Differentiation of benign prostatic hyperplasia from prostate cancer using prostate specific antigen dynamic profile after transrectal prostate biopsy

Abstract

Purpose: Serum prostate specific antigen (PSA) level is increased after needle biopsy (Bx) of the prostate. This study tested the hypothesis that the prostate harboring malignant lesions demonstrates less leakage of PSA after prostate biopsy and this phenomenon can be helpful in discriminating benign from cancer diagnosis.

Materials and methods: This prospective study was divided into 3 separate phases. Sextant prostate biopsy was done with transrectal ultrasound guidance, and the change and PSA values after biopsy were evaluated. Phases 1 and 2 had 20 and 41 patients, respectively. PSA dynamic profiles were plotted. We defined the most appropriate timing for blood sampling and the cutoff value of the PSA ratio (post-Bx total PSA-to-pre-Bx total PSA) to be applied for further assessment. Phase 3 recruited 97 cases, of which 66 satisfied the end point criteria in which a diagnosis such as malignancy, or 3 successive benign biopsies or benign transurethral resection of prostate was obtained.

Results: From phases 1 and 2 the cutoff value for the PSA ratio was 2.0, and the timing of blood sampling was 60 minutes after the biopsy. In phase 3 of those whose PSA ratio was less than 2.0, 92.6% (25) had cancer. For those whose PSA ratio was greater than 2.0, 82.1% (32) were benign. Of the 4 cases with a PSA ratio less than 2.0 and an initial benign biopsy, 3 (75%) were proven to have cancer later.

Conclusions: Evaluating the 1-hour PSA ratio might be helpful for clinicians to select the high risk patients who might have cancer in the prostate. Repeat biopsy should be suggested for cases with a smaller PSA ratio in spite of initial benign results.