Prognostic Benefit of Additional Treatment After Endoscopic Submucosal Dissection for Esophageal Squamous Cell Carcinoma.

Abstract

Although additional treatment is considered for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD), the actual benefits of this method remain to be elucidated. We aimed to evaluate the prognostic benefits of additional treatment in such patients. Between 2006 and 2017, we enrolled patients with pT1a-MM/pT1b-SM ESCC after ESD at 21 institutions in Japan. Overall survival (OS) and disease-specific survival (DSS) were compared between the additional treatment and follow-up groups after propensity score matching, to reduce the bias of baseline characteristics. A subgroup analysis was performed according to the pathological findings: category A, pT1a-MM but negative for lymphovascular invasion (LVI) and vertical margin (VM); category B, tumor invasion into the submucosa ≤ 200 μm but negative for LVI and VM; category C, others. Of 593 patients with pT1a-MM/pT1b-SM ESCC after ESD, 101 matched pairs were extracted after propensity score matching. The OSs were similar between the additional treatment and follow-up groups (80.6% vs. 78.6% in 5 years; P = 0.972). In a subgroup analysis, the OS in the additional treatment group was significantly lower than that in the follow-up group (65.7% vs. 95.2% in 5 years; P = 0.037) in category A, whereas OS did not significantly differ in category C (76.8% vs. 69.5% in 5 years; P = 0.360). Additional treatment after ESD in patients with pT1a-MM/pT1b-SM ESCC was not associated with an improved prognosis.