Background: Germline mutations in CDKN2A have been associated with increased risk of melanoma and tobacco-related cancers in respiratory and upper digestive tissues. In CDKN2A wild-type (wt) melanoma families, other known high-risk, melanoma-predisposing mutations are rare, and no increased risk has been observed for nonskin cancers in this group. This study is the first to compare survival in germline CDKN2A mutated (mut) and nonmutated melanoma cases.
Methods: Melanoma-prone families participating in this study were identified through a nationwide predictive program starting in 1987. Information on cancer diagnoses (types, stages, and dates) and deaths (causes and dates) were obtained through the Swedish Cancer Registry and Cause of Death Registry. Kaplan Meier and Cox proportional hazards regression models were used to assess survival in CDKN2Amut (n = 96) and CDKN2Awt (n = 377) familial melanoma cases and in matched sporadic melanoma cases (n = 1042). All statistical tests were two-sided.
Results: When comparing CDKN2Amut and CDKN2Awt melanoma cases, after adjusting for age, sex, and T classification, CDKN2Amut had worse survival than melanoma (hazard ratio [HR] = 2.50, 95% confidence interval [CI] = 1.49 to 4.21) and than nonmelanoma cancers (HR = 7.77, 95% CI = 3.65 to 16.51). Compared with matched sporadic cases, CDKN2Amut cases had statistically significantly worse survival from both melanoma and nonmelanoma cancers while no differences in survival were seen in CDKN2Awt compared with sporadic cases.
Conclusions:CDKN2Amut cases had statistically significantly worse survival from nonmelanoma cancers and, intriguingly, also from melanoma, compared with melanoma cases with no CDKN2A mutations. Further studies are required to elucidate possible mechanisms behind increased carcinogen susceptibility and the more aggressive melanoma phenotype in CDKN2A mutation carriers.