The Significance of Prostate-specific Antigen after Transrectal Prostate Biopsy / 대한비뇨기과학회지

ABSTRACT

Purpose: The serum prostate-specific antigen (PSA) level is increased after needle biopsy (Bx) of the prostate. This study tested the hypothesis that the prostate that harbors malignant lesions demonstrates less leakage of PSA after transrectal prostate Bx, and this phenomenon can be helpful in discriminating benign protrates from cancer ous prostrates. Materials and Methods: Eighty three patients were included in this prospective study because they had an increase PSA level (from 4 to 30ng/ml) and/or an abnormal digital rectal examination, and the serum PSA level was checked 60 minutes later after biopsy. We checked the pre-Bx total serum PSA, the post-Bx total serum PSA and the PSA ratio (post-Bx total serum PSA to pre-Bx total serum PSA), and we analyzed the sensitivity, specificity, positive predictive value, negative predictive value and the statistical differences. Results: Of the 31 men whose PSA ratio was less than 2.0, 27 (87%) men were proven to have prostate cancer. Of the 52 men whose PSA ratio was greater than 2.0, 49 (94%) were proven to have benign lesions. When setting 2.0 as the cutoff value, the difference was statistically significant (p<0.001); the sensitivity was 90.0%, the specificity 92.4%, the positive predictive value (PPV) 87.0% and the negative predictive value (NPV) 94.2%. Conclusions: Evaluating the 1-hour PSA ratio might be helpful for clinicians to diagnosis the high risk patients who might have cancer in their prostate glands. Repeat biopsy should be considered for patients who initially had negative biopsy results with a smaller PSA ratio.