Side Effects of Prostate Cancer Treatments
The current study involved 1,655 men who had stage 1 or 2 prostate cancer, which had not spread beyond the prostate. Men were diagnosed between ages 55 and 74 in 1994 and 1995, and most were treated in the year of diagnosis.
About 70 percent of the participants had radical prostatectomy, while the remaining 30 percent had external-beam radiation therapy, in which high-energy rays are directed from outside the body.
Treatment choice can vary based on a number of factors including age, prostate cancer stage and other diseases, Resnick said. The researchers took into account these differences when analyzing treatment outcomes.
The study authors asked the men about their urinary, sexual and bowel function before they had been diagnosed, as well as in the months following treatment. Participants also rated their own health in these areas.
Although there were declines after both treatments, men who received surgery reported sharper declines in urinary and sexual health, from a score of about 95 and 70, respectively, before surgery to about 60 and 20 in the months after.
"We would look at these changes and say they are meaningful," said Dr. John Wei, a professor of urology at the University of Michigan who was not involved in the study.
Even though their urinary and sexual health rebounded about a year after treatment, surgical patients were still six times more likely to have urinary incontinence and 3.5 times more likely to erectile dysfunction two years after treatment than radiation patients.
"The trajectory of the lines is different," Resnick said. "Obviously surgery is much more of an acute insult than radiation."
However, men who received radiation therapy reported greater early loss in bowel function, from a score of about 90 to 75. Although they went on to recover some function, the men who had surgery were 39 percent and 47 percent less likely to report bowel urgency two and five years later, respectively.
"I have been telling patients for years about these types of differences associated with prostate cancer treatment," Wei said.
This study gives a reference point when explaining these issues to patients, Wei said, adding that he applauds the authors for following the men in this study for 15 years.
By 15 years after treatment, the declines were in the same range for both treatment groups. Men reported a score of between 70 and 80 for urinary function, about 20 for sexual function and 80 for bowel function.
Nonetheless, "I would be somewhat careful in showing the results [of this study] to my patients," Wei said.
Intensive prostate cancer treatments are done differently today; for example, surgery can be done with a robot or with minimally invasive laproscopy using small incisions in the abdomen. Cancers also tend to be detected earlier when they are less aggressive, and so treatment could be less aggressive.