Men with a history of prostate cancer (PCa) are at increased risk of melanoma, a new study suggests.

Researchers came to that conclusion based on a study of 42,372 men in the Health Professionals’ Follow-Up Study (HPFS) and 18,603 men in the Physicians’ Health Study (PHS). A history of PCa was associated with an 83% increased risk of melanoma in the HPFS, a 2.2-fold increased risk in the PHS, and an 89% increased risk when the results of the two cohorts were combined.

The investigators, led by Jiali Han, PhD, of Tianjin Medical University Cancer Institute and Hospital in Tianjin, China, found no association between PCa and other non-skin cancers, “suggesting that the association between PCa and melanoma risk may not be explained by increased medical surveillance,” according to a report published online ahead of print in the Journal of Clinical Oncology.

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Dr. Han’s group postulated that androgens may have a role in the etiology of melanoma. “PCa develops in an androgen-dependent epithelium and is a well-recognized androgen-related cancer, although the relationships between circulating androgens and PCa risk have not been elucidated from epidemiologic studies,” the authors explained.

The researchers documented 539 melanomas in the HPFS and 166 in the PHS during 747,176 person-years and 251,850 person-years, respectively.

“Our finding of a PCa diagnosis as a risk predictor for melanoma holds general public health significance, which may inform clinical practice to address the queries and aid the care of patients with PCa,” the researchers concluded.

They noted that severe acne, a surrogate for androgen activity, was positively associated with PCa risk in a previous study by Elizabeth A. Platz, ScD, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues. That study, which was published in the International Journal of Cancer (2007;121:2688-2692), also looked at men in the HPFS. The investigators found that men with severe acne—as measured by tetracycline use for four or more years—had a significant 70% increased risk of PCa compared with men who did not have severe acne.

Dr. Han and colleagues noted that acne is a chronic inflammatory disease with androgen-induced sebum production as a major contributing factor.

Androgens may influence melanoma risk by suppressing host immune response, and deficiency in immune response has been implicated in prostatic tumorigenesis, the researchers observed. “Therefore, PCa and a suppressed immune system might contribute to melanoma development,” they wrote, adding that common genetic variations also have been identified for PCa and melanoma.