Résumé : Objective: The aim of this study was to the determine impact of severe esophageal anastomotic leak (SEAL) upon long-term survival and locoregional cancer recurrence. Background: The impact of SEAL upon long-term survival after esophageal resection remains inconclusive with a number of studies demonstrating conflicting results. Methods: A multicenter database for the surgical treatment of esophageal cancer collected data from 30 university hospitals (2000-2010). SEAL was defined as a Clavien-Dindo III or IV leak. Patients with SEAL were compared with those without in terms of demographics, tumor characteristics, surgical technique, morbidity, survival, and recurrence. Results: From a database of 2944 operated on for esophageal cancer between 2000 and 2010, 209 patients who died within 90 days of surgery and 296 patients with a R1/R2 resection were excluded, leaving 2439 included in the final analysis; 208 (8.5%) developed a SEAL and significant independent association was observed with low hospital procedural volume, cervical anastomosis, tumoral stage III/IV, and pulmonary and cardiovascular complications. SEAL was associated with a significant reduction in median overall (35.8 vs 54.8 months; P=0.002) and disease-free (34 vs 47.9 months; P=0.005) survivals. After adjustment of confounding factors, SEAL was associated with a 28% greater likelihood of death [hazard ratio=1.28; 95% confidence interval (CI): 1.04-1.59; P=0.022], as well as greater overall (OR=1.35; 95% CI: 1.15-1.73; P=0.011), locoregional (OR=1.56; 95% CI: 1.05-2.24; P=0.030), and mixed (OR=1.81; 95% CI: 1.20-2.71; P=0.014) recurrences. Conclusions: This large multicenter study provides strong evidence that SEAL adversely impacts cancer prognosis. The mechanism through which SEAL increases local recurrence is an important area for future research.