Lymph Node Ratio: Is It an Independent Prognostic Factor for Stage III Cutaneous Melanoma?

Objective: Lymph node ratio (LNR) is defined as the ratio of the number of metastatic lymph nodes to the dissected lymph nodes. LNR is a prognostic factor for many tumor types. The present study aimed to evaluate the prognostic value of LNR in melanoma. Methods: This retrospective cohort study was conducted on 123 patients with stage III cutaneous melanoma. Multivariate Cox proportional hazards model was used to evaluate the correlations between LNR and other clinicopathological factors associated with survival. The patients were divided into four groups in terms of the LNR, including groups A (LNR≤0.18), B (0.18<LNR≤0.37), C (0.37<LNR≤0.625), and D (LNR>0.625). Results: Initially, LNR was evaluated as a continuous quantity associated with survival. In the univariate analysis, a significant correlation was observed between LNR, overall survival (OS), and disease free survival (DFS). Meanwhile, the only association observed in the multivariate analysis was between LNR and OS. Increased LNR from group A to group D reduced OS from 46 (±44.09) to 22.5 (±16.33) months (P=0.022). According to the multivariate analysis, prognostic factors in OS were tumor thickness, American joint committee of cancer (AJCC) N stage, interferon administration, and undergoing chemotherapy. Conclusion: According to the results, LNR could be used as an independent prognostic factor for estimating the survival of patients with stage III cutaneous melanoma also designing an effective adjuvant treatment protocol for these patients.