PurposeTo determine the prevalence of attrition and the frequency of transition from a primarily clinical role to an industry-related role among oncology physicians.MethodsWe tracked yearly Centers for Medicare & Medicaid Services (CMS) billing between 2015 and 2022 to estimate attrition of oncology physicians. A subanalysis of a random sample of 300 oncologists with fewer than 30 years of experience and who had stopped billing were used to conduct a more thorough assessment of current employment. Employment was primarily found through LinkedIn; otherwise a secondary search was done through a Google search. Type of employer was categorized as industry (pharmaceutical or biotechnology), nonindustry (academic/clinical/government), others, or no information found. The results are provided separately by sex.ResultsOf the 16,870 oncologists who billed to CMS in 2015, 3,558 (21%) had stopped billing by 2022. Among a randomly selected 300 oncologists, we found current employment information for 223 (74%); 78 of the 223 (35%) were most recently employed within industry. Among all CMS-billing oncologists, 30% (5,126 of 16,870) identified as female. Women stopped billing at the rate of 18% (929 of 5,126) by 2022. Surgical oncologists had the lowest overall attrition (17%, 149 of 855). Radiation oncologists had 21% (881 of 4,244) overall attrition and 7% (5 of 71) sampled attrition to industry.ConclusionBy 2022, 21% of oncology physicians billing to CMS in 2015 had stopped. 78 of the 300 sampled physicians were found to be working in industry. In total, 1 in 17 oncologists (5%) moved to industry over a 5-year period.