Risk of second primary malignancies following cutaneous melanoma diagnosis: a population-based study

Understanding risk patterns for developing a second primary malignancy (SPM) after cutaneous melanoma (CM) has implications for both research and clinical practice, including cancer screening.

We sought to describe incidence patterns of SPMs occurring after CM.

We calculated incidence rates and relative risks for the development of 65 different SPMs occurring in 16,591 CM survivors during 1.3 million person-years of observation in the Surveillance, Epidemiology, and End Results program data from 1973 to 2003.

Compared with the general population, CM survivors had a 32% higher risk of developing any SPM and demonstrated significantly elevated risks for 13 cancers: melanoma of the skin (standardized incidence ratio [SIR] 8.99), soft tissue (SIR 2.80), melanoma of the eye and orbit (SIR 2.64), nonepithelial skin (SIR 2.31), salivary gland (SIR 2.18), bone and joint (SIR 1.70), thyroid (SIR 1.90), kidney (SIR 1.29), chronic lymphocytic leukemia (SIR 1.29), brain and nervous system (SIR 1.31), non-Hodgkin lymphoma (SIR 1.25), prostate (SIR 1.13), and female breast (SIR 1.07). Risks of second primary melanoma of the skin, melanoma of the eye and orbit, and cancers of the prostate, soft tissue, salivary gland, and bone and joint were elevated throughout the study period, implying no surveillance bias.

Possible underreporting of CM incidence in cancer registries is a limitation. In addition, the lack of individual-level data in cancer registry data precludes detailed examination of coincident risk factors.

Risks of particular SPMs after CM may be explained by surveillance bias or shared risk factors. However, these probably do not explain the increased risks observed for prostate, soft tissue, salivary gland, and bone and joint cancers years after CM diagnosis. Further investigation into genetic or environmental commonalities between CM and these cancers is warranted.