Incidence of Second Primary Melanoma in Cutaneous Melanoma Survivors

Background Cutaneous melanoma survivors are at increased risk of a second primary melanoma. Valid estimates facilitate counseling on recommended surveillance after a melanoma diagnosis. However, most estimates of 5- and 10-year incidences of second melanomas are from older cohorts and/or single institutions. This study aimed to determine the 5- and 10-year incidences of second primary cutaneous melanomas in survivors of cutaneous melanoma. Methods The Surveillance, Epidemiology, and End Results (SEER) database was used to identify cases of non-metastatic, first cutaneous melanoma diagnosed between 1998 and 2012 (follow-up through December 2017). Eligible survivors were 18 years old or older who underwent surgery as a treatment component. Kaplan-Meier survival analysis was used to estimate 5- and 10-year incidences of a second melanoma, excluding new diagnoses within 3 months after the initial diagnosis. Patients were censored at second melanoma diagnosis, death, or 10-years, whichever was first. Multivariable Cox regression analysis was used to identify factors associated with a second cutaneous melanoma diagnosis. Results The study cohort comprised 152,811 patients. The incidence of second primary melanoma was 3.9% at 5 years (95% confidence interval [CI], 3.8–4.0%) and 6.7% at 10 years (95% CI, 6.6–6.9%). Older age, male sex, and regional disease were associated with increased risk of a second primary melanoma diagnosis. Conclusion Melanoma survivors are at risk of a second primary melanoma, making routine skin surveillance part of recommended follow-up evaluation. A higher incidence of second melanoma with older age and regional disease at presentation is possibly explained by increased health care use providing more diagnostic opportunities, whereas male sex may represent an inherent risk factor.