There are few reports of conversion surgery (CS) after nivolumab monotherapy because it is considered as a third-line standard chemotherapy for unresectable or recurrent gastric cancer. Here, we report a rare case of stage IV gastric cancer effectively treated with CS after nivolumab monotherapy as a third-line chemotherapy. A 73-year-old man was referred to our hospital with loss of appetite and abdominal discomfort. Stage IV gastric cancer with liver metastasis was diagnosed via upper gastrointestinal endoscopy and CT. Twelve courses of capecitabine, cisplatin, and trastuzumab were administered as the first-line treatment, 25 courses of paclitaxel plus ramucirumab as the second-line treatment, and 31 courses of nivolumab monotherapy as the third-line treatment. After 31 courses of nivolumab monotherapy, CT showed that the primary tumor shrank with no liver metastasis or ascites. Diagnostic laparoscopy was performed with no peritoneal dissemination (P0), and the peritoneal lavage cytology was negative (CY0). CS was performed with total gastrectomy and D2 lymph node dissection (R0 resection). The pathological diagnosis was U, Ant-Less, Type 2, 70 × 63 mm, poorly differentiated adenocarcinoma (ypT3N0M0 ypStage IIA). R0 resection was performed, and the histological response was grade 1a. The patient did not show recurrence for 9 months after CS.
Case Rep Gastroenterol 2021;15:562–567

中文翻译：

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纳武单抗单药疗法作为三线化疗后，IV 期胃癌成功进行转化手术


纳武单抗单药治疗后进行转化手术（CS）的报道很少，因为它被认为是不可切除或复发性胃癌的三线标准化疗。在这里，我们报告了一个罕见的 IV 期胃癌病例，在纳武单抗单药疗法作为三线化疗后，经 CS 有效治疗。一名 73 岁男性因食欲不振和腹部不适被转至我们医院。经上消化道内镜及CT诊断为IV期胃癌伴肝转移。一线治疗采用卡培他滨、顺铂和曲妥珠单抗 12 个疗程，二线治疗采用紫杉醇加雷莫芦单抗 25 个疗程，三线治疗采用纳武单抗单药治疗 31 个疗程。纳武单抗单药治疗31个疗程后，CT显示原发肿瘤缩小，无肝转移或腹水。进行诊断性腹腔镜检查，未发现腹膜播散（P0），腹膜灌洗细胞学检查结果呈阴性（CY0）。 CS 采用全胃切除术和 D2 淋巴结清扫术（R0 切除）。病理诊断为U，Ant-Less，2型，70×63 mm，低分化腺癌（ypT3N0M0 ypStage IIA）。进行R0切除，组织学反应为1a级。 CS后9个月患者未出现复发。

胃肠病病例代表 2021 年；15:562–567