Prognostic value of three different lymph node staging systems in the survival of patients with gastric cancer following D2 lymphadenectomy

Abstract

The log odds of positive lymph nodes (LODDS) was defined as the log of the ratio between the number of positive lymph nodes and the number of negative lymph nodes, which is a novel and promising nodal staging system for gastric cancer. Here, we aimed to compare the prognostic effect of pN, lymph node ratio (LNR) and LODDS. The association between overall survival and pN, LNR and LODDS was retrospectively analysed. The discriminatory ability and monotonicity of gradients (linear trend χ 2 score), homogeneity ability (likelihood ratio test) and prognostic stratification ability (Akaike information criterion [AIC] and receiver operating characteristic [ROC] curve) were compared among three lymph node staging systems. The pN, LNR and LODDS were all identified as independent prognostic factors for gastric cancer patients in the multivariate analysis. LODDS showed the best prognostic performance (linear trend χ 2 score 266.743, likelihood ratio χ 2 test score 427.771, AIC value 5670.226, area under the curve (AUC) 0.793), followed by LNR and pN. In patients with different levels of retrieved lymph nodes (≤10, 11–14, 15–25 and >25), LODDS was the most powerful for prognostic prediction and discrimination of the heterogeneity among the subgroups. Significant differences in survival were observed among patients in different LODDS subgroups after being classified according to the pN and LNR classifications. LODDS appears to be a more powerful system for predicting the overall survival of gastric cancer patients, as compared to LNR and pN, and may serve as an alternative nodal staging system for gastric cancer.

Proposal of a Dukes-Mac-Like Staging System for Gastric Cancer

“…Several authors agreed with this system's prognostic value 16 17. The second one refers to the log odds of positive lymph nodes (LODDS), which is known as the log of the ratio between the number of positive and negative lymph nodes 17. The third one was proposed by Choi et al 18 in 2016, in East Asia, and is a topographic-based classification.…”

“…All of these three systems proved to have similar prognostic performance in comparison with the current pN staging system 14 16–18. Compared with the current WHO-pN stage sytem, the Choi's system and LNR seems to be more adequate for evaluation of the lymph node status,17 18 whereas LODS could be used as a prognostic parameter 16 17. The LNR system is especially useful as a prognostic parameter for patients with pT2 staged tumors and few dissected lymph nodes 16 17…”

Increased number of negative lymph nodes is associated with improved survival outcome in node positive gastric cancer following radical gastrectomy

“…Although it has been shown that a 15-node minimum has been endorsed as a consensus standard for proper tumor stage and associated with a good survival outcome in patients treated with gastrectomy for GC [2]; However, a subgroup of them die of recurrence and metastases. In fact, the node-positive patients with GC are heterogeneous and the prognosis of these patients cannot be stratified by the node-stage only [3-5]. In view of these, pinpoint of prognostic factors, especially a common clinicopathological factor, for recurrence and metastasis would allow to find patients at high risk that may benefit from adjuvant chemotherapy or intensive care, usually proposed to node-positive GC patient only [6].…”

The prognostic value of lymph nodes count on survival of patients with node-negative gastric cancer

“…Compared with node-positive gastric cancer, node-negative tumors have less aggressive biological features and a more favorable prognosis [2, 6, 9]. However, patients with node-negative gastric cancer also experience recurrences [4, 10].…”

“…Complete resection remains the only treatment that can lead to cure for gastric cancer and the presence or absence of lymph node (LN) metastasis was widely considered to be the most important predictor for gastric cancer survival, and LN-negative patients have been shown to have better survival than those with LN metastasis [2, 3]. However, patients with node-negative gastric cancer also experience recurrences and may have fatal outcomes [2, 4, 5]. For such reasons, many researchers make efforts to investigate the prognostic factors related to recurrence and survival.…”