The prognostic value of lymph node status among breast cancer subtypes.

Background: Breast cancer subtypes (BCSs) are predictive of responses to specific therapies and of prognostic value for clinical outcomes. This study aimed to evaluate the relative 5-year overall survival (OS) and recurrence-free survival rates (RFS) based on lymph node (LN) status among BCSs.

Methods: Medical records of 1,399 breast cancer patients treated from 2006 to 2011 were retrospectively reviewed. Pathologic findings, type of treatment, and OS and RFS were evaluated for 5 molecular subtypes.

Results: Luminal A cancers accounted for 40.9% of the total, luminal B 21.5%, luminal human epidermal growth factor receptor 2 (HER2) 24.8%, HER2 6.9%, and triple negative 5.9%, of which 30% (n = 395) were LN positive. Analysis of patient characteristics showed significant differences among BCSs in age, tumor size, LN status, chemotherapy, and endocrine therapy. Adjustments for age and tumor size revealed significant differences in OS according to the nodal status in luminal A, luminal B, and luminal HER2 subtypes, and with RFS in the luminal B and luminal HER2 subtypes.

Conclusion: LN status in BCS presents an important prognostic factor of OS and RFS.