Extended sampling at first biopsy improves cancer detection rate: results of a prospective, randomized trial comparing 12 versus 18-core prostate biopsy

Purpose: We determined whether increasing the number of cores at first prostate biopsy would improve the cancer detection rate without increasing the detection of clinically insignificant tumors.

Materials and methods: From January 2009 to January 2010 patients scheduled for prostate biopsy were randomized to 12 or 18-core sampling. Study inclusion criteria were 1) age 45 to 75 years, 2) abnormal digital rectal examination and/or prostate specific antigen 4 to 20 ng/ml, and 3) no previous biopsy. The primary end point was the cancer detection rate. Secondary end points were clinically insignificant cancer detection and morbidity.

Results: A total of 150 patients were enrolled in the study. Preoperative variables were similar in the 2 groups of 75 patients each. Cancer was detected in 23 patients (30.7%) in group 1 and in 36 (48%) in group 2 (p = 0.02). More cases of insignificant cancer were detected in group 2 (p not significant). In men with prostate volume 65 cc or less the detection rate was 30.9% in group 1 and 52.8% in group 2 (p = 0.02). In men with prostate specific antigen 10 ng/ml or less the detection rate was 19.6% in group 1 and 38.4% in group 2 (p = 0.03). Two group 2 patients (5.5%) were diagnosed based on additional samples but the diagnosis corresponded to insignificant cancer. There was no statistically significant difference in morbidity.

Conclusions: The 18-core protocol improves prostate cancer detection without increasing morbidity. Results suggest that the 12-core biopsy protocol is adequate for prostate cancer detection at first biopsy.