Prognostic significance of molecular subtype in T1N0M0 breast cancer: Korean experience

Abstract Purpose Gene expression profiling studies have identified several breast cancer subtypes associated with markedly different clinical outcomes. In general, patients with stage I breast cancer have excellent outcomes. We assessed the clinicopathological characteristics and outcomes of patients with T1N0M0 breast cancer according to molecular subtype. Methods Seven hundred and sixty-two T1N0M0 breast cancer patients undergoing curative surgery between January 1990 and December 2007 were analyzed. Subtypes were classified according to hormone receptor (HR) and human epidermal growth factor receptor-2 (HER2) status as follows: HR+/HER2−, HR+/HER2+, HR−/HER2− (triple-negative, TN), and HR−/HER2+. Results The distribution of subtypes was HR+/HER2−, 56.6%; HR+/HER2+, 10.1%; TN, 20.1%; and HR−/HER2+, 13.3%. Marked differences were observed among subtypes in multifocality/multicentricity, histological grade, extensive intraductal components, p53 expression and the Ki-67 index. There were differences in recurrence-free survival and overall survival among patients with different molecular subtypes (log-rank p