The long-term outcome of adjuvant hypofractionated radiotherapy and conventional fractionated radiotherapy after breast-conserving surgery for early breast cancer: a prospective analysis of 107 cases

Background: This study aimed to evaluate the long-term outcomes of hypofractionated and conventional fractionated radiotherapy after breast-conserving surgery in patients with early-stage breast cancer. In addition, cosmetic and delayed toxic effects in the breast were also investigated. Methods: A total of 107 female patients were recruited and randomly classified into the hypofractionated radiotherapy (HF) group (53 participants) and the conventional fractioned radiotherapy (CF) group (54 participants). The HF group was subjected to the following treatments: whole-breast irradiation (+/- irradiation of the infra-supraclavicular region) at 42.56 Gy/16 fractions + tumor bed boost at 7.98 Gy/3 fractions. The CF group received the following treatments: whole-breast irradiation (+/- irradiation of the infra-supraclavicular region) at 50 Gy/25 fractions + tumor bed boost at 10 Gy/5 fractions. Results: The 10-year local recurrence (LR) rate, tumor-specific survival rate, disease-free survival rate, and overall survival rate of the HF and CF groups were 9.6% vs. 7.9% (P=0.712); 88.1% vs. 90.1% (P=0.738); 81.1% vs. 82.9% (P=0.792); and 86.5% vs. 88.5% (P=0.748), respectively. The 10-year rates of patients with good or excellent cosmetic results in the HF and CF groups were 72.7% vs. 67.4% (P=0.581), respectively. The 10-year rates of patients with delayed toxicity-free effects in the skin and the rates of patients with toxicity-free subcutaneous tissues in the HF and CF groups were 70.5% vs. 65.2% (P=0.595) and 52.3% vs. 47.8% (P=0.673), respectively. Conclusions: Hypofractionated and CF showed comparable long-term efficacy, cosmetic effects, and delayed toxic effects. Hence, HF may be used as an alternative to conventional fractionated radiotherapy.