Vitiligo is an independent favourable prognostic factor in stage III and IV metastatic melanoma patients: results from a single-institution hospital-based observational cohort study.

Background: The clinical features and the prognostic relevance of vitiligo lesions in melanoma patients are still controversial. This prospective observational study was designed to characterise the clinical features of melanoma-associated vitiligo, to analyse the association with other autoimmune manifestations and to ascertain whether the development of vitiligo lesions carries a prognostic relevance on the clinical course of melanoma. Materials and methods: A total of 2954 consecutive patients have been included; multivariate analyses of distant metastasis-free survival (DMFS) and overall survival (OS) were carried out to ascertain the independent prognostic role of vitiligo as a time-dependent covariate. Results: Vitiligo was demonstrated in 83 of 2954 melanoma patients (2.8%). A significantly higher percentage of autoimmune diseases was demonstrated in vitiligo patients (7 of 83) with respect to patients without vitiligo (80 of 2871) (P = 0.004). Multivariate analyses selected the time-dependent covariate vitiligo as the favourable independent prognostic variable associated to a longer DMFS in stage III and a higher OS in both stage III and stage IV. Conclusion: Melanoma-associated vitiligo should be considered as a distinct clinical entity, separate from vitiligo vulgaris, and identifies a subgroup of patients characterised by a high prevalence of immune-mediated diseases and by a favourable prognosis.