For years, physicians have debated whether surgery, which can cause incontinence and impotence, is unnecessarily risky and harsh early in the course of the disease, given the slow growth of most prostate tumors -- among the most sluggish of cancers. But doctors in the United States have increasingly been operating on younger patients, believing it would extend their lives.

The new study, published today in the New England Journal of Medicine, offers the first long-term data showing that aggressive surgical intervention does indeed save more lives than watchful waiting in patients under 65, and also more effectively prevents prostate tumors from spreading and causing pain.

The researchers did not examine radiation therapy. The study was notable for the length of time the researchers followed the nearly 700 patients in Sweden, Finland, and Iceland.

"For years, surgeons in this country have been preaching the gospel that it's better to be aggressive. But there's never been any long-term data," said Dr. Richard K. Babayan, chairman of the urology department at Boston University's medical school. "This study validates the majority opinion in the US."

Much of the surgery-related reduction in deaths occurred in patients whose cancers were diagnosed before age 65, the study found, indicating that older men -- in whom the majority of prostate cancers are diagnosed -- may not necessarily benefit from surgery. US doctors now often counsel patients 65 and older against surgery.

The new study, conducted by a consortium of Scandinavian research centers, will probably make US doctors even more inclined to recommend surgery to patients under 65, cancer specialists said.

In Europe, where doctors lean toward watchful waiting in younger patients, the study is likely to dramatically change many physicians' practices. With watchful waiting, physicians carefully monitor patients but do not actively treat them unless their health worsens.

"This is a very important study, very compelling evidence for counseling patients, no question about it," said Dr. Douglas M. Dahl, a Massachusetts General Hospital urologist.

However, the study also underscored that prostate cancer treatment merits continued research.

The study found that regardless of treatment, prostate cancer patients were more likely to die of causes other than their cancer -- evidence that many such tumors are indeed slow-growing. But doctors cannot currently differentiate between fast-growing and slow-growing prostate tumors, so surgery is offered to many patients, even though only some may actually need it.

"Who needs to be treated with surgery? That's the biggest unanswered question in prostate cancer," said Dr. Philip Kantoff, a prostate cancer specialist at Dana-Farber Cancer Institute.

Kantoff and his colleagues are working with the Scandinavian researchers to develop DNA tests that would indicate how quickly a prostate tumor will grow. The Scandinavian team has sent to Boston tumor samples taken during the course of its study.

Once physicians can discern which tumors are truly threatening, Kantoff said, they will be able to be more selective in which patients to recommend for surgery.

"There will be an increasing number of people who will be candidates for watchful waiting," he said.

This year, more than 232,000 Americans will be diagnosed with prostate cancer, and about 30,000 people will die of it, the American Cancer Society estimates.

In the United States, about 60,000 radical prostatectomies are performed annually. In the procedure, surgeons cut out the prostate gland and some surrounding tissue. Men are often left impotent and incontinent, though skilled surgeons can reduce these risks.

Federal statistics from the 1990s, the most recent available, indicate that about 30 percent of US prostate cancer patients of all ages underwent surgery, while 30 percent received radiation therapy and 20 percent opted for watchful waiting, though the frequency of surgery has been rapidly increasing over the last decade, cancer specialists said.

The new study followed 695 men with prostate cancer, with a mean age of about 65, from October 1989 to February 1999. Half were randomly assigned to get radical prostatectomies, and the other half got watchful waiting.

In the group that got radical prostatectomies, 30 men died of prostate cancer. In the watchful waiting group, 50 men died of the cancer. Most of the deaths occurred after four years or more.

Among the surviving men, in 50 of those who had surgery, the cancer had spread throughout their bodies, while the same was true of 79 men in the watchful-waiting group.

Though these patients did not die during the study, they were at high risk for death in the years after. Also, 64 surgery patients experienced local growth of their cancer, while 149 of the watchful waiting patients did.

Most of the men in the study were diagnosed with prostate cancer before their tumors had spread outside the gland, but when the tumor was large enough to be felt during a rectal exam.

In the United States, many men are diagnosed even earlier, with a blood test. Dr. Durado Brooks, director of prostate cancer for the American Cancer Society, told the Associated Press that more research is needed to clarify how best to treat these men.

© 2005 The Boston Globe. All rights reserved.
© 2005 Daily News Central. All rights reserved.