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

Abstract

Introduction: Prostate biopsies incur the risk of being false-negativeand this risk has not yet been evaluated for 12-core prostatebiopsy. We calculated the false-negative rate of 12-core prostatebiopsy and determined the patient characteristics which mightaffect detection rate.Methods: We included 90 prostate cancer patients (mean age of64, range: 49-77) diagnosed with transrectal ultrasound guided12-core prostate biopsy between December 2005 and April 2008.All patients underwent radical retropubic prostatectomy and the12-core prostate biopsy procedure was repeated on surgical specimenex-vivo.Results of preoperative and postoperative prostatebiopsies 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.Results: In 67.8% of patients, prostate cancer was detected withrepeated ex-vivo biopsies using the same mapping postoperatively.We found an increase in PSA level, PSA density and biopsyGleason score; patient age, decreases in prostate weight and free/total PSA ratio yielded higher detection rates. All cores, exceptthe left-lateral cores, showed mild-moderate or moderate internalconsistency. Preoperative in-vivo biopsy Gleason scores remainedthe same, decreased and increased in 43.3%, 8.9% and 47.8% ofpatients, respectively, on final specimen pathology.Conclusions: The detection rate of prostate cancer with 12-corebiopsy in patients (all of whom had prostate cancer) was considerablylow. Effectively, repeat biopsies can still be negative despitethe patient’s reality of having prostate cancer. The detection rate ishigher if 12-core biopsies are repeated in younger patients, patientswith high PSA levels, PSA density and Gleason scores, in additionin patients with smaller prostates, lower free/total PSA ratios.