LOS ANGELES, Aug. 2 (UPI) -- Although there has been some suggestion in studies that erectile dysfunction drugs can lower the risk for prostate cancer, a recent study showed little effect on rates of the disease, researchers report.
Roughly the same number of people using drugs for erectile dysfunction were diagnosed with prostate cancer as those not prescribed the drugs during in a study at Cedars-Sinai Medical Center.
Between 20 percent and 40 percent of men in their 60s and nearly 75 percent of men in their 70s experience erectile dysfunction, with a range of phosphodiesterase type 5 inhibitor, or PDE-5is, drugs available to treat the problem.
Some studies with mice have suggested an anticancer effect of using the drugs, though researchers involved with the study note this has been seen to a lesser extent with humans.
"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, said in a press release.
For the study, published in the Journal of Urology, researchers followed 6,501 men for four years, 364 of whom were using PDE-5is drugs, while the rest were not.
During the study, 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 the researchers call statistically insignificant.
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 size of the study, researchers say 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 followup 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.