Abstract:Objective To explore the effect of breast-conserving surgery and mastectomy on the overall survival (OS) of T1 triple negative breast cancer (TNBC) patients with different metastasis status of lymph node,and to provide a basis for clinical decision-making.Methods The clinicopathological data of T1 non-distant metastatic TNBC patients from 2010 to 2014 in the surveillance,epidemiology and results database (SEER database) were extracted and divided into breast-conserving group and mastectomy group according to the surgical method.The propensity score matching (PSM) method was used to balance confounding factors.The Cox regression method was used to analyze the effect of different clinicopathological factors on the survival of T1 TNBC patients;the Kaplan-Meier method was used to calculate the OS,and the Log-rank method was used to analyze the difference in overall survival between two groups.Results A total of 2 082 patients were enrolled in this study.After PSM controlled confounding factors,a total of 838 patients were screened out,of which 419 were in breast-conserving group and mastectomy group.There was no statistically significant difference in baseline characteristics between the two groups (P>0.05).After PSM,multivariate Cox regression analysis showed that age,tumor stage,surgical method,and chemotherapy were independent factors that affect the patient′s OS (P<0.05,P<0.01).The survival curve showed that the 2-year and 5-year survival rate in the breast-conserving group was 96.8% and 86.9%,in the mastectomy group was 93.1% and 81.8%.The survival rate of the breast-conserving group was significantly higher than that of the mastectomy group in stage I(P<0.01);There was no significant difference in survival rate between the two groups in stage ⅡA and ⅢA/C (P=0.17,P=0.54).conclusions Age,tumor stage,surgical methods,and chemotherapy are independent influence factors of OS in T1 TNBC patients.Regardless of the local axillary lymph node staging,breast-conserving surgery and mastectomy are equally safe and effective for patients with T1 stage TNBC.For patients with stage I TNBC,breast-conserving surgery can benefit them from OS.