A recent study has implicated Viagra as a cause of skin cancer. A study found that men who used the erection-enhancing drug sildenafil (Viagra) were 84% more likely to develop melanoma, a very significant skin cancer. That’s especially important for older men, who are at greater risk for developing melanoma and also at greater risk for dying from it. An estimated 76,000 Americans (more than half of them men) will be diagnosed with melanoma this year, and almost 10,000 will die from it.
Here are two truths about this work that you need to know. 1) This study does not show that Viagra causes skin cancer. Instead, it shows that in a large group of men, those who said they used Viagra ended up being diagnosed more often with melanoma than those who didn’t use this drug. The study shows a connection, but not a cause. 2). Even if Viagra does promote melanoma, the absolute increase is small.
The study grew out of laboratory research on how Viagra acts on cell-to-cell signaling pathways. This work demonstrated that the drug mimics key parts of a process that lets melanoma cells spread to other parts of the body. Skin cancer that spreads (metastasizes) is hard to control and can end in death.
Over the next decade, among the 29,929 men who said they had never used Viagra, 128 developed melanoma. Among the 1,618 Viagra users, 14 developed melanoma. In other words, 4.3 of every 1,000 who didn’t take Viagra developed melanoma compared to 8.6 of every 1,000 men who took Viagra.
After statistical adjustments, the increase from 4.3 to 8.6 is the 84% increase in risk that many news reports focused on. Researchers call that the relative risk (one group compared to another). The absolute increase, 4.3 cases per 1,000 men, represents an increase of 0.43%.
Whether a similar connection might exist between other erectile dysfunction drugs and melanoma isn’t known.
The raw numbers suggest that the risk for melanoma associated with Viagra is small. It’s even smaller than what was reported in the study because not all of the 14 cancers in the Viagra group can be attributed to the drug. Many factors affect a man’s risk of melanoma—the most important of which are age and cumulative exposure to ultraviolet (UV) radiation.
Should men who use Viagra worry about getting melanoma? Right now, no one can say. The relationship could be pure coincidence.
My advice to men: Protect your skin from too much sun and have routine skin checks to identify melanoma and other types of skin cancer early, while they are still treatable.
Bottom Line: In short, be afraid—but not of Viagra. Be concerned about getting too much sun and pay attention to weird-looking moles that could turn into metastatic cancer. Cover up when you go outside, and use a broad-spectrum sunscreen liberally when you do go out into the sun to work and play.
