5 Year Longitudinal Analysis of Myocardial Perfusion SPECT Scans. Prospective Comparison of Long-Term Cardiac Function of Patients Participating in a Phase III Randomized Study of Breast Conserving Surgery and Radiotherapy

Abstract

This study was aim to evaluate whether hypofractionated adjuvant radiotherapy (RT) increased breast-related complication(s) compared to conventional RT in reconstructed breast cancer patients. Materials/Methods: This study included 397 patients with breast cancer who underwent breast reconstruction following total mastectomy (TM) or breast-conserving surgery (BCS) between 2009 and 2019 in two institutions. All patients were treated with adjuvant radiotherapy via either hypofractionated or conventional fractionated regimen. We defined major breast complication as a breast-related toxic event requiring re-operation or re-hospitalization during follow-up period after RT. Results: The median follow-up was 34.6 months (range, 3.6-116.9 months). Among 397 patients, 162 patients had conventional fractionated RT and 235 patients received hypofractionated RT. The 1-year and 2-year actuarial rate of any breast-related complications were 22.2% and 30.5%, and those of major breast-related complications were 7.9%, 10.2%, respectively. There was no significant difference in any and major breast-related complications between two fractionation regimens (P Z 0.087 for any and P Z 0.528 for major breast-related complication). In the subgroup analysis of patients with TM, hypofractionated RT showed similar breast-related complications compared to conventional fractionated RT. Major breast complications occurred 47 cases; 20 cases of wound infection, 10 wound dehiscence, 7 fat necrosis, 4 implant leakage, 3 flap contracture, 1 mastectomy skin flap necrosis, 1 seroma and 1 hematoma. In multivariate analysis, hypofractionated RT and delayed reconstruction were statistically significant factors for lower incidence of any breast complications. The factor adversely affecting major breast complications was implant reconstruction. Among patients with TM, implant reconstruction and age over 45 were associated with higher risk of major breast complications. Conclusion: Hypofractionated RT may be used comparably with conventional fractionated RT in terms of breast-related complications in reconstructed breast cancer patients.