Optimum lymphadenectomy for esophageal cancer.

OBJECTIVE: Using Worldwide Esophageal Cancer Collaboration data, we sought to (1) characterize the relationship between survival and extent of lymphadenectomy, and (2) from this, define optimum lymphadenectomy. SUMMARY BACKGROUND DATA: What constitutes optimum lymphadenectomy to maximize survival is controversial because of variable goals, analytic methodology, and generalizability of the underpinning data. METHODS: A total of 4627 patients who had esophagectomy alone for esophageal cancer were identified from the Worldwide Esophageal Cancer Collaboration database. Patient-specific risk-adjusted survival was estimated using random survival forests. Risk-adjusted 5-year survival was averaged for each number of lymph nodes resected and its relation to cancer characteristics explored. Optimum number of nodes that should be resected to maximize 5-year survival was determined by random forest multivariable regression. RESULTS: For pN0M0 moderately and poorly differentiated cancers, and all node-positive (pN+) cancers, 5-year survival improved with increasing extent of lymphadenectomy. In pN0M0 cancers, no optimum lymphadenectomy was defined for pTis; optimum lymphadenectomy was 10 to 12 nodes for pT1, 15 to 22 for pT2, and 31 to 42 for pT3/T4, depending on histopathologic cell type. In pN+M0 cancers and 1 to 6 nodes positive, optimum lymphadenectomy was 10 for pT1, 15 for pT2, and 29 to 50 for pT3/T4. CONCLUSIONS: Greater extent of lymphadenectomy was associated with increased survival for all patients with esophageal cancer except at the extremes (TisN0M0 and >or=7 regional lymph nodes positive for cancer) and well-differentiated pN0M0 cancer. Maximum 5-year survival is modulated by T classification: resecting 10 nodes for pT1, 20 for pT2, and >or=30 for pT3/T4 is recommended.