Relation between Hypofractionated Radiotherapy, Toxicity and Outcome in Early Breast Cancer.

To compare adjuvant conventional radiotherapy (C-RT) to hypofractionated schedule (HF-RT) in early breast cancer. Between May 2012 and September 2015, 120 patients were included in the analysis. All patients underwent conservative surgery and adjuvant RT. RT was delivered in C-RT (50 Gy; 2 Gy/fr) or HF-RT (42.5 Gy; 2.66 Gy/fr), followed by a tumor bed boost (10 Gy; 2 Gy/fr). RT-induced toxicity was recorded and compared between groups. Toxicity results were graded according to the Common Terminology Criteria for Adverse Events guidelines. A multivariate analysis was performed of the factors associated with acute toxicity onset. Mild acute skin toxicity was observed in 71.7% of patients. No grade 4 toxicity was observed. From the multivariate analysis, Breast volume and RT fractionation significantly affected acute radiation-related toxicity. No increase in late toxic effects has been reported between C-RT and HF-RT schedules. Overall, the 2-year disease free survival was 94.4%. HF-RT represents a valid adjuvant treatment option in early breast cancer patients, without negative impact on acute and late radiation sequelae, as well as tumor control.