Prospective evaluation of lateral biopsies of the peripheral zone for prostate cancer detection

Purpose: We evaluate the usefulness of adding 4 lateral biopsies of the peripheral zone to the routine sextant biopsy regimen for prostate cancer. Materials and Methods: A total of 273 consecutive patients referred for abnormal digital rectal examination and/or prostate specific antigen 4 ng./ml. or greater underwent transrectal ultrasound and systematic biopsy. Lateral biopsies of the peripheral zone taken just medial to the lateral border of the prostate were added to the routine lesion directed and systematic sextant biopsy regimen. Comparisons between positive and negative biopsy groups as well as among various biopsy schemes were performed. Results: Of the patients 44% had cancer on biopsy (121 of 273). While routine sextant biopsies detected 82% of cancers, 77% (17 of 22) of missed cancers were detected on lateral biopsies. Overall, lateral biopsies detected 70% of cancers, and tended to be positive in patients with small prostates and high grade tumors. A significant correlation was found between hypoechoic lesions on transrectal ultrasound and positive lateral biopsies (Fisher's exact test p = 0.0005). Cancer was found in 74 of 147 patients with lesions on transrectal ultrasound (50%). Routine sextant biopsies detected 76% of cancers (56 of 74 patients) while lateral biopsies detected 80% (59). Of these patients 15 (20%) had positive lateral and negative sextant biopsies. Routine sextant biopsies detected 91% of cancers in 121 patients without lesions on ultrasound (43 of 47). Conclusions: The addition of lateral peripheral zone biopsies increases the sensitivity for cancer detection while nearly eliminating the need for lesion directed biopsies.