Does a higher cutoff value of lymph node retrieval substantially improve survival in patients with advanced gastric cancer? : time to embrace a new digit

Background. The present study assessed the impact of the retrieval of >25 lymph nodes (LNs) on the survival outcome of patients with advanced gastric cancer after curative-intent gastrectomy. Patients and Methods. A total of 5,386 patients who had undergone curative gastrectomy for gastric cancer from 1994 to 2011 were enrolled.The clinicopathological parameters and overall survival (OS) were analyzed according to the number of LNs examined (≤ 15, n5 916; 16–25, n5 1,458; and >25, n5 3,012). Results. The percentage of patients with >25 LNs retrieved increased from 1994 to 2011. Patients in the LN >25 group were more likely to have undergone total gastrectomy and to have a larger tumor size, poorer tumor differentiation, and advanced T and N stages. Hospital mortality among the LN ≤ 15, LN 16–25, and LN >25 groups was 6.1%, 2.7%, and 1.7%, respectively (p<.0001). The LN >25 group consistently exhibited the most favorable OS, in particular, with stage II disease (p5.011) when OS was stratified according to tumor stage. Similarly, the LN >25 group had significantly better OS in all nodal stages (from N1 to N3b). The discrimination power of the lymph node ratio (LNR) for the LN ≤ 15, LN 16–25, and LN >25 groups was 483, 766, and 1,560, respectively.Multivariate analysis demonstrated that the LNR was the most important prognostic factor in the LN >25 group. Conclusion. Retrieving more than 25 lymph nodes during curative-intent gastrectomy substantially improved survival and survival stratification of advanced gastric cancer without compromising patient safety.