Clinical characteristics of synchronous and metachronous superficial esophageal squamous cell carcinoma during surveillance after endoscopic submucosal dissection

Abstract Background Although endoscopic submucosal dissection (ESD) is the standard treatment for superficial esophageal squamous cell carcinoma (SESCC), the clinical characteristics of synchronous and metachronous (secondary) lesions detected during follow-up remain unclear. This study aimed to compare the clinicopathologic characteristics and outcomes of initial and secondary SESCC lesions. Methods This single-center study analyzed 307 esophageal squamous cell carcinoma lesions in 188 patients who underwent ESD as their initial treatment between January 2005 and January 2025. The lesions were categorized as initial ( n = 208) or secondary ( n = 99) based on their timing of detection. Clinicopathological features and short-term outcomes were compared between the two groups. Results Patients with multiple lesions were younger and had a higher prevalence of prior head and neck cancer and a higher prevalence of Lugol-voiding lesion grades B/C. The median time to detection of secondary lesions was 18 months. Secondary lesions were smaller (< 20 mm: 88% vs. 44%) and shallower (epithelial/lamina propria mucosa: 89% vs. 74%) than initial lesions. Multivariate analysis revealed that tumor size < 20 mm (odds ratio 0.12, 95% confidence interval 0.06–0.23) and epithelial/lamina propria mucosa invasion depth (odds ratio 0.37, 95% confidence interval 0.17–0.84) were independently associated with secondary lesions. In secondary lesions, curative resection rates were higher (84% vs. 68%, p < 0.005) and complications less frequent (12% vs. 34%, p < 0.001). Esophageal stenosis occurred less frequently in secondary lesions. The cumulative incidences of secondary lesions were 10.2%, 18.9%, and 28.2% at 1, 3, and 5 years, respectively. Conclusion Secondary SESCC lesions tend to be smaller and shallower, enabling higher curative resection rates and lower complication risks. These findings suggest that secondary lesions are more amenable to curative ESD when detected at an early stage. Regular surveillance after ESD facilitates early detection of secondary lesions and their curative resection. Graphical Abstract