Rehab program improves erectile function after RP

February 1, 2006

New York--A multifaceted rehabilitation program designed to improve erectile performance and penile length in men undergoing radical prostatectomy was successful in nearly three-fourths of cases, according to researchers from the M.D. Anderson Cancer Center in Houston.

The program was initiated at M.D. Anderson nearly 4 years ago, said Run Wang, MD, who is director of sexual medicine there. It was modeled on a pioneering program developed by Francesco Montorsi, MD, Universita Vite Salute San Raffaele in Mi-lan, Italy. Dr. Montorsi's data documented return of erectile function in 67% of men who had bilateral nerve-sparing radical prostatectomies.

"Erectile dysfunction and decreased penile length are commonly reported side effects of radical prostatectomy," Dr. Wang noted in his presentation at the Sexual Medicine Society of North America fall meeting here.

Its main interventions were daily use of a vacuum erection device and biweekly intracavernosal injections combining papaverine, phentolamine, and prostaglandin E1 (Trimix). These were accompanied by patient-directed use of sildenafil citrate (Viagra). Penile length was measured before surgery, 6 weeks after surgery, and then at 4-month intervals up to 2 years.

Some patients dropped out of the study, leaving 39 available for evaluation of penile length and return of erectile dysfunction at the mean follow-up of 12 months. Of these, 25 had undergone sural nerve grafting at the time of surgery; the others had not.

The potency rate, as measured by responses to questions 2 and 3 of the Sexual Encounter Profile, were 72% (18 of 25) for men who had sural nerve grafting, and 71% (10 of 14) for the men who did not receive grafts, a statistically insignificant difference. However, Dr. Wang noted, the potency rate for the men who did not have nerve grafts was significantly better than in previously reported patient cohorts elsewhere (less than 40%).

Penile measurements were performed on 33 of the 39 patients 12 months postoperatively. Those who had return of erectile function had a significant improvement compared with the 6-week postoperative measurement, Dr. Wang said, with a mean increase of 1.5 centimeters, compared with 0.2 centimeters for those who did not re-gain function.

"Our data clearly show return of erectile function even though only the unilateral nerve is spared," he said, noting that the results reported by Dr. Montorsi were for men who had undergone bilateral nerve-sparing prostatectomy.

Dropout rate puzzling

With such promising results, Dr. Wang said he is seeking an answer to a puzzling question: Why did so many men drop out of the program?

Among the first 100 men who took part in the program, recommended five-times-weekly use of the vacuum erection device fell from 73% at 4 months to 66.7% at 8 months, and to 47% at 12 months. The percentage of men receiving intracavernosal injections was 52% at 4 months and 26% at 8 months, although it rose to 35% at 12 months.

One possible reason for dropping out is treatment success.

"They have return of function, so they no longer need rehabilitation," Dr. Wang said.

Older patients, specifically those 57 years and older, were more likely to continue the program. It's possible that younger patients were too busy with their work, Dr. Wang said, although that remains unclear. Stopping use of the vacuum device or intracavernosal injections is understandable because they are "not natural, inconvenient, can be unpleasant, or time consuming," he noted.

The dropout rate has made Dr. Wang and his colleagues rethink the length of the program.

"We thought that 2 years would be ne cessary, but probably 1 year is enough," Dr. Wang said.

His research on the reasons for dropping out is ongoing.

"We will find out more about compliance," Dr. Wang said. "If it is return of function, that is good news."