NEW YORK (Reuters) -- Men with prostate cancer are just as likely to develop impotence with radiation therapy as they are with surgical removal of the prostate gland, a new study suggests. Yet, the new findings seem to contradict previous research, which has found that radiation treatment has a lower risk of sexual dysfunction, experts caution.
"I think our data are a long first step at showing that differences [in impotence rates] aren't going to be dramatically different," said lead author Dr. James Talcott, an assistant professor of medicine at Harvard Medical School in Boston.
"People getting treatment for prostate cancer should expect to be impotent eventually. Some won't, but most will," said Talcott, who presented his findings this week at the American Society of Therapeutic Radiology and Oncology meeting in Los Angeles. "The difference doesn't appear big enough to be using as a basis for choosing treatment."
According to a survey of 260 men, about 96% were impotent three months after a radical prostatectomy -- a complete surgical removal of the prostate -- compared to only 58% of men after radiation treatment. One year later, 93% of surgical patients were impotent, as were 67% of radiation patients. But two years after the treatment, 85% of surgical patients were impotent and 88% of radiation group experienced sexual dysfunction.
However, those who underwent radiation were slightly older -- about 68 year of age versus 62 years of age -- compared to those having surgery, and were more likely to be impotent before the treatment began (45% versus 32%).
"The character of impotence for radiation therapy patients is a little different from surgery patients -- who tend to be completely impotent," said Talcott. "Radiation therapy patients commonly have erections which are not firm enough for sexual activity."
Impotence worsens over time for patients who have radiation therapy because of the development of scar tissue, according to the Boston researcher.
"With radiation it starts off well, but over time the scarring it produces has effects," he said. Scarring can damage nerves and blood vessels that direct blood flow into the penis or may interfere with valves that maintain an erection by preventing blood from leaving the penis, according to Talcott.
However, a second study also presented at the meeting found that of 45 patients between 50 and 65 years of age, only 27% of men who functioned sexually before radiation therapy were impotent three years after radiation therapy.
"I don't know what [Talcott's] data means; I can't reconcile the two," said study co-author Dr. Gerald Hanks, chairman of the department of radiation oncology at Fox Chase Cancer Center in Philadelphia.
The best advice for men with a diagnosis of prostate cancer is to discuss all their treatment options with their doctor, according to Talcott. Many times prostate cancer grows very slowly and can be treated with "watchful waiting" -- monitoring of the cancer while taking no further action.
"It is useful for many men to think of prostate cancer as a disease less like lung cancer or acute leukemia, which kills you quickly, and perhaps more like a diagnosis of diabetes or heart disease," he said. "You are not looking down the barrel of a gun."
