3714 - The Active U.S. Radiation Oncology Workforce: A Medicare Billing-Based Analysis, 2013-2023

Purpose/Objective(s):

An accurate understanding of the size of the active radiation oncology (RO) workforce is essential for policymakers, who collectively help determine the sizes of incoming RO residency classes. Prior studies have relied largely on surveys, job postings, or training pipeline data, which may not fully reflect the number of active clinicians. Thus, we sought to characterize the size and longitudinal trends of the active U.S. RO workforce using Medicare billing data.

Materials/Methods:

We analyzed Medicare Provider Utilization and Payment data from 2013-2023, which is publicly available via the Centers for Medicare & Medicaid Services (CMS). ROs were identified using CMS rendering provider type and National Provider Identifiers (NPIs) and were tracked longitudinally across years. Manual verification was performed to address specialty misclassification and non-RO billing of radiation-related codes with the use of RO-specific Healthcare Common Procedure Coding System (HCPCS) codes (including treatment management, simulation/localization, treatment planning/dosimetry, device construction, treatment delivery (including IMRT and proton therapy), and brachytherapy-related procedures). Of note, physicians practicing exclusively in settings that do not bill Medicare, including those working within the VA system, military-based institutions, or pediatric-only practices, were not captured in this analysis.

Results:

Between 2013 and 2023, 6,204 unique individuals listed as ROs submitted at least one Medicare claim. Among these, 6,180 billed RO-specific HCPCS codes and were therefore classified as actively practicing ROs. Annual counts of active ROs increased gradually over the study period, rising from 4,124 in 2013 to 4,771 in 2023. Manual curation further identified 222 providers misclassified as ROs based on CMS specialty designation, as well as 3,234 non-ROs who billed RO-specific codes. A small subset of ROs (ranging from 49 to 67 providers annually) submitted Medicare claims without billing RO-specific codes, likely reflecting consult-only, administrative, or semi-retired roles. This verification process revealed two primary sources of dataset bias: (1) true ROs lacking RO-specific billing, most commonly associated with semi-retired physicians or consult-dominant practices, and (2) non-ROs billing RO-associated codes, including heterogeneous specialties and organizational NPIs, suggesting billing attribution artifacts.

Conclusion:

Using Medicare billing activity as a proxy for clinical practice, the U.S. radiation oncology workforce demonstrated gradual growth and overall stability from 2013-2023. Billing-based workforce surveillance, when paired with manual curation, provides a more accurate approach to traditional workforce assessments and may inform evidence-based discussions regarding residency training capacity and workforce planning.