Defining the Supply of Radiation Oncologists in the United States: An American Society for Radiation Oncology Workforce Report.

An accurate accounting of the current number of practicing radiation oncologists (ROs) is critical to the complete understanding of the workforce dynamics of the field. At present, there is no clear standard on how to assess this, with multiple approaches available. Therefore, the American Society for Radiation Oncology (ASTRO) Workforce Committee reviewed and evaluated multiple approaches in assessing the radiation oncology (RO) workforce supply, including the pros and cons of each approach, while comparing supply estimates in order to define a recommended standard for assessing the RO workforce supply in the United States. Most methods use data from the Centers for Medicare & Medicaid Services (CMS), the American Medical Association, and/or the American Association of Medical Colleges. The ASTRO-sponsored Health Management Associates Workforce Analysis and the American Society of Clinical Oncology (ASCO) approach used multiple data sources, with the ASCO approach including the American Medical Association and CMS data sources. Limitations of each approach are reflective of the data sources used and include an inability to capture all physicians, a lack of routine updating, and/or a lag-time in incorporating entrants to and exits from the workforce. Overall, the assessments across methods demonstrated substantial consistency in results (range of maximum difference, 2.2%-5.0%; mean, 3.0%), with unfiltered data sets consistently reporting higher estimates, likely due to inclusion of ROs not actively practicing. For example, in 2023, filtered estimates ranged from 4935 (ASCO) to 5072 (American Association of Medical Colleges), whereas in 2024, the estimates ranged from 4992 (ASCO) to 5103 (CMS) ROs. Using the ASCO model, we estimate a total of 5100 ROs in 2024, accounting for Veterans Affairs and pediatric-only ROs, understanding this may not account for nonclinical ROs. Additionally, these methods capture "head counts" of the number of ROs, but not their clinical capacity. After reviewing the various approaches, the ASTRO Workforce Committee recommends applying a similar methodology to that in use by ASCO for RO workforce supply assessments. This would allow subsequent workforce models to be compared with a consistent methodology to prevent erroneous conclusions when comparing across methodologies.