Back to Annual Meeting Program

Objectives: The number of lymph nodes removed during esophagectomy and the impact on survival remains undefined. We sought to determine the effects of post-operative radiation therapy and lymph node dissection on survival in esophageal cancer. Methods: We performed an analysis of patients who underwent esophagectomy for cancer from the SEER database between 2004-2008 to determine association of adjuvant radiation and lymph node dissection on survival. Patients treated with neoadjuvant radiation were excluded. Survival curves were calculated according to the Kaplan-Meier method with log-rank analysis. Multivariate analysis (MVA) was performed by the Cox proportional hazard model. Results: We identified 2109 patients who met inclusion criteria. There were 467 and 1642 patients treated with and without radiation. Radiation was associated with increased survival in stage III patients (HR 0.71; 95% CI: 0.56 - 0.90; p=0.005), no benefit in stage II (p=0.075) and IV (p=0.913) patients, and decreased survival in stage I patients (HR 2.73: 95% CI: 1.76 - 4.22; p<0.0001). Univariate analysis revealed that radiation therapy was associated with a survival benefit in node positive (N1) patients while it was associated with a detriment in survival for node negative (N0) patients. The median and 3 year survival with and without radiation is 23 months and 34%, and 20 months and 26.7%, respectively (p=0.0225) for N1 patients and the 3-year survival with and without radiation is 48.8% and 68.8%, respectively (p<0.0001) for N0 patients. In node negative patients, removing <12 versus >12 lymph nodes (HR 1.316; 95% CI 1.060 - 1.634; p=0.013) and <15 versus >15 (HR 1.313; 95% CI: 1.032 - 1.670; p=0.027) was associated with increased mortality. Similarly, in node positive patients, removing <8 versus >8 (HR 1.325; 95% CI 1.066 - 1.646; p=0.011), <10 versus >10 (HR 1.311; 95% CI 1.069 - 1.608; p=0.009), <12 versus >12 (HR 1.299; 95% CI 1.066 - 1.582; p=0.009), <15 versus >15 (HR 1.258; 95% CI 1.031 - 1.535; p=0.024), and <20 versus >20 (HR 1.325; 95% CI 1.056 - 1.662; p=0.015) was associated with increased mortality. In node negative patients, age and tumor stage, were prognostic for worse survival, while gender and number of lymph nodes removed were prognostic for better survival. Adjuvant radiation, tumor location, and histopathology were not prognostic for survival. In node positive patients, age and tumor stage were associated with increased mortality while number of lymph nodes removed and adjuvant radiation were associated with decreased mortality. Gender, tumor location, and histopathology were not prognostic for survival in node positive patients. Conclusion: The number of lymph nodes removed in esophageal cancer is associated with increased survival. The benefit of adjuvant radiation therapy on survival in esophageal cancer is limited to N1 patients.