TUESDAY, Sept. 14, 2004 (HealthDayNews) -- A large majority of men who have surgery or external beam radiation treatment for prostate cancer are impotent five years after either procedure, a new study finds.
Previous research had found that surgery was likelier to lead to impotence in the short term, but this study from the National Cancer Institute (NCI) discovered that men who had radiation underwent a decline in sexual function between two and five years later.
The incidence of urinary incontinence was higher in men who had surgery, but bowel urgency and painful hemorrhoids were more common in those who had radiation therapy, said a report on the research in the Sept. 15 issue of the Journal of the National Cancer Institute.
The study results "are one element to be considered among men who want to be treated for prostate cancer," said study author Arnold L. Potosky, an epidemiologist at the NCI's division of cancer control and prevention.
But the findings provide only partial guidance, since they do not cover the long-term side effects of hormonal therapy or implanted radioactive seed treatment, which were not available when the study began, Potosky said.
Moreover, the study says nothing that could help resolve a heightening debate about whether watchful waiting, rather than any treatment, is best for men who are newly diagnosed with prostate cancer on the basis of elevated readings of prostate-specific antigen (PSA), a test now widely used to screen for the cancer, he said.
Potosky's cautious appraisal is that, "given the uncertainty about which treatment is best in terms of survival, having information about possible side effects can be useful in determining treatment."
Other studies have shown that surgery reduces deaths from prostate cancer compared to watchful waiting, but does not improve overall survival. There have been no studies that directly compare the survival benefits of radiation therapy vs. surgery.
The new report is the latest on a study that has followed more than 1,100 men with prostate cancer that had not spread beyond the gland. Earlier reports found a higher incidence of impotence -- the inability to achieve an erection -- after two years among men who had surgery (82.1 percent) than for those who had radiation therapy (50.3 percent).
But the difference had narrowed greatly after five years, with impotence reported in 79.3 percent of the surgical patients and 63.5 percent of those who had radiation. While that difference is significant, "I'm not sure it is critical in a decision about treatment," Potosky said.
Urinary incontinence was reported by 15.3 percent of men who had surgery and 4.1 percent of those treated with radiation. Bowel urgency was experienced by 29 percent of the men who had radiotherapy and 19 percent of those who had surgery, while the incidence of painful hemorrhoids was 20 percent in the radiation group, 10 percent in the surgery group."
The report is "an update on a very important study showing that interventions have a substantial impact on the quality of life" of men diagnosed with prostate cancer," said Dr. Howard L. Parnes, chief of the prostate group at the NCI's division of cancer control.
Several NCI studies now are being done to determine whether treatment is better than watchful waiting for men in screening program who have high PSA levels that traditionally have been interpreted as indicators of prostate cancer, he said. Results are not expected for several years.
The new report of a high incidence of major side effects after treatment is important because "if interventions were not toxic, you wouldn't need much proof to do an intervention," Parnes said.
"This is an issue of risk vs. benefits," he said. "The risks have been clear for a while. The benefit is less clear."
For patients and doctors, Parnes recommends "a cautious approach, which takes both risk and benefit into account."
One source of guidance about prostate cancer is the National Cancer Institute.