New PSA Values Better Detect Prostate Cancer in Black Men

BETHESDA, Md--Physicians who screen for prostate cancer usingprostate-specific antigen (PSA) need to use a different set ofnormal age-adjusted values for their African-American patients,say Judd W. Moul, MD, LTC, MC, USA, and colleagues from the WalterReed Army Medical Center, Mayo Clinic, and Uniformed ServicesUniversity of the Health Sciences funded by the Department ofDefense (DOD) Center for Prostate Disease Research.

The reference ranges in common use were derived from white populations,Dr. Moul says. His study compared PSA levels in 3,475 men (allmilitary personnel) with no clinical evidence of prostate cancer(1,802 white and 1,673 black) and a group of 1,783 men with prostatecancer (1,372 white and 411 black).

The investigators found that PSA levels were significantly higherin black men (mean, 1.48 ng/mL in controls and 7.46 ng/mL in patients)than in whites (1.33 ng/mL in controls, 6.28 ng/mL in patients).In addition, there was more variation in PSA levels with increasingage among blacks than among whites.

Traditional age-specific reference ranges continued to work wellwhen applied to the data on whites, but would have missed 41%of cases of prostate cancer in blacks, with the test specificitykept at 95%. "This poor sensitivity is especially disturbingbecause black men are at higher risk than white men," Dr.Moul writes in the New England Journal of Medicine (335:304-310,1996).

The problem was the traditional strategy's 95% specificity, whichresulted in very low sensitivity for blacks. The researchers thenused their new PSA data to develop reference ranges that wouldhave 95% sensitivity and acceptable specificity for blacks (seetable,).

AUA Endorses New Ranges

The American Urological Association (AUA) hailed the new researchas "unusually significant" because it will alert physiciansto the special need for early detection of prostate cancer andhelp urologists better diagnose prostate cancers earlier in African-Americanmen.

The article "lends increased credence to the AUA policy regardingthe early detection of prostate cancer," the associationsaid in a statement. The policy calls for digital rectal examinationand PSA measurement in men 50 years of age or older and in those40 or older who are at high risk, including African-Americansand those with a family history of prostate cancer.

Use as a Guide

Dr. Moul warns that the new ranges for black men are only guides,and that the decision to evaluate a patient's condition furthershould be based on a number of factors. "In a given patient,"he says, "it is important to take into account associatedrisk factors and coexisting conditions and the patient's determinationand desire to undergo further evaluation."

He noted that in younger men and men at increased risk, the cutofflevels should emphasize sensitivity, whereas in older men or menwith a limited life expectancy, the cutoff levels should emphasizespecificity.

Dr. Moul's colleagues in the study were Ted Morgan, MD; StevenJacobsen, MD; William McCarthy, PhD; Debra Jacobson, MS; and DavidMcLeod, MD.