Colorectal cancer (CRC) remains a leading cause of cancer-related deaths in the United States. Although immunotherapy has dramatically changed the landscape of treatment for many advanced cancers, the benefit in CRC has thus far been limited to patients with microsatellite instability high (MSI-H):DNA mismatch repair-deficient (dMMR) tumors. Recent studies in the refractory CRC setting have led to US Food and Drug Administration approvals for pembrolizumab as well as nivolumab (with or without ipilimumab) for tumors harboring an MSI-H:dMMR molecular profile. Several randomized controlled trials are underway to move immunotherapy into the frontline for metastatic cancer (with or without chemotherapy) and the adjuvant setting. Awareness of these studies is critical given the relatively low incidence (approximately 3%-5%) of MSI-H:dMMR in advanced or metastatic CRC to support study completion, because the results could be potentially practice changing. The real challenge in this disease is related to demonstrating the benefit of immunotherapy for the vast majority of patients with CRC not harboring MSI-H:dMMR. Given the rapid pace of scientific changes, this article provides a narrative review regarding the current landscape of immunotherapy for CRC. Particular attention is paid to the currently available data that inform today's clinical practice along with upcoming randomized controlled trials that may soon dramatically change the treatment landscape for CRC.

中文翻译：

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结直肠癌的免疫治疗：当前和新型治疗方法的回顾。

结直肠癌（CRC）仍然是美国癌症相关死亡的主要原因。尽管免疫疗法极大地改变了许多晚期癌症的治疗格局，但迄今为止，CRC 的获益仅限于微卫星不稳定性高 (MSI-H):DNA 错配修复缺陷 (dMMR) 肿瘤的患者。最近在难治性结直肠癌领域的研究导致美国食品和药物管理局批准派姆单抗和纳武单抗（含或不含伊匹单抗）用于治疗具有 MSI-H:dMMR 分子谱的肿瘤。几项随机对照试验正在进行中，旨在将免疫疗法转移到转移性癌症（联合或不联合化疗）和辅助治疗的一线。鉴于晚期或转移性 CRC 中 MSI-H:dMMR 的发生率相对较低（约 3%-5%），了解这些研究对于支持研究完成至关重要，因为结果可能会改变实践。这种疾病的真正挑战在于证明免疫疗法对绝大多数不携带 MSI-H:dMMR 的 CRC 患者的益处。鉴于科学变革的快速步伐，本文对结直肠癌免疫治疗的现状进行了叙述性回顾。我们特别关注当前可用的数据，这些数据为当今的临床实践提供信息，以及即将进行的随机对照试验，这些试验可能很快就会极大地改变结直肠癌的治疗前景。