The role of transrectal saturation biopsy in tumour localization: pathological correlation after retropubic radical prostatectomy and implication for focal ablative therapy

OBJECTIVE To evaluate the accuracy of an initial 24-core prostate biopsy scheme (PBx24) in predicting unilateral prostate cancer (PCa) in radical prostatectomy (RP) specimens. PATIENTS AND METHODS Between 2005 and 2008, 203 consecutive patients underwent PBx24 followed by RP for PCa. The area under the curve (AUC) was used to evaluate the accuracy of unilateral PCa on PBx24 to predict unilateral PCa in RP specimens. The positive predictive value (PPV) and negative predictive value (NPV) were also calculated. Moreover, in patients with unilateral PCa on biopsy, univariable and multivariable logistic regression analyses tested the relationship between the presence of unilateral PCa in an RP specimen and the variables: age, prostate-specific antigen (PSA), total prostate volume, clinical stage, primary Gleason grade, secondary Gleason grade and the number of positive cores. RESULTS PCa cores were unilateral in 115 patients (56.7%) on biopsy. Of those, only 26 (22.6%) had unilateral PCa in the RP specimen (AUC, 72.9%; PPV, 22.6%; NPV, 98.8%). In patients with clinically low-risk tumours, only 17 of 63 (27%) had a unilateral PCa on PBx24 and in the RP specimen (AUC, 59.1%; PPV, 27.0%; NPV, 100.0%). None of the examined variables was an independent predictor of the presence of unilateral PCa in the RP specimen (all P > 0.05). CONCLUSIONS Initial PBx24 is not sufficiently accurate to be dependable as a method of predicting tumour laterality in RP specimens. Therefore, the use of PBx24 to guide hemi-ablation therapy of PCa may lead to mistreatment in a considerable proportion of patients. Moreover, none of the routinely available clinical and pathological characteristics appears to improve the ability of unilateral PCa on biopsy to predict unilateral PCa in the RP specimen.