Triple-negative breast cancer: clinical features and patterns of recurrence.

Purpose: To compare the clinical features, natural history, and outcomes for women with "triple-negative" breast cancer with women with other types of breast cancer.

Experimental Design: We studied a cohort of 1,601 patients with breast cancer, diagnosed between January 1987 and December 1997 at Women's College Hospital in Toronto. Triple-negative breast cancers were defined as those that were estrogen receptor negative, progesterone receptor negative, and HER2neu negative.