Prostate specific antigen cannot distinguish stage T1a (A1) prostate cancer from benign prostatic hyperplasia.

To determine if serum prostate specific antigen (PSA) has decreased the prevalence of stages T1a (A1) and T1b (A2) prostate cancer, and to compare the PSA values for patients with stages T1a and T1b prostate cancer and men with symptomatic benign prostatic hyperplasia, 966 patients undergoing transurethral resection of the prostate were evaluated retrospectively. Included in the study population were 499 consecutive patients who underwent transurethral resection of the prostate for obstructive urinary symptoms in 1986 (no PSA group), and 467 consecutive patients who underwent resection in 1989 and 1990 who were evaluated with serum PSA preoperatively (PSA group). The mean age for the no PSA group was 71 years compared to 70 years for the PSA group (p = 0.36). The overall prevalence of stages T1a and T1b prostate cancer in the no PSA group was 8.6% compared to 10.3% in the PSA group (p = 0.37). The prevalence of stages T1a and T1b prostate cancer in the no PSA group was 3.6% and 5.0%, respectively, compared to 7.3% and 3.0%, respectively, for the PSA group (p = 0.01). In the PSA group the median PSA value for patients with stages T1a and T1b prostate cancer was 3.8 ng/ml compared to 3.4 ng/ml for the patients without cancer (p = 0.59). The median PSA level for the stage T1a cancer patients was 2.4 ng/ml, which was not statistically different from that in patients without cancer (p = 0.31), and the median PSA level for the stage T1b cancer patients was 5.9 ng/ml, which was statistically different than that in patients without cancer (p = 0.01). These findings suggest that the routine use of serum PSA does not decrease the prevalence of stage T1a prostate cancer and that PSA may decrease the prevalence of stage T1b tumors but a larger study would be necessary to document this finding.