Comparison of lesions detected and undetected by template-guided transperineal saturation prostate biopsy.

OBJECTIVES: To compare the characteristics of lesions detected or undetected by template-guided transperineal saturation prostate biopsy and to evaluate the potential impact of undetected lesions.

MATERIALS AND METHODS: We evaluated the characteristics of lesions in radical prostatectomy (RP) specimens, compared the differences between lesions detected and undetected by systematic transperineal ultrasonography-guided 11-region biopsy with regard to tumour volume, Gleason score, surgical margin, spatial location and clinical significance, and assessed the potential impact of undetected clinically significant lesions.

RESULTS: The median number of biopsy cores was 24. Sixty-four percent of the clinically significant lesions (170/264) were detected. There were significant differences between the detected and undetected lesions in tumour volume, Gleason score and clinical significance. Inconsistencies found in lesion position between biopsy and RP specimens in the anterior and posterior zones and the left and right sides was 3.4% (7/203) and 5.4% (11/203), respectively. Of the 129 patients, 13 (10.1%) were found to have undetected clinically significant lesions in the biopsy lying on the same side but in a different zone from the detected clinically significant lesions, whereas 23 patients (17.8%) had undetected clinically significant lesions in the biopsy lying on the opposite side from the detected clinically significant lesions.

CONCLUSIONS: Template-guided transperineal saturation prostate biopsy detected approximately two-thirds of clinically significant lesions. Most of the undetected lesions were those with small tumour volume. Approximately 20-30% of patients had clinically significant undetected lesions in a different lobe or different quadrant from the detected lesions in the biopsy.