Background: This study was undertaken to determine whether the prostate specific antigen (PSA) density (PSAD) and PSAD of the transition zone (PSADT) are useful in the detection of prostate carcinoma in Japanese men with intermediate levels of serum PSA.
Methods: Two hundred and eighty-seven Japanese men with intermediate serum PSA levels (2.1 ng/mL to 10 ng/mL) underwent measurement of prostate volume by transrectal ultrasound (TRUS) and systematic biopsy under TRUS guidance. The volume of the transition zone was also measured by TRUS in 134 patients. The PSAD and PSADT were determined for each patient, and their relationship to prostate carcinoma detection was examined.
Results: Prostate carcinoma was detected in 30 of 287 patients (10.5%). Although the serum PSA levels were similar in patients with benign and malignant prostate disease (P = 0.541), the prostate volume (P 0.0009) and PSAD (P < 0.0001) differed significantly in the two groups; in the patients with prostate carcinoma, the prostate volume was smaller, and the PSAD higher, than in the patients with benign disease. At the PSAD cutoff value of 0.18 ng/mL/cm3 or greater, the sensitivity was 70% and the specificity was 67% for the diagnosis of prostate carcinoma. The PSAD was found to be significantly better in the differentiation between benign and malignant prostate disease than the serum PSA in the receiver operating characteristic analyses (P = 0.045). However, the receiver operating characteristic curve for PSAD was not significantly different compared with that for PSA in the men with negative digital rectal examination findings. Prostate carcinoma was detected in 9.0% (12 of 134) of the patients who underwent PSADT determination. Receiver operating characteristic analyses showed that PSADT was not superior to PSA in the detection of prostate carcinoma.
Conclusions: In Japanese men with intermediate serum PSA concentrations, PSAD offers additional information useful in the detection of prostate carcinoma, but PSADT does not. Although use of PSAD may decrease the number of unnecessary biopsies, a significant number of prostate carcinomas may be overlooked. Therefore, the authors recommend that serum PSA levels continue to be used as an indicator for biopsy in Japanese men.