Open Access

REVIEW

Immune Checkpoint Inhibitors in Gastrointestinal Cancers: Current Evidence and Future Directions

Takeshi Toyozumi^1,*, Hideaki Shimada², Hisahiro Matsubara¹

1 Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, 260-0856, Japan
2 Department of Gastroenterological Surgery and Clinical Oncology, Toho University Graduate School of Medicine, Tokyo, 143-8541, Japan

* Corresponding Author: Takeshi Toyozumi. Email:

(This article belongs to the Special Issue: Advances in Cancer Immunotherapy)

Oncology Research 2025, 33(11), 3185-3206. https://doi.org/10.32604/or.2025.065818

Received 22 March 2025; Accepted 12 August 2025; Issue published 22 October 2025

Abstract

Cancer immunotherapy has long been established as an important treatment option for cancers. In particular, Immune Checkpoint Inhibitor (ICI) has been reported to be effective against various gastrointestinal cancers (esophageal cancer, gastric cancer, colorectal cancer); however, the treatment phase in which ICI should be used and how it should be incorporated into the treatment strategy vary depending on the cancer type being treated. Multiple clinical trials and basic research on ICIs are currently underway, and new insights from these results will continue to change the clinical treatment strategy of gastrointestinal cancers. While it is desirable to have an increasing number of treatment strategy options for gastrointestinal cancers, it is necessary to organize increasingly complex treatments and select more appropriate ICI-based treatments. In addition, as gastrointestinal cancers are being controlled through multidisciplinary treatment using ICI-based treatment, local control by conversion surgery is becoming an important treatment option. We may soon see an era in which gastrointestinal cancers can be systematically controlled with ICI-based treatment, while difficult-to-control lesions can be removed by conversion surgery. In this review, we summarize the evidence of ICI-based treatment for gastrointestinal cancers and provide an overview of the treatment strategies currently underway.

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