Provider-Level Variation in Treatment Planning of Radiation Oncology Procedures in the United States.

PURPOSE: Variation in the use of radiation oncology procedures and technologies is poorly characterized. We sought to identify associations between the treatment planning codes used to bill for radiotherapy procedures and the demographic characteristics of the radiation oncologists submitting them. METHODS: The Physician and Other Supplier Public Use File was linked to the Physician Compare database by using the physician National Provider Identifier for the year 2016. Analysis was stratified by practice setting, considering both the freestanding non-facility-based (NFB) setting and the facility-based (FB) setting. Multivariable logistic regression was used to determine provider characteristics (gender, practice rurality, and years since graduation) that predicted for the use of 3D-conformal RT (3DCRT) planning, intensity-modulated RT (IMRT) planning, and brachytherapy planning in the Medicare population. RESULTS: Three thousand twenty-nine physicians were linked for analysis. In both the FB and NFB settings together, male gender predicted for decreased likelihood of 3DCRT planning (OR, 0.70, 95% CI, 0.62 to 0.80, P < .001) and increased likelihood of IMRT planning (OR, 1.35, 95% CI, 1.19 to 1.54, P < .001). Brachytherapy planning was also more likely with increasing years since medical school graduation (OR, 1.03, 95% CI, 1.01 to 1.04, P < .001) in the combined FB and NFB settings. These significant associations persisted when examining the NFB and FB settings individually. In both settings overall, brachytherapy planning was more likely in male providers (OR, 1.75, 95% CI, 1.10 to 2.76, P = .02) and also more likely for providers practicing in metropolitan regions compared with those practicing in rural areas (OR, 3.01, 95% CI, 1.23 to 7.39, P = .02). CONCLUSION: Male gender predicts for utilization of IMRT planning, whereas female gender predicts for utilization of 3DCRT planning. Future research is warranted to better understand the role that provider gender and rurality play in the selection of radiation planning techniques for Medicare patients.