Prognostic value of sequencing of radiotherapy and chemotherapy following breast-conserving surgery for patients with breast cancer

Abstract

Objective: To evaluate the prognostic value of sequencing of adjuvant radiotherapy and chemotherapy following breast-conserving surgery for patients with breast cancer. Methods: A total of 1 154 patients withT1-2N0-3M0 breast cancer retrospectively reviewed. All patients received sequential radiotherapy and chemotherapy following breast-conserving surgery. Among them, 603 patients received radiotherapy first and 551 patients received chemotherapy first. Log-rank tests were used to determine significance of disease-free survival (DFS) and overall survival (OS) rates in the Kaplan-Meier curve. Results: The 5-year DFS and OS rates for all patients were 93.0% and 97.8%. The 5-year OS rate was 98.6% in the radiotherapy first group and 96.4% in the chemotherapy first group (P=0.191), and the corresponding DFS rate was 92.7% and 93.2% (P=0.430), respectively. Among the patients with Luminal A subtype, the 5-year OS rate was 99.6% in the radiotherapy first group and 97.8% in the chemotherapy first group (P=0.789). Among the patients with Luminal B subtype, the 5-year OS rate was 94.2% and 96.0%, respectively (P=0.680). Among the patients with triple negative breast cancer, the 5-year OS rate was 100% and 90.9%, respectively, with statistically significant differences (P=0.019). Among the patients with HER-2 positive breast cancer, The 5-year DFS rate was 80.1% and 100%, respectively (P=0.045). Conclusions: The OS and DFS rates in the chemotherapy first group are not significantly different from those of radiotherapy first group after breast-conserving surgery. Patients with HER-2 positive breast cancer in chemotherapy first group have a much higher DFS rate than that of radiotherapy first group, whereas patients with triple negative breast cancer in radiotherapy first group have a better OS rate than that of chemotherapy first group. Further research is warranted to investigate the benefit of different molecular types in different sequencing of radiotherapy and chemotherapy after breast-conserving surgery.