Background: Microsatellite instability-high (MSI-H) colon cancer with isolated peritoneal metastases (iPM) represents a molecularly and anatomically distinct clinical subset with limited evidence to guide treatment. Given the unique immunogenic profile of MSI-H tumors and the historically poor prognosis of peritoneal dissemination, we evaluated the association of immunotherapy, chemotherapy, and surgery with survival outcomes in this population. Methods: Using the National Cancer Database, we identified patients with MSI-H colon cancer and iPM diagnosed between 2016–2021. Patients were stratified by systemic therapy type (immunotherapy, chemotherapy, combination) and surgical resection status. Kaplan–Meier and multivariable Cox regression analyses were used to assess overall survival (OS). Results: Among 598 patients, 22% received systemic treatment with immunotherapy and 76% underwent surgical resection. Immunotherapy was associated with significantly longer median OS compared to chemotherapy (33 vs. 18 months,p< 0.001). On multivariable analysis, immunotherapy remained independently associated with improved survival (HR: 0.46;p< 0.001). Surgical resection of the primary tumor with (HR: 0.40;p< 0.001) or without metastatectomy (HR: 0.41;p< 0.001) was associated with longer survival, and the combination of surgery and immunotherapy yielded the greatest survival benefit. Conclusions: Patients with MSI-H colon cancer and iPM treated with immunotherapy had significantly improved survival, compared to chemotherapy. Surgical resection combined with immunotherapy is associated with the greatest survival benefit, supporting a multimodal approach. These findings provide real-world evidence supporting integration of immunotherapy and surgery in this molecularly and anatomically distinct population.
背景：伴有孤立性腹膜转移（iPM）的微卫星高度不稳定（MSI-H）结肠癌在分子学和解剖学上属于独特的临床亚型，目前指导其治疗的证据有限。鉴于MSI-H肿瘤独特的免疫原性特征及腹膜播散历来预后较差的特点，本研究评估了该人群中免疫治疗、化疗及手术治疗与生存结局的关联。方法：利用美国国家癌症数据库，我们筛选出2016年至2021年间诊断为MSI-H结肠癌伴iPM的患者。根据全身治疗类型（免疫治疗、化疗、联合治疗）和手术切除状态对患者进行分层，采用Kaplan-Meier法和多变量Cox回归分析评估总生存期（OS）。结果：在598例患者中，22%接受了免疫治疗，76%接受了手术切除。与化疗相比，免疫治疗的中位OS显著延长（33个月 vs 18个月，p<0.001）。多变量分析显示，免疫治疗仍是改善生存的独立相关因素（HR：0.46；p<0.001）。无论是否联合转移灶切除，原发肿瘤的手术切除均与更长的生存期相关（联合转移灶切除HR：0.40，p<0.001；未联合转移灶切除HR：0.41，p<0.001），且手术联合免疫治疗可带来最大的生存获益。结论：与化疗相比，接受免疫治疗的MSI-H结肠癌伴iPM患者生存期显著改善。手术切除联合免疫治疗可获得最大的生存获益，这支持了针对这一特殊分子与解剖亚型人群采用多模式治疗策略。本研究为在该特定人群中整合免疫治疗与手术提供了真实世界证据支持。
肿瘤(癌症)患者之家