Prostate Cancer Surgery May Not Always Up Survival
Study Finds Surgery Doesn't Cut Death Risk Compared to Watchful Waiting for Early-Stage Prostate Cancer
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Surgery Becoming More Common continued...
"The idea that we are overtreating prostate cancer has been well known for a long time. Many men with low-risk prostate cancer will probably die of other causes rather than die of prostate cancer," says Manish Vira, MD, director of the Fellowship Program in Urologic Oncology at the North Shore-LIJ Health System's Smith Institute for Urology in New Hyde Park, N.Y.
For that group, says Vira, who was not involved in the research, treatment will almost certainly do more harm than good.
But other independent experts think the study is limited in what it can say because it only followed most people for around a decade. Because prostate cancers grow so slowly, says Ballentine Carter, MD, director of adult urology at the Johns Hopkins School of Medicine, 10 years may not be enough time to see a difference.
"In the world of prostate cancer, 10 years is not very long follow-up, he says. Because over a 10-year period, men who are diagnosed with a disease that's potentially harmful aren't harmed in 10 years, and the study shows that because very few people in either group died of prostate cancer," he says.
But there were important differences between the two groups in the number of men who went on to develop cancer that spread to the bone, Carter says.
In the surgery group, 17 men had their cancer spread to their bone over the course of the study, compared with 39 in the observation group. Surgery appeared to reduce a man's risk of having his cancer spread by about 60% over observation alone.
The study followed 731 men with cancer than had not yet spread beyond the prostate. The average age of men in the study was 67.
About half the men were assigned to have radical prostatectomies; the other half were assigned to observation. All the men saw a doctor every six months. They had bone scans every five years to check for cancer spread to the bone.
"This really is the first large study to address the kind of men who are dealing with prostate cancer as it's being diagnosed in the United States these days," primarily through PSA tests, says researcher Michael J. Barry, MD, a clinical professor of medicine at Harvard Medical School.
Based on a combination of factors that included a man's PSA, the way the cancer looked under a microscope, and the size of the tumor, doctors assessed how risky the cancer appeared to be. Forty percent of men in the study had tumors that were considered low-risk; 34% were intermediate-risk; and 21% were considered high-risk.
After an average of 12 years, there was no significant difference in the number of overall deaths or deaths related to prostate cancer between the two groups -- 47% of men who had surgery died compared to 49.9% of men who didn't have surgery. Among men assigned to radical prostatectomy, 21 (5.8%) died from prostate cancer or treatment, compared with 31 men (8.4%) assigned to observation -- a difference so small that it might have been caused by chance alone.
Only men who had PSA levels higher than 10 and perhaps those with intermediate- or high-risk tumors appeared to gain any benefit from surgery.
"What was remarkable was that even with observation, the chance of dying of prostate cancer was quite low -- about seven chances in 100 over 12 years," Barry says. "People have always said that for these PSA-discovered cancers that you're much more likely to die with prostate cancer than of it, and I think we proved that's way more likely."