Evaluation Of The Effect Of Neoadjuvant Therapy On Survival Of Women Diagnosed With Triple Negative Breast Cancer With Stage ?-? Based On Propensity Score Matching

Objective: Triple negative breast cancer(TNBC)is a kind of breast cancer with strong heterogeneity and poor prognosis,and adjuvant systemic therapy is an important treatment.Preoperative neoadjuvant therapy has the some advantages of operation,new drug development,drug sensitivity results and so on.It is more and more widely used in clinical application.Early breast cancer has a better survival advantage than advanced breast cancer,so the application of neoadjuvant therapy in early triple negative breast cancer is still controversial.The purpose of this study was to analyze the effects of neoadjuvant therapy and non-neoadjuvant therapy on overall survival(OS)and breast cancer-specific survival(BCSS)in women with triple negative breast cancer in stage ?-?.Methods: According to the inclusion and exclusion criteria of this study,the clinicopathological characteristics of triple negative breast cancer cases from 2010 to 2013 were obtained from the Surveillance,Epidemiology,and End Results(SEER)Program supported by the National Cancer Institute.The Kaplan-Meier curve method of X-tile software was used to group the age according to the best cut-off value of the classification variable obtained by the continuous variable(age filed).Chi-square test was used to compare the differences of these influencing factors between non-neoadjuvant therapy and non-neoadjuvant therapy groups.The tendency score matching method was used to match the proportion of 1:1 between the neoadjuvant treatment group and the non-neoadjuvant treatment group.Cox proportional hazard regression model was used to analyze the effect of neoadjuvant therapy on the survival of patients with ?-? triple negative breast cancer before and after propensity score matching.Kaplan-Meier survival curve and Log-Rank test were used to compare the difference of survival curve distribution between groups.Results: 9811 cases of female patients diagnosed triple negative breast cancer were included,all cases were unilateral breast cancer and received operation and chemotherapy,7781 cases received non-neoadjuvant therapy and 2030 cases received neoadjuvant therapy.72.4% of the cases in the study were white women,with an age range of 21 to 91 years old and a median age of 55 years old.According to the Kaplan-Meier method of X-tile software,the best two-classification truncation of age is 21?69 and 70? 91.Univariate analysis of Cox proportional hazard regression model showed that age(P<0.001),marital status(P<0.001),race(P<0.001),differentiation(P=0.036),histology(P=0.015),T stage(P<0.001),N stage(P<0.001),breast-conserving surgery(P<0.001),radiotherapy(P<0.004)and neoadjuvant therapy(P<0.001)were associated with overall survival.Age(P<0.001),marital status(P<0.001),race(P<0.001),differentiation(P=0.001),T stage(P<0.001),N stage(P<0.001),breast-conserving surgery(P<0.001),radiotherapy(P=0.050)and neoadjuvant therapy(P<0.001)were related to the breast cancer-specific survival.Chi-square test compared the differences of survival and prognostic factors between non-neoadjuvant therapy group and neoadjuvant therapy group.It was found that there were significant differences in age(P<0.001),T stage(P<0.001),N stage(P<0.001),breast-conserving surgery(P<0.001)and radiotherapy(P<0.001)between the two groups.However,there was no significant difference in marital status(P=0.075),race(P=0.080),differentiation(P=0.890)and histology(P=0.110).There were no significant differences in age(P=0.898),marital status(P=0.949),race(P=0.633),differentiation(P=0.430),histology(P=0.402),T stage(P=0.082),N stage(P=0.189),breast conserving surgery(P=0.975)and radiotherapy(P=0.724)between the two groups after matching.The absolute values of standardized differences of the influencing factors were all less than 0.1 after matching the scores of propensity score between the two groups.Based on the multivariate analysis of Cox proportional hazard regression model,it was found that neoadjuvant therapy affected the overall survival and breast cancer-specific survival of triple negative breast cancer with stage ?-?(P<0.05).In the matched cohort analysis,the overall survival curve distribution and breast cancer specific survival curve distribution of stage T0-1 treated with neoadjuvant therapy were significantly worse than those of patients without neoadjuvant therapy(P=0.015 and 0.012,respectively).There was no significant difference in the distribution of overall survival curve and breast cancer specific survival curve between stage T2 after neoadjuvant therapy and those without neoadjuvant therapy(P=0.529 and 0.137,respectively).There was no significant difference in the distribution of overall survival curve and breast cancer specific survival curve between stage T3 after neoadjuvant therapy and those without neoadjuvant therapy(P=0.271 and 0.372,respectively).There was no significant difference in the distribution of total survival curve and breast cancer-specific survival curve between breast-conserving surgery patients after neoadjuvant therapy and those who received breast-conserving surgery at the beginning(P= 0.231 and 0.118,respectively).Conclusions: It is necessary to judge comprehensively whether triple negative breast cancer with stage ?-? is receiving neoadjuvant therapy according to T stage,mode of operation,survival prognosis and so on.The patients with stage T0-1 did not gain survival benefit from neoadjuvant therapy,suggesting that the focus above 2cm is still one of the bases for choosing neoadjuvant therapy.There was no significant difference in the distribution of survival curve between the initial breast-conserving surgery group and the breast-conserving surgery group after neoadjuvant therapy for ?-? stage triple negative breast cancer.