Cedars-Sinai Medical Center (Photo : Cedars-Sinai Medical Center)
A four-year study of 6,501 men has found no proof that taking erectile dysfunction drugs such as Viagra can lower the incidence of prostate cancer among men.
The study by the Cedars-Sinai Medical Center showed 19.5 percent of men on erectile dysfunction drugs were diagnosed with prostate cancer compared to 22.7 percent of men not using the drugs -- a difference researchers called statistically insignificant. The study did, however, discover a lower incidence of prostate cancer diagnosis among men on erectile dysfunction drugs.
Between 20 percent and 40 percent of men in their 60s and nearly 75 percent of men in their 70s experience erectile dysfunction. A range of phosphodiesterase type 5 inhibitor or PDE-5is drugs are available to treat erectile dysfunction.
There were suggestions in other studies that erectile dysfunction drugs can lower the risk for prostate cancer. Some studies with mice suggested an anticancer effect of using the drugs, but Cedars-Sinai researchers involved with the study note this has been seen to a lesser extent with humans.
The Cedars-Sinai study said about the same number of men using erectile dysfunction drugs were diagnosed with prostate cancer as those not prescribed the drugs.
"Given the routine use of PDE-5i and the possibility that these agents may have anticancer activity, we wanted to test the association between their use and risk of developing prostate cancer," Dr. Stephen Freedland, a researcher in the departments of urology and surgery at Cedars-Sinai.
The study published in the Journal of Urology followed 6,501 men for four years, 364 of whom were using PDE-5is drugs while the rest did not.
The researchers also looked at men in North America because of a higher prevalence of using the drugs, finding a similar, but also statistically insignificant, effect on prostate cancer diagnosis.
Despite the small size of the study, researchers said more work is required to establish whether there is a link between the drugs and cancer diagnosis, regardless of how small the evidence has been thus far.
"Future studies with longer follow-up and larger study populations are warranted to determine the association between PDE-5i and prostate cancer," said Dr. Juzar Jamnagerwalla, a urology resident at Cedars-Sinai.
