Rate of increase in PSA value predicts risk of death following radiation therapy

Men who have a higher rate of increase in their PSA value in the year prior to their prostate cancer diagnosis have a significantly higher risk of death following radiation therapy, according to a study in the July 27 issue of JAMA: The Journal of the American Medical Association.

Information obtained from serial PSA values in the form of a PSA velocity (i.e., the change in PSA level during the year prior to diagnosis) has been shown to be significantly associated with tumor stage, grade, time to prostate cancer-specific death following radical prostatectomy, according to background information in the article.

Anthony V. D'Amico, M.D., Ph.D., of Brigham and Women's Hospital and the Dana Farber Cancer Institute, Boston, and colleagues evaluated whether a PSA velocity greater than 2.0 ng/mL during the year prior to diagnosis was significantly associated with prostate cancer-specific death following radiation therapy (RT). The study, conducted between January 1989 and December 2002, included 358 men treated with RT for localized prostate cancer. One-hundred twenty-five men were classified as having low-risk prostate cancer (clinical tumor category T1c or T2a and PSA level less than 10.0 ng/mL and Gleason score 6 or less; 233 men had higher-risk disease, stratified by the PSA velocity.

The researchers found that a PSA velocity greater than 2.0 ng/mL per year was significantly associated (12 times increased risk) with a shorter time to prostate cancer-specific death and all-cause death (2.1 times the risk) when compared with men whose PSA velocity was 2.0 ng/mL per year or less. Men presenting with low-risk disease and a PSA velocity greater than 2.0 ng/mL per year had a 7-year estimate of prostate cancer-specific death rate of 19 percent compared with 0 percent for men whose PSA velocity was 2.0 ng/mL per year or less. The corresponding values for men with higher-risk disease were 24 percent and 4 percent, respectively.

"Such men [higher PSA velocity] who are planning to undergo RT and are in good health could be considered for RT combined with androgen suppression therapy because this approach improves survival in men with higher-risk disease," the authors conclude.