Lymph Node Yield and Lymph Node Ratio for Prognosis of Long-Term Survival in Gastric Carcinoma

Background: Lymphadenectomy is fundamental part of surgical strategy in patients with gastric cancer. Lymph node (LN) status is a key point in assessment of prognosis in gastric cancer. The LN ratio (LNR) - number of positive LNs / number of sampled LNs, offers a new approach for predicting survival. The aim of the study was to find factors affecting LN yield and the impact of LNR on 5-year survival. Methods: Prospective multicentre quality assurance study. Only LN-positive patients were included in the LNR calculations. Results: 4946 patients from 149 hospitals were enrolled. The inclusion criteria were met by 1884 patients. Patients were divided into two groups: Group 1 (<16 LN) 456 patients and Group 2 (≥16 LN) 1428 patients. The multivariate analysis found G2 (OR 1.98; 95%CI 1.11-3.54), G3 (OR 2.15; 95%CI 1.212-3.829), UICC-stage II (OR 1.44; 95%CI 1.01-2.06) and III (OR 1.71; 95%CI 1.14-2.57), age <70 (OR 1.818 95%CI 1.19-2.78) and female gender ( OR 1.37; 95%CI 1.00-1.86) as independent factors of ≥16 LN yield. Patients with a LNR≥0.4 have a lower probability of survival (p=0.039 and <0.001) than patients with LNR=0.1. Patients with UICC-II have a lower probability of survival than UICC-I (p=0.023). Age 70-80 (p=0.045) and >80 years (p=0.003) were negative prognostic factors for long-term survival. Conclusion: Long-term survival is directly related to adequate lymphadenectomy. LNR could be superior to pN-stage for estimating survival, and adds remarkable nuances in prognosis compared to UICC-stage. LNR also appears valid, even in the case of insufficient LN yield.