No Conclusive Link Between Erectile Dysfunction Drugs & One of the Most Dangerous Forms of Skin Cancer
A rigorous analysis of more than 20,000 medical records concludes that erectile dysfunction drugs, such as Viagra, are not a cause of melanoma, an often deadly form of skin cancer, despite the higher risk for the disease among users of these drugs. A is to be published in the Journal of the American Medical Association online June 23.
Led by researchers at 秘密研究所 Langone Medical Center and its Laura and Isaac Perlmutter Cancer Center, the analysis of medical records for some 20,235 mostly white men suggests instead that the likely source of the observed uptick in malignant melanoma risk among users of erectile dysfunction drugs is socioeconomic and lifestyle based.
鈥淲hat 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鈥攎en who likely can also afford more vacations in the sun鈥攁nd who also have the means to buy erectile dysfunction medications, which are very expensive,鈥 says Stacy Loeb, MD, lead study investigator and 秘密研究所 Langone urologist.
鈥淲hile 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,鈥 says Loeb, an assistant professor at 秘密研究所 Langone and member of its Perlmutter Cancer Center.
鈥淧hysicians 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,鈥 says Loeb, whose latest study was prompted by a highly cited 2014 analysis in 14 men who had taken Viagra and were later diagnosed with melanoma.
Among the more than 20,000 men whose records were studied, 4,065 were found to have malignant melanoma between 2006 and 2012. Among these men were 2,148 who had used any of the three main drugs for erectile dysfunction鈥擵iagra (also known as sildenafil), Levitra (vardenafil), and Cialis (tadalafil)鈥攁nd some 435 had the skin cancer.
Researchers who led the analysis say that while there was a greater statistical risk of developing malignant melanoma among erectile dysfunction drug users鈥攁n overall increased risk of 21 percent for having filled a single prescription鈥攁 closer look at the numbers revealed no increased risk among those men with the most prescriptions. Researchers say that a 鈥渄ose relationship,鈥 meaning the more drugs taken the higher the risk, would usually be expected if the drugs were a direct cause of the cancer.
The 秘密研究所 Langone team and their colleagues in Sweden also found no correlation between the more advanced stages of the disease and drug usage. The only detected association was between any use of the drugs and the earliest stages of melanoma, further weakening the idea that the drugs were behind the overall observed increase in risk.
Moreover, researchers say their calculations of statistical risk would have been expected to be different for other types of skin cancer if the drugs, known collectively as phosphodiesterase type-5 inhibitors (PDE5i), actually caused the disease. Instead, researchers found almost the same increased risk for another type of skin cancer, basal cell carcinoma, at 19 percent higher risk, which is linked to different biological pathways than the shared pathway involved in PDE5i use and malignant melanoma.
鈥淲hen used appropriately, erectile dysfunction medications are very effective and improve the quality of life for many men, so men should know it is doubtful that taking these medications puts them at greater risk of getting skin cancer,鈥 says Loeb, who encourages her male patients to always practice skin cancer prevention by minimizing their exposure to the sun.
For the study, researchers matched and analyzed the medical records of men whose care was being monitored by the National Melanoma Register and the Prescribed Drug Register in Sweden, one of the few countries in the world taking a population-wide approach to battling melanoma and other types of cancer, and for which no comparable North American data source exists.
Funding support for the study was provided by grants from the Swedish Research Council (825-2012-5047), the Swedish Cancer Foundation (11-0471), Vasterbotten County Council, and the Lion鈥檚 Cancer Research Foundation at Umea University in Umea, Sweden. Additional funding support was provided by the Laura and Isaac Perlmutter Cancer Center, and the Louis Feil Charitable Lead Trust. Loeb has received speaking fees about a prostate cancer medication manufactured by Bayer, which also markets Levitra.
In addition to Loeb, other investigators involved in the study were Yasin Folkvaljon, MD, at Uppsala University Hospital in Uppsala, Sweden; Mats Lambe, MD, PhD, at the Karolinska Institute in Stockholm, Sweden; Hans Garmo, PhD, at King鈥檚 College in London, UK; Christian Ingvar, MD, PhD, at Lund University in Helsingborg, Sweden; David Robinson, MD, PhD, and senior study investigator Par Stattin, MD, PhD, both at Umea University in Umea, Sweden.
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