Effect of Prostate Size on Cancer Detection Rate of Traditional Sextant Prostate Biopsy

Park, Yong Sul; Kwak, Cheol; Shim, Hong Bang

Abstract

PURPOSE: We aimed to evaluate whether cancer detection rates could vary with prostate size using a systematic sextant biopsy.
MATERIALS AND METHODS
We performed a systematic sextant biopsy in 225 consecutive men from January 1997 to August 2002. Indications for biopsy included an elevated prostate specific antigen(PSA) level(more than 4.0ng/ml), or the hypoechoic lesion on TRUS. Prostate volume was calculated using the following fomula: volume=0.52 x length x width x height. We examined biopsy yield according to gland-volume intervals of 10cc.
RESULTS
Adenocarcinoma was detected in 68 out of 225 patients(30.22%). The mean volume of prostate in all patients was 51.5cc. The highest biopsy rate(65.7%) was recorded among men with prostates between 20 to 29.9cc. The lowest biopsy rate (17.2%) was recorded among men with prostates larger than 80cc. Decreasing yield of sextant biopsy was strongly associated with increasing gland volume(p<0.001). The biopsy rate was significantly higher in patients with smaller prostates(<30cc) than in those with larger prostates(> or =30cc)(62.63% and 22.09%, respectively, p<0.001). Age, serum PSA, PSAD, and Gleason grade were comparable between small (<30cc) and large(> or =30cc) prostate groups.
CONCLUSION
Our cancer detection rate using a systematic sextant biopsy was higher in men with prostates less than 30cc. Our results suggest that significant sampling error may occur in men with large glands, and more biopsies may be needed under these circumstances.