Survival Analysis Of HR Positive/HER2 Negative Early Breast Cancer With Diverse HER2 Protein Expression Levels

Objective:To compare the clinicopathological features and prognosis of patients with diverse HER2 protein expression levels in early HR+/HER2-breast cancer and the efficacy difference between TAM and AI adjuvant endocrine therapy of the same HER2 protein expression.Methods:In this study,387 HR-positive/HER2-negative(HR+/HER2-)early breast cancer patients with TAM or AI adjuvant endocrine therapy were collected in Liaoning Cancer Hospital from Jan 2007 to Dec 2014,and the patients were divided into three groups;HER2(0),HER2(+)and HER2(++)(FISH negative)according to HER2 protein expression level determined by immunohistochemistry.Prognostic factors and the efficacy difference of adjuvant endocrine therapy were retrospectively analyzed.Results:After a median follow-up of 73.4 months,HER2 protein expression levels were identified in 350 cases:HER2(0),HER2(+),and HER2(2+)were 161(46.0%),126(36.0%),and 63(18.0%).high HER2 protein expression was significantly associated with high Ki-67 index(G=0.234,P=0.003)and was more frequently experiencing a recurrence within 5-years follow-up(?~2=11.131,P=0.001).No significant association was found between HER2 protein expression and DFS(P=0.984)and OS(P=0.772).In premenopausal patients,AI significantly improved DFS compared with TAM(95.5%vs 71.5%,HR=0.103,95%CI 0.013-0.794,P=0.008)under HER2(0)expression,whereas there was no efficacy difference in the two other cohorts,HER2(+)and HER2(2+)expression(both,P>0.05).Conclusion:For HR+/HER2-breast cancer,HER2 protein expression may be not a valuable prognostic maker for DFS and OS in HR+/HER2-breast cancer patients,but the Ki67 index increased accordingly and patients were more likely to experience a recurrence within 5-year follow-up with HER2 protein expression increase.In premenopausal patients,no efficacy difference was seen between TAM and AI.