BACKGROUND: The current TNM classification system does not consider tumor length or the number of lymph nodes in the staging and classification scheme for patients with esophageal carcinoma. Using data from the National Cancer Institute SEER Program, the authors explored the effect of tumor length and number of positive lymph nodes on survival in patients with esophageal carcinoma. METHODS: Patients with esophageal adenocarcinoma or squamous cell carcinoma were subgrouped according to historic stage with localized, regional, or distant disease. Demographic factors (age at diagnosis, race, and gender) and tumor characteristics (morphology, histologic grade, tumor length, primary site, depth of invasion, number of positive lymph nodes, proportion of positive lymph nodes dissected, and distant metastatic sites) were examined. RESULTS: Overall factors that were associated with an increased mortality risk included increasing age at diagnosis, black race versus white race, histologic grade, primary tumor site in the lower esophagus and abdomen versus upper regions, and increasing depth of invasion. Among patients with regional disease, the number of positive lymph nodes (>/= 5 vs. < 5) was related to an increasing risk (hazard ratio [HR], 1.29; 95% confidence interval [95%CI], 1.06-1.56). The proportion of positive lymph nodes compared with the number of lymph nodes dissected conferred an increased risk (HR, 1.63; 95%CI, 1.26-2.11). Among patients with distant disease, sites other than distant lymph nodes implied an increased mortality risk (HR, 1.37; 95%CI, 1.37-1.65). Tumor length was an independent predictor of mortality when controlling for depth of invasion in patients with localized disease (HR, 1.15; 95%CI, 1.08-1.21). CONCLUSIONS: Tumor length, the number of involved lymph nodes, and the ratio of positive lymph nodes are important prognostic factors for survival in patients with esophageal carcinoma. A revised TNM classification system for patients with esophageal carcinoma might consider adding tumor length and number of positive lymph nodes as two important prognostic factors.