[Examination for indication of systematic biopsy for diagnosis of prostate cancer]

Systematic biopsy has been commonly used for detection of prostate cancer. Nevertheless, as this examination occasionally gives patients severe complications it is necessary to give careful consideration for application of this examination. Thus, we analyzed retrospectively 145 cases who underwent transrectal ultrasonography (TRUS) guided systematic biopsy to evaluate the application of systematic biopsy, correlating with the findings of digital rectal examination (DRE), prostate specific antigen (PSA), the findings of transrectal ultrasonography (TRUS) and the results of biopsies.

Between May, 1995 and May, 1997, 143 patients who were suspected to have prostate cancer with either of PSA and DRE, and 2 patients who received visual laser ablation of prostate (VLAP), underwent TRUS guided systematic biopsy of prostate. We evaluated diagnostic efficacy of PSA, DRE, TRUS, prostate-volume-specific PSA, and PSA density (PSAD).

Sensitivity, specificity and positive predictive value (P.P.V.) are 78.4%, 62.8% and 53.5% for DRE, 100.0%, 4.4% and 41.8% for PSA, 88.2%, 60.0% and 52.9% for TRUS, 87.8%, 72.1% and 64.2% for prostate-volume-specific PSA, 100.0%, 30.6% and 45.4% for PSAD, respectively. Ten of 69 patients (14.5%) whose PSA levels were 4.0 to 10.0 ng/ml were diagnosed as cancer, and positive for both or either of DRE and TRUS. Twenty-seven who were negative for both of DRE and TRUS were not diagnosed as prostate cancer. Using the combination of prostate-volume-specific PSA, DRE and TRUS, we could eliminate 29 non-cancer men (21.5%) whose PSA level was greater than 4.0 ng/ml from systematic biopsy.

On the diagnosis of prostate cancer, the combination of prostate-volume-specific PSA, DRE and TRUS is very useful to exclude unnecessary systematic biopsy, if an urologist could be used to and trained for DRE and TRUS.