ORIGINAL ARTICLES: Clinical researchLymph node ratio as a prognostic factor in melanoma: results from European Organization for Research and Treatment of Cancer 18871, 18952, and 18991 studiesTestori, Alessandro A.a; Suciu, Stefanb; van Akkooi, Alexander C.J.d; Suppa, Marianoc; Eggermont, Alexander M.M.g; de Vries, Esthere,h; Joosse, Arjenf; on behalf of the European Organization for Research and Treatment of Cancer (EORTC) Melanoma GroupAuthor Information aEuropean Organization for Research and Treatment of Cancer Melanoma Group bEuropean Organization for Research and Treatment of Cancer (EORTC) cDepartment of Dermatology, Erasmus Hospital, Free University, Brussels, Belgium dDepartment of Surgical Oncology, Netherlands Cancer Institute – Antoni van Leeuwenhoek, Amsterdam eDepartment of Public Health, Erasmus University Medical Center, Rotterdam fDepartment of Medical Oncology, Leiden University Medical Center, Leiden, The Netherlands gGustave Roussy Oncology Institute, Villejuif/Paris-Sud, France hDepartment of Clinical Epidemiology and Biostatistics, Faculty of Medicine, Pontifical Javeriana University, Bogota, Colombia Correspondence to Alessandro A. Testori, MD, European Organization for Research and Treatment of Cancer Melanoma Group, Piazza Sant Ambrogio, 14 Milan 20123, Italy Tel: +39 335 829 0752; fax: +39 023 216 1018; e-mail: [email protected] Melanoma Research: June 2018 - Volume 28 - Issue 3 - p 222-229 doi: 10.1097/CMR.0000000000000433 Buy SDC Metrics Abstract The aim of this study was to assess the prognostic importance of lymph node ratio (LNR) in stage III melanoma after complete lymph nodal dissections. From European Organization for Research and Treatment of Cancer randomized trials 18871, 18952, and 18991, 2358 patients had full information on positive and examined lymph nodes (LNs) and were included. Cox proportional hazards models stratified by trial were used to assess the prognostic impact of LNR adjusted for confounders on melanoma-specific survival. Optimal cutoff values for LNR were calculated for each LN dissection site (axillary, inguinal, and neck). LNR (≥ vs. <35%: hazard ratio=1.44, 95% confidence interval: 1.23–1.69) and number of positive LNs appeared to be of independent strong prognostic importance. Dissection sites impacted the optimal LNR cutoff: 35% for axillary, 40% for inguinal, and 50% for neck dissections. Combining these into one ‘high versus low LNR’ resulted in a highly significant multivariately adjusted hazard ratio of 1.48 (95% confidence interval: 1.26–1.74). In subgroup analyses, LNR was only significant in advanced disease (American Joint Committee on Cancer stage N2b, N3; IIIC). LNR was most significant for inguinal dissections, followed by axillary dissections, but seemed less useful in neck dissections. LNR is an independent significant prognostic factor in stage III melanoma patients. Our study showed higher than previously reported cutoffs that differed per dissection site. However, because of conflicting results compared with other studies and apparent limited prognostic impact confined to subgroups, the practical use of LNR seems limited. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.