Purpose Nodal downstaging after preoperative therapy for gastric cancer has been shown to impart excellent prognosis, but this has not been validated in a national cohort. The role of neoadjuvant chemoradiation (NACR) in nodal downstaging remains unclear when compared with that of neoadjuvant chemotherapy alone (NAC). Furthermore, it is unknown whether the prognostic implications of nodal downstaging differ by preoperative regimen. Materials and Methods Using the National Cancer Database, overall survival (OS) duration was compared among natural N0 (cN0/ypN0), downstaged N0 (cN+/ypN0), and node-positive (ypN+) gastric cancer patients treated with NACR or NAC. Factors associated with nodal downstaging were examined in a propensity score-matched cohort of cN+ patients, matched 1:1 by receipt of NACR or NAC. Results Of 7,426 patients (natural N0 [n=1,858, 25.4%], downstaged N0 [n=1,813, 24.4%], node-positive [n=3,755, 50.4%]), 58.2% received NACR, and 41.9% received NAC. The median OS durations of downstaged N0 (5.1 years) and natural N0 (5.6 years) patients were similar to one another and longer than that of node-positive patients (2.1 years) (P<0.001). In the matched cohort of cN+ patients, more recent diagnosis (2010–2015 vs. 2004–2009) (odds ratio [OR], 2.57; P<0.001) and NACR (OR, 2.02; P<0.001) were independently associated with nodal downstaging. The 5-year OS rate of downstaged N0 patients was significantly lower after NACR (46.4%) than after NAC (57.7%) (P=0.003). Conclusions Downstaged N0 patients have the same prognosis as natural N0 patients. Nodal downstaging occurred more frequently after NACR; however, the survival benefit of nodal downstaging after NACR may be less than that when such is achieved by NAC.

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术前治疗方案影响胃癌患者淋巴结降期的发生率和意义

目的 胃癌术前治疗后淋巴结降期已被证明具有良好的预后，但这尚未在全国队列中得到验证。与单独的新辅助化疗 (NAC) 相比，新辅助放化疗 (NACR) 在淋巴结分期中的作用仍不清楚。此外，尚不清楚淋巴结降期的预后影响是否因术前方案而异。材料和方法 使用美国国家癌症数据库，对接受 NACR 或 NAC 治疗的自然 N0 (cN0/ypN0)、降期 N0 (cN+/ypN0) 和淋巴结阳性 (ypN+) 胃癌患者的总生存期 (OS) 持续时间进行比较。在倾向评分匹配的 cN+ 患者队列中检查了与淋巴结分期相关的因素，通过接受 NACR 或 NAC 以 1:1 匹配。结果 7,426 名患者（自然 N0 [n=1，858, 25.4%]，降级 N0 [n=1,813, 24.4%]，节点阳性 [n=3,755, 50.4%])，58.2% 接受 NACR，41.9% 接受 NAC。降期 N0（5.1 年）和自然 N0（5.6 年）患者的中位 OS 持续时间彼此相似，并且比淋巴结阳性患者（2.1 年）更长（P<0.001）。在 cN+ 患者的匹配队列中，最近的诊断（2010-2015 年与 2004-2009 年）（优势比 [OR]，2.57；P<0.001）和 NACR（OR，2.02；P<0.001）与淋巴结独立相关降级。NACR 后降期 N0 患者的 5 年 OS 率（46.4%）显着低于 NAC 后（57.7%）（P=0.003）。结论降期N0患者与自然N0患者预后相同。NACR 后淋巴结降期更频繁；然而，