The role of MRI in detection and staging of upper urinary tract cancer: a systematic review of the literature.

INTRODUCTION

Upper urinary tract tumors (UUTT) are imprecisely diagnosed. Recent data have shown the benefit of adding systemic treatments to advanced local stage tumors (≥T2). MRI has provided useful information for evaluating the local T stage of urinary bladder tumors, which may be used for UUTT. The objective of this study was to review the literature on the diagnostic and staging capabilities of MRI for UUTT. Additionally, the methods for performing MRI on the UUT were evaluated.

METHODS

This review was conducted according to the PRISMA using MEDLINE and EMBASE. All original articles published between January 2000 and February 2024 that investigated the diagnostic and staging performance of MRI in patients with suspected UUTT were included in this study.

RESULTS

Fifteen studies were included, comprising 999 patients, of whom 593 had UUTT. A wide heterogeneity in the sequences was observed. While standard acquisition (T1 weighted + T2 weighted) showed insufficient diagnostic performance, dynamic contrast imaging (DCE) and diffusion weighted imaging (DWI) presented strong diagnostic scores for pooled sensitivity (92.5% and 93.2%), specificity (76.7% and 84.2%), and accuracy of diagnosis (91.1% and 90.1%), respectively. DWI and apparent diffusion coefficient (ADC) seem to be informative for staging and prognostic evaluation.

DISCUSSION AND

CONCLUSION

MRI has strong potential to enhance UUTT diagnosis and staging. Despite heterogeneous data and limited evidence, the findings of this study suggest that further large multicentric studies should be conducted to better evaluate the diagnostic performance of MRI in UUT, with a predefined standard acquisition compared to the pathology report of radical nephroureterectomy or long-term follow-up by medical imaging. We hope to establish an Upper Urinary Tract Imaging-Reporting and Data System (MRI UUTI-RADS) score for predicting muscle invasion and tumor stage.

PATIENT SUMMARY: We performed a systematic evaluation and summary of all studies published on the diagnostic and staging capabilities of MRI for upper urinary tract tumors. This review showed a lack of evidence data but a strong potential for MRI. A predefined MRI protocol was proposed for future studies.

SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/, identifier CRD42022319265.