Comparison Of Prognosis Between Breast-conserving Surgery And Total Mastectomy For Early-stage Triple-negative Breast Cancer

Objective:To compare the prognosis of patients with early-stage triple-negative breast cancer after breast-conserving surgery and total mastectomy.To explore whether BCS will increase the risk of local recurrence and death compared with TM in the treatment of stage T_1-2N_0-1M₀ triple-negative breast cancer.To provide scientific basis for selecting BCS in stage T_1-2N_0-1M₀ TNBC.Methods:Using the method of historical cohort study,140 female patients with primary invasive and early-stage(stage T_1-2N_0-1M₀)TNBC who received surgery in China-Japan Friendship Hospital of Jilin University from January 2016 to December 2019 were selected and divided into observation group（BCS group）and control group（TM group）according to different methods of breast surgery.Among them,BCS group（52 cases）received breast-conserving surgery combined with postoperative radiotherapy,TM group（88 cases）received total mastectomy combined with or without postoperative radiotherapy.The clinicopathological data and postoperative follow-up information of all patients were collected（including age of onset,menstrual status at onset,tumor location,tumor clinical stage,histological grade,vascular thrombus,Ki-67,P53,surgical methods,and chemoradiotherapy,etc.）.Clinicopathological features of the two groups were described and compared.The main observation endpoints of this study were Overall Survival（OS）,Disease-Free Survival（DFS）and Local Recurrence Free Survival（LRFS）.The 3-year overall survival（OS）,disease-free survival（DFS）and local recurrence-free survival（LRFS）rates of BCS group and TM group were calculated by Kaplan-Meier method,and the OS,DFS and LRFS curves of the two groups were plotted respectively.The differences between groups were determined by Log-Rank test（P<0.05 was statistically significant）.Univariate Cox regression and multivariate Cox regression were performed using Cox proportional hazard model to explore the effect of BCS on OS,DFS and LRFS of patients with stage T_1-2N_0-1M₀ TNBC.Results:（1）There were significant differences in the following clinicopathological features between the BCS and TM groups:the proportion of patients with tumor maximum diameter≤2cm in the BCS group was higher than that in the TM group（71.2%vs.52.3%,P<0.05）.The proportion of patients with stage I in the BCS group was higher than that in the TM group（67.3%vs.45.5%,P<0.05）.The proportion of histological grade III in the BCS group was lower than that in the TM group（42.3%vs.65.9%,P<0.05）.The proportion of sentinel lymph node biopsy in the BCS group was significantly higher than that in the TM group（65.4%vs.14.8%,P<0.001）.All patients in the BCS group received postoperative radiotherapy,while only 7 patients（8.0%）in the TM group received postoperative radiotherapy（P<0.001）.（2）Five of 140 patients were lost to follow-up.A total of 135 patients（96.4%）were followed up,including 49 patients in the BCS group and 86 patients in the TM group.Follow-up time was6-83 months,median follow-up time was 55 months.In the BCS group,1 patient（2.0%）died,2patients（4.1%）had recurrence or metastasis,1 patient（2.0%）had local recurrence,and 2 patients（4.1%）had distant metastasis.In the TM group,4 patients（4.7%）died,8 patients（9.3%）had recurrence or metastasis,3 patients（3.5%）had local recurrence,2 patients（2.3%）had contralateral new disease,and 4 patients（4.7%）had distant metastasis.（3）The 3-year overall survival rate（98.0%vs.95.3%）,disease-free survival rate（95.9%vs.90.7%）and local recurrence-free survival rate（98.0%vs.96.5%）in the BCS group were higher than those in the TM group,but the difference was not statistically significant（P>0.05）.（4）Compared with TM,BCS was not an independent risk factor for OS（HR=0.95,95%CI0.09-10.32,P=0.969）,DFS（HR=0.51,95%CI 0.11-2.41,P=0.392）and LRFS（HR=0.60,95%CI 0.06-5.81,P=0.662）.Conclusions:1.Compared with total mastectomy,patients with T_1-2N_0-1M₀ triple-negative breast cancer who choose breast-conserving surgery have smaller primary tumors,earlier stages,lower histological grades,and are more likely to choose sentinel lymph node biopsy for axillary surgery.2.For patients with T_1-2N_0-1M₀ TNBC,breast-conserving surgery（combined with postoperative radiotherapy）does not increase the risk of local recurrence and death,and has the same survival prognosis as total mastectomy.Breast-conserving surgery is a more recommended local treatment method.