Diagnostic Performance of ¹⁸F-FDG PET and PET/CT for the Detection of Recurrent Esophageal Cancer After Treatment with Curative Intent: A Systematic Review and Meta-Analysis

The aim of this study was to assess the diagnostic performance of (18)F-FDG PET and integrated (18)F-FDG PET/CT for diagnosing recurrent esophageal cancer after initial treatment with curative intent.

Methods: The PubMed, Embase, and Cochrane library were systematically searched for all relevant literature using the key words "(18)F-FDG PET" and "esophageal cancer" and synonyms. Studies examining the diagnostic value of (18)F-FDG PET or integrated (18)F-FDG PET/CT, either in routine clinical follow-up or in symptomatic patients in whom recurrence of esophageal cancer was suspected, were deemed eligible for inclusion. The primary outcome was the presence of recurrent esophageal cancer as determined by histopathologic biopsy or clinical follow-up. Risk of bias and applicability concerns were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Sensitivities and specificities of individual studies were meta-analyzed using bivariate random-effects models.

Results: Eight eligible studies were included for meta-analysis, comprising 486 patients with esophageal cancer who underwent (18)F-FDG PET or PET/CT after previous treatment with curative intent. The quality of the included studies assessed by the QUADAS-2 tool was considered reasonable; there were few concerns with regard to the risk of bias and applicability. Integrated (18)F-FDG PET/CT and standalone (18)F-FDG PET were used in 4 and 3 studies, respectively. One other study analyzed both modalities separately. In 4 studies, (18)F-FDG PET or PET/CT was performed as part of routine follow-up, whereas in 4 other studies the diagnostic test was performed on indication during clinical follow-up. Pooled estimates of sensitivity and specificity for (18)F-FDG PET and PET/CT in diagnosing recurrent esophageal cancer were 96% (95% confidence interval, 93%-97%) and 78% (95% confidence interval, 66%-86%), respectively. Subgroup analysis revealed no statistically significant difference in diagnostic accuracy according to type of PET scanner (standalone PET vs. integrated PET/CT) or indication of scanning (routine follow-up vs. on indication).

Conclusion: (18)F-FDG PET and PET/CT are reliable imaging modalities with a high sensitivity and moderate specificity for detecting recurrent esophageal cancer after treatment with curative intent. The use of (18)F-FDG PET or PET/CT particularly allows for a minimal false-negative rate. However, histopathologic confirmation of (18)F-FDG PET- or PET/CT-suspected lesions remains required, because a considerable false-positive rate is noticed.