You may remember a large study published last year that seemed to find a link between Viagra use and melanoma. The study, from Harvard Medical School Brigham and Women s Hospital, included data on more than 51,000 men aged 40-75, and reported recent use of Viagra (sildenafil) with a near-doubling of the risk of malignant melanoma. An accompanying commentary in the same journal attempted to explain a proposed biological pathway for sildenafil to enhance malignant melanoma risk. However, when covering the study, ACSH approached it with the type of skepticism we normally direct at association studies and called for more data.
We weren t the only ones who thought this tenuous relationship needed a better look. Dr. Stacy Loeb, a urologic oncologist at NYU Medical Center, was worried about this study too, particularly after subsequent interactions with several patients.
I ve had numerous patients asking me if this is something to be worried about, and I just thought that before we jump to some kind of conclusion, or lawyers act on this, we ought to look more carefully at the details, Dr. Loeb told ACSH.
It was these patient interactions, as well as some google searches that turned up several pending lawsuits based on this study, that made her and some collaborators look at this correlation more closely. In their review of the study, one thing they picked up on was the sample size. It was a rather small sample size, in which they reported an association between reported use of sildenafil and melanoma. So, we just weren t totally convinced if this was really a causal relationship or just two things that are tracking together, she explained.
For her own study, published in JAMA, Dr. Loeb and co-authors wanted to use a large, detailed source of data to analyze, and therefore decided on the Swedish registries: The Swedish registries are really extremely comprehensive so it s just a very unique and excellent data source. They have complete record on all of the prescriptions that someone has obtained in their lifetime.
This registry afforded them a sample set that included 20,000 men s medical records. Of the men included in the study, 4,065 were found to have malignant melanoma between 2006 and 2012, and 2,148 men had used any of the three main drugs for ED, including Viagra (sildenafil), Levitra (vardenafil), and Cialis (tadalafil). Among the men who had taken ED medications, 435 had malignant melanoma.
With this data set, Dr. Loeb and her colleagues found that yes erectile dysfunction (ED) drug users are still at higher risk for serious skin cancer. The researchers discovered that there was a greater statistical risk of developing malignant melanoma among ED drug users an overall increased risk of 21 percent. However, the real reasons are likely due to lifestyle factors among men who frequently use ED medications, and not the ED medications themselves.
Socioeconomic situation tracked much better with melanoma. She explained that men who have disposable income that can be spent on expensive ED medications are also men who can afford more sunny vacations. In essence, time spent at beaches with no or inadequate use of sunscreen leads to melanoma, something we here at ACSH say a lot.
Furthermore, Dr. Loeb and her colleagues found that several other factors didn t add up for the link between ED medications and melanoma to be causal. She explained that a dose-relationship was not found, meaning if it was a causal relationship, you would expect the more prescriptions for ED drugs that you have, the higher risk of melanoma you would have, and that was not true. Additionally, there was no correlation found between drug usage and more advanced stages of melanoma.
The researchers also found a similar increased risk with another type of skin cancer, basal cell skin cancer. If there was a biological mechanism behind ED medications causing melanoma, then there likely wouldn t be a similar increased risk in this biologically distinct cancer.
These drugs are highly effective for the treatment of ED, so I don t think that the men of the world should be terrified to take them because they think that it s going to cause skin cancer, says Dr. Loeb. But, I think they should be aware that they are an at-risk population for melanoma. If anything, I hope that this raises more awareness to proven risk factors for melanoma.
So men, when you re packing for your next cruise, make sure to bring the SPF too and not just the Viagra.
