	Unspecified
Cigna	Unspecified	Unspecified	≤ 15 over 12 mo
Aetna	Unspecified	Unspecified	≤ 15 over 12 mo
Humana	Unspecified	Unspecified	Unspecified

Focuses on coverage requirements for repeat stereotactic radiosurgery of brain metastases among Medicare Advantage Organizations, including extracranial disease stability, life expectancy, and limits on lesion number/volume within a specified time frame.

Notably, 4 MAOs (Aetna, Cigna, UnitedHealthcare, Anthem) either explicitly require stable extracranial disease or cite reasonable systemic therapy options for new BM, despite no such requirement appearing in CMS LCD L39553.^6,8, 9, 10 Three of the 5 MAOs (UHC, Cigna, Aetna) impose numerical limits on the number or total volume of lesions, with upper thresholds ranging from ≤10 to ≤15 lesions for either new or repeat BM.^6,8,10 Humana includes an additional size criterion by referencing “less than 5 cm,” and UHC requires lesions to be less than 15 cc.⁷ These number of lesions, total volume of lesions, and size criterion limits are absent from the CMS LCD.

Criteria for repeat BM therapy likewise reveal both alignment and divergence. Most MAOs incorporate stable extracranial disease, reflecting CMS LCD requirements that call for stability beyond 2 months; however, only 1 MAO policy (UHC) echoes the life expectancy stipulation of >6 months.⁶ Limitations on the number of treated lesions within 12 months appear in 3 MAO policies but not in CMS LCD L39553, potentially impacting patients with multiple sequential relapses.^6,8,10 Two MAOs introduce specific rules for postoperative SRS, limiting both the number (up to 4) and size (<5 cm) of resected or unresected lesions, thereby excluding certain scenarios otherwise covered by CMS LCD guidelines.^6,8 Collectively, these additional constraints, particularly those related to systemic therapy, lesion count/volume, and lesion size, illustrate instances where MAO policies may introduce additional requirements beyond those specified by the CMS LCD L39553.

Discussion

This comparative analysis highlights that although Medicare Advantage plans generally follow the fundamental criteria of our local CMS LCD, the more restrictive requirements introduced by certain MAOs have practical consequences for patient access to SRS.⁵ In particular, stipulations regarding the acceptability of systemic therapy options, mandatory stability of extracranial disease for new BM, and specified lesion number or size caps do not appear in the underlying CMS LCD L39553.⁵ By inserting these additional hurdles, MAOs may deny coverage to individuals who satisfy all of the CMS requirements yet fail to meet the extra conditions set forth by a particular plan. Furthermore, the more restrictive policies implemented by MAOs necessitate rigorous prior authorization processes, which can lead to delays in treatment initiation and increased administrative burdens for health care providers, ultimately impacting timely access to SRS for eligible patients.

Clinical literature supports the role of SRS in achieving local tumor control, particularly in patients with limited intracranial disease burden who maintain a good performance status.⁴ Although lesion-number limitations exist in some retrospective studies, they are far from uniform and rarely absolute. Innovative techniques and evolving evidence also indicate that controlling multiple small metastases may confer survival or quality-of-life benefits under select circumstances, which implies that strict numerical thresholds could be overly restrictive.⁵

Similarly, insisting on strong systemic therapy options or stable extracranial disease in new BM may oversimplify the complex clinical decisions that radiation oncologists and neuro-oncologists face. One particularly noteworthy area is the treatment of small cell lung cancer (SCLC). Although CMS LCD L39553 excludes small cell carcinoma from SRS coverage, emerging evidence suggests that select patients with SCLC may benefit from upfront radiosurgery.⁴ A recent analysis (the FIRE-SCLC Cohort Study) comparing first-line SRS with whole-brain radiation therapy for SCLC BM indicates that SRS may confer favorable local control and neurocognitive outcomes in carefully chosen patients.¹¹ Additionally, Aizer et al¹² demonstrated in a multi-institutional prospective phase 2 trial indicating that SRS for SCLC BM yields reduced neurologic morbidity of 11% after SRS compared with the historically provided rate after whole-brain radiation therapy of 17.5%. These findings highlight the evolving landscape of SRS applications across various histology, underscoring the need for coverage policies to adapt as new, high-quality data emerge.

The policy discrepancies described in this report highlight the complexity in applying the “no more restrictive” stipulation in Title 42 CFR § 422.101, which seeks to ensure that Medicare Advantage plans do not curtail coverage below what is offered by CMS.^1,2,5 By statute, Medicare Advantage plans are not allowed to impose more restrictive criteria than Medicare when coverage requirements are fully defined^1,2; however, if Medicare's coverage criteria are not fully established, MAOs may develop internal coverage guidelines (42 CFR § 422.101(b)(6)). In the case of SRS for BM, the LCD's lack of specific limits on certain factors (such as the number of lesions) has prompted some MA plans to add their own requirements. Nonetheless, if these plan-specific rules effectively deny SRS to patients who meet all CMS LCD conditions, it raises concerns that the principle of actuarial equivalence could be undermined. Ongoing dialogue among professional societies, regulatory bodies, and third-party payers is essential to reconcile evidence-based guidelines for SRS with coverage policies that can meaningfully affect patient outcomes and resource allocation.

In addition to policy implications, our findings provide practical guidance for clinicians. To reduce the risk of SRS coverage denials under Medicare Advantage plans, physicians should familiarize themselves with each MAO's specific SRS criteria and ensure that documentation for prior authorization explicitly addresses those requirements. Key considerations include confirming the patient's performance status meets the threshold, noting the number and size of lesions (and that they fall within any plan limits), documenting stability of extracranial disease, and estimating life expectancy when relevant. If a prior authorization is denied, a proactive approach is warranted. Providers can request clarification of the denial rationale and engage in a peer-to-peer discussion with the plan's medical director to review the case. Should a formal appeal be needed, the appeal letter ought to emphasize that the patient satisfies the local LCD criteria and the plan's criteria, supported by clinical evidence or guidelines. Notably, a high proportion of initial Medicare Advantage denials are overturned on appeal, nearly 75% between 2014 and 2016, so persistence in following the appeals process can often secure approval for medically necessary SRS.¹³ By anticipating common denial reasons and preparing comprehensive justifications, clinicians may avoid delays and improve the likelihood of approval for appropriate SRS treatments.

Conclusions

In summary, although local Medicare LCD L39553 and the evaluated Medicare Advantage policies align with foundational coverage elements for SRS in BM, important gaps remain. The introduction of specific lesion-number thresholds, lesion-size caps, stricter requirements for extracranial disease control, and mandatory systemic therapy options in several MAO policies exceeds the coverage requirements stipulated by CMS. These additional conditions risk excluding a subset of patients who would otherwise meet LCD-based criteria for medically necessary SRS. Greater oversight and collaboration among CMS, MAOs, and clinical stakeholders may be necessary to ensure that Medicare Advantage coverage remains aligned with best clinical practices and the requirement of equivalence to original Medicare. Concerted efforts from CMS to monitor policy adherence, along with advocacy by clinicians and professional groups, are warranted to ensure that Medicare Advantage remains consistent with both best clinical practices and the mandated principle of offering coverage at least as comprehensive as that afforded by original Medicare. By refining these policies to align more closely with evolving clinical evidence, MAOs can reduce barriers to optimal care for patients with BM.

Disclosures

All disclosures are complete and the authors have nothing to disclose.