Even without treatment, only a small minority of men diagnosed with early-stage prostate cancer die from the disease, Swedish researchers reported Friday.

Drawing from a national cancer register, they estimated that after 10 years prostate cancer would have killed less than three percent of these men.

“What the data is showing is that for most patients with low-risk cancer, there is no need to panic,” said Grace Lu-Yao, a cancer researcher who was not involved in the new study. “Prostate cancer really is no longer a fatal disease.”

With modern screening tests, said Lu-Yao, of the University of Medicine and Dentistry of New Jersey in New Brunswick, many prostate cancers are found that might never have developed into serious disease. In such cases, the slight reduction of risk by surgically removing the prostate or treating it with radiation may not outweigh the substantial side effects of these treatments.

In the Swedish study, published in the Journal of the National Cancer Institute, researchers compared deaths among more than 6,800 men with prostate cancer who underwent treatment - surgery or radiation - or were simply monitored regularly by their doctors, the so-called “watchful waiting” approach. With watchful waiting, patients are only treated if their cancer progresses.

The men, who were younger than 70, had low- or intermediate-risk cancers, as judged by several factors, including blood levels of prostate-specific antigen (PSA) and Gleason score, a measure of abnormal cells in the prostate.

After about eight years, 20 percent of the men in the watchful waiting group had died, almost twice as many as in the treatment group. However, the number of deaths was no different than what would be expected in the general population. Less than three percent had actually died from prostate cancer, and those who weren’t treated turned out also to be sicker in the first place.

The researchers calculated that of those men with low-risk cancer, 2.4 percent would die from the disease within 10 years without treatment. While this number was about three times higher than in men who had had surgery or radiation therapy, it wasn’t clear how much of the difference was due to worse general health in the men who didn’t get treatment.

The Swedish findings jibe with earlier results, including a large US study.

Given the overall low death risk, the researchers said watchful waiting “appears to be suitable” for many men with low-risk prostate cancer.

Instead of panicking, Lu-Yao said, men diagnosed with this type of cancer should see it as “a wake-up call, an opportunity to improve their health,” for instance by exercising more and eating a more healthy diet. That, she said, was much more likely to influence their chances of living a long life.

SOURCE: http://link.reuters.com/quj82m and Journal of the National Cancer Institute, online June 18, 2010.

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By Frederik Joelving

NEW YORK (Reuters Health)