The number of metastatic lymph nodes and the ratio between metastatic and examined lymph nodes are independent prognostic factors in esophageal cancer regardless of neoadjuvant chemoradiation or lymphadenectomy extent

OBJECTIVE: To investigate whether the number of lymph nodes metastasis (LNMs) and the ratio between metastatic and examined lymph nodes (LNs) are better prognostic factors when compared with traditional staging systems in patients with esophageal carcinoma. SUMMARY BACKGROUND DATA: The accuracy of the 6th UICC/TNM classification is suboptimal, especially when not taking into account neoadjuvant therapy and lymphadenectomy extent. METHODS: For 536 patients who underwent curative en bloc esophagectomy, in whom 51.5% (n = 276) received neoadjuvant chemoradiation, LNMs were classified according to the 6th UICC/TNM classification and systems based on the number (< or =4 and >4) or the ratio (< or =0.2 and >0.2) of LNMs. Survival of the respective stages, predictors of survival, and influence of both chemoradiation and number of examined LNs were studied. RESULTS: After a median follow-up of 50 months, the 5-year survival rates were 47% for the entire population, significantly poorer for patients with >4 LNMs (8% vs. 53%, P < 0.001) or a ratio of LNMs >0.2 (22% vs. 54%, P < 0.001). After adjustment for confounding variables, a number of LNMs >4 and a ratio of LNMs >0.2 were the only predictors of poor prognosis. The prognostic role of both the number and the ratio of LNMs was maintained whether patients received neoadjuvant chemoradiation or not. Moreover, LN ratio is shown to be more accurate for inadequately staged patients (<15 examined LNs), whereas the number of LNMs is pertinent for adequately staged patients (> or =15 examined LNs). CONCLUSION: Staging systems for esophageal cancer that use the number (< or =4 or >4) and the ratio (< or =0.2 or >0.2) of LNMs have greater prognostic importance than the current staging systems because of the good stratification of the groups and their clinical utility, taking into account neoadjuvant therapy and lymphadenectomy extent.