Immunotherapy for esophageal squamous cell carcinoma: a review

Abstract

Cancer vaccines and immune checkpoint inhibitors (ICI) have recently been employed as immunotherapies for esophageal squamous cell carcinoma (ESCC). Cancer vaccines for ESCC have yielded several promising results from investigator-initiated phase I and II clinical trials. Furthermore, a Randomized Controlled Trial as an adjuvant setting after curative surgery is in progress in Japan. On the other hand, ICI, anti-CTLA-4 mAb and anti-PD-1 mAb, have demonstrated tumor shrinkage and improved overall survival in patients with multiple cancer types. For ESCC, several clinical trials using anti-PD-1/anti-PD-L1 mAb are underway with several recent promising results. In this review, cancer vaccines and ICI are discussed as novel therapeutic strategies for ESCC.

Keywords: cancer vaccine; esophageal squamous cell carcinoma; immune checkpoint inhibitors; immunotherapy.

Fig. 1.

Schematic tumor immune response and mechanisms of ICI. Figure modified from Mimura K et al.⁾ with permission from Japanese Journal of Cancer and Chemotherapy.

Fig. 2.

Four subclassifications of tumor microenvironments from the view point of expected clinical effects of anti-PD-1/anti-PD-L1 mAb. Figure modified from Mimura K et al. with permission from Japanese Journal of Cancer and Chemotherapy.