Basal-Like Breast Cancer; Clinicopathological, Molecular, and Prognostic Features

Abstract

Background: Molecular classification of breast tumors has identified the basal-like subtype, with high heterogeneity and very poor prognosis. These tumors are mainly triple negative, characterized by the expression of basal markers CK5/6 and EGFR. In this study, we sought to investigate the features, outcome, and therapeutic modalities of basal-like breast cancers (BLBC).Methods: We retrospectively identified 90 BLBC patients diagnosed at the Department of Surgical Oncology of Salah Azaiez Institute between January 2009 and December 2013. Results: The mean age of our patients was 50 years, and 15.5% had a family history of breast cancer. The mean tumor size was 43.8 mm. Histological examination revealed invasive ductal carcinoma in 88.9% of the cases, metaplastic carcinoma in 5.6%, and medullary carcinoma and adenoid cystic carcinoma in 2.2%. BLBC was most often associated with a high tumor grade (55.3% had a grade 3 tumor) and a high Ki-67 proliferative index. Vascular invasion was found in 31.1% of the cases. Regarding lymph node involvement, 42.9% had positive lymph nodes and 7.9% featured distant metastases. Surgical treatment was provided for 85 patients. It consisted of conservative surgery in 40 cases and radical surgery in 45 cases. Neoadjuvant chemotherapy was administrated to 23 patients, with a 13% complete pathologic response. The rates of overall survival and disease-free survival at 3 years for localized BLBC were 74.4% and 75.9%, respectively. Conclusion: BLBCs are aggressive tumors associated with poor prognosis. Thus, to identify novel prognostic factors and therapeutic targets, prospective studies should investigate the epidemiological and evolutive profile of these tumors.