Patients taking PDE5 inhibitors had a higher risk of melanoma likely due to increased sun exposure.
Findings from a recent study suggest there is no increased risk of melanoma for patients taking phosphodiesterase type 5 (PDE5) inhibitors for erectile dysfunction, despite previous studies showing conflicting results about their association.
This class of drugs block PDE5, but are also linked to growth of melanoma cells in vitro, according to a study published in PLOS. The study included 145,104 patients prescribed PDE5 inhibitors, such as sildenafil, tadalafil, and vardenafil, and also included 560,933 patients in the control group.
The researchers found a small increased risk of melanoma (adjusted hazard ratio 1.14, 95% CI 1.01-1.29, p=0.04), but an increased risk of basal cell carcinoma and solar keratosis was also observed.
Both basal cell carcinoma and solar keratosis are related to sun exposure. However, researchers did not see an increase in cancer unrelated to sun exposure, such as colorectal carcinoma.
The patients taking PDE5 had an increased risk of solar keratosis prior to starting treatment, which could explain the increased risk of melanoma, according to the study.
"All of our observations pointed towards the small apparent increase in risk of melanoma in men prescribed PDE5 inhibitors being explained by greater sun exposure, rather than a side-effect of the drugs themselves,” concluded study senior author Krishnan Bhaskaran, MSc PhD.