We aimed to compare breast-related complications between hypofractionated adjuvant postmastectomy radiation therapy (PMRT) and conventional fractionated radiation therapy (RT) in patients with breast cancer undergoing reconstruction by reconstruction surgery type.

Data from a total of 396 patients with breast cancer who underwent breast reconstruction after mastectomy between 2009 and 2018 were retrospectively reviewed. All patients received adjuvant PMRT according to either a conventional fractionation or hypofractionation schedule. We analyzed breast-related complications according to the timing of breast reconstruction (immediate or delayed). In cases of delayed reconstruction, only PMRT delivered before final delayed reconstruction was included. A major breast complication was defined as a breast-related toxicity that required reoperation or rehospitalization after the end of RT.

The median follow-up time was 35.3 months (range, 8.8-122.7 months). Of all patients, 267 received immediate breast reconstruction and 129 received delayed breast reconstruction. In patients with immediate breast reconstruction, 91 were treated with conventional RT and 176 received hypofractionated RT. The occurrence of major breast-related complications did not differ significantly between the 2 fractionation regimens. Hypofractionated RT did not increase major wound problems (infection and dehiscence) compared with conventional RT. Furthermore, major contracture occurred significantly less frequently in hypofractionated RT. Of the patients who had delayed breast reconstruction, 48 received conventional RT and 81 received hypofractionated RT. There was no difference in the incidence of major breast complications between these 2 RT groups, and no difference in major breast complications were reported for either 1- or 2-stage delayed reconstruction. A time interval of >10 months between PMRT and final definitive reconstruction had a significantly lower incidence of major breast complications.

Hypofractionated RT appears to be comparable with conventional fractionated RT in terms of breast-related complications in patients with breast cancer undergoing reconstruction, regardless of breast reconstruction type. An ongoing prospective randomized trial should confirm our findings.