Purpose Patients with gastric cancer who receive neoadjuvant therapy are staged before treatment (cStage) and after treatment (ypStage). We aimed to compare the prognostic reliability of cStage and ypStage, alone and in combination. Materials and Methods Data for all patients who received neoadjuvant therapy followed by surgery for gastric adenocarcinoma from 2004 to 2015 were extracted from the National Cancer Database. Kaplan-Meier (KM)curves were used to model overall survival based on cStage alone, ypStage alone, cStage stratified by ypStage, and ypStage stratified by cStage. P-values were generated to summarize the differences in KM curves. The discriminatory power of survival prediction was examined using Harrell's C-statistics. Results We included 8,977 patients in the analysis. As expected, increasing cStage and ypStage were associated with worse survival. The discriminatory prognostic power provided by cStage was poor (C-statistic 0.548), while that provided by ypStage was moderate (C-statistic 0.634). Within each cStage, the addition of ypStage information significantly altered the prognosis (P<0.0001 within cStages I–IV). However, for each ypStage, the addition of cStage information generally did not alter the prognosis (P=0.2874, 0.027, 0.061, 0.049, and 0.007 within ypStages 0–IV, respectively). The discriminatory prognostic power provided by the combination of cStage and ypStage was similar to that of ypStage alone (C-statistic 0.636 vs. 0.634). Conclusions The cStage is unreliable for prognosis, and ypStage is moderately reliable. Combining cStage and ypStage does not improve the discriminatory prognostic power provided by ypStage alone. A ypStage-based prognosis is minimally affected by the initial cStage.

中文翻译：

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在新辅助治疗时代为胃癌患者提供可靠的预后：AJCC 分期示意图的比较

目的 接受新辅助治疗的胃癌患者在治疗前（cStage）和治疗后（ypStage）进行分期。我们旨在比较 cStage 和 ypStage 单独和组合的预后可靠性。材料与方法 从国家癌症数据库中提取 2004 年至 2015 年接受胃腺癌新辅助治疗后接受手术的所有患者的数据。Kaplan-Meier (KM) 曲线用于对仅基于 cStage、仅 ypStage、由 ypStage 分层的 cStage 和由 cStage 分层的 ypStage 的总生存期进行建模。生成 P 值以总结 KM 曲线的差异。使用 Harrell 的 C 统计量检查生存预测的辨别力。结果 我们在分析中纳入了 8,977 名患者。正如预期的那样，增加 cStage 和 ypStage 与较差的生存率相关。cStage 提供的区分性预后能力较差（C 统计量 0.548），而 ypStage 提供的区分性预后能力适中（C 统计量 0.634）。在每个 cStage 中，添加 ypStage 信息显着改变了预后（cStages I-IV 内 P<0.0001）。然而，对于每个 ypStage，添加 cStage 信息通常不会改变预后（在 ypStages 0-IV 内分别为 P = 0.2874、0.027、0.061、0.049 和 0.007）。cStage 和 ypStage 的组合提供的鉴别性预后能力与单独的 ypStage 相似（C 统计量 0.636 对 0.634）。结论 cStage 预后不可靠，ypStage 可靠。结合 cStage 和 ypStage 并不能提高 ypStage 单独提供的区分性预后能力。基于 ypStage 的预后受初始 cStage 的影响最小。