Lymph node ratio may be supplementary to TNM nodal classification in node-positive breast carcinoma based on the results of 2,151 patients.

Background: The aim of the present study was to determine how lymph node ratio (LNR; the ratio of the number of metastatic lymph nodes to the number of removed lymph nodes) can supplement the TNM nodal classification in breast carcinoma.

Methods: We retrospectively reviewed the file records of 2,151 patients.

Results: Lymph node ratio-based low- (LNR ≤ 0.20), intermediate- (LNR 0.21-0.65), and high-risk (LNR > 0.65) patient groups had significantly different disease-free survival (DFS) (P < 0.001). The DFS of patients with N1, N2, and N3 disease was significantly different (P < 0.001). When LNR and TNM nodal groupings were included together in the Cox analysis, both groupings had independent prognostic significance (P < 0.001 and P < 0.001, respectively). The most significant LNR threshold value separating patients in low-risk and high-risk groups in terms of disease recurrence was 0.20 for N1 disease (P < 0.001), 0.35 for N2 disease (P < 0.001), and 0.90 for N3 disease (P < 0.001).

Conclusions: Lymph node ratio and TNM nodal groupings show no superiority over each other in categorizing patients with node-positive breast carcinoma into prognostic groups of low-, intermediate-, and high-risk. However, LNR grouping may supplement TNM nodal classification by categorizing patients within each TNM nodal group into low-risk and high-risk groups with significantly different survival.