本研究的目的是调查失配修复（MMR）状态、程序性死亡受体1（PD-L1）表达和艾普斯坦-巴尔病毒（EBV）状态对手术后II/III期胃癌预后的影响。本研究包括在2007年至2015年期间接受根治性全胃切除手术后接受辅助化疗（AC）或观察的679例病理II/III期胃癌患者。回顾性地审查临床结果并根据AC和其他临床病理因素进行比较。患者分为接受AC组（n = 484）和仅手术治疗组（SA组；n = 195），并进一步按MMR和EBV状态分层：MMR缺陷（DMMR）和MMR正常（PMMR）组。将AC-DMMR组与AC-PMMR组进行比较，5年总生存率分别为92.0％与74.0％（对数秩和p <0.01）；将SA-DMMR组与SA-PMMR组进行比较，5年总生存率分别为71.1％与73.7％（对数秩和p = 0.89）。 DMMR（风险比0.25，95％置信区间0.07-0.81）被确定为AC组的独立预后因素，但不是SA组。在亚组分析中，EBV阳性患者或DMMR组中PD-L1阴性患者在AC和SA组中预后不良。 PD-L1表达对PMMR和EBV阴性患者的预后无影响。 DMMR与II/III期胃癌手术后和辅助治疗后的有利预后有关。 PD-L1表达可能会影响DMMR和EBV阳性胃癌的预后。 © 2023年。外科肿瘤学会。

The aim of this study was to investigate the prognostic impact of mismatch repair (MMR) status, programmed death-ligand 1 (PD-L1) expression, and Epstein-Barr virus (EBV) status in stage II/III gastric cancer after surgery.This study included 679 patients diagnosed with pathological stage II/III gastric cancer who underwent curative gastrectomy followed by adjuvant chemotherapy (AC) or observation between 2007 and 2015. Clinical outcomes were retrospectively reviewed and compared with stratification by AC and other clinicopathological factors.Patients were divided into AC (n = 484) or surgery alone (SA; n = 195) groups and were further stratified by MMR and EBV status: MMR-deficient (DMMR) and MMR-proficient (PMMR) groups. Comparing the AC-DMMR group versus the AC-PMMR group, 5-year overall survival was 92.0% versus 74.0% (log-rank p < 0.01), and comparing the SA-DMMR group versus the SA-PMMR group, 5-year overall survival was 71.1% versus 73.7% (log-rank p = 0.89). DMMR (hazard ratio 0.25, 95% confidence interval 0.07-0.81) was identified as an independent prognostic factor in the AC group but not in the SA group. In the subgroup analysis, PD-L1-negative patients among the EBV-positive patients or in the DMMR group had a poor prognosis in both the AC and SA groups. The prognosis of the PMMR and EBV-negative patients was similar regardless of PD-L1 expression.DMMR was associated with a favorable prognosis in stage II/III gastric cancer after surgery and adjuvant therapy. PD-L1 expression may affect the prognosis of DMMR and EBV-positive gastric cancer.© 2023. Society of Surgical Oncology.