Fifty percent of men in the United States undergo regular screening for prostate cancer, using a test that measures levels of prostate-specific antigen (PSA), a protein secreted by the prostate gland. However, recent research looking at PSA levels after a prostate biopsy has revealed that PSA level is not a very accurate predictor of prostate cancer risk. Prostate cancer can occur when PSA levels are "normal." Other variables, such as family history, age, race, and digital rectal examination (DRE) results also play a role in assessing prostate cancer risk.

To better assess prostate cancer risk, Ian M. Thompson, M.D., of the University of Texas Health Science Center at San Antonio, and colleagues analyzed information on 5519 men aged 55 or older from the placebo group of the Prostate Cancer Prevention Trial (PCPT). Men in the PCPT were followed for 7 years, receiving regular PSA screening and DREs annually. If tests were abnormal, men underwent a prostate biopsy to check for prostate cancer. Men also underwent biopsies at the end of the study if they had not undergone a biopsy during the study. The researchers used various statistical tests to analyze biopsy results, family history of prostate cancer, race, age, rectal examination results, and previous biopsy history.

The authors used the equations generated by their analysis to develop a risk calculator that can be used to assess an individual's risk of prostate cancer. The risk calculator is available online and can be used to calculate risk of prostate cancer and high-grade disease for men aged 50 years or and older who have no previous history of prostate cancer and who have had recent PSA screening and DRE tests.

The authors write, "This risk calculator model
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Contact: Ariel Whitworth
jncimedia@oxfordjournals.org
301-841-1287
Journal of the National Cancer Institute
18-Apr-2006