Adoption of hypofractionated radiation therapy for early breast cancer in private practice: the GenesisCare experience 2014-2106.

Introduction Cancer Australia guidelines recommend that hypofractionation should be considered for women over the age of 50 years with early breast cancer. GenesisCare is the largest provider of radiation therapy services in Australia. This study aimed to investigate variation in hypofractionation across 4 states encompassing the period when the most recent guidelines had been released. Methods Patients with T1 N0 and T2 N0 breast cancer who received radiation therapy as adjuvant therapy after breast conservation surgery between 2014 and 2016 were reviewed. Patient, treatment and disease-related variables were included in the univariate and multivariate models together with other potential explanatory variables such as the state, in which the patient was treated, radiation oncologist and distance from the treatment centre. Results Of 3374 patients included, 44% received a hypofractionated schedule. There was an increase in the use of hypofractionation from 32% in 2014 to 56% in 2016. Older patients were more likely to receive a hypofractionated treatment schedule - 75% for patients 80 years and over. Multivariate modelling revealed older age, year of treatment, higher T stage and grade, chemotherapy and the individual radiation oncologist (and state) as independent predictors of the use of hypofractionation. There was no difference in hypofractionation based on laterality. Conclusions Guidelines from Cancer Australia may impact clinician behaviour. The influence of the individual radiation oncologist remains paramount, and their practice is affected by their immediate colleagues. Subsequent analysis of hypofractionation rates after presentation of these data has resulted in a significant increase in its use.