The increased risk of skin cancer identified among men taking PDE5 inhibitors is not thought to be caused by the pill itself.
The results are published in the journal JAMA, and the study was led by Dr. Stacy Loeb, of the NYU Langone Medical Center in New York City. She says:
"What our study results show is that groups of men who are more likely to get malignant melanoma include those with higher disposable incomes and education - men who likely can also afford more vacations in the sun - and who also have the means to buy erectile dysfunction medications, which are very expensive."
The researchers looked into the link because a recent study based on 14 cases of malignant melanoma among men taking phosphodiesterase type 5 (PDE5) inhibitors - which also include vardenafil (Levitra) and tadalafil (Cialis) - saw an increased risk.
The enzyme PDE5 is the target of oral erectile dysfunction and part of a pathway that has been implicated in the development of malignant melanoma.
Among the more than 20,000 men whose records were studied, 4,065 were found to have malignant melanoma between 2006 and 2012.
In that group, 2,148 had used one of the three PDE5 inhibitors, of which 435 men had the skin cancer.
A modest but statistically significant increased risk of melanoma was found in men taking PDE5 inhibitors. The most pronounced increase in risk was observed in men who had filled a single prescription - an overall increased risk of 21%.
But this risk was not significant among men with multiple filled prescriptions - a lack of dose-response that formed one of the reasons for doubting a causal relationship.
Dr. Loeb says:
"Physicians should still screen men for melanoma risk, but they do not need to add use of erectile dysfunction drugs to their list of screening criteria."
The assistant professor at NYU Langone adds: "While medications for erectile dysfunction come with serious risk of a drop in blood pressure if taken together with other medicines called nitrates, overall they are safe medications, and our results suggest that physicians should not be concerned that the drugs cause melanoma."
- Melanoma is one of three common types of skin cancer and the most dangerous form.
- It is rare compared with the other two common skin cancer types.
- Numerous risk factors have been identified for melanoma.
The NYU Langone team and their colleagues in Sweden also found no correlation with more advanced melanoma.
The only association found was with the earliest stages of melanoma. Further, the researchers say their calculations of statistical risk would have been different for other types of skin cancer if the drugs caused the disease, but the risk for basal cell carcinoma was similar.
"When used appropriately, erectile dysfunction medications are very effective and improve the quality of life for many men,: says Dr. Loeb, "so men should know it is doubtful that taking these medications puts them at greater risk of getting skin cancer."