Determination of the Minimum Number of Lymph Nodes to Examine in Esophagectomy Specimens to Maximize Survival in Patients with Esophageal Carcinoma: Data from the Surveillance Epidemiology and End Results Database

Abstract

Objective: We used a population-based cancer registry to examine the association between lymph node counts and survival in order to determine the minimum number of lymph nodes that should be examined as part of esophageal resection. Methods: Using the Surveillance Epidemiology and End Results (SEER) database, we identified patients who underwent esophagectomy for invasive esophageal carcinoma from 1988 through 2005 and who had a known number of lymph nodes examined pathologically. After stratifying patients into groups (0, 1 to 11, 12 to 29, and 30 or more lymph nodes examined) based on a recursive partitioning analysis, we assessed the association between lymph nodes counts and survival using the Kaplan-Meier method. To adjust for potential confounding covariates, we used a Cox proportional hazards regression model. Results: Of the patients in the SEER database with esophageal cancer, 4,882 met our inclusion criteria. We noted a significant difference between the lymph node groups with regards to unadjusted overall (p < 0.0001) and cancer-specific survival (p = 0.004). After adjusting for geographical location (cancer registry), patient factors, tumor characteristics, and timing of radiation therapy, we noted a significant difference between the lymph node groups with regards to overall and cancer-specific survival. As compared with patients who had no lymph node evaluation, only patients who had more than 12 lymph nodes examined had a significant improvement in survival. Patients who had 30 or more lymph nodes examined had significantly better survival rates than the other groups. Conclusion: In order to maximize overall and cancer-specific survival, esophageal cancer patients should have at least 30 lymph nodes examined pathologically as part of esophageal resection.