Predictive model of prostate cancer risk

Combining PSA with other risk factors for prostate cancer (CaP) may result in individualized risk prediction.

In the April 19, 2006 issue of the Journal of the National Cancer Institute, Dr. Ian Thompson and colleagues report a predictive model for CaP based upon the Prostate Cancer Prevention Trial (PCPT) database.

PCPT included 18,882 men with a normal rectal exam and PSA level in a study of chemoprevention using finasteride or placebo over a 7-year period. At the end of the 7-year study period, participants in the placebo group who underwent prostate biopsy were included in this report. CaP risk modeling was performed using risk variables such as family history of CaP, race, PSA, DRE, previous biopsy history, age, and PSA velocity. Multivariable logistic regression model analyzed the data.

The study cohort consisted of 5,519 men. Most were Caucasian, and did not have a previous biopsy. Variables statistically associated with an increased risk of CaP included increasing PSA, positive family history, and abnormal DRE. Having a previously negative prostate biopsy was linked to a statistically decreased risk of CaP.

Interestingly, PSA velocity was associated with a 6-fold increase in CaP risk by itself, but in combination with the above significant variables neither PSA velocity nor patient age added independent prognostic information. African Americans had a 40% increased risk of CaP, which was just statistically significant.

The authors point out that the report is limited by patient characteristics not reflecting those of the general population.

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