A comparative study of daily 3-Gy hypofractionated and 1.8-Gy conventional breast irradiation in early-stage breast cancer

Abstract

We retrospectively compared accelerated hypofractionation (AHF) with conventional fractionation (CF) in the radiation therapy (RT) for early-stage breast cancer patients.Three hundred seventy-nine early-stage (pT1-2 and pN0-1a) breast cancer patients who received RT with AHF after breast-conserving surgery (BCS) were included. These patients were matched with 379 corresponding patients who received BCS and RT with CF at a different center with respect to the year BCS was performed, patient age (3 years), and cancer stage. The AHF regimen consisted of 39Gy in 13 fractions to the whole breast and a consecutive boost of 9 to 12Gy in 3 to 4 fractions to the tumor bed. CF comprised whole-breast irradiation up to 50.4Gy in 28 fractions and a boost of 9 to 14Gy in 5 to 7 fractions to the tumor bed.The median follow-up period was 75 months (range, 3.8-110.8 months). There was no statistically significant difference between the AHF and CF groups in terms of age distribution, T and N stage, resection margin, and histologic grade. There were 5 ipsilateral breast tumor relapse (IBTR) cases in the AHF group compared with 7 cases in the CF group. Seven and eight locoregional relapse (LRR) cases were observed in the AHF and CF groups, respectively. The 7-year rates of IBTR-free survival, LRR-free survival, and disease-free survival were 98.9%, 98.4%, and 97.1% in the AHF group and 98.1%, 97.9%, and 96.0% in the CF group, respectively (P>0.05). The incident rates of grade 3 edema, hyperpigmentation, or wet desquamation at the end of RT were higher in the CF group than in the AHF group (16.4% vs 0.2%, respectively; P<0.01).AHF RT of 39Gy to the whole breast plus a 9-Gy boost in 16 fractions showed excellent tumor control and tolerable skin toxicity, a finding that is comparable to CF RT in patients with early-stage breast cancer.