Histo- and clinico-pathological analysis of a large series of triple-negative breast cancer in a single center in China: Evidences on necessity of histological subtyping and grading.

Abstract

ObjectiveTo investigate histo-pathological distribution and clinico-pathological significance in a large Chinese triple-negative breast cancer (TNBC) patients serials based on the latest understanding of its clinico-pathological diversity, and to provide more information to clinicians to improve precision of individualized treatment of TNBC.MethodsA retrospective analysis was performed on patients with TNBC at Breast Disease Center, Peking University First Hospital between January 2010 and December 2019. Histo- and clinico-pathological characteristics were analyzed by Chi-square test and Student’s t-test, and prognoses were calculated using Kaplan-Meier method and a Cox proportionate hazards model. Bonferroni correction was used to correct for multiple comparison. ResultsConventional type of TNBC (cTNBC) were identified in 73.7% of 582 TNBC, while special type of TNBC (sTNBC) were 26.3%, including 71 apocrine carcinoma, 20 medullary carcinoma, 31 metaplastic carcinoma, 18 invasive lobular carcinoma, 7 invasive micropapillary carcinoma, 5 adenoid cystic carcinoma and 1 acinic cell carcinoma. Compared to sTNBC, cTNBC was associated with high histologic grade (P<0.001) and lower androgen receptor (AR) expression (P<0.001). TNM stage of low-grade cTNBC was significantly lower than that of high-grade cTNBC (P=0.002). Although no significant difference, there was a trend that the rate of 5-year disease-free survival (DFS) and 5-year overall survival (OS) were longer in high-grade cTNBC than in high-grade sTNBC (P=0.091 and 0.518), and were longer in low-grade sTNBC than in high-grade sTNBC (P=0.051 and 0.350). Metaplastic carcinomas showed larger tumor size (P=0.008) and higher proliferative Ki67 index (P=0.004) than cTNBCs.ConclusionsResults from our cohort imply that sub-categorization or subtyping and histological grading could be meaningful in pathological evaluation of TNBC, and need to be clarified in more large collections of TNBC.