Relationship between chemotherapy and prognosis in different subtypes of node-negative breast cancer.

Knowledge is limited about the relationship between chemotherapy and prognosis among the subtypes of axillary node-negative breast cancer (ANNBC). In this study, a population including 2,236 primary and operable ANNBC patients, with a median age of 53, were included. All breast tumors were classified into five immunohistochemically defined subtypes-luminal A, luminal B, luminal human epidermal growth factor receptor 2 (HER2), HER2 overexpression, and triple negative. With a median follow-up of 73.6 months, the rate of relapse was lowest in luminal A (6.5 %) and highest in HER2 overexpression subtype (16.4 %). Multivariate analysis indicated that the risks of relapse and death were enhanced in HER2 overexpression and triple-negative (TN) subtypes, and these two subtypes were independent predictors of relapse and death. Luminal A patients with risk factors could benefit from chemotherapy in terms of relapse-free survival (RFS). The relapse rate of TN patients after chemotherapy with taxanes was lower compared with that after chemotherapy without taxanes. In conclusion, women with ANNBC were at higher risks of relapse and death if suffering from HER2 overexpression or TN diseases. Chemotherapy could reduce the recurrence rate of luminal A patients with risk factors. TN patients may benefit from adjuvant chemotherapy containing taxanes.