Purpose: We evaluated differences in the prostate cancer detection rate among black and white men with serum prostate specific antigen (PSA) levels between 2.6 and 4.0 ng./ml., and benign findings on digital rectal examination.
Materials and methods: From May 1995 through June 1997 we screened 14,209 white and 1,004 black men 50 years old or older with serum PSA and rectal examinations at 6-month intervals. If PSA was greater than 2.5 ng./ml. or the rectal examination was suspicious for cancer, we recommended an ultrasound guided sextant biopsy of the prostate. We compared differences in clinical characteristics, compliance with the recommendation for biopsy, cancer detection rate, and stage and grade of tumors detected for 924 white and 57 black men.
Results: Black men were younger (60 versus 63 years old, p = 0.005) and presented with slightly higher PSA levels (3.3 versus 3.1 ng./ml., p = 0.03) than white men. Overall cancer detection rate was 27% (106 of 391 patients), with cancer detection 2-fold higher among black (13 of 29, 45%) than among white (93 of 362, 26%) men (p = 0.03, odds ratio 2.4, 95% confidence interval 1.1 to 5.1). Controlling for age, total PSA, PSA density, percent free PSA and number of prior screening visits, race remained a significant predictor of cancer (adjusted odds ratio 3.4, confidence interval 1.4 to 8.4). We found trends for worse pathological stage and grade among black men but these differences did not reach statistical significance.
Conclusions: Black race was an independent predictor of prostate cancer even at lower PSA cutoffs (2.6 to 4.0 ng./ml.). Although the positive predictive value for cancer detection was relatively high in black men, long-term outcomes studies are necessary to determine whether the use of lower PSA cutoffs would result in favorable shifts in cancer stage and grade, and a reduction in racial differences in prostate cancer mortality rates.