A population-based analysis of risk factors for a second primary cutaneous melanoma among melanoma survivors

BACKGROUND. The results of several studies have provided evidence that patients diagnosed with cutaneous melanoma (CM) are at a higher risk of developing a second primary CM than the general population. In this study, the authors examined how the risk of a second primary tumor varied with time from diagnosis of CM and examined the patient- specific factors that modify a CM patient's risk of developing a second primary tumor. METHODS. Survival curves for time from first CM to second CM were calculated using the Kaplan-Meier method. The Cox proportional hazards model was used to determine which demographic- and disease-related factors influence the risk of a second CM. RESULTS. Approximately 0.5% of Surveillance, Epidemiology, and End Results (SEER) CM patients were found to have synchronous second primaries. The estimated cumulative probability of having a second primary CM was 0.99% at 1 year after initial CM diagnosis, 2.06% at 5 years, 3.17% at 10 years, and 5.34% at 20 years. Risk was significantly greater for males; older patients; patients with first CM on the face, neck, or trunk; those from the Atlanta, Hawaii, or Connecticut registries; and more recently diagnosed patients. Risk was lower for patients from the Utah registry and those with Stage IV disease. CONCLUSIONS. The elevated risk for CM among CM survivors appears to be greatest in the first few months, and then subsequently declines. However, the risk for a second CM among CM survivors was found to remain substantially higher than the risk for a first CM in the general population throughout the observation period (> 20 years). Demographic- and disease-related factors substantially modify the risk of a second primary CM. Cancer 2003;97:639-43. (C) 2003 American Cancer Society.