Long-term Outcomes After Endoscopic Resection for pMM/SM1 Esophageal Cancer: A Multicenter Prospective Cohort Study

BACKGROUND AIMS: The optimal management of esophageal cancer with muscularis mucosae or shallow submucosal invasion (post-endoscopic resection [ER] pMM/SM1 cancer) remains controversial. Evidence is largely retrospective, and prospective data are lacking. METHODS: This study enrolled patients with squamous cell carcinoma (SCC) or esophageal adenocarcinoma (EAC) diagnosed as post-ER pMM/SM1 cancer. Outcomes included overall survival, metastatic recurrence, local recurrence, and second primary esophageal cancer. RESULTS: Overall, 385 patients were enrolled, including 315 with SCC and 70 with EAC. Five-year overall survival was 92.3% (95% Confidence interval [CI], 88.8%-94.8%) for SCC and 94.2% (95% CI, 85.4%-97.8%) for EAC. Among post-ER lymphovascular invasion (LVI)-negative patients managed without additional treatment, 5-year survival rates were 94.0% (95% CI, 90.2%-96.4%) for SCC and 93.3% (95% CI, 83.5%-97.5%) for EAC. Cumulative metastatic recurrence rates for LVI-negative SCC were 6.3% (95% CI, 3.0%-12.6%) for pMM and 10.5% (95% CI, 2.6%-33.7%) for pSM1 disease, whereas corresponding rates for EAC were 2.2% (95% CI, 0.3%-13.9%) and 0.0% (95% CI could not be calculated). In LVI-negative SCC, lesion size and macroscopic appearance were independent predictors of metastatic recurrence: type 0-II lesions ≤30 mm had a low cumulative metastatic recurrence rate of 2.9% (95%CI, 1.1%-7.5%). The 5-year cumulative incidence of second primary esophageal cancer was 25.8% for SCC and 3.6% for EAC. CONCLUSIONS: Post-ER pMM/SM1 esophageal cancer is associated with excellent long-term survival. Surveillance is a reasonable option for many LVI-negative cases, although additional treatment may be considered for selected higher-risk patients.