Outcomes and Risk Factors in Patients with Multiple Primary Melanomas

The incidence and patient survival rates of melanoma have increased over the last several decades, with a growing population of patients who develop multiple primary melanomas (MPMs). To determine risk factors for developing MPMs and compare the survival of patients with MPMs to those with single primary melanomas, a prospective, multidisciplinary database of patients with melanoma at a single tertiary care institution was retrospectively reviewed. From 1985 to 2013, 6,963 patients with single primary melanomas and 305 patients with MPMs were identified. Mean follow-up was 8.3 ± 6.3 years for patients with single primary melanomas and 8.8 ± 5.9 years for patients with MPMs. Risk of developing multiple melanomas increased with age at diagnosis of first melanoma (hazard ratio [HR] = 1.20 for a 10-year increase in age, 95% confidence interval [CI] = 1.11-1.29, P < 0.001), male sex (HR = 1.44, 95% CI = 1.12-1.84, P = 0.005), and white race (HR = 3.07, 95% CI = 1.45-6.51). Patients with invasive MPMs had increased risk of melanoma-specific death both before (HR = 1.47, 95% CI = 1.0-2.2) and after adjusting for age, sex, site, race, family history of melanoma, personal history of other cancer, and Surveillance, Epidemiology, and End Results Program (SEER) stage (HR = 1.44, 95% CI = 0.95-2.2); however, this result did not reach statistical significance.