Individuals with pN3 gastric cancer (GC) account for a large proportion of pN + GC, and exhibit poor survival outcomes. The pN3 stage is defined based upon the number of metastatic lymph nodes (mLNs), but the subclassification of pN3 patients based upon the number of examined LNs (eLNs) is rarely performed. In total, 2894 pTxN3M0 GC patients in the Surveillance, Epidemiology, and End Results database that had undergone surgery from 2000 to 2016 were selected for analysis. The X-tile software was used to select the optimal cutoff values. Cox proportional regression analyses were used to evaluated hazard ratios corresponding to the risk of death. Selection bias was minimized via propensity score matching (PSM). As the number of eLNs rose, the risk of death for patients trended downwards. Survival analyses indicated that patients with ≤ 31 eLNs exhibited significantly poorer survival outcomes as compared to patients with > 31 eLNs (5-year OS: 18.4% vs. 24.7%), and this result remained significant when analyzing 857 pairs of patients following PSM analysis. Significant differences in prognosis were additionally observed when comparing pN3a and pN3b patients with ≤ 31 or > 31 eLNs under pT3/4a stage. For pT4b stage, pN3a patients with > 31 eLNs also exhibited a better prognosis than other patients. The novel TNM staging system designed exhibited excellent utility as a tool for the prognostic evaluation of this GC patient population. These results suggest that in pN3 GC, a minimum of 32 LNs should be examined. The novel TNM staging system for pN3 patients described herein, which was developed based upon the number of eLNs, may thus be of value in clinical settings.

中文翻译：

---

基于超过 31 个淋巴结检查的具有优越预后效用的新型 pN3 胃癌分期系统：倾向评分匹配分析

患有 pN3 胃癌 (GC) 的个体占 pN + GC 的很大一部分，并且表现出较差的生存结果。pN3 分期是根据转移性淋巴结 (mLN) 的数量定义的，但很少根据检查的 LN (eLN) 的数量对 pN3 患者进行亚分类。在监测、流行病学和最终结果数据库中，总共选择了 2894 名在 2000 年至 2016 年间接受过手术的 pTxN3M0 GC 患者进行分析。X-tile 软件用于选择最佳截止值。Cox 比例回归分析用于评估与死亡风险相对应的风险比。通过倾向评分匹配 (PSM) 将选择偏差降至最低。随着 eLN 数量的增加，患者的死亡风险呈下降趋势。生存分析表明，与大于 31 个 eLN 的患者相比，≤ 31 个 eLN 的患者表现出明显较差的生存结果（5 年 OS：18.4% 对 24.7%），并且在对 857 对患者进行 PSM 分析后分析时，该结果仍然显着. 在比较 pT3/4a 分期 ≤ 31 或 > 31 eLN 的 pN3a 和 pN3b 患者时，还观察到预后的显着差异。对于 pT4b 期，具有 > 31 个 eLN 的 pN3a 患者也表现出比其他患者更好的预后。设计的新型 TNM 分期系统作为该 GC 患者群体预后评估的工具表现出出色的实用性。这些结果表明，在 pN3 GC 中，至少应检查 32 个 LN。本文描述的 pN3 患者的新型 TNM 分期系统，它是基于 eLN 的数量开发的，