The impact of radiation oncologist on the early adoption of hypofractionated radiotherapy for early-stage breast cancer

Abstract Purpose Despite multiple randomized trials showing efficacy of hypofractionated radiotherapy in early-stage breast cancer, the US has been slow to adopt this treatment. The goal of this study was to evaluate the impact of individual radiation oncologists on the early adoption of hypofractionated radiotherapy for early-stage breast cancer. Methods We identified 22,233 Medicare beneficiaries with localized breast cancer diagnosed from 2004-2011 who underwent breast-conserving surgery with adjuvant radiation. Multi-level, multivariable logistic models clustered by radiation oncologist and geographic practice area were used to determine the impact of the provider and geographic region on the likelihood of receiving hypofractionated compared to standard fractionated radiotherapy while controlling for a patient’s clinical and demographic covariates. Odds ratios (OR) describe the impact of demographic or clinical covariates, and the median odds ratio (MOR) describes the relative impact of the individual radiation oncologist and geographic region on the likelihood of undergoing hypofractionated radiotherapy. Results Among the entire cohort, 2,333 women (10.4%) were treated with hypofractionated radiotherapy with unadjusted rates ranging from 0.0% in the bottom quintile of radiation oncologists to 30.4% in the top quintile. Multivariable analysis found that the individual radiation oncologist (MOR 3.08) had a greater impact on the usage of hypofractionation than geographic region (MOR 2.10) or clinical and demographic variables. The impact of the provider increased from 2004-2005 (MOR 2.82) to 2010-2011 (MOR 3.16) despite the publication of long-term randomized trial results in early 2010. Male physician and radiation oncologists treating the highest volume of breast cancer patients were less likely to perform hypofractionation (p