The usefulness of combining narrow-band imaging with magnifying endoscopy and 18F-fluorodeoxyglucose positron emission tomography for predicting the depth of invasion in superficial esophageal squamous cell carcinoma.

Background: To ascertain the indication of endoscopic resection (ER) for esophageal squamous cell carcinoma (ESCC), accurate preoperative diagnosis of the tumor depth beyond cT1b-SM2 is crucial. This study aimed to assess the efficacy of the combined approach utilizing narrow-band imaging with magnifying endoscopy (NBI-ME) and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for accurate discrimination of lesions of pT1b-SM2 or deeper.

Methods: Between 2016 and 2023, we retrospectively enrolled 127 cases (137 lesions) of superficial, treatment-naïve ESCC at Akita University Hospital, involving patients who underwent either ER alone or surgery alone. All patients underwent preoperative NBI-ME and FDG-PET. Preoperative tumor depth was estimated using type B vessels based on NBI-ME and SUVmax based on FDG-PET, and we confirmed the final tumor depth through histopathological evaluation of resected samples. The diagnostic performance of the tests in discriminating pT1b-SM2 or deeper was evaluated in terms of sensitivity, specificity, and accuracy.

Results: Treatment consisted of ER in 97 lesions and surgery in the remaining 40. Fifty-three lesions (44.7%) had pT1b-SM2 or deeper invasion. The sensitivity, specificity, and accuracy of NBI-ME using type B3 vessels were 41.5%, 97.6%, and 75.9%, respectively. For FDG-PET with a cutoff SUVmax of ≥ 2.4, these were 79.2%, 69.0%, and 73.0%, respectively. Combining both tests substantially improved diagnostic performance, with sensitivity, specificity, and accuracy of 83.0%, 89.3%, and 86.9%, respectively.

Conclusion: The combination of FDG-PET and NBI-ME offers enhanced diagnostic performance for ESCC with ≥ pT1b-SM2, thereby facilitating a more efficacious preoperative narrowing of the indications for ER of superficial ESCC.