By MICHELLE L. BRANDT
Tom Stamey, MD, knows that his most recent study on prostate specific antigen has created "a hell of dilemma" for physicians and patients. But that doesn’t stop him from wanting to spread the word about the study’s findings: PSA is an unreliable indicator of prostate cancer and a new marker is needed. The American Urological Association has also taken note and wants to help get Stamey’s word out.
A revised version of Stamey’s study, which was originally published in the January issue of the Journal of Urology, is included in the latest issue of AUA News. The AUA wanted to reprint the study, Stamey said, so that the message about PSA could reach all practicing urologists in the country — especially those who don’t read the journal.
"We thought the paper would interest readers of AUA News," said Martin Resnick, MD, president-elect of the AUA. "This is an area of controversy and Dr. Stamey is a well-known thought leader. We wanted to bring his ideas to the table."
Stamey’s study found that PSA levels are not meaningfully related to prostate cancer, but are rather caused by harmless increases in prostate size, called benign prostatic hyperplasia or BPH. It also showed PSA’s failure as an indicator of surgical success rates: success rates were no different in men with PSA less than 4 nanograms per milliliter than in men with levels as high as 10 ng/ml.
"I was astonished over how poor PSA really is in telling us about cancer," said Stamey, a professor of urology. "We can’t predict anything from PSA levels under 10-12 ng/ml."
In his rewrite for AUA News, Stamey discussed his paper’s findings and elaborated on the ubiquity of prostate cancer, noting that "almost all men will get it if they live long enough." He also discussed the cancer’s low death rate: 226 per 100,000 men age 65 or older.
"My chances of getting in an accident on the freeway are higher than dying from prostate cancer," Stamey commented. He expressed concern that the cancer, due to the perception that PSA is an accurate marker, is being overdiagnosed and overtreated.
According to estimates from the American Cancer Society, 189,000 cases of prostate cancer will be diagnosed in the United States this year. Levels of PSA have commonly been thought to increase with men with early prostate cancer, so older men whose PSA reaches a certain level are typically monitored and often undergo biopsies.
"There’s nothing wrong with the test itself — the problem is when doctors take the test results and do an unnecessary biopsy," he said.
In light of the disease’s low death rate, Stamey encouraged his colleagues to ask themselves who should be diagnosed and treated — admitting that he himself does not have the answers. He also stressed the importance of finding a more reliable marker for the cancer.
Stamey’s laboratory is currently searching for better markers based on the genes expressed in high-grade prostate cancers.
Stanford Report, October 9, 2002