TORONTO - A significant proportion of men newly diagnosed with prostate cancer can be safely managed with "active surveillance" instead of undergoing radical treatment that can cause a variety of unpleasant side-effects, a Canadian study suggests.
Active surveillance means frequent monitoring of a patient's PSA (prostate-specific antigen) levels and periodic biopsies to make sure the cancer hasn't become more aggressive and spread.
The long-term study found that men with low-grade, slow-growing prostate cancer who were managed with active surveillance had a 10-year cancer-related actuarial survival rate of more than 97 per cent, and an overall survival rate of almost 80 per cent.
Furthermore, researchers determined that patients in the study had an almost 19 times greater likelihood of dying at 10 years from a cause other than prostate cancer.
About 40 per cent of men newly diagnosed have a prostate cancer profile that makes them candidates for active surveillance, said principal researcher Dr. Laurence Klotz of Sunnybrook Health Sciences Centre in Toronto.
"We recognized about 15 years ago that PSA screening resulted in a diagnosis of a lot of men who had indolent, slow-growing prostate cancer that really was not a threat to their life," Klotz said Monday.
"And we tried to come up with a way to reduce the overtreatment, which is now widely acknowledged as being a major problem," he said, noting that prostate removal or radiation treatment can lead to erectile dysfunction, urinary incontinence and rectal problems.
In 2009, an estimated 25,500 Canadian men will be diagnosed with prostate cancer and about 4,400 will die of the disease.
The study, published Tuesday in the Journal of Clinical Oncology, enrolled 452 men with a median age of 70, whose prostate cancer was picked up through screening. The researchers followed their progress for up to 14 years, giving the men PSA testing every three months and periodic biopsies up to age 80.
Over the course of the study, 30 per cent of the patients' cancers were reclassified as higher risk and the men were offered treatment.
"Seventy per cent did not require treatment," said Klotz.
In all, 97 (22 per cent) of the men died during the study period, but only five from prostate cancer.
Gary Dailey, 66, of Whitby, Ont., was diagnosed with prostate cancer in 2005. Despite a rising PSA level, biopsies showed the cancer appeared to be restricted to a small area.
After being told he could undergo surgery or radiation where he lives northeast of Toronto, Dailey decided to see what other options were available and was enrolled in Sunnybrook's active surveillance study.
"I thought I like that idea far better, because you can always go for radical treatment any time later on," said Daily, explaining that unlike some people, he is able to live comfortably with the knowledge he has cancer.
"It gives me an opportunity to wait and see. It wasn't that I was all that afraid of the operation, it's that I couldn't convince myself that there was enough risk to do it."
Dr. Gilbert Welch, an expert in cancer screening at Dartmouth College in Hanover, N.H., said opting for active surveillance for men with low-grade, low-PSA prostate cancer "makes a hell of a lot of sense."
"This is exactly the kind of thing we need to be thinking about, is how can we separate people into meaningful groups and determine those groups where treatment is worse than the disease," Welch said from Hanover.
Klotz said the implications of the study's findings could be "huge" because 40 per cent of North American men each year - about 150,000 - would be candidates for this approach - even though the latest statistics show about 90 per cent receive radical treatment.
"One of the key facts that patients need to understand is that small amounts of prostate cancer develop normally with age," he said. "So your likelihood of harbouring prostate cancer is roughly equivalent to your age. In 60-year-olds, it's about 60 per cent of men."
Klotz stressed, however, that active surveillance isn't advisable for every man with prostate cancer.
"The patients who have higher-grade or more extensive prostate cancer need radical therapy."