Based on recent studies, the American Urological Association will soon release revised guidelines that, experts hope, will reduce unnecessary biopsies and prostate surgeries, which even in the best hands can leave a man impotent and incontinent. The revised guidelines are expected to reduce the cost of screening, the cost per life saved and overall deaths from prostate cancer.
The new guidelines will no longer rely on a single reading. Rather, they will suggest that doctors focus on changes in levels over time. They will also suggest that testing start at 40 to obtain a baseline measurement, with the test repeated at 45 and 50, after which it should be given annually until 70.
"If a 70-year-old man has a PSA history that hasn't changed over the years, maybe he doesn't need further testing," Carter suggested. "PSA testing of men over 70 is not rational."
He pointed to a Scandinavian study showing that among men older than 65, to prevent one death from prostate cancer over 10 years, 330 men would have to have prostate surgery.
"This has created a huge dilemma in urology," Carter said. "We don't want to miss the possibility of a life-threatening disease, but we end up diagnosing and treating disease that would never have caused harm."
The new guidelines will lower the PSA level at which a biopsy should be considered, because, as Carter put it, "there's no level below which we can tell a man he doesn't have prostate cancer or life-threatening prostate cancer."
As one important trial showed, among men with a very low PSA — that is, a reading below the current cutoff of four — biopsies found that 15 percent had prostate cancer. Among that 15 percent, Carter said, 15 percent had high-grade, potentially life-threatening cancers. That means that 2.25 percent of the total number of men with a PSA less than four had life-threatening cancers.
But, he added, "If we biopsied every man with a PSA below four, we'd be looking at a sea of cancers that would never grow to be life threatening."
These facts and the results of a recent study by Carter, among others, indicated that rather than acting on the basis of a single PSA test, the rate of change in levels over time is a better indicator of who might have a serious cancer. This rate, known as PSA velocity, will be part of the new guidelines, which will suggest that in men with low readings, doctors consider the changes in levels over the course of three measurements.
"We need at least 1 1/2 to 2 years' worth of data" to make a meaningful judgment about how to proceed, Carter said.
He explained that in men with an initially high level — say 10 or higher — velocity is not an issue. For them, if other factors like prostate infection are not the cause of the high level, a biopsy is in order. But in men with a PSA from zero to four, knowing the velocity of changes can add useful information, he said.
Another approach to assessing the meaning of a PSA reading is to analyze how much antigen is traveling free in the blood and how much is bound to a companion protein, Scardino suggested. If more than 25 percent of the PSA is free, chances are that it is being produced by a benignly enlarged prostate. The lower the amount of free PSA, the more likely cancer is the cause and the more likely the disease is aggressive, requiring treatment, according to Patrick Walsh, a Johns Hopkins urologist and the author of Dr. Patrick Walsh's Guide to Surviving Prostate Cancer.
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