MONDAY, May 16, 2011 (HealthDay News) -- Amid the controversy swirling around the value of PSA testing as a screen for prostate cancer, new evidence emerges that there may be ways to fine-tune the screening so it benefits more men, while avoiding unnecessary biopsies and treatment.
PSA refers to the blood protein known as prostate-specific antigen. Higher PSA levels in the blood can mean that a man has prostate cancer or is at greater risk for the disease.
The results of four studies detailing the latest findings were presented during a news conference Monday at the American Urological Association (AUA) annual meeting, in Washington, D.C. Research presented at medical meetings should be viewed as preliminary until they are published in peer-reviewed medical journals.
The first study found that one measure of PSA, taken before a man turns 50, could gauge how likely he is to die of prostate cancer later on.
In this trial, which had an unusually long average follow-up of 27 years, nearly half of the men who died of prostate cancer had PSA scores of 1.5 or higher before the age of 50, representing the top 10 percent of scores in this group.
"This information may be able to improve our ability to predict death from prostate cancer [at an early age]," said study author Andrew Vickers, associate attending research methodologist at Memorial Sloan-Kettering Cancer Center in New York City. "A PSA above 1.5 is not a reason to panic, but I would tell patients that I really need to see them [again] in two years."
The second study, this time from researchers at Johns Hopkins University in Baltimore, found that some men over the age of 60 may be able to forego PSA testing without any undue effects.
Although a universal cut-off point was unclear, the researchers did note that men with a PSA under 1.0 when they were in their 60s were less likely to develop aggressive prostate cancer.
A third study looked at how fast PSA levels rose via a measurement known as prostate-specific antigen velocity (PSAV). It found that adding PSAV to standard screening may improve the accuracy of traditional PSA screening.
The problem was that there were a lot of false-positives, said the authors, from the Feinberg School of Medicine at Northwestern University in Chicago.
The final study, from European and American researchers, also looked at PSAV, concluding that this marker may be able to pinpoint more aggressive tumors.
Again, when added to the PSA test, it may give more accurate insight into what the PSA test actually means.
"We're not making any claims right now, but this may give us clues about [how to modify] practice," said study author Thomas Neville, chief scientist and founder of Soar Biodynamics, in Los Altos, Calif.
According to news conference moderator Dr. Christopher Amling, chief of urology at Oregon Health & Science University in Portland, the AUA modified its prostate cancer screening guidelines in 2009 to recommend that men should start screening at age 40, or age 45 at the latest.
The U.S. National Cancer Institute has more on PSA screening.