Takahashi Goro, Matsuda Akihisa, Yamada Takeshi, Uehara Kay, Shinji Seiichi, Yokoyama Yasuyuki, Iwai Takuma, Miyasaka Toshimitsu, Kanaka Shintaro, Yoshimori Daigo, Matsui Takanori, Hayashi Koki, Yoshida Hiroshi
Department of Gastroenterological Surgery, Nippon Medical School Hospital, Tokyo, Japan.
Surg Case Rep. 2025;11(1). doi: 10.70352/scrj.cr.25-0070. Epub 2025 Jun 14.
Patients with obstructive colon cancer (OCC) with distant metastases often present with a poor general condition, including malnutrition, anemia, and systemic inflammation. Traditionally, these patients undergo stoma creation and/or primary tumor resection followed by systemic chemotherapy. However, for patients with DNA mismatch repair-deficient/microsatellite instability high (dMMR/MSI-H) colorectal cancer, the emergence of immune checkpoint inhibitors (ICIs) has revolutionized treatment strategies, with remarkable antitumor effects. We report two cases of successful management of MSI-H OCC, achieving curative resection while avoiding decompressive procedures, including colostomy creation.
A 29-year-old man diagnosed with MSI-H obstructive transverse colon cancer (cT4b stomach, N1b, M1c1) was treated with pembrolizumab monotherapy (200 mg/body, every 3 weeks). The colorectal obstructive scoring system score was 2 at pembrolizumab administration. The patient showed rapid improvement in his abdominal symptoms within 3 days and achieved clinical complete response after eight courses. Laparoscopic partial colectomy with D3 lymph node dissection was subsequently performed safely. He was discharged on postoperative day 8 without postoperative complications. Histopathological analysis confirmed pathological complete response, and the patient was recurrence-free 15 months after surgery without adjuvant chemotherapy. A 58-year-old man diagnosed with MSI-H obstructive ascending colon cancer (cT4aN3M1a, LYM) was treated with pembrolizumab monotherapy. The colorectal obstructive scoring system score was 1 at pembrolizumab administration. The patient's abdominal symptoms improved within 5 days, with marked tumor shrinkage after nine courses. Laparoscopic extended right hemi-colectomy with D3 lymph node dissection was subsequently performed safely, and he was discharged on postoperative day 7 without postoperative complications. Histopathological analysis showed major pathological response (less than 10% viable cancer cells in the resected specimen), with no viable tumor cells in the primary lesion. The patient was recurrence-free 1-year post-surgery, without adjuvant chemotherapy.
This report highlights the potential benefits of ICI treatment for dMMR/MSI-H OCC, particularly for rapid relief of obstruction-related symptoms and facilitating oncologically safe R0 resection. In cases of MSI-H OCC, ICIs can be highly effective as an alternative to traditional decompression procedures.
患有远处转移的梗阻性结肠癌（OCC）患者通常全身状况较差，包括营养不良、贫血和全身炎症。传统上，这些患者会接受造口术和/或原发性肿瘤切除，随后进行全身化疗。然而，对于DNA错配修复缺陷/微卫星高度不稳定（dMMR/MSI-H）的结直肠癌患者，免疫检查点抑制剂（ICI）的出现彻底改变了治疗策略，具有显著的抗肿瘤效果。我们报告了两例成功治疗MSI-H OCC的病例，实现了根治性切除，同时避免了包括结肠造口术在内的减压手术。
一名29岁男性被诊断为MSI-H梗阻性横结肠癌（cT4b胃，N1b，M1c1），接受帕博利珠单抗单药治疗（200mg/体，每3周一次）。在给予帕博利珠单抗时，结直肠梗阻评分系统评分为2分。患者在3天内腹部症状迅速改善，8个疗程后达到临床完全缓解。随后安全地进行了腹腔镜部分结肠切除术及D3淋巴结清扫术。他在术后第8天出院，无术后并发症。组织病理学分析证实为病理完全缓解，患者术后15个月无复发，未接受辅助化疗。一名58岁男性被诊断为MSI-H梗阻性升结肠癌（cT4aN3M1a，LYM），接受帕博利珠单抗单药治疗。在给予帕博利珠单抗时，结直肠梗阻评分系统评分为1分。患者的腹部症状在5天内改善，9个疗程后肿瘤明显缩小。随后安全地进行了腹腔镜扩大右半结肠切除术及D3淋巴结清扫术，他在术后第7天出院，无术后并发症。组织病理学分析显示主要病理反应（切除标本中存活癌细胞少于10%），原发灶无存活肿瘤细胞。患者术后1年无复发，未接受辅助化疗。
本报告强调了ICI治疗dMMR/MSI-H OCC的潜在益处，特别是对于快速缓解梗阻相关症状和促进肿瘤学上安全的R0切除。在MSI-H OCC病例中，ICI作为传统减压手术的替代方案可能非常有效。
