Role of "saturation biopsy" in the detection of prostate cancer among difficult diagnostic cases.

OBJECTIVES

To determine the role of extensive prostate biopsy ("saturation biopsy") among selected men with unexplained worrisome prostate-specific antigen (PSA) parameters. Clinicians are commonly faced with the dilemma of elevating PSA levels despite negative prostate biopsy results in patients without symptoms of prostatitis.

METHODS

Thirty-seven patients underwent saturation biopsy. This consisted of 24 peripheral zone cores, 6 to 12 transition zone cores, and 2 lateral lobe transurethral samples. All procedures were done under anesthesia. Patients were discharged home with catheters in situ. All patients had undergone at least three prior sets of transrectal ultrasound-guided prostate biopsies, including transition zone assessment. Twelve, eight, and five patients had had four, five, and six prior prostate biopsies, respectively. Specimens were sent for pathologic examination in groups of six to determine the marginal benefit of the additional sampling.

RESULTS

The mean age of the cohort was 62.4 years (range 39 to 75). The median PSA and percent free PSA was 22.4 ng/mL (range 7.8 to 73.8) and 0.11 (range 0.04 to 0.17), respectively. Five patients (13.5%) had detectable carcinoma at saturation biopsy. The grade distribution was Gleason score 8 for 1 patient, Gleason score 7 for 2 patients, and Gleason score 6 for 2 patients. In all cases, carcinoma was detected in the first 18 peripheral zone cores. Acute prostatitis was noted in 19% of specimens. The procedure was well tolerated, although 4 patients required prolonged (greater than 1 week) catheter drainage for urinary retention. All patients were spontaneously voiding by week 3.

CONCLUSIONS

Most men with multiple previous biopsies and increasingly worrisome PSA parameters do not have cancer. The marginal utility of the saturation biopsy is low. Although rare additional cases will be detected using this technique, 18-core peripheral sampling is recommended for these difficult diagnostic cases.