Nabekura Taiki, Sato Yu, Hiruta Nobuyuki, Kitahara Natsumi, Moriyama Yuki, Kadoya Kengo, Sato Ayami, Wakamatsu Kotaro, Tsuchiya Masaru
Department of Surgery, Toho University Sakura Medical Center, Sakura, Chiba, Japan.
Department of Surgical Pathology, Toho University Sakura Medical Center, Sakura, Chiba, Japan.
Surg Case Rep. 2025;11(1). doi: 10.70352/scrj.cr.25-0007. Epub 2025 Apr 25.
Colorectal cancer is a prevalent malignancy that necessitates personalized chemotherapy, especially with the advent of molecular-targeted drugs and immune checkpoint inhibitors. In Japan, immune checkpoint inhibitors have been approved for unresectable advanced and recurrent colorectal cancer; however, their use in preoperative therapy for colorectal cancer has not yet been approved. Globally, neoadjuvant immunotherapy has demonstrated promising outcomes in colorectal cancer cases with high immunogenicity, including microsatellite instability-high and deficient mismatch repair.
We report a case of a microsatellite instability-high, clinically unresectable, locally advanced ascending colon cancer treated with immune checkpoint inhibitors, which showed significant tumor shrinkage, facilitating standard surgery while avoiding adjunct organ resection. The patient, a 70-year-old male, experienced chronic abdominal pain and diarrhea. Lower gastrointestinal endoscopy and computed tomography confirmed a diagnosis of ascending colon cancer with suspected invasion into the descending duodenum. Although curative resection was technically feasible with pancreatoduodenectomy, neoadjuvant chemotherapy was selected to reduce tumor size, considering the patient's overall condition. Companion diagnostics revealed microsatellite instability-high status and mutation, leading to the initiation of chemotherapy combined with an immune checkpoint inhibitor (pembrolizumab). Subsequently, prolonged pembrolizumab administration was challenging due to suspected immune-related adverse events, including diarrhea and pruritus. However, significant tumor reduction was observed during a follow-up computed tomography scan, facilitating surgery approximately 6 months after treatment initiation. The perioperative period was uneventful, and the patient was discharged on the eighth day after operation. The final pathological results revealed complete tumor disappearance (histological effect of chemotherapy: Grade 3).
This case highlights the potential of neoadjuvant immunotherapy in reducing surgical invasiveness in patients with colorectal cancer.
结直肠癌是一种常见的恶性肿瘤，需要个性化化疗，尤其是随着分子靶向药物和免疫检查点抑制剂的出现。在日本，免疫检查点抑制剂已被批准用于不可切除的晚期和复发性结直肠癌；然而，它们在结直肠癌术前治疗中的应用尚未得到批准。在全球范围内，新辅助免疫治疗在具有高免疫原性的结直肠癌病例中显示出了有前景的结果，包括微卫星高度不稳定和错配修复缺陷。
我们报告一例微卫星高度不稳定、临床不可切除的局部晚期升结肠癌患者，接受免疫检查点抑制剂治疗后肿瘤显著缩小，从而在避免切除附属器官的情况下顺利进行了标准手术。该患者为一名70岁男性，有慢性腹痛和腹泻症状。下消化道内镜检查和计算机断层扫描确诊为升结肠癌，怀疑侵犯降部十二指肠。尽管胰十二指肠切除术在技术上可行，但考虑到患者的整体状况，选择了新辅助化疗以缩小肿瘤大小。伴随诊断显示微卫星高度不稳定状态和 突变，因此开始使用化疗联合免疫检查点抑制剂（帕博利珠单抗）。随后，由于怀疑出现包括腹泻和瘙痒在内的免疫相关不良事件，延长帕博利珠单抗给药具有挑战性。然而，在后续的计算机断层扫描中观察到肿瘤显著缩小，在开始治疗约6个月后顺利进行了手术。围手术期顺利，患者术后第八天出院。最终病理结果显示肿瘤完全消失（化疗组织学效果：3级）。
本病例突出了新辅助免疫治疗在降低结直肠癌患者手术侵袭性方面的潜力。
