Long-Term Oncological Outcomes after Endoscopic Submucosal Dissection of Superficial Esophageal Cancer

Background/Aims: Long-term data on the cumulative risk of lymph node metastasis (LNM), particularly after non-curative resection, remain limited. This study aimed to analyze long-term outcomes and clarify the risk of LNM. Methods: This retrospective study included 892 patients (951 cases) who underwent endoscopic submucosal dissection for superficial esophageal cancer. Extraesophageal recurrence-free survival (RFS) and overall survival (OS) were analyzed based on pathological strata, including depth of invasion and lymphovascular invasion (LVI). Results: In the observation group, the 5-year RFS and OS rates were 95.6% (95% confidence interval [CI], 92.8% to 97.3%) and 91.4% (95% CI, 88.2% to 93.8%) for mucosal/LVI-negative, and 92.7% (95% CI, 73.7% to 98.1%) and 84.9% (95% CI, 72.9% to 91.9%) for submucosal/LVI-negative subgroups, respectively. Conversely, the submucosal/LVI-positive group showed lower 5-year RFS (51.9%; 95% CI, 16.4% to 78.8%) and OS rates (61.4%; 95% CI, 29.9% to 82.2%) (p<0.001). Additional surgery was associated with higher 5-year RFS and OS rates of 76.1% (95% CI, 59.8% to 86.4%) and 87.5% (95% CI, 71.9% to 94.7%), respectively, in the submucosal/LVI-positive subgroup. The LNM risk in mucosal cases was primarily synchronous. However, the submucosal/LVI-positive group exhibited a cumulative increase in LNM detection, with the rate increasing from 28.3% at the time of surgery to 50.0% during follow-up. Conclusions: Esophageal endoscopic submucosal dissection achieves excellent long-term outcomes for curative resection. Non-curative cases, particularly those with submucosal invasion and LVI, exhibit an evolving LNM risk over time. These high-risk patients may be considered for additional treatment when medically suitable, alongside meticulous, long-term oncological surveillance.