Usefulness of comparing of magnetic resonance imaging (MRI) findings prior to repeat biopsy and negative initial biopsy as a decision-making method for repeat prostate biopsy

We retrospectively reviewed the data from a cohort of 44 patients with one initial negative transrectal ultrasound-guided prostate biopsy who underwent a repeat biopsy from 2006 to 2013. At each biopsy session, we checked patient age, serum prostate specific antigen (PSA), prostate volume, PSA density, PSA velocity, months from the initial biopsy session, multiparametric magnetic resonance imaging (MRI) findings (T2-weighted, dynamic contrast-enhanced and diffusion-weighted, 1.5 Tesla pelvic-phased array) prior to repeat biopsy and initial negative biopsy. Mean age was 68.2±8.82 years. PSA was 11.5±7.65 ng/ml before repeat biopsy. Prostate cancer was detected in 15 (34.0%) patients at repeat biopsy. In univariate and multivariate analysis, positive MRI findings before repeat biopsy were significant independent predictors of a positive repeat biopsy. At per patient analysis, the sensitivity, specificity, positive and negative predictive values were 66.6, 68.9, 71.4 and 80.0% for MRI before repeat biopsy. No suspicious lesion on MRI before repeat biopsy was relevant to negative biopsy. According to the comparison of MRI findings prior to repeat biopsy and negative initial biopsy, suspicious MRI findings at the peripheral zone before repeat biopsy and initial negative biopsy were relevant to a high cancer detection rate (83.3%) at repeat prostate biopsy. These results suggested that the absence of a suspicious lesion on MRI before repeat biopsy could guide the avoidance of repeat biopsy and suspicious MRI findings at the peripheral zone before repeat biopsy and initial negative biopsy could guide repeat biopsy.