MONDAY, April 7 (HealthDay News) -- In 2004, Medicare reduced its reimbursement rates to doctors for drugs that treat prostate cancer by blocking the activity of male hormones.

Coincidentally or not, the use of surgery -- castration -- to accomplish that same goal started to increase at just the same time, a new study found.

It's not possible to say that financial incentives had a direct influence on medical practice in the treatment of prostate cancer, said Dr. J. Stephen Jones, chairman of regional urology at the Cleveland Clinic, who led the study. "Certainly, I would not take that interpretation," he said, citing other possible explanations, such as increased concern about the side effects of the hormone-blocking drugs.

Still, Jones added, after the reimbursement rates were cut, "our study shows, essentially aligned with that change, progressive change in the two forms of treatment for prostate cancer. There was a major reduction in the use of lutenizing hormone-releasing (LHRH) agonists, which block the male hormone testosterone, and a less noticeable increase in surgery, which accomplishes the same thing," he said.

The use of only one of the LHRH agonists -- triptorelin -- increased after the Medicare reimbursement policy changed, the study said. It was the only drug in the class whose reimbursement rate was not changed.

The findings were expected to be published in the May 15 issue of the journal Cancer.

Medically, the drug therapy -- sometimes called hormonal castration -- and surgery are virtually equivalent in their effect on prostate cancer, Jones said. The goal is to combat the disease by shutting off the supply of male hormones -- called androgens, including testosterone -- that encourage prostate cancer growth.

But "socially or economically, there are other factors involved," Jones said, when considering the two treatment options.

Whether the men in the study had all the factors involving the two treatment options described for them wasn't addressed by the research, Jones said. "It has always been clear that the effectiveness and side effects of the two treatments appeared to be equal," he said. "So, the choice remains one of preference. When two treatments are equal, the choice is the patient's."

LHRH agonists render the testicles as inactive as surgical removal does, Jones said, so, "the choice is to some degree in the eyes of the beholders. Is it better to have a one-time operation or to come in for an injection every few months?"

Almost all the men in the study were 65 or older, and it's not possible to say whether different choices might have been made by younger men, Jones said.

In a way, the change in medical practice detailed in the study represents a reversion to the earlier treatment of prostate cancer, to the era before the drugs were developed, Jones said. "Before these medications came into existence, almost everyone was treated by surgical removal of the testicles," he said.

In an accompanying editorial in the journal, Dr. Gerald W. Chodak, director of the Midwest Prostate and Urology Health Center in Chicago, wrote that "changing a recommendation to a patient from an LHRH agonist to surgical castration solely for economic reasons is ethically inappropriate."

"However," he added, "asking urologists to take a financial loss while treating patients also is inappropriate."

Chodak said doctors should be totally honest with patients, making them aware of their choices in prostate cancer treatment.

Dr. Ethan Basch, an assistant attending physician at Memorial Sloan-Kettering Cancer Center in New York City, called the new study an interesting but incomplete picture.

"The trend is probably real, but I feel the study doesn't get in as deep as one would want and show what's really going on," he said. "What we don't have is information on the number of people affected."

What's also not known are the characteristics of the specific patients in the study, Basch said. "Either the treatment is more consistent with medical guidelines, or people who were being appropriately treated before are no longer getting it. We can't tell from this paper. It's very important that we have more detailed information about the patients themselves," he said.

Another report in the same issue of the journal had encouraging news. It showed increased life expectancy for people with late-stage testicular, colorectal and ovarian cancer. Treatment improvements have increased life expectancy by two years for ovarian cancer, 2.8 years for colorectal cancer, and 24 years for testicular cancer, with the testicular cancer gains largely due to an increase in the cure rate from 23 percent to 81 percent, according to the study by researchers at the U.S. National Cancer Institute.

More information

An overview of prostate cancer and its treatment is given by the American Cancer Society.