Does triple-negative breast cancer (TNBC) have distinct clinicopathologic characteristics and prognostic significance?

Abstract

21088 Background: Studies have suggested that TNBC, defined by estrogen receptor-negative, progesterone receptor-negative, and HER2-negative, may represent the subset of breast cancer(BC) with different biologic behavior. Here we investigated the clinicopathologic characteristics of TNBC and its prognostic significance in Korean BC patients. Methods: Patients diagnosed as invasive BC and underwent curative surgery at Seoul National University Hospital between Jan. 2000 and Jun. 2003, were reviewed, retrospectively. We excluded the patients whose immunohistochemistry for hormone receptor nor HER2 status had not been evaluated, and who had been treated with adjuvant trastuzumab or neoadjuvant chemotherapy (CT). Clinicopathologic variables (age, T and N stage, endovascular or lymphatic tumor emboli, nuclear and histologic grade, p53, bcl2, Ki67) and 3 year relapse free survival (3YRFS) rate of TNBC were compared with those of non- TNBC. Results: 1,136 patients were eligible for analysis. The median follow-up was 48.7 months. 341 patients underwent breast conserving surgery followed by adjuvant radiotherapy. 249 patients were TNBC and 62.1% of those were node negative. 86.4% of node negative TNBC, 88.3% of node positive TNBC, 53.9% of node negative non-TNBC, and 90.2% of node positive non-TNBC received adjuvant CT. Compared with non-TNBC, TNBC was correlated with younger age (age<35,14.1% vs. 8.2%, p=0.013), higher nuclear and histologic grade(62.2% vs. 23.6%, p=0.001;60.2% vs. 24.6%, p=0.001, respectively); positive staining for p53 (p=0.001) and higher positivity for Ki67 (p=0.001), suggesting the biologic aggressiveness of TNBC. During the follow-up periods, 17.3% of TNBC were relapsed. In particular, 3YRFS in node negative TNBC and non-TNBC were 86% and 96%, respectively (p<0.001). But, in node positive BC, 3YRFS was not different between TNBC and non-TNBC (80.6% vs. 83%, p=0.99). Conclusions: We confirm that TNBC shows more aggressive clinicopathologic characteristics and in particular, higher relapse in node negative BC. Thus, triple-negativity(TN) may be integrated into risk factor analysis in node negative BC. Final results of more detailed molecular analysis for TNBC would be available in the meeting. No significant financial relationships to disclose.