Parasagittal biopsies add minimal information in repeat saturation prostate biopsy.

OBJECTIVES: To compare the outcome and efficacy of lateral biopsies with parasagittal biopsies in detecting prostate cancer during repeated biopsies performed using the "saturation" technique, which includes 24 cores per biopsy. Prostate biopsy may miss cancer in up to 38% of men eventually found to harbor the disease. Lateral biopsies are more likely than parasagittal biopsies to detect adenocarcinoma according to the findings of several studies.
METHODS: A total of 100 patients, average age 62.1 +/- 7.9 years, underwent repeated transrectal ultrasound-guided saturation biopsy. The study group included 31 patients with previous biopsy results demonstrating high-grade prostatic intraepithelial neoplasia, 7 with atypia, and 62 with benign prostatic tissue but persistently elevated prostate-specific antigen levels. Patients had undergone an average of 1.65 previous biopsies. The average prostate-specific antigen level was 9.4 +/- 6.8 ng/mL. Biopsies were obtained from five sectors on each side and examined histologically.
RESULTS: Cancer was detected in 25 (25%) of the 100 patients. Malignancy was identified in the lateral cores of all patients with positive biopsies. Parasagittal biopsy cores were positive in association with a lateral-based biopsy in 9 (36%) of the 25 malignancies, for an overall parasagittal biopsy core rate of 9% (9 of 100 patients). No cancers were detected in the parasagittal biopsy cores alone.
CONCLUSIONS: Inclusion of parasagittal zone biopsy cores proved to have a low yield in detecting cancer on repeated biopsy. As all patients found to have cancer in the parasagittal biopsy cores also had cancer on the lateral biopsy cores, most time and effort can be spent obtaining lateral biopsy cores to increase the sensitivity on repeated saturation biopsy.