The Efficacy Of Neoadjuvant Chemotherapy In HER-2 Low Breast Cancer

Background:Based on the positive results of DB04 and other studies,has changed the treatment landscape for patients with human epidermal growth factor receptor 2(HER2)low-expressing breast cancer,but there is a lack of further medical evidence as a novel molecular subtype.The prognostic value of HER low expression and the efficacy of neoadjuvant chemotherapy(NAC)are still controversial.The aim of this study was to explore the prognostic factors of the pathological complete response of HER2 low-expressing breast cancer after neoadjuvant chemotherapy and and its effect on breast cancer prognosis.Methods:We retrospective analyzed the clinical and pathological Data of 283patients with primary breast cancer who received NAC and treated at Affiliated Cancer Hospital of Xinjiang Medical University between January 2018 and December 2021,were collected and follow-up median 26 months.Patients were divided into HER2-0,HER2-low,and HER2-high groups according to HER2 expression levels.Predictors of p CR after NAC in breast cancer were analyzed byχ~2 test,Fisher and logistic regression for univariate and multivariate analysis,respectively.Meanwhile,the Kaplan-Meier curve and Cox regression were used for prognostic analysis.Results:Among the 283 patients,138 patients(48.8%)classified as low HER2 expression.And 61 patients obtained p CR,of which low expression accounted for 13.8%.Without considering HR status,the highest rate of achieving p CR after NAC was observed in the HER2-high group and the lowest in the HER2-low group(χ~2=9.82,P=0.007).Univariate analysis showed that histological grade,Ki-67 and HR status and HER2 level were statistically significantly associated with p CR(P<0.05).Further multifactorial logistic regression analysis showed that HR status,Ki-67 level,and low HER2 expression(OR=0.331,95%CI 0.151-0.725,P=0.006)were predictors of NAC efficacy in this study cohort.K-M survival curve analysis showed that HER2 expression level was negatively associated with postoperative IDFS rate.cox regression prognostic analysis the results showed that HER2 levels were independent factors affecting patients’prognosis.Conclusion:The results suggest that no statistically significant differences were seen between the clinicopathological features of HER2 low expression and HER2 zero expression breast cancers,and that HER2 low expression breast cancers have an unstable status before and after NAC and are prone to transform into HER2zero expression.HER2 low expression,HR status and Ki-67 levels are independent influences on p CR,may be predictors of NAC outcome and serve as independent risk factors affecting prognosis.