United States Radiation Oncology Fellowship Growth From 2010 to 2020.

Purpose To provide a comprehensive analysis of radiation oncology (RO) fellowship growth from 2010 to 2020. Methods and Materials A collated database of RO fellowship programs and matriculants was created using (1) RO residency program (n = 92) and graduate (n = 2082) web searches, (2) prospective American Society for Radiation Oncology (ASTRO) Career Center postings database, (3) Association of Residents in Radiation Oncology Fellowship Directory, (4) RO fellowship survey data, (5) ASTRO Membership Directory, and (6) direct e-mail contact with fellowship program directors. Linear regression was used to assess the statistical significance of RO fellowship program, position, and matriculant growth over time. Results From 2010 to 2020, the number of RO fellowship programs and annual positions significantly increased from 20 to 37 (1.60 increase per year; 95% confidence interval, 1.32-1.89; P 12) residency programs, respectively. Twenty-eight (29.8%), 13 (13.8%), 25 (26.6%), and 27 (28.7%) trained in the Northeast, Midwest, South, and West, respectively. Conclusions There has been significant growth in unaccredited RO fellowship programs and annual positions during the past decade, although the number of matriculants has remained stable. We report for the first time the recent establishment of fellowships at institutions without an Accreditation Council for Graduate Medical Education–accredited RO residency program. The impact of fellowship programs on the training of RO residents should be studied.