Oral drugs called phosphodiesterase type 5 (PDE5) inhibitors are often a first-line treatment for erectile dysfunction (ED). They include medications like sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra). Experts have wondered whether there is a connection between these drugs and prostate cancer, but studies suggest that there is not.
In 2016, a team of American scientists examined the medical records of 6,501 men. Overall, about 6% of the men used a PDE5 inhibitor when the study began. About 20% of the men on ED drugs eventually developed prostate cancer. The rate was approximately 23% for the men who did not take PDE5 inhibitors. Using an ED drug did not seem to affect the severity of the cancer.
Because PDE5 inhibitors use is common in North America, the researchers also studied a subset of men from this region. They found a small link between ED drugs and fewer diagnoses of prostate cancer, but the results were not statistically significant.
Overall, the scientists concluded that there is no link between ED drugs and prostate cancer risk.
Another study, published in December 2015, looked at whether taking ED drugs raised a man’s risk of prostate cancer recurrence. Researchers studied a group of men who had had prostate cancer. Each man had had a radical prostatectomy – a surgical procedure that completely removes the prostate gland. ED is common in men who have had this operation.
The scientists focused on biochemical recurrence of prostate cancer. A man experiences a biochemical recurrence if his PSA (prostate-specific antigen) levels increase. Elevated levels might mean that the cancer has come back.
The scientists compared five years of data from two groups of men who had been treated for localized prostate cancer. (Cancer cells had not spread beyond the prostate gland.) Two-hundred ninety three men had a biochemical recurrence. The other group – 5,767 men – did not.
Fifty-one percent of the men with biochemical recurrence had taken PDE5 inhibitors. Among the men with no biochemical recurrence, the number was 58%.
The scientists concluded that there was no association between the drugs and biochemical recurrence. This result was the same even after they accounted for PSA levels, stage of cancer, marital status, education, and income.
Men who have concerns about ED or prostate cancer should always feel free to discuss them with their doctor.