The risk of developing a second primary cancer in melanoma patients: a comprehensive review of the literature and meta-analysis

The number of cutaneous melanoma survivors has been increasing for years due to improvements in early diagnosis and subsequent prolonged survival. These patients are at increased risk of developing a second melanoma and a second primary malignancy (SPM) at other sites as well. We performed a review of scientific literature and meta-analysis to evaluate the risk of developing a SPM (other than melanoma) among melanoma patients. Twenty-three independent papers and over 350,000 melanoma patients were included. Risk of cancer among melanoma survivors was increased overall (1.57, 95% CI 1.29-1.90) and at several sites: bone (2.09, 95% CI 1.08-4.05), non-melanoma skin cancer (4.01, 95% CI 1.81-8.87), soft tissue (6.80, 95% CI 1.29-35.98), colon-rectum (1.12, 95% CI 1.00-1.25), female breast (1.14, 95% CI 1.07-1.22), kidney (1.34, 95% CI 1.23-1.45), prostate (1.25, 95% CI 1.13-1.37) and non-Hodgkin lymphoma (1.37, 95% CI 1.22-1.54). The overall risk of SPM showed a tendency to decrease as the time from melanoma diagnosis lengthened. Most of our findings may be explained by the tendency of some exposures, which are risk factors for different tumors, to occur simultaneously in the same individuals. These results suggest primary and secondary cancer prevention counselling for melanoma survivors.