Exploring the association between melanoma and glioma risks.

PURPOSE: Gliomas are one of the most fatal malignancies, with largely unknown etiology. This study examines a possible connection between glioma and melanoma, which might provide insight into gliomas' etiology. METHODS: Using data provided by the Surveillance, Epidemiology, and End Results program from 1992 to 2009, a cohort was constructed to determine the incidence rates of glioma among those who had a prior diagnosis of invasive melanoma. Glioma rates in those with prior melanoma were compared with those in the general population. RESULTS: The incidence rate of all gliomas was greater among melanoma cases than in the general population: 10.46 versus 6.13 cases per 100,000 person-years, standardized incidence ratios = 1.42 (1.22-1.62). The female excess rate was slightly greater (42%) than that among males (29%). Sensitivity analyses did not reveal evidence that radiation treatment of melanoma is responsible for the detected gap in the rates of gliomas. CONCLUSIONS: Our analysis documented increased risk of glioma among melanoma patients. Because no common environmental risk factors are identified for glioma and melanoma, it is hypothesized that a common genetic predisposition may be responsible for the detected association.