PURPOSE To determine the indications for adjuvant chemotherapy (AC) in patients with stage IIa gastric cancer (T3N0M0 and T1N2M0) according to the 7th American Joint Committee on Cancer (AJCC). METHODS A total of 1593 patients with T3N0M0 or T1N2M0 stage gastric cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) database for the period 1988.1-2012.12. Cox multiple regression, nomogram and decision curve analyses were performed. External validation was performed using databases of the Fujian Medical University Union Hospital (FJUUH) (n = 241) and Italy IMIGASTRIC center (n = 45). RESULTS Cox multiple regression analysis showed that the risk factors that affected OS in patients receiving AC were age > 65 years old, T1N2M0, LN dissection number ≤ 15, tumor size > 20 mm, and nonadenocarcinoma. A nomogram was constructed to predict 5-year OS, and the patients were divided into those predicted to receive a high benefit (points ≤ 188) or a low benefit from AC (points > 188) according to a recursive partitioning analysis. OS was significantly higher for the high-benefit patients in the SEER database and the FJUUH dataset than in the non-AC patients (Log-rank < 0.05), and there was no significant difference in OS between the low-benefit patients and non-AC patients in any of the three centers (Log-rank = 0.154, 0.470, and 0.434, respectively). The decision curve indicated that the best clinical effect can be obtained when the threshold probability is 0-92%. CONCLUSION Regarding the controversy over whether T3N0M0 and T1N2M0 gastric cancer patients should be treated with AC, this study presents a predictive model that provides concise and accurate indications. These data show that high-benefit patients should receive AC.

中文翻译：

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AJCC IIa期T3N0M0和T1N2M0胃癌患者辅助化疗的适应症-一项东西方多中心研究。

目的根据第7届美国癌症联合委员会（AJCC）确定IIa期胃癌（T3N0M0和T1N2M0）患者的辅助化疗（AC）适应症。方法从1988.1-2012.12期间的监测，流行病学和最终结果（SEER）数据库中鉴定出1593例T3N0M0或T1N2M0期胃癌患者。进行Cox多元回归，列线图和决策曲线分析。使用福建医科大学联合医院（FJUUH）（n = 241）和意大利IMIGASTRIC中心（n = 45）的数据库进行外部验证。结果Cox多元回归分析显示，接受AC的患者影响OS的危险因素是年龄> 65岁，T1N2M0，LN夹层数≤15，肿瘤大小> 20 mm和非腺癌。构建了一个诺模图以预测5年OS，根据递归分区分析，将患者分为那些预计会从AC获得高获益（点≤188）或从AC获得低获益（点> 188）的患者。SEER数据库和FJUUH数据集中高收益患者的OS显着高于非AC患者（Log-rank <0.05），低收益患者与非AC患者之间的OS没有显着差异。三个中心中任何一个的AC患者（对数秩分别为0.154、0.470和0.434）。决策曲线表明，当阈值概率为0-92％时，可获得最佳的临床效果。结论关于T3N0M0和T1N2M0胃癌患者是否应接受AC治疗的争议，这项研究提出了一种预测模型，可提供简明而准确的指示。这些数据表明，高收益患者应接受AC。