The assessment of pathological response to neoadjuvant chemotherapy in muscle- invasive bladder cancer patients with DCE- MRI and DWI: a systematic review and meta-analysis

Objective: The purpose of this meta-analysis was to determine the value of dynamic contrast-enhanced- MRI (DCE- MRI) and diffusion-weighted imaging (DWI) in evaluating the pathological response of muscle invasive bladder cancer (MIBC) to neoadjuvant chemotherapy (NAC), and further indirectly compare the diagnostic performance of DCE- MRI and DWI. Methods: Literatures associated to DCE- MRI and DWI in the evaluation of pathological response of MIBC to NAC were searched from PubMed, Cochrane Library, web of science, and EMBASE databases. The quality assessment of diagnostic accuracy studies 2 tool was used to assess the quality of studies. Pooled sensitivity (SE), specificity (SP), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the receiver operating characteristic curves (AUC) with their 95% confidence intervals (CIs) were calculated to evaluate the diagnostic performance of DCE- MRI and DWI in predicting the pathological response to NAC in patients with MIBC. Results: There were 11 studies involved, 6 of which only underwent DCE-MRI examination, 4 of which only underwent DWI examination, and 1 of which underwent both DCE-MRI and DWI examination. The pooled SE, SP, PLR, NLR, DOR of DCE- MRI were 0.88 (95% CI: 0.78- 0.93), 0.88 (95% CI: 0.67-0.96), 7.4 (95% CI: 2.3-24.2), 0.14 (95% CI: 0.07-0.27), and 53 (95% CI: 10-288), respectively. The pooled SE, SP, PLR, NLR, DOR of DWI were 0.83 (95% CI: 0.75-0.88), 0.88 (95% CI: 0.81-0.93), 7.1 (95% CI: 4.3-11.7), 0.20 (95% CI: 0.14-0.28), and 36 (95% CI:18-73), respectively. The AUCs of SROC curve for DCE- MRI and DWI were 0.93 (95% CI: 0.91-0.95) and 0.92 (95% CI: 0.89-0.94), respectively. There were no significant differences between DWI and DCE- MRI for SE, SP, and AUC. Conclusion: This meta-analysis demonstrated high diagnostic performance of both DCE- MRI and DWI in predicting the pathological response to NAC in MIBC. DWI might be a potential substitute for DCE- MRI, with no significant difference in diagnostic performance between the two. However, caution should be taken when applying our results, as our results were based on indirect comparison. Advances in knowledge: No previous studies have comprehensively analysed the value of DCE- MRI and DWI in evaluating the pathological response to NAC in MIBC. According to the current study, both DCE- MRI and DWI yielded high diagnostic performance, with the AUCs of 0.93 and 0.92, respectively. Indirect comparison no significant difference in the diagnostic performan-ceof DCE- MRI and DWI.