PURPOSE: Radiation oncologists are known to be burdened with prior authorization and insurance denials more than other medical specialties. This analysis sought to use publicly available data and determine whether Medicare Advantage plans are inappropriately denying radiation therapy (RT) services more than other health services. METHODS AND MATERIALS: Data from the Appeals Decision Search on the Centers for Medicare & Medicaid Services website were extracted from 2022 through June 2024. The data contain appeal decisions from a third-party independent review entity, which uses Medicare coverage guidelines to determine the appropriateness of a denial. Percentages of inappropriate denials were calculated for RT services and all health services. A chi-square test was used to compare inappropriate denial levels between RT and everything else. Decisions were also filtered by "keyword" and "condition" to analyze trends in treatment modalities and diagnosis, respectively. RESULTS: RT services were inappropriately denied in 15.04%, 18.69%, and 16.01% of cases for 2022, 2023, and 2024, respectively, while inappropriate denials for all health services were only 4.69%, 5.28%, and 3.44%, respectively. Overall, since 2022, 274 out of 1576 RT appeals were inappropriately denied (17.39%), while only 20,195 out of 433,788 total appeals were inappropriately denied for all health services (4.66%). The difference was statistically significant for all 3 years and for the entire time period, with all P values <
.00001. Using keywords brachytherapy, stereotactic body radiation therapy, proton, and intensity-modulated RT, inappropriate denial rates varied at 12.75%, 26.11%, 13.02%, and 41.06%, respectively, from 2022 to 2024. Prostate cancer appeals for protons had particularly low rates of inappropriate denial at 3.45%, while breast cancer appeals for intensity-modulated RT had particularly high rates of inappropriate denial at 82.14%. CONCLUSIONS: Medicare Advantage plans are inappropriately denying RT services more than non-RT services. These data warrant urgent policy changes to prevent Medicare-eligible patients from being inappropriately denied access to cancer treatments.