IS PROSTATE-SPECIFIC ANTIGEN DENSITY MORE USEFUL THAN PROSTATE-SPECIFIC ANTIGEN LEVELS IN THE DIAGNOSIS OF PROSTATE-CANCER

Objectives. To compare the performance of prostate-specific antigen (P SA) levels with the performance of PSA density (PSAD), the ratio of th e serum to the size of the prostate, as predictors of the presence of prostate cancer. Methods. We analyzed the results of digital rectal ex amination (DRE), transrectal ultrasonography (TRUS), serum PSA levels, and PSAD in 244 patients who had a needle biopsy of the prostate. Res ults. Cancer was detected in 110 patients (45%). Compared with DRE, TR US and serum PSA levels 4.0 ng/mL or higher, PSAD at a cutoff point of 0.15 ng/mL/cm(3) was significantly more specific and had a higher pos itive predictive value than each of the other tests but was significan tly less sensitive than TRUS and PSA (P < 0.05 for each). In a receive r operating characteristic analysis, PSAD was significantly more accur ate than PSA (P < 0.001). In 80 patients with a normal PSA, PSAD added no additional information, and PSAD was not able to identify a subset at low risk. In 82 patients with a high PSA level (10 ng/mL or higher ), 15% had a PSAD less than 0.15 and only 8% had a cancer. Conclusions . Overall, PSAD was significantly more accurate than PSA for predictin g the results of needle biopsy of the prostate, but in practice PSAD p roved useful in only a small subset of patients. If the serum PSA leve l was high but the PSAD was low, cancer was rarely detected. These pat ients may be suitable candidates for careful follow-up rather than ear ly repeat biopsy.