PET–CT for staging patients with muscle invasive bladder cancer: is it more than just a fancy tool?

Purpose We aim to evaluate the diagnostic accuracy of PET–CT/MRI in the local and distant staging of patients with muscle invasive bladder cancer (MIBC). Methods Medline, Pubmed and EMBASE were searched for studies evaluating the diagnostic performance of PET–CT/MRI in the primary staging of MIBC patients. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR, respectively) and diagnostic odds ratio (DOR = PLR/NLR) are reported. Results We retrieved 35 articles. For local staging, a pooled sensitivity and specificity of 88% (95% CI: 81–92%) and 68% (95% CI: 50–82%), respectively, were found. The PLR and NLR are 2.88 (95% CI: 1.71–4.73) and 0.19 (95% CI: 0.12–0.30) resulting in a DOR of 16.60 (95% CI: 5.98–37.50). For regional lymph node staging, the pooled sensitivity and specificity are 57% (95% CI: 5–63%) and 89% (95% CI: 83–3%). The PLR is 5.33 (95% CI: 3.44–8.09) and NLR is 0.48 (95% CI: 0.42–0.55). The corresponding DOR is 11.10 (95% CI: 6.62–17.60). For distant metastases, a pooled sensitivity and specificity of 89% (95% CI: 61–98%) and 95% (95% CI: 80–99%), respectively, were found. The PLR is 23.70 (95% CI: 4.19–72.10) and the NLR is 0.13 (95% CI: 0.02–0.36) with a DOR of 236.00 (95% CI: 38.00–871.00). Conclusion PET–CT/MRI appears to have higher diagnostic accuracy than CT or MRI for local and distant staging of MIBC but it cannot (yet) be recommended in clinical practice because the quality of the evidence is insufficient and the effects on treatment decisions and patient’s outcome remain unclear.