Extensive repeat transrectal ultrasound guided prostate biopsy in patients with previous benign sextant biopsies

Abstract

Purpose: Standard sextant prostate biopsy may underestimate cancer in men in whom clinical findings are suspicious for localized prostate cancer. We describe our experience with extensive transrectal ultrasound guided prostate biopsy in men in whom previous sextant biopsy was negative.

Materials and methods: Between November 1997 and March 1999, 57 men 47 to 72 years old (mean age 61.4) underwent extensive transrectal ultrasound guided biopsy of the prostate using intravenous sedation at our institution. An average of 22.5 cores (range 15 to 31) were obtained depending on prostate size. Biopsies were obtained from each of 6 sagittal regions, including samples from the far lateral and mid transitional zones. Each patient had undergone at least 1 previous benign transrectal ultrasound guided sextant biopsy (mean 2.1, range 1 to 4). Indications for repeat biopsy were persistently elevated prostate specific antigen (PSA) in 89% of the cases, increased PSA velocity in 63%, suspicious free-to-total PSA in 39% and a previous suspicious biopsy finding in 32%. Clinical factors (PSA, PSA velocity, free-to-total PSA and previous suspicious biopsy) were analyzed for the ability to predict positive biopsy, and tumor parameters were assessed pathologically in patients undergoing radical prostatectomy.

Results: Adenocarcinoma was identified in 17 of the 57 men (30%). Biopsy revealed a Gleason score of 6 to 8 (mean 6.4). In 7 of the 17 patients (41%) in whom cancer was identified only 1 biopsy core was positive. Of the 15 patients in whom previous sextant biopsy had demonstrated high grade prostatic intraepithelial neoplasia or atypical small acinar proliferation extensive biopsy revealed cancer in 7 (47%). Although serum PSA was higher and free-to-total PSA was lower in those with cancer, the only statistically significant predictor of positive biopsy was PSA velocity (p <0.001). Prostate cancer was noted in 64% of the men with PSA velocity 1 ng./ml. or greater. Of the 13 patients undergoing radical prostatectomy pathologically significant disease was identified in all but 1 (92%). Complications of extensive biopsy included urinary retention in 6 patients and limited rectal bleeding in 1.

Conclusions: Extensive prostate biopsy identifies significant prostate cancer in many men in whom previous sextant biopsy was benign. This procedure should be considered when findings are suspicious for adenocarcinoma despite previously negative sextant biopsy.