帕博利珠单抗治疗dMMR/MSI-H晚期结肠癌实现长期生存1例

Long-term complete remission achieved by pembrolizumab for dMMR/MSI-H advanced colon cancer: a case report

摘要

结直肠癌(colorectal cancer,CRC)是全球第三大最常见恶性肿瘤和第二大癌症相关死亡原因,已成为全球健康的主要威胁。近年来各种筛查和检测技术兴起,但约25%的CRC患者在诊断时已处于晚期,高达50%的最初局限性疾病的患者会发生转移,转移性CRC的5年生存率仍不足15%,且传统治疗对分子异质性肿瘤的应答差异显著。免疫检查点抑制剂(immune checkpoint inhibitors,ICIs)的突破性进展为晚期CRC提供了新的治疗模式,尤其是错配修复缺陷(mismatch repair deficiency,dMMR)/微卫星高度不稳定(microsatellite instability-high,MSI-H)亚型患者。本文报道1例55岁男性dMMR/MSI-H晚期CRC患者在多线治疗失败后,启用帕博利珠单抗实现肿瘤迅速缩小,肿瘤标志物持续下降,在完成7个周期治疗后实现完全缓解(complete remission,CR),并获得5年长期生存的典型病例,探讨癌症诊疗过程中的决策分析,为临床实践提供进一步参考。

Abstract

Colorectal cancer (CRC) is the third most common malignancy and the second leading cause of cancer-related deaths worldwide and has become a major threat to global health. In recent years, various screening and detection technologies have emerged; however, approximately 25% of CRC patients are still diagnosed at an advanced stage. Up to 50% of patients with initially localized disease develop metastases, and the 5-year survival rate for metastatic CRC remains below 15%. Furthermore, traditional treatments exhibit significant variability in response to molecularly heterogeneous tumors. Breakthroughs in immune checkpoint inhibitors (ICIs) have provided new treatment modalities for advanced CRC, particularly for patients with the microsatellite instability-high (MSI-H)/mismatch repair deficiency (dMMR) subtype. This report details the case of a 55-year-old man with dMMR/MSI-H advanced colorectal cancer (CRC). Following multiple prior treatment failures, the initiation of pembrolizumab led to rapid tumor shrinkage and a sustained decline in tumor markers. The patient attained complete remission (CR) after seven treatment cycles and achieved long-term survival, with a follow-up of five years. This case study explored the decision-making process in cancer diagnosis and treatment, thereby providing a valuable reference for clinical practice.

关键词

晚期结直肠癌 / 错配修复缺陷/微卫星高度不稳定 / 帕博利珠单抗 / 免疫治疗 / 林奇综合征

Key words

advanced colorectal cancer / dMMR/MSI-H / pembrolizumab / immunotherapy / lynch syndrome