The lymph node ratio has limited prognostic significance in melanoma

Background: The importance of the lymph node ratio (LNR) after regional lymphadenectomy for cutaneous melanoma is unknown. Materials and methods: A post hoc analysis was performed for patients after the completion of lymphadenectomy for cutaneous melanoma. LNR was calculated as the number of tumor-positive nodes divided by the total number of lymph nodes. Comparison of disease-free survival (DFS) and overall survival (OS) and univariate and multivariate analyses with regard to LNR was performed. Comparison of the performance of LNR to other measurements of lymph node disease was performed. Results: A LNR of 0.10 was a significant cutoff point for determining DFS and OS. On multivariate analysis, LNR >0.10 was an independent predictor of DFS and OS without other measures of lymph node disease burden. Patients with LNR >0.10 had worse DFS and OS. Absolute counts of tumor-positive lymph nodes differentiated survival differences better than LNR. LNR was not a significant predictor of survival in patients with neck or axillary dissections but was for inguinal dissections. In multivariate analysis of alternative nodal measures, LNR was an inferior prognostic factor. Conclusions: A LNR >0.10 has a negative prognostic significance when it is the only measurement of lymph node disease considered but is an inferior prognostic factor to alternative measures of lymph node disease.