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.