Effects of post-mastectomy radiation therapy on T1-2 stage and one to three positive lymph node breast cancer patients with differ-ent risk factors / 中国肿瘤临床

ABSTRACT

Objective:To retrospectively evaluate the prognostic risk factors of T1-2 stage breast cancer patients with one to three positive node(s) and their effects on the benefits of post-mastectomy radiation therapy (PMRT). Methods:We retrospectively analyzed 457 breast cancer patients with T1-2 stage and one to three positive axillary lymph nodes treated in our hospital between 2000 and 2002. The independent prognostic factors of the patients were calculated by the Cox proportional hazards model. The patients were fur-ther classified into high-risk and low-risk subgroups according to the risk factors to explore the benefit of PMRT on the prognosis of dif-ferent subgroups using survival analysis. Results:PMRT was not an independent beneficial factor of overall survival (OS) (HR=0.949;CI0.435-2.074;P=0.896) or loco-regional recurrent free survival (LRRFS) (HR=0.611;CI0.231-1.614;P=0.320) in all patients. Ex-tracapsular extension (ECE) and pathological grades were independent prognostic risk factors, and the benefits of PMRT were signifi-cantly different on the prognosis of high-risk subgroup patients (group ECE+OSP=0.020, LRRFSP=0.014;group GradeⅢOSP=0.002, LRRFSP<0.001). Meanwhile, PMRT failed to prolong the OS and LRRFS of low-risk subgroup patients (group ECE+OSP=0.353, LRRFSP=0.796;group GradeⅠtoⅡOSP=0.267, LRRFSP=0.589). Conclusion:ECE and gradeⅢwere the independent risk factors of death and loco-regional recurrence in the T1-2 breast cancer patients with one to three positive lymph node(s). PMRT was an effective adjuvant therapy to improve the prognosis of patients with high-risk factors. However, the benefit of PMRT had no sig-nificance in patients with ECE-or gradeⅠ-Ⅱ.