The Prostate Specific Antigen test

Marc Siegel, MD
Marc Siegel, MD

The general purpose of Antidote is to compensate when the media vilifes a good drug. This time I want to take on a test—the Prostate Specific Antigen.

The Prostate Specific Antigen is a protein unique to the prostate which increases when the prostate gland is irritated, inflamed, enlarged, infected, or cancerous. It is specific for the prostate, but not for prostate cancer. It can lead to unnecessary biopsies, but the fault is not the PSA test, it is the doctor who overreacts to it. The test is our best diagnostic tool for prostate cancer, and a large part of the reason that death from prostate cancer has declined. Several studies have shown this, and a new European study, published in the New England Journal of Medicine, shows that the PSA test adds eight years of quality life. That's the key—not just years, but quality-of-life years.

A few years from now, MRI technology will have evolved to the point where PSAs lead to MRIs rather than directly to biopsies. In the meantime, it takes a skilled, experienced urologist to know when to biopsy and when to continue to follow a trend.

Two weeks ago, a 65-year-old African American came to me with a PSA that had been rising over several months. I sent him to one of the top prostate surgeons around for a biopsy. My suspicion of cancer was high. What would the U.S. Preventive Services Task Force, which has recommended against these biopsies have had me do? Since prostate cancer is almost always asymptomatic, with over 200,000 new cases and 30,000 deaths in the US every year, the next test after the PSA to diagnose it is the autopsy.

Marc Siegel, MD, is an internist and professor of medicine at New York University and the author of False Alarm: The Truth About the Epidemic of Fear