Abstract
PURPOSE/OBJECTIVE(S): Adjuvant radiation therapy (RT) is an effective treatment in the management of patients with breast cancer. Evidence supports both standard fractionation and, more recently, moderate hypofractionation and ultra hypofractionation leading to a potential diversity of clinical practice. Whether or not physicians at main academic centers adopt hypofractionated regimens more readily than those working at community centers is not known. Practice patterns were analyzed within our large healthcare network comprising one main and eight community sites before and after 2020. MATERIALS/METHODS: Patients treated with adjuvant breast RT between 2017 and 2022 in our radiation oncology department were identified. Treatment techniques were evaluated: standard fractionation (25-28 fractions to 50-50.4 Gy), moderate hypofractionation (15-16 fractions to 40.05-42.56 Gy), and ultra hypofractionation (5 fractions of 26-30 Gy) for intact breast, partial breast, and chest wall cases. Use of each technique was compared between the main academic center (Main) versus eight community sites (Community) in two time periods, 2017-2019 and 2020-2022. Differences were assessed using z-ratios for the difference between independent proportions. RESULTS: There was a statistically significant decrease in the use of standard fractionation for intact breast and chest wall cases from the early to the late period at both the community sites and the main center; however, a higher proportion of patients were treated with standard fractionation at the community sites versus the main center in the late period (7.8% community versus 2.0% main, p < 0.01 for intact breast and 80.7% community versus 37.4% main, p < 0.01 for chest wall). There was a statistically significant increase in the use of hypofractionation for intact breast and chest wall cases from the early to the late period at both the community sites and the main center; however, a higher proportion of patients were treated with hypofractionation at the main center versus the community sites during the late period (92.2% community versus 98.0% main, p < 0.01 for intact breast and 19.3% community versus 62.6% main, p < 0.01). CONCLUSIONS: The present study shows that recent trial evidence supporting the use of shorter RT treatments changed practice among providers more rapidly at our main academic center versus our community sites. The reasons for this difference are not known; however, standardization of treatment by implementation of an adjuvant RT treatment algorithm may facilitate uniform care among patients with breast cancer and we are investigating the impact of this approach.