SAN ANTONIO — A large longitudinal study of men who underwent radical prostatectomy has shown a small but statistically significant increase in sexual potency between 2 and 5 years after radical prostatectomy, David F. Penson, M.D., reported at the annual meeting of the American Urological Association.
On the other hand, incontinence worsened between 2 and 5 years post surgery after improving between 6 months and 2 years, according to Dr. Penson of the University of Southern California, Los Angeles.
Part of the Prostate Cancer Outcomes Study (PCOS), the population-based, longitudinal study used tumor registries to identify all men with prostate cancer in three states—Connecticut, New Mexico, and Utah—and three metropolitan areas—Atlanta, Los Angeles, and Seattle.
Dr. Penson's study included 1,288 men with localized prostate cancer who underwent radical prostatectomy. The patients completed surveys at baseline and then again at 6, 12, 24, and 60 months after surgery.
At baseline, 17% of the men reported having erections that were not firm enough for intercourse. That figure rose to 89% at 6 months following surgery and declined, thereafter, to 81% at 12 months, 75% at 24 months, and 71% at 60 months.
Discussing the study at a press briefing, Dr. Penson expressed surprise at the increase in potency between 24 and 60 months. “That's statistically significant, but it's also clinically meaningful,” he said.
He listed three possibilities for this finding:
▸ The first reason is that the study could have been inadequate. Some patients were lost to follow-up, and this may have skewed the results.
▸ The second reason is that perhaps there was a true late return of function. “That's a new idea,” Dr. Penson said. “Most urologists would say, if you're not potent by 2 years it's probably not going to get any better. Certainly that's what I've been telling my patients.”
▸ The last possibility is what Dr. Penson called the Viagra effect. Viagra became available in 1998, year 3 of the PCOS study.
Patients in the study were asked whether they tried Viagra (sildenafil), and if so, how much they thought it helped. About two-thirds of the men under age 60 at the time of surgery who tried Viagra said the drug helped somewhat or a lot. This percentage declined significantly among men over 60, however. For example, 66% of men aged 60–64 years said that Viagra didn't help at all.
The study also examined the effect of nerve-sparing surgery. As expected, bilateral nerve-sparing surgery proved to be significantly more effective at preserving potency than unilateral nerve-sparing surgery or no nerve sparing.
Bilateral nerve-sparing surgery helped younger men significantly more than older men. Among men aged 39–54 years at the time of the surgery, 71% reported erections firm enough for intercourse. But only 46% of the men aged 60–64 years and 18% of the men aged 65 and older reported that bilateral nerve-sparing surgery preserved their potency.
Dr. Penson disclosed a relationship with Pfizer Inc., maker of Viagra, as well as with several other pharmaceutical companies.