结直肠癌（CRC）是与胃癌（GC）同时发生的最常见癌症。尽管全结肠镜检查 (TCS) 作为 CRC 筛查工具在术前 GC 患者中的有效性已有报道，但同期 CRC (SCRC) 患者的长期结果仍不清楚。本研究旨在阐明术前 GC 筛查 TCS 对生存结果的重要性。我们纳入了 796 名接受 GC 术前 TCS 筛查的患者。对 SCRC 的危险因素、临床病理特征和生存结果进行了检查。此外，从改善CRC引起的死亡率的角度评估了成本效益。在43名患者（5.4%）中观察到了SCRC。对 30 名患者进行了 SCRC 的内镜治疗。总共有 15 名患者接受了手术切除，其中 2 名患者在内镜治疗后需要进行额外手术。关于病理分期，25名患者为0期，12名患者为I期，5名患者为II期，1名患者为IIIB期疾病。累积死亡率如下：GC相关死亡，12.6%；死于结直肠癌以外的癌症，1%；其他原因造成的死亡，5.5%。没有死亡是由 SCRC 造成的。与未接受 TCS 的患者相比，增量成本效益比分析表明，需要 586 万日元的筛查成本才能防止 1 例 CRC 死亡。所有 SCRC 患者都有可能获得治愈性治疗。没有死亡归因于 SCRC，这表明筛查 TCS 进行 GC 是有效的。© 2023。外科肿瘤学会。

Colorectal cancer (CRC) is the most common cancer that coincides with gastric cancer (GC). Although the usefulness of total colonoscopy (TCS) as a CRC screening tool has been reported in preoperative patients with GC, the long-term outcome of patients with synchronous CRC (SCRC) remains unclear. This study aims to clarify the significance of preoperative screening TCS for GC in terms of survival outcomes.We included 796 patients who underwent preoperative screening TCS for GC. The risk factors, clinicopathological features, and survival outcome of SCRC were examined. Furthermore, the cost-effectiveness was evaluated from the perspective of improving the rates of mortality caused by CRC.SCRC was observed in 43 patients (5.4%). Endoscopic treatment for SCRC was performed on 30 patients. In total, 15 patients underwent surgical resection, including 2 patients requiring additional surgery after endoscopic treatment. Regarding pathological stages, 25 patients had stage 0, 12 patients had stage I, 5 patients had stage II, and 1 patient had stage IIIB disease. The cumulative mortality rates were as follows: GC-related deaths, 12.6%; deaths from cancers other than CRC, 1%; deaths from other causes, 5.5%. No deaths were attributed to SCRC. Comparing the patients who did not undergo TCS, an incremental cost-effectiveness ratio analysis suggested that a screening cost of 5.86 million yen was required to prevent one CRC death.Curative treatment was possible in all patients with SCRC. No deaths were attributed to SCRC, suggesting that screening TCS for GC is effective.© 2023. Society of Surgical Oncology.