Peritoneal recurrence is a significant cause of treatment failure after radical gastrectomy for gastric cancer. The prediction of metachronous peritoneal recurrence would have a significantly impact risk stratification and tailored treatment planning. This study aimed to externally validate the previously established PERI-Gastric 1 and 2 models to assess their generalizability in an independent population. Retrospective external validation was conducted on a cohort of 8564 patients who underwent elective gastrectomy for stage Ib-IIIc gastric cancer between 1998 and 2018 at the Yonsei Cancer Center. Discrimination was tested using the area under the receiver operating characteristic curves (AUROC). Accuracy was tested by plotting observations against the predicted risk of peritoneal recurrence and analyzing the resulting calibration plots. Clinical usefulness was tested with a decision curve analysis. In the validation cohort, PERI-Gastric 1 and PERI-Gastric 2 exhibited an AUROC of 0.766 (95 % C.I. 0.752–0.778) and 0.767 (95 % C.I. 0.755–0.780), a calibration-in-the-large of 0.935 and 0.700, a calibration belt with a 95 % C.I. over the bisector in the risk range of 24%–33 % and 35%–47 %. The decision curve analysis revealed a positive net benefit in the risk range of 10%–42 % and 15%–45 %, respectively. This study presents the external validation of the PERI-Gastric 1 and 2 scores in an Eastern population. The models demonstrated fair discrimination and satisfactory calibration for predicting the risk of peritoneal recurrence after radical gastrectomy, even in Eastern patients. PERI-Gastric 1 and 2 scores could also be applied to predict the risk of metachronous peritoneal recurrence in Eastern populations.

中文翻译：

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预测胃癌根治性胃切除术后腹膜复发：在韩国数据库上验证预测模型（PERI-Gastric 1 和 PERI-Gastric 2）

腹膜复发是胃癌根治术后治疗失败的重要原因。异时性腹膜复发的预测将对风险分层和定制治疗计划产生重大影响。本研究旨在从外部验证先前建立的 PERI-Gastric 1 和 2 模型，以评估其在独立人群中的普遍性。对 1998 年至 2018 年间在延世癌症中心因 Ib-IIIc 期胃癌接受选择性胃切除术的 8564 名患者进行了回顾性外部验证。使用接收者操作特征曲线下面积（AUROC）测试区分度。通过根据预测的腹膜复发风险绘制观察结果并分析所得校准图来测试准确性。通过决策曲线分析来测试临床实用性。在验证队列中，PERI-Gastric 1 和 PERI-Gastric 2 的 AUROC 分别为 0.766 (95% CI 0.752–0.778) 和 0.767 (95% CI 0.755–0.780)，大校准为 0.935 和 0.700 ，在风险范围为 24%–33% 和 35%–47% 的平分线上具有 95% CI 的校准带。决策曲线分析显示，风险范围分别为 10%–42% 和 15%–45% 时具有正净收益。本研究展示了东部人群 PERI-Gastric 1 和 2 评分的外部验证。该模型在预测根治性胃切除术后腹膜复发风险方面表现出公平的辨别力和令人满意的校准，即使是在东部患者中也是如此。 PERI-Gastric 1 和 2 评分也可用于预测东部人群异时性腹膜复发的风险。