How reliable is 12-core prostate biopsy procedure in the detection of prostate cancer?

Prostate biopsies incur the risk of being false-negative and this risk has not yet been evaluated for 12-core prostate biopsy. We calculated the false-negative rate of 12-core prostate biopsy and determined the patient characteristics which might affect detection rate. We included 90 prostate cancer patients (mean age of 64, range: 49-77) diagnosed with transrectal ultrasound guided 12-core prostate biopsy between December 2005 and April 2008. All patients underwent radical retropubic prostatectomy and the 12-core prostate biopsy procedure was repeated on surgical specimen ex-vivo. Results of preoperative and postoperative prostate biopsies were compared. We analyzed the influence of patient age, prostate weight, serum prostate-specific antigen (PSA) level, free/total PSA ratio, PSA density and Gleason score on detection rate. In 67.8% of patients, prostate cancer was detected with repeated ex-vivo biopsies using the same mapping postoperatively. We found an increase in PSA level, PSA density and biopsy Gleason score; patient age, decreases in prostate weight and free/total PSA ratio yielded higher detection rates. All cores, except the left-lateral cores, showed mild-moderate or moderate internal consistency. Preoperative in-vivo biopsy Gleason scores remained the same, decreased and increased in 43.3%, 8.9% and 47.8% of patients, respectively, on final specimen pathology. The detection rate of prostate cancer with 12-core biopsy in patients (all of whom had prostate cancer) was considerably low. Effectively, repeat biopsies can still be negative despite the patient s reality of having prostate cancer. The detection rate is higher if 12-core biopsies are repeated in younger patients, patients with high PSA levels, PSA density and Gleason scores, in addition in patients with smaller prostates, lower free/total PSA ratios.