Melanoma-specific survival before and after inclusion in a familial melanoma dermatologic surveillance program in CDKN2A mutation carriers and non-carriers

Abstract

Background: Inherited mutations in the CDKN2A gene are among the strongest known risk factors for cutaneous melanoma. Further, previous studies have reported inferior melanoma-specific survival in CDKN2A mutation carriers. Objectives: Here, the melanoma-specific survival was studied, depending on CDKN2A carrier status and if the melanomas had been diagnosed before or after families were included in a surveillance program. Methods: Melanoma-prone families participating in this study were identified through a nationwide preventive program starting in 1987. Information on melanoma tumours and deaths was obtained through the Swedish Cancer Registry and Cause of Death Registry. Kaplan–Meier and Cox proportional hazards regression models were used to assess melanoma-specific survival in four defined cohorts, CDKN2A mutation (MUT) carriers with first invasive melanoma before or after inclusion [MUT-pre (n = 53) and MUT-post (n = 43)] and likewise in CDKN2A wild type (WT) cases [WT-pre (n = 255) and WT-post (n = 122)]. Results: The MUT-pre and MUT-post cases were diagnosed with their first invasive melanoma at a significantly younger ages (38 and 42 years, respectively) than the WT-pre and WT-post cases (48 and 57 years, respectively). The melanomas in the MUT-pre had significantly higher T stage compared with MUT-post (p = 0.006), whereas no such difference was seen comparing WT-pre with WT-post (p = 0.849). MUT-pre had compared with WT-pre, significantly worse melanoma-specific survival, unadjusted (HR 2.33, 95% CI 1.33–4.08, p = 0.003) adjusted (HR 2.70, 95% CI 1.46–5.00, p = 0.001). However, the MUT-post cases had compared with the WT-post cases, no significant survival differences. Conclusion: This study is the first to address the impact on survival from introducing a dermatologic surveillance program to familial melanoma cases with or without CDKN2A mutations. The CDKN2A-mut carriers appeared to have a clear benefit with less advanced melanomas diagnosed and better melanoma-specific survival after inclusion. Among the CDKN2A-wt cases, the effect of the inclusion on the studied outcomes was less evident.