Detectability of prostate cancer in different parts of the gland with 3-Tesla multiparametric magnetic resonance imaging: correlation with whole-mount histopathology.

backgroundWe investigated whether the detectability of prostate cancer with 3-Tesla (3T) multiparametric magnetic resonance imaging (mpMRI) differs by tumor location.

methodsWe identified 136 patients with prostate cancer who underwent 3-T mpMRI before prostatectomy at a single academic center. Two uroradiologists scored all MRIs with Prostate Imaging-Reporting and Data System version 2 (PI-RADS v2). A genitourinary pathologist mapped tumor foci from serial whole-mount radical prostatectomy sections. We assessed concordance of images with cancer sites. Tumor foci with Gleason score ≥  3 + 4 or volume ≥ 0.5 mL were considered significant.

resultsA total of 122 foci in 106 cases were identified with mpMRI. Twenty-four were PI-RADS 3, 52 were 4, and 46 were 5. A total of 274 tumor foci were identified with whole-mount pathology. The sensitivity stratified by location to detect significant cancer with a PI-RADS cutoff value of 3 was 56.0% overall, 50.0% in the peripheral zone (PZ), 71.2% in the transitional zone (TZ), 62.4% anterior, 49.5% posterior, 42.0% apical, 63.6% in the midgland, and 43.8% in the gland base. In multivariate analysis, tumor location was not a significant predictor of identification by mpMRI. Tumor volume, Gleason score, and index tumor status were significantly associated with identification by mpMRI.

conclusionsmpMRI detected the majority of high-grade and large cancers, but had low sensitivity in the PZ, posterior, and apex and base of the gland. The high prevalence of low-volume, low-Gleason score index tumors, as well as satellite tumors in those areas, accounted for the difference.