383P - Comparison of Molecular Subtypes of Breast Cancer in Women ≤35 Years and > 35 Years: Does Age Matter?

Abstract

ABSTRACT Aim: Primary objective was to evaluate the impact of age, on determining molecular subgroups and whether the different outcome of patients ≤35 years and ≥35 years of age is related to the diversity of molecular subgroups. Methods: A total of 216 patients ≤35 years and randomly selected 212 patients of all patients ≥35 years presented to Ege University Faculty of Medicine Department of Oncology between 2000 and 2011 diagnosed with breast cancer were enrolled in the study. Demographic data, clinico-pathological characteristics and treatment modalities were reviewed and recorded for each patient. Molecular subtyping was based on estrogen, progesteron receptors (ER, PR), cerb-B2 and Ki-67 proliferation index. Luminal A disease was defined as ER (+), PR (+), cerb-B2(-), Ki-67 ≤ %15. Cases that were ER/PR (+), cerb-B2 (-)/(+), Ki-67 ≥ %15 were classified as Luminal B. If all three receptors were negative, then it was accepted as triple negative disease and Her-2 positive disease was characterized by lack of hormon receptors and presence of cerb-B2. Results: 166 of 216 patients ≤35 years of age, and 154 of 212 patients ≥35 years were found to be appropriate and pathologically have been assessed for molecular subtyping. Accordingly, 87 patients (%40.3) in younger group were Luminal B and 32 patients (%14.8) were triple negative, which composed the largest proportion of all very young group. 29 patients (%13.4) were Luminal A, 18 patients (%8.3) were Her-2 positive. Among the ≥35 years group the majority was Luminal B (%28.3) as similar in very young population,however followed by Luminal A (%22.6) that has favorable prognostic features. 28 patients (%13.2) were triple negative, 18 patients (%8.5) were Her-2 positive. There was no statistically significant difference in molecular subtypes between the two age groups. However, triple negative subtype and Ki-67≥ %15 which is associated with poorer prognosis was numerically higher among ≤ 35 years group. Conclusions: In our study there was no statistically significant difference in molecular subtypes between two diverse age groups. This could be explained by small size of the study population, but also could be an indication that age is an independent prognostic factor apart from all other clinico-pathologic features. Further studies based on genotypic analyses with larger patient series are required. Disclosure: All authors have declared no conflicts of interest.