Clinical significance of lymph node ratio in locally advanced breast cancer molecular subtypes.

Abstract

Background: The ratio of metastatic to dissected lymph nodes (lymph node ratio; LNR) is a sensitive and superior prognostic factor for lymph node evaluation, but its relationship to cancer subtypes is unclear.

Patients and methods: Data from 469 patients with axillary lymph node metastasis out of 640 early breast cancer cases were retrospectively analyzed. They were classified into 4 molecular subtypes; luminal A, luminal B HER2(+), HER2 overexpression, basal-like. LNRs were compared between groups and with other prognostic factors.

Results: The distribution of LNRs was 35.2% in luminal A, 43.2% in luminal B HER2(+), 46.9% in HER2 over-expression, and 39.1% in basal-like. A significant difference was found between luminal A and HER2 over-expression subtypes (p = 0.023). LNR was significantly correlated with tumor size and lymphovascular invasion, but not with other prognostic factors including menopausal status, laterality, grade, and perineural invasion. An LNR of 29.8% was defined as the cut-off value, and significant differences in survival rates were identified accordingly between basal-like and both luminal A (p = 0.003) and luminal B HER2(+) (p = 0.04).

Conclusion: The LNR differs between some molecular subtypes of breast cancer, and it correlates with certain prognostic factors and survival. These data support using the LNR to assess breast cancer patients.