P-305 Surgery or Endoscopy for 'High-Risk' Early Esophageal Cancer: Prospective Observational Study Including Detailed Analysis of Lymph Node Involvement

Esophagectomy is standard of care in patients with high-risk early esophageal cancer, however, boundaries determining limits for curative endoscopic treatment are not firmly established and change over time. Our aims were to evaluate long-term results of endoscopic vs. surgical treatment in patients with 'high-risk' early esophageal cancer (HRC) and to determine its metastatic potential. A total of 65 patients underwent endoscopic resection for HRC at our institution and were then referred for surgery (n=30) or continued in endoscopic therapy if necessary (n=35). We defined HRC as cancer with submucosal (sm) invasion or mucosal (m) invasion with at least one of the following: poor differentiation, invasion to blood (A+) or lymphatic (L+) vessels or high tumor cell dissociation. Patients were followed for at least 24 months. The main endpoint was the proportion of patients with curative endoscopic treatment (absence of residual tumor and lymph nodes involvement including micrometastases in the surgical group or no local residuum/relapse and/or generalization at least 2 years after completing endoscopic treatment). Resected lymph nodes were evaluated for the presence of metastases and micrometastases. Candidate variables for predictors of generalization were analysed. Forty-eight of included patients had adenocarcinoma and 17 had squamous cell carcinoma. In the surgical group, long term remission was achieved in 26 (86.7%) patients, two patients (6.7%) died due to post-procedural complications. Among surgically treated patients, 17 (56.7%) would have been possibly cured by endoscopy as there were no residua of malignancy in the surgical species nor lymph node involvement found after the procedure. Long-term remission was then obtained in 22 (62.9%) of endoscopically treated patients and there was no procedure-related mortality. Considering the depth of tumor invasion, positive lymph nodes or metastatic disease were detected in 6% (1/17) patients with mucosal invasion, 4/16 (25%) with sm1, 2/10 (20%) with sm2 and 8/22 (36%) patients with sm3 invasion. Invasion into blood or lymphatic vessels represented the only significant predictor of metastatic potential (A+: p=0.034; L+: p=0.007). Endoscopic treatment may be curative in substantial proportion of patients with HRC. Invasion into blood and/or lymphatic vessels appears to predict metastatic potential.