The test measures the level of the PSA in the blood and high levels are indicative of malignancy. These results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood. In the past, most doctors considered a PSA level below 4.0 ng/mL as normal.

Many men who are diagnosed with prostate cancer undergo aggressive therapy, even when they have low PSA scores and low-risk disease. Prostate cancer has been diagnosed in 15.2% of men with a PSA level at or below 4.0 ng/mL and 15% of these men, or approximately 2.3% overall, had high-grade cancers. In another study, 25 to 35% of men who had a PSA level between 4.1 and 9.9 ng/mL and who underwent a prostate biopsy were found to have prostate cancer, meaning that 65% to 75% of the remaining men did not have prostate cancer.

It has been suggested that these results underscore the fact that PSA levels, the current biomarker, are not a sufficient basis for treatment decisions. In a recent comment published in the July 2010 issue of Archives of Internal Medicine, it was stated that "Prostate-specific antigen testing has led to an epidemic of prostate cancer, but a substantial proportion of PSA-detected cancers will never be clinically significant, and continuing to aggressively treat most men with low-risk cancers will certainly do more harm than good."

However, this view is not held by all and in a report in the same journal other authors point out that the tremendous improvement in survival has been attributed to early detection and treatment. Because of early detection, 90% of patients are diagnosed before the cancer spreads beyond the prostate and nearly 100% of those patients survive at least five years. The US National Cancer Institute (Bethesda, MD, USA) has acknowledged the PSA test cuts the prostate cancer mortality rate by nearly 50%. A screening trial in Sweden has shown the risk of overdiagnosis has been blown out of proportion for some time and is actually less than previously thought, with just 12 men needed to be diagnosed to save one man's life.

Quentin Lockwood, III, the CEO of ZERO - The Project to End Prostate Cancer, (Washington, DC, USA), said, "When it comes to 'overtreatment,' the PSA test is not to blame it is what happens next. Low-risk or not, many men choose to undergo aggressive treatment to eliminate the cancer from their bodies and their conscience, rather than simply monitoring the disease throughout their lives. Some doctors and patients are too quick to rush to treatment rather than carefully determine the risks and benefits of various procedures."

Related Links:
US National Cancer Institute
ZERO - The Project to End Prostate Cancer