Negative predictive value of systematic ultrasound-guided prostate biopsy: which tumours do we miss?

BACKGROUND The aim of the study was the determination of the negative predictive value of sextant core prostate biopsy. PATIENTS AND METHODS Prostate cancer was diagnosed in 126 patients by systematic ultrasound-guided sextant biopsy and was subsequently treated with radical prostatectomy. The prostatectomy specimens were examined histopathologically using the whole-mount section technique. RESULTS 81 patients were diagnosed with unilateral and 45 with bilateral prostate cancer after biopsy. In 15/81 patients, the diagnosis of unilateral disease was confirmed by the whole-mount sections; 66 patients turned out to have bilateral disease. In 14/66 cases, the missed tumour foci were diminutive. In the remaining 52 patients, an erroneous diagnosis of unilateral prostate cancer had been made after biopsy, although the missed tumour foci were not diminutive. The negative predictive value of sextant core biopsy with respect to unilateral disease was 36%. CONCLUSION An unexpectedly high number of tumour foci are missed by systematic ultrasound-guided sextant prostate biopsy.