3-DIMENSIONAL COMPUTER-ASSISTED ANALYSIS OF SECTOR BIOPSY OF THE PROSTATE

Objectives. To assess the relationship between tumor volume, gland vol ume, number of sectors submitted to biopsy, and prostatic biopsy detec tion rate. Methods. Using a three-dimensional mathematical model of th e prostate, we assessed detection rates achieved with 4-, 6-, 8-, 10-, and 12-sector biopsies for glands ranging from 20 to 100 cc and perip heral zone tumors ranging from 0.3 to 1.4 cc. Results. Quadrant and se xtant biopsy approaches only yielded from 6.2% to 13.4% and 8.6% to 18 .3%, respectively, of lesions in a 40-cc gland. Conversely, 10- and 12 -sector approaches yielded, respectively, from 19.8% to 48.8% and 25.4 % to 62% of lesions for the same gland size. When assessed according t o the density of sampling, one biopsy core used for every 1.5 to 3.5 c c of prostatic tissue detected 42.5% of 0.5-cc lesions. For the same l esion size, the density of sampling per biopsy core was then decreased to intervals extending from 3.6 to 7.5 cc, 7.6 to 12.5 cc, and 12.6 t o 25 cc. These sampling density intervals yielded, respectively, 25.0% , 15.8%, and 9.8% detection rates. Conclusions. On the basis of our re sults, a gland volume-based biopsy algorithm is likely to result in im proved detection of clinically significant prostate cancer. UROLOGY 52 : 208-212, 1998. (C) 1998, Elsevier Science inc. All rights reserved.