Epidemiology and survival outcomes of ocular and mucosal melanomas: A population‐based analysis

Extracutaneous melanomas are poorly characterized tumors that include ocular (OM), mucosal (MM) and leptomeningeal melanomas, often lacking standardized staging and treatment guidelines. We analyzed cases of cutaneous melanoma (CM, N = 219,890), OM (N = 7,069) and MM (N = 2,755) of different anatomical origins, diagnosed between 1988 and 2010, recorded in the Surveillance Epidemiology and End Results (SEER) database. Relative survival was studied in patients grouped by summary stage classification (localized, regional or distant disease) and in multivariate models adjusting for varying distribution of baseline factors. Unlike in CM, the incidence rate in MM increased exponentially with age. Five-year relative survival was significantly worse for OM (78%) and for most mucosal sites (aggregate 34%, range 3-69%) compared with CM (89%). The differences between primary sites were particularly pronounced in localized disease, with a hazard ratio of 5.7 for OM, 4.3-9.0 for external genital or oral cavity MM and 19.8-90.4 for other mucosal locations. Melanomas of the pharynx, gastrointestinal, urinary tract and vagina had poor outcomes regardless of clinical stage. In contrast to CM, there was no evidence of improved survival in OM and MM during the study period. A substantial proportion of patients with operable OM or MM underwent radical organ resections (13-88% depending on site and stage) or perioperative radiotherapy (0-66%). In conclusion, extracutaneous melanomas have a markedly worse survival than CM and aggressive locoregional management appears to be insufficient for their control. Because of poor outcomes in MM, studies of systemic therapy are warranted regardless of the extent of disease at presentation.