Clinicopathological, Genetic and Survival Advantages of Naevus-associated Melanomas: A Cohort Study
Xavier Bosch-Amate, Sebastian Podlipnik, Constanza Riquelme-Mc Loughlin, Cristina Carrera, Alicia Barreiro-Capurro, Adriana García-Herrera, Llucia Alós, Josep Malvehy, Susana Puig
Several studies have suggested that naevus-associated melanomas differ from de novo melanomas, being thinner and with less ulceration; however, the prognostic implication is unclear. The objective of this study was to describe clinicopathological, genetic and survival characteristics of de novo and naevus-associated melanomas in a cohort of primary invasive cutaneous melanomas over a 20-year period. Of the 2,227 patients included in the study, 509 (22.86%) had naevus-associated melanomas. Compared with patients with de novo melanoma, they were younger, with a fairer phototype and a higher naevus count, tumours were predominantly the superficial spreading subtype, American Joint Committee on Cancer stage I, located on the trunk, and there were fewer signs of invasiveness (thinner Breslow index, less ulceration, lower mitotic index and less satellitosis). Germline mutational status did not show any significant association. As determined through univariate analysis, overall survival was significantly better in patients with naevus- associated melanoma (hazard ratio 0.64; 95% confidence interval 0.51–0.80, p < 0.001), but multivariate analysis did not support this prognostic indication (hazard ratio 0.94; 95% confidence interval 0.75–1.18, p < 0.606). Despite this, we conclude that naevus- associated and de novo melanomas should be considered as different subtypes of melanoma.
Several studies have suggested that naevus-associated melanomas differ from de novo melanomas, being thinner and less ulcerated; however, the prognostic implication is unclear. In the study cohort of 2,227 patients, there were 509 (22.86%) naevus-associated melanomas, and when compared with patients with de novo melanoma, they were younger with a fairer phototype, tumours were located on the trunk, and showed fewer signs of invasiveness. Germline mutational status did not show significant associations. Overall survival was not significantly better for naevus- associated melanoma on multivariate analysis. However, despite this finding, it is concluded that they should be considered as different types of melanoma.