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Since 2014, there have been several reports linking sildenafil (Viagra), a phosphodiesterase inhibitor (PDE5i), to an increased risk of melanoma.
In a paper published in the Journal of the National Cancer Institute
[1] (online, 19 May 2017), researchers carried out a meta-analysis on data from three case-control studies and two cohort studies, which were carried out between 1998 and 2016, involving a total of 866,049 men.
They found that men exposed to PDE5i had an increased risk of melanoma (relative risk 1.11, 95% confidence interval 1.02–1.22). However, there was a lack of dose response or clear relationship to melanoma staging, nor was there specificity for the type of skin cancer which, the researchers say, suggests against a causal relationship.
The observed association is possibly due to confounding factors, most likely sunlight exposure, the team conclude.
References
[1] Loeb S, Ventimiglia E, Salonia A et al. Meta-analysis of the association between phosphodiesterase inhibitors (PDE5Is) and risk of melanoma. J Natl Cancer Inst 2017;109. doi: 10.1093/jnci/djx086
