The diagnostic performance of 2-[18F]FDG PET/CT for the recurrent colorectal cancer in patients with elevated CEA versus normal CEA: a systematic review and meta-analysis

Purpose We aimed to conduct a systematic review and meta-analysis of the existing literature to evaluate the diagnostic performance of 2-[18F]FDG PET/CT in detecting recurrent colorectal cancer in patients with elevated CEA vs. normal CEA. Method We searched for relevant articles in PubMed and Embase until May 2022. All published studies regarding the diagnostic performance of 2-[18F]FDG PET/CT in recurrent colorectal cancer with elevated CEA or normal CEA were included. The quality of each study was assessed using the Quality Assessment of Diagnostic Performance Studies-2 (QUADAS-2) tool. Results 18 studies including a total of 1406 patients were included. For elevated CEA group, the pooled sensitivity, specificity and AUC were 0.95 (95% CI: 0.93-0.97), 0.84 (95% CI: 0.76-0.90) and 0.97 (95% CI: 0.95-0.98). For normal CEA group, the pooled sensitivity, specificity and AUC were 0.97 (95% CI: 0.91-0.99), 0.87 (95% CI: 0.80-0.92) and 0.88 (95% CI: 0.85-0.91). The evidence from this study suggested that 2-[18F]FDG PET/CT in elevated CEA group had a higher AUC (0.97 vs. 0.88) compared with 2-[18F]FDG PET/CT in normal CEA group. Conclusions Based on the pooled results, we tentatively conclude that 2-[18F]FDG PET/CT has a good performance in recurrent CRC patients and the diagnostic performance of 2-[18F]FDG PET/CT will significantly improve if there is a prior CEA elevation. Further prospective studies with a larger sample size would draw more accurate conclusions.