Post-endoscopy esophageal squamous cell carcinoma with invasion of the muscularis mucosa or deeper detected in surveillance endoscopy after esophageal endoscopic resection

Background: Surveillance endoscopy is recommended after endoscopic resection of esophageal squamous cell carcinomas (ESCCs). However, surveillance endoscopy sometimes detects advanced subsequent ESCCs with invasion of the muscularis mucosa (MM) or deeper. We aimed to clarify the clinicopathological features of these advanced subsequent ESCCs. Methods: This single-center retrospective study identified subsequent ESCCs detected during surveillance endoscopy. ESCCs that invaded the MM or deeper and were detected within 24 months after the previous endoscopy were defined as post-endoscopy esophageal advanced lesions (PEEALs), while the first ESCC detected in the patient was defined as the primary lesion. Study 1 compared the clinicopathological characteristics of PEEALs versus non-advanced lesions. Study 2 compared the endoscopic features of pT1a-MM PEEALs versus pT1a-MM primary lesions. Results: A total of 307 subsequent ESCCs were analyzed in Study 1. Of these, 20 were PEEALs and 287 were non-advanced lesions (pT1a-EP/LPM). The median intervals from the previous endoscopy for PEEALs and non-advanced lesions were 6.1 months and 6.7 months, respectively (P = 0.283). The morphological feature of marginal elevation was seen in 60% of PEEALs. In Study 2, 15 pT1a-MM PEEALs were compared with 149 pT1a-MM primary lesions. Compared with primary lesions, pT1a-MM PEEALs were smaller (median 10 mm vs. 30 mm, P < 0.001) and had a higher prevalence of marginal elevation morphology (53.3% vs. 10.1%, P < 0.001). Conclusions: The specific feature of PEEALs was marginal elevation. Surveillance endoscopy with careful observation for these lesions is recommended after endoscopic resection of ESCCs.