PROSTATE-CANCER DIAGNOSED BY THE 5 REGION BIOPSY METHOD IS SIGNIFICANT DISEASE

Purpose: The 5 region method of prostate biopsy takes standard sextant biopsies and additional systematic biopsies of the far lateral and mi ddle aspects of the prostate gland. This method has been shown to incr ease the cancer detection rate of prostate biopsy by 35% over the stan dard sextant biopsy method, and it is most effective in patients with prostate specific antigen less than 10. Concern has arisen that by tak ing additional biopsies, cancers are being detected which would otherw ise be clinically insignificant. We compare pathological findings of r adical prostatectomy specimens detected by the 5 region and sextant bi opsy methods to determine if there is a significant difference between tumors diagnosed by each method. Materials and Methods: A total of 21 patients enrolled in the 5 region prostate biopsy study with biopsy p roved prostate cancer underwent radical prostatectomy. Prostatectomy s pecimens of 5 zone detected cancers in 11 cases were compared to sexta nt method detected cancer in 10. Radical prostatectomy specimens were analyzed for tumor volume, ploidy status, Gleason score and TNM pathol ogical stage. Tumor volumes were determined by point counting morphome tric analysis using an overlying grid. Tumor ploidy status was determi ned by deoxyribonucleic acid (DNA) image analysis. Results: Mean tumor volume was 2.4 cc (range 0.10 to 9.6, median 1.4) for 5 region detect ed cancers versus 1.9 cc (range 0.10 to 6.1, median 1.0) for sextant m ethod detected cancers. This difference was not statistically signific ant (p = 0.643). Mean DNA index was 1.1 (range 0.93 to 1.64) for 5 reg ion detected cancer compared to 1.4 (range 0.96 to 2.2) for sextant me thod detected cancer. Overall there were 8 diploid tumors and 3 aneupl oid tumors in the 5 region group compared to 4 diploid tumors and 6 an euploid tumors in the sextant group. Mean Gleason scores were not sign ificantly different for the 5 region (6.5) and sextant (6.7) groups (p = 0.672). Final tumor stage for the 5 region group was 4 pT3 (36%) an d 7 pT2 (64%) tumors compared to 2 pT3 (20%) and 8 pT2 (80%) tumors fo r the sextant group. Conclusions: Our data demonstrated no significant difference in tumor volume, DNA ploidy status, Gleason score or final pathological tumor stage between tumors diagnosed using the 5 region versus sextant biopsy techniques.