Abstract: Objective The aim of this study was to evaluate the effect of postoperative radiotherapy on local recurrence-free survival(LRFS)and overall survival(OS)in patients with triple-negative breast cancer(TNBC).Methods The clinical data of 186 cases for TNBC were collected from the Affiliated Tumor Hospital of Harbin Medical University from January 2003 to December 2006.These cases were confirmed by pathology.The patients were divided into radiotherapy and non-radiotherapy groups.The survival curves were plotted by Kaplan-Meier method.Log-rank test method was used to detect the difference between the radiotherapy and non-radiotherapy groups for 10 years.Univariate and multivariate analyses were used to determine the prognostic factors for TNBC patients.Results The 10-year LRFS of radiotherapy group and non-radiotherapy group were 80.2% and 76.0%,respectively.The 10-year OS was 86.0% and 74.0% in radiotherapy group and non-radiotherapy group,respectively.Both of them showed a statistically difference(P＜0.05).Subgroup analysis showed that LRFS and OS were 81.8% and 81.8% in 10 years for radiotherapy in patients with T_1-2N₁(1-3 lymph node metastases)M₀,respectively,76.4% and 79.4% for non-radiotherapy group,respectively.No differences were observed in both of LRFS and OS in radiotherapy and non-radiotherapy groups(P＞0.05).Multivariate analysis showed that radiotherapy and clinical staging were independent factors influencing the survival of TNBC patients.Conclusion Radiotherapy can improve the LRFS and OS in TNBC patients,but radiotherapy does not improve LRFS and OS for TNBC patients with T_1-2N₁(1~3 lymph node metastases)M₀.Radiotherapy and clinical staging are independent factors that affect the prognosis of TNBC patients.

Key words: Triple-negative breast cancer, Radiotherapy, Local recurrence-free survival, Overall survival