When prostate surgery fails to remove all traces of cancer, men face a decision about whether to have radiation therapy.
Radiation can lead to bowel and urinary problems, but patients might find that risk acceptable if there were evidence it guaranteed a longer, healthier life.
A new study finds no such guarantee. It suggests radiation following surgery may not make a difference in how long a man lives, or in how long he lives without his prostate cancer spreading.
Radiation did lessen the chances a man would have an abnormal PSA test, an abnormal biopsy or other clinical finding showing prostate cancer’s return during the next 10 years, the researchers found.
The findings apply to up to 35,000 American men annually. That’s how many have their prostates surgically removed, but whose followup tests show some cancer cells may linger in surrounding tissue.
The study will help each of these men “make the decision based on whether he would want to trade off perhaps some bowel or urinary complications to reduce his risk of cancer coming back,” said study co-author Dr. Ian Thompson, a urologist at the University of Texas Health Science Center at San Antonio.
The study, appearing in Wednesday’s Journal of the American Medical Association, was funded by grants from the National Cancer Institute and the National Cancer Institute of Canada.
Researchers tracked 425 men, ages 43 to 79, for an average of 10 years following prostate removal. All the men had tests suggesting the surgery had failed to remove all the cancer cells.
No perfect cure
About half the men were randomly assigned to radiation treatment. The others waited while doctors monitored their blood for PSA, or prostate-specific antigen, an imperfect test that can indicate prostate cancer.
Compared to the men who waited, the men who received radiation soon after surgery cut in half their risk for a later abnormal PSA test or a finding of cancer.
But the two groups showed no significant difference in survival — or in how long they lived without cancer spreading to other organs.
The study may have been too small to find a difference in survival, said Dr. John Concato, a clinical epidemiologist at the VA Connecticut Healthcare System who was not involved in the study. Or the men’s cancers may not have had a large effect on their life expectancy.
Radiation wasn’t a perfect cure. Some men in both groups saw their cancer spread, or metastasize: 17 out of 214 men in the radiation group, and 35 out of 211 men in the waiting group.
The study didn’t evaluate the cost of the two approaches, but radiation therapy can cost up to $40,000, Thompson said.
Dr. Anthony D’Amico of Boston’s Dana Farber Cancer Institute said he doesn’t expect a change in treatment in the United States because of the findings, but European doctors might increase their use of post-surgical radiation or PSA testing, which aren’t used as commonly there.
U.S. doctors will continue to choose radiation for more extreme cases, and wait until the PSA test shows signs of cancer return for other men, D’Amico said. He was not involved in the study.
“We have to use some clinical common sense,” D’Amico said.
The prostate is a gland the size of a walnut under the bladder that makes fluid for semen. Prostate cancer is second only to skin cancer in its prevalence among American men.
About 234,000 U.S. men are expected to be diagnosed with it this year and just over 27,000 will die of it. A diet high in fruits and vegetables may reduce the risk.
Also in Wednesday’s JAMA, a study from the U.S. Department of Veterans Affairs found a surprisingly high number of elderly veterans, with no previous history of prostate cancer, received screening PSA tests. Current recommendations say doctors shouldn’t test men with limited life expectancies, but researchers found one-third of men older than 85 and in poor health got PSA tests.