Clinical and pathological characteristics of basal -like breast carcinomas

Abstract

10768 Clinical and pathological characteristics of basal -like breast carcinomas. Background: Genetic studies have revealed different subtypes of breast carcinomas with particular molecular characteristics. Basal-like breast carcinomas are characterized by negative hormonal receptors and negative HER-2 receptor. We have compared basal-like breast carcinomas with a randomized control population selected from our data base of breast cancer. Methods: From 2127 breast invasive carcinomas, 716 were evaluated with immunohistochemical methods, considering the expression of estrogen receptors, progesterone receptor, HER-2 and p53 protein, between 1989 and 2005. According to the molecular classification the results were: 1) Luminal 398 (55.6%), 2) HER- 2 positive: 193 (26.9%) and 3) Basal-like 124 (17.5%). We retrospectively analyzed the age at diagnosis, menopausal status, tumor size, histological grade, histopathology, lymph node status, stage and the evolution of the breast cancer. The average follow-up was 66.2 months. The control group consisted of 170 patients. The statistical analysis was performed with chi-square test, Fisher’s test and the non parametric test of the Mac Nemar’s signs. Results: The median age at diagnosis was 52 years old. This is lower than the average age of the Tumor Register of Mendoza, that is 60 years (p: < 0.01). The basal-like carcinomas predominated in premenopausal women (p = 0.07), and had a higher proportion of high tumor grade (p ≤ 0.0001) and expression of p53 protein (p=0.01). There were not significant statistical differences concerning the tumor size, the lymph node status, histopathology, and the stage at presentation. The 5-year disease-free survival (DFS) of basal-like breast carcinomas was 71.7% and the 5-year overall survival (OS) was 83.3%. Whereas the DFS for the control group was 77.3% and the OS was 87.3%. Conclusions: The basal-like breast carcinomas are characterized by having a younger age at presentation, predominating in premenopausal women, and presenting a high tumor grade with overexpression of p53 protein. No significant financial relationships to disclose.