Test helps determine prostate cancer treatment

November 17, 2009 7:57:57 PM PST
Bay Area researchers are using a new test to help determine whether a patient should be treated for prostate cancer. The result is that many men are being told their healthiest option may be to simply wait.

John Shoemaker certainly looks the part of a fighter. But when it came to battling a diagnosis of prostate cancer, he decided against going for the quick knockout.

"I understand where my disease is. I maintain a normal quality of life, I have no side effects like incontinence or sexual dysfunction from surgery or radiation," he said.

Instead of surgery or radiation, he's signed on to a regimen known as active surveillance. It is essentially, doing nothing beyond regular testing, as long as the low-grade cancer is not advancing.

"The negatives of over-treating early stage cancer are far more concerning than the potential benefits," said Shoemaker.

Like most men, Shoemaker's condition was flagged by a PSA test, which measures prostate specific antigens in the blood. Over the last 20 years, the test has led to cancer diagnosis in more than one million American men and is credited with saving thousands of lives.

But with so many men being tested, there is growing evidence that it may also be increasing the number of unnecessary procedures as well.

"Now whether that's 10 percent of men, or 20 percent, or 40 percent, you'll get much debate. In my mind and I'm a high-volume surgeon, I think there is too much treatment being delivered nowadays," said Dr. Peter Carroll who heads the Department of Urology at UCSF.

Dr. Carroll believes the slow progressing nature of many prostate cancers doesn't justify a rush to treatment, which can produce serious side effects in a significant percentage of cases.

"In this country, if you're detected with low-risk prostate cancer you're treated, and that's where the problem is. Not so much over-detection, its over-treatment," he said

But convincing most men that waiting might be their best option can be a challenge, especially given that prostate cancer in its advanced form is the second most common cause of cancer death among men. It is second after lung cancer.

"Part of it, we have this problem with the 'c-word,' people hear cancer and that's it," said Dr. Matthew Cooperberg from UCSF.

That's why Dr. Cooperberg set out with Dr. Carroll to develop a new test to help predict which prostate cancers are likely to turn deadly in which patients.

The test, known as CAPRA, combines information including risk factors and family history, with data from ultrasounds and biopsies.

"We put all of those variables together and we can start to get a reasonable, predictive estimate of what the likelihood is of progression. And our thought at UCSF and other centers like this is that many men, if not most men at the lower end of the risk spectrum, probably don't need treatment," said Dr. Cooperberg.

The more detailed readings could also allow patients with early or slow moving forms of the cancer to choose courses like the one Shoemaker is following -- diet, exercise and regular monitoring of his prostate for a condition that might never develop into a life-threatening disease.

"I've had three biopsies and lo and behold, they've found less cancer each time. In fact, in the last biopsy they found none," said Shoemaker.

With so many men now getting PSA screenings, it's now estimated the odds of being diagnosed with some form of prostate cancer has nearly doubled to 1 in 6.


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