Abstract P6-06-42: Impact of molecular subtype on overall survival according to age in Korean women

Abstract

Abstract Introduction: Breast cancer is a heterogeneous diseases, which is based on expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Using these factors, molecular subtype can be determined as luminal A, luminal B, HER2+, and TNBC. This is considered as an important prognostic factor. In breast cancer, age is the one of the important prognostic factors and prognosis is varied according to patients’ age. We performed this study to analyze the impact of molecular subtypes on prognosis of breast cancer according to patients’ age. Patients and methods: We performed this study by using Korean Breast Cancer Society Registration Program data. Total 15,286 patients are included into this study, and they underwent surgery during the period Jan. 2001 to Dec. 2006. All patients were divided into two groups according to age (younger: age≤34, older: age≥35) and molecular subtypes were classified into four groups as follows: luminal A (ER+ and/or PR+, HER2-), luminal B (ER+ and/or PR+ HER2+), HER2+ (ER-, PR-, HER2+), and triple-negative (ER-, PR-, HER2-). We determined prognostic impact of molecular subtype on overall survivals (OS). Clinicopathologic results and OS were compared by chi-square test, Kaplan Meier test, and Cox's hazards model. Results: Younger group more frequently had tumors with negative hormone receptor (ER-/PR-), worse prognostic factors and diagnosed with more advanced stage compared to older group. In univariate analysis, molecular subtype was not related with OS in younger group (p = 0.069), but not in older group (p<0.001). In multivariate analysis, molecular subtype was an independent prognostic factor for OS only in older group (p = 0.690 vs p<0.001). Conclusion: In young breast cancer patients, less than 35 years, the impact of molecular subtypes on overall survival was not significant compared to other age group. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-42.