Patterns of recurrence and outcome according to breast cancer subtypes in lymph node-negative disease: Results from international breast cancer study group trials VIII and IX

Abstract

Purpose To retrospectively evaluate the pattern of recurrence and outcome of node-negative breast cancer (BC) according to major subtypes. Patients and Methods In all, 1,951 patients with node-negative, early-stage BC randomly assigned in International Breast Cancer Study Group Trials VIII and IX with centrally reviewed pathology data were included. BC subtypes were defined as triple negative (TN; n = 310), human epidermal growth factor receptor 2 (HER2) positive (n = 369), and hormone receptor positive with high (luminal B-like [LB-like]; n =763) or low (luminal A-like [LA-like]; n = 509) proliferative activity by Ki-67 labeling index. BC-free interval (BCFI) events were invasive BC recurre..