Diagnostic accuracy of magnetic resonance imaging for tumour staging of bladder cancer: systematic review and meta‐analysis

Abstract

The purpose of this study is to evaluate accuracy of magnetic resonance imaging (MRI) for local staging of bladder cancer for four clinical scenarios (T-stage thresholds) considered against current standards for clinical staging and secondarily to identify sources for variability in accuracy. Systematic review of patients with bladder cancer undergoing T-staging MRI to evaluate the diagnostic accuracy using bivariate random-effects meta-analysis. Sub-group analysis was done to explore variability; risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. The search identified 30 studies (5156 patients). Pooled accuracy at multiple T-stage thresholds: ≤T1 vs ≥T2 = sensitivity 87% (95% confidence interval [CI] 82-91), specificity 79% (95% CI 72-85); T-any vs T0 = sensitivity 65% (95% CI 23-92), specificity 90% (95% CI 83-94); ≤T2 vs ≥T3 = sensitivity 83% (95% CI 75-88), specificity 87% (95% CI 78-93); and <T4b vs pT4b = sensitivity 85% (95% CI 63-95), specificity 98% (95% CI 95-99). For ≤T1 vs ≥T2, accuracy was higher in studies at low risk of bias. No variability in accuracy was identified for: field strength, transurethral resection of bladder tumour status, publication date, index test parameters. For ≤T1 vs ≥T2, accuracy was higher than reported for clinical staging. For T-any vs T0 accuracy was lower than clinical staging. For ≤T2 vs ≥T3, sensitivity was slightly lower than clinical staging but specificity was considerably higher. For <T4b vs pT4b sensitivity exceeded the estimated accuracy for clinical staging. Limitations: two scenarios had few studies (T-any vs T0; <T4b vs pT4b) and several studies were at high risk of bias. MRI staging for ≤T1 vs ≥T2, ≤T2 vs ≥T3, and <T4b vs pT4b should be considered as potentially superior to the current standard for clinical staging. MRI accuracy for T-any vs T0 may not be superior to clinical staging. However, cautious interpretation is warranted related to risk of bias and sample size; validation in trials comparing clinical staging strategies vs MRI is warranted.

Development of a noninvasive tool to preoperatively evaluate the muscular invasiveness of bladder cancer using a radiomics approach

“…However, its diagnostic accuracy is less than satisfactory, with a reported range between 64.7% and 83% . Although other sequences, such as diffusion‐weighted and dynamic contrast‐enhanced imaging, are proposed to assist the local staging of BCa, a recent meta‐analysis revealed that there was no significant difference in the accuracy of discrimination between MIBC and NMIBC . Currently, there currently insufficient data on the use of diffusion‐weighted imaging in MIBC to allow for a recommendation to be made in the guidelines .…”

Update on multiparametric MRI of urinary bladder cancer

“…In a study by Parikh et al, this technique, which employed free‐breathing continuous acquisition without a predetermined temporal resolution (which can be later reconstructed at various temporal resolutions from source data) using compressed sensing with radial acquisition (GRASP, Siemens Healthcare) achieved high‐quality imaging at varying temporal resolutions during simultaneous MRU . The added value of DCE in addition to DWI and T 2 W sequences for the local staging of bladder cancer is unclear, and there are limited data directly comparing the individual mp‐MRI sequences …”

“…The manifestation of each T stage depends on the MRI sequence, with different features for T 2 W images, DCE images, and DWI (Table ). Multiple studies suggest that the accuracy of MRI for determining bladder cancer T stage is optimized when using all three of these sequences together (mp‐MRI); however, a recent meta‐analysis found that there was no significant difference in accuracy of discrimination between non‐MIBC and MIBC, and between the absence and presence of peri‐vesical invasion, using different MRI techniques …”

“…A recent systematic review and meta‐analysis evaluating the accuracy of MRI for local staging of bladder cancer for four T‐stage thresholds (compared to current standards for clinical staging) identified that MRI may be more accurate than originally estimated, and perhaps superior to some clinical staging strategies . The four thresholds evaluated were: MRI to differentiate <T1 from >T2 stage before and/or after initial TURBT identifying <T1 tumor.…”

“…It is anticipated that utilization of mp‐MRI for bladder cancer local staging will increase as awareness of its accuracy in the urology community improves. Several recent meta‐analyses assessing the topic of local staging of bladder cancer with mp‐MRI confirm an increased interest in the genitourinary community …”