Predictors of mucosal melanoma survival in a population-based setting.

BACKGROUND: Mucosal melanomas are rare and aggressive neoplasms, with little published population-based data on predictors of survival.

OBJECTIVE: We sought to assess the influences of race/ethnicity, sex, tumor stage, tumor thickness, and anatomic site on mucosal melanoma survival estimates.

METHODS: We analyzed 132,751 cases of melanoma, including 1824 mucosal melanomas, diagnosed between 1994 and 2015 and reported to the California Cancer Registry. Kaplan-Meier survival analysis and Cox proportional hazards regression assessed the prognostic variables.

RESULTS: The 5-year relative survival for mucosal melanomas (27.64% [95% confidence interval {CI} 25.42-29.91) was significantly lower than for cutaneous melanomas (76.28% [95% CI 76.03-76.53]). Stage independently influenced survival, and thickness did not predict survival for neoplasms of known depth. Less common anatomic sites conferred worse prognoses (hazard ratio 1.93 [95% CI 1.41-2.64]).

LIMITATIONS: The lack of a standardized staging system may have resulted in misclassification of stage for some neoplasms. The influence of genetics is unknown because our database did not contain genetic characteristics.

CONCLUSIONS: Stage and anatomic site, but not thickness (ie, Breslow depth), race, or ethnicity, determine the prognosis of mucosal melanomas. Considering the poor prognosis for all stages of mucosal melanoma, dermatologists should incorporate examination of the oropharynx and genitalia in the full body skin examination.