Performance characteristics of multiparametric-MRI at a non-academic hospital using transperineal template mapping biopsy as a reference standard

Abstract

Objectives: To evaluate diagnostic accuracy of mpMRI in a non-academic hospital using transperineal template prostate mapping (TPM) biopsy as a reference standard. Secondary objectives included evaluating why mpMRI missed significant cancer. Materials and methods: 101 men received pre-biopsy mpMRI and TPM-biopsy over 16 months. Disease status was assigned at hemigland level. Primary histological definition of clinical significance was Gleason grade >/ = 4 + 3 or maximum cancer core length (MCCL) >/ = 6 mm. Positive mpMRI was defined as Prostate Imaging Reporting and Data System (PI-RADS) score >/ = 3. Results: Median age 69 (IQR 62–76). Median PSA 7 ng/ml (IQR 4.6–9.8). mpMRI had sensitivity 76.9%, specificity 60.7%, PPV 40.4% and NPV 88.3% at primary definitions. For detecting any Gleason >/ = 7 mpMRI had sensitivity 73.2%, specificity 60.3%, PPV 41.4% and NPV 85.4%. Mean MCCL was lower where significant cancer was missed compared to those correctly identified (5.8 mm versus 7.7 mm respectively, p = 0.035). Conclusion: mpMRI performance characteristics were very encouraging when compared to contemporary clinical trials. In a non-academic hospital setting, negative mpMRI was just as good at ruling-out significant disease, though the ability of positive mpMRI to accurately detect significant disease was lower. An mpMRI-guided diagnostic pathway should be accompanied by appropriate mpMRI protocol optimisation, training, and quality control. Highlights:

MRI-based nomogram for the prediction of prostate cancer diagnosis: A multi-centre validated patient–physician decision tool

“…In addition, the calculator has been calibrated with an mpMRI-positive predictive value of 20% for detecting Grade Group ⩾ 2, which is notably lower in comparison with other studies. 1,9,10,16…”

“…The mpMRI has been one of the more recent advances in tech nology, showing high sensitivity and negative predictive values. 1,9,10 Its incorporation into nomograms has been shown to increase accuracy, with numerous risk calcula tors published, although few of these have been externally validated.…”

“…In addition, the calculator has been calibrated with an mpMRIpositive predictive value of 20% for detecting Grade Group ⩾ 2, which is notably lower in comparison with other studies. 1,9,10,16 Alongside this, in the United States, Mehralivand et al developed an MRIbased risk calculator for predicting MRITRUS fusion biopsy outcome based on age, African American ethnicity, prior negative biopsy, abnormal DRE, PSA, and PIRADSv2 score. 17 This was derived from one development cohort of 400 men in a single institution and further external validation using a cohort of 251 men from two independent centres.…”