Study: Potency after prostate cancer varies
Tuesday, September 27, 2011
CHICAGO -- A new study addresses one of the most worrying questions faced by men with prostate cancer: What are my chances of losing sexual function after treatment?
The answers vary greatly by age, sexual potency before treatment, PSA levels and whether a man has surgery, standard radiation or radioactive seeds, the study found.
Using the findings, men can get a rough idea of their personal odds by answering questions that also include weight and race, experts said. Unsurprisingly, older men whose sexual function is already low have the worst chances of good sexual function after treatment.
"This will make it possible for patients to have a more realistic view of what to expect for themselves, rather than trying to guess where they fit in overall compared to the average guy with prostate cancer," said study co-author Dr. Martin Sanda of Beth Israel Deaconess Medical Center in Boston.
The federally funded study, which appeared in Wednesday's Journal of the American Medical Association, included only men with early-stage cancers, and it didn't address cure rates for different treatments. In the real world, some patients have limited treatment choices. For instance, only men with early-stage, slow-growing cancers can choose radioactive pellets.
That means the findings may be most useful in giving a realistic picture of the sexual side effects of a treatment that's already chosen, rather than helping men pick a treatment.
Researchers studied factors affecting potency in men and developed a questionnaire to help measure it. They evaluated its usefulness among 1,027 prostate cancer patients ages 38 to 84 and validated its accuracy in a separate group of more than 1,900 men. It correctly predicted the chances of post-treatment potency in 77 percent of the men who had surgery to 90 percent of the men who had radiation.
The study found great variation in men's odds of having firm erections after treatment.
For surgery, the prospects for maintaining top sexual function for a 50-year-old man could range from 21 percent to 70 percent, depending on his PSA level and whether a nerve-sparing technique was used.
For standard radiation, the study found, the odds for a man keeping top sexual function ranged from 53 percent to 92 percent depending on PSA level and whether hormones were used along with radiation.
For radiation pellets, a 60-year-old man's chances of keeping top sexual function ranged from 58 percent to 98 percent depending on race and body mass index. African-Americans and trimmer men had better chances.
The study has some deficiencies, experts said.
It didn't include men who chose what's called "active surveillance," where a doctor keeps track of a tumor through regular tests and treats it only if the cancer markedly worsens. Many prostate cancer patients with slow-growing tumors can live their whole lives without symptoms or treatment, said Dr. Durado Brooks, prostate cancer director for the American Cancer Society. They die of something else before the cancer kills them.
Most patients treated for early-stage prostate cancer survive, so the common side effects of treatment -- incontinence and sexual problems -- have become more important for patients making choices.
Jerry Hardy, 57, of Detroit had nerve-sparing surgery for prostate cancer in 2000 and lost sexual function. It took three years of trying different pills and injections before he decided on a penile implant, which has worked for him and his wife. He's not sure whether having a better prediction method for future sexual function would have meant anything to him -- even with all he's been through.
"The most important thing was to cure the cancer. Then we would deal with the side effects later," Hardy said. "If you're not alive, you don't have to worry about sex."
Brooks of the American Cancer Society cautioned that sexual problems can show up later for men who have either type of radiation therapy. A two-year follow-up may not have been long enough, he said.
The study was done from 2003 through 2006, a time when laparoscopic surgery, with small incisions and often performed robotically, was less common than it is today.
Dr. Michael Barry of Massachusetts General Hospital in Boston and president of the Foundation for Informed Medical Decision Making said it's not clear yet whether the newer surgical technique is better or worse for sexual function.
"This paper gives us one piece of the puzzle," said Barry, who wrote an accompanying editorial. "It doesn't address what are my chances with problems of incontinence? Or what are my chances of dying of prostate cancer for these different treatments? A patient would want to synthesize all that information to figure out what to do."