The Prognostic Significance of the Luminal A, Luminal B, Basal and Her 2 Neu Subtypes of Breast Cancer in Saudi Women

Abstract

Background: Breast Cancer (BC) is molecularly diverse disease that has been sub-classified in four major subtypes; (a) luminal A (estrogen and/or progesterone positive and Her 2neu negative), (b) luminal B (estrogen and/or progesterone positive and Her 2 neu positive), (c) Basal (triple negative) and (d) Her 2 neu (estrogen and/or progesterone negative and Her 2 neu positive). Luminal A and luminal B are less aggressive subtypes and are associated with better prognosis as compared to basal and Her 2 neu subtypes. We aimed to evaluate the pattern of breast cancer subtypes and response to treatment and outcomes in Saudi women. Materials and Methods: Between February 1988 and August 2008, confirmed BC from a cohort of 112 patients were subtyped according to the hormone receptor status and Her 2 neu overexpression which were determined by immunohistochemistry (IHC) and Fluorescence in situ hybridization (FISH). The prognostic value of the BC subtypes for locoregional control (LRC), distant metastases control (DMC), disease free survival (DFS) and overall survival (OS) was investigated using Kaplan-Meier curves and multivariable Cox regression model. Results: Pattern of BC subtypes in Saudi women were as; luminal A (32.1%), Her 2 neu ((32.1%), luminal B (25.9%) and basal (9.8%). Luminal A and Her 2 neu subtypes were predominant (34.4% and 33.3%) in premenopausal and basal subtype (26.3%) was predominant in postmenopausal women. Ten year DFS was 95%, 62%, 50% and 42.8% in luminal A, B, Her 2 neu and basal types respectively (p 0.003). No difference in LRC among different subtypes was seen (p 0.9) and DMC was found poor in Her 2 neu and basal subtypes (p 0.03). Conclusion: Luminal A subtypes has favorable prognosis in Saudi women with breast cancer as compared to other subtypes. Molecular subtyping can be helpful in predicting the treatment outcomes in breast cancer patients.