NEW YORK — Only 10 percent of men treated for early prostate cancer could sustain an erection sufficient for sex 15 years later, said researchers who found impotence rates were the same whether the treatment was surgery or radiation.
The findings were produced by the longest and broadest study on quality of life outcomes in two common therapies for prostate cancer. Researchers repeatedly surveyed 1,655 men diagnosed with localized disease and given surgery or external beam radiation.
While surgery patients had higher impotence rates two years after treatment, by 15 years erection failure “was nearly universal” with both treatments, according to the study reported Wednesday in the New England Journal of Medicine. The research adds to the controversy over whether doctors treat men with early prostate cancer too aggressively.
“This is a picture of what really happens in prostate cancer,” said David Penson, an urologist at Vanderbilt University Medical Center in Nashville, Tenn., and a senior author on the study. “It is the most comprehensive portrait of the patient experience in prostate cancer that is out there.”
Last May, the U.S. Preventive Services Task Force advised against using the prostate-specific antigen blood test to spot a tumor, saying the screening leads to over treatment and unnecessary side effects. In July 2012, a 731-patient study comparing prostate cancer surgery with observation found no statistical difference in death rates between the two groups after 10 years.
“We are starting to realize we are over-treating this disease,” Penson said in a telephone interview. Some low-risk patients with prostate cancer “don’t need treatment.”
More than 238,000 American men are diagnosed with prostate cancer each year, and more than 29,000 die from it, making it the second leading cause of cancer death in men, according to the American Cancer Society. Most cases are discovered before the cancer spreads. In those cases, patient survival is almost 100 percent over five years.
In the Vanderbilt study, 87 percent of men treated with surgery were impotent at 15 years, while 93.9 percent of those treated with radiation therapy were impotent. The median age at the start of the study in 1994 was 64 for men in the surgery group and 69 for men in the radiation therapy group. Most reported not being bothered by the problem.
The study didn’t have a comparison group of older men without prostate cancer, so it was impossible to parse out how much of the impotence was due to the prostate treatment versus other age-related problems.
In terms of other side effects, men who had radiation therapy had more bowel urgency after two years, while men who received surgery had higher rates of urinary incontinence after the same period of time. By 15 years, though, there was no significant difference in rates of bowel urgency or urinary incontinence between the two groups, according to the results.
“For a guy who is looking at this, it is a quantity versus quality of life question,” said Penson. “What am I trading off from a survival benefit, and if I choose to do therapy, what is the quality-of-life hit going to be?”
The results make a case for monitoring the disease in more men without immediately treating it, Penson said. Under such a strategy, called active surveillance, doctors perform regular biopsies and blood tests, and only proceed with curative treatment if the prostate disease shows signs of progressing, he said.
Active surveillance “is certainly what I would do if I had low-risk prostate cancer,” he said.
Patients should quiz their doctors about how advanced their prostate disease is and what the risk is that it will spread before they assume they need immediate curative treatment, Penson said.
“There is much more openness” now among doctors about holding off on treatment for those who are at low risk of dying from their prostate cancer, he said.