Immunotherapy in Gastrointestinal Cancers: Current Insights

Gastrointestinal cancer is one of the most prevalent malignant tumors worldwide. The treatment landscape of gastrointestinal cancer has entered a new era with the advent of immunotherapy, which activates the immune system to identify and eliminate tumor cells. Immunotherapy has demonstrated high efficacy and tolerable toxicity profiles compared to conventional therapies. Immune checkpoint inhibitors including PD-1, PD-L1, CTLA-4 and LAG-3 in combination with targeted therapy or chemotherapy have been approved for the treatment of gastrointestinal tumors with good clinical patient benefit. In recent years, a variety of novel immunotherapeutic approaches have emerged. For example, adoptive T-cell therapy, such as claudin18.2-targeted CAR-T has achieved an objective remission rate of 48.6% in patients with advanced gastric cancer and gastroesophageal junction cancer. Oncolytic viruses inhibits tumor growth in both tumor lysis and immune activation, and is currently showing its efficacy against gastrointestinal tumors in some clinical trials. In addition, cancer vaccines, with their unique high degree of precision, have improved the effectiveness of individualized therapy. Personalized neoantigen vaccines combined with other immunotherapeutic drugs or chemotherapy, have shown some efficacy and safety in gastrointestinal patients. In this review, we summarize these recent advances in immunotherapy for the treatment of gastrointestinal tumors. Additionally, the challenges and limitations linked to immunotherapy were explored. This review will expand our understanding of clinical studies on immunotherapy in gastrointestinal cancer and assist in individualizing patient treatment strategies, maximizing therapeutic benefits, and improving patient prognosis.