It is a desperate measure, but spreading prostate cancer is a killer, and some men become impotent anyway from prostate-removal surgery.
The study is the first to show that hormone-blocking treatments sometimes called "chemical castration" can save the lives of men with spreading prostate cancer, which kills 37,000 men a year in the United States.
Such treatments should start at once if cancer cells are found in lymph nodes after prostate removal, Dr. Edward Messing of the University of Rochester Medical Center wrote in today's New England Journal of Medicine.
Normally, doctors wait for further signs that the disease has spread, because the hormone-blocking treatments can cause impotence, weak bones, loss of muscle and personality changes.
Dr. Logan Holtgrewe of Annapolis, Md., a past president of the American Urological Association and current chairman of the group's health policy council, said the study is an important step toward answering a big question: when to start a treatment that may be as bad as the disease.
"I think patients really need a heart-to-heart discussion with their doctors before they accept the findings in the study and act upon them," said Dr. Patrick Walsh of Johns Hopkins University in Baltimore, perhaps the nation's best-known prostate surgeon.
Hormone treatment deprives the tumor of testosterone, which it needs to grow. Hormone-blocking medicine is often used to reduce the pain of spreading disease, but doctors generally thought it was unlikely to improve longevity.
Messing and doctors in five other cities around the country treated a total of 98 men whose lymph nodes were shown to contain cancer after prostate removal men who often do "disastrously poorly" without treatment, Messing said.
The men were randomly assigned to undergo castration either medically or through removal of the testicles or to be watched until their disease progressed. Thirty-three of the men chose the hormone treatment; 13 chose surgical castration.
After seven years of follow-up, three of the men castrated chemically or surgically had died of prostate cancer, compared with 16 in the men who were watched for further symptoms before starting hormone treatment. Cancer recurred in 41 of 51 men who got delayed treatment, compared with seven of 47 who immediately got hormone therapy.
In some states, sex offenders are given chemical castration. Chemical castration is reversible when the patient stops the treatment. But prostate cancer patients usually must stay on the treatment for the rest of their lives to keep the cancer from recurring.
The prostate is a doughnut-shaped gland that surrounds the male urethra and creates much of the fluid that makes up semen.
In the vast majority of the men studied, cancr cells in the lymph nodes were the only sign that the disease had spread. They showed no other signs at all not even detectable amounts of PSA, or prostate-cancer specific antigen, a reliable early sign of cancer.
When Messing and his team followed the cases of 98 men who had cancer cells in the lymph nodes after their prostates had been removed, they found that the dogma was wrong.
Only three of the 47 men who either had their testicles removed or received hormone-blocking therapy had died from a recurrence of prostate cancer after seven years.
In contrast, 16 of the 51 men whose treatments were put off until the cancer showed signs of reappearing had died.
Overall, 77 percent of those who received immediate treatment were alive and cancer-free at the end of the study, compared to 18 percent in the watch-and-wait group.
Previous studies testing the same treatment produced results that were far less dramatic.
Messing and his colleagues said that "it is unlikely that it will be feasible to repeat our study (because) ... there would be fewer eligible men because widespread use of serum PSA testing has led to earlier diagnosis of prostate cancer."
Because of the more common use of serum PSA testing, cancer has spread to the lymph nodes in fewer than 5 percent of men who have their prostates removed, the researchers said.
Written by Janet McConnaughey