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.