Distribution of prostate carcinoma foci within the peripheral zone:: analysis of 8,062 prostate biopsy cores

The aim of this study was to evaluate the distribution of prostate cancer within the peripheral zone by prostate biopsies excluding the influence of the transition zone. A prospective, multicenter study was carried out using a consecutive series of men who underwent transrectal ultrasound guided prostate biopsies using different biopsy techniques at six institutions. Biopsies were directed strictly within the peripheral zone or strictly within the transition zone. A model of the peripheral zone with 18 sectors of similar volume was established and the biopsy cores obtained were associated with these sectors and analysed with respect to prostate cancer detection rate. A total of 904 men (mean age 66.8 years, range 42-86) with a median serum PSA of 8.1 ng/ml (2.2-940 ng/ml) entered the study. A total of 8,062 biopsy cores (mean 8.92/patient) were obtained. Each of the peripheral zone sectors tested by biopsies yielded a similar percentage of prostate cancer (P=0.6). There was no increase in the incidence of cancer toward the lateral sectors compared to midline sectors (P=0.53) of the peripheral zone. Biopsy sampling of the peripheral zone from the apex to the base yielded a similar percentage of prostate cancer (P=0.47). Our data suggest that the distribution of cancer foci detected by biopsies in the peripheral zone of the prostate is homogeneous.