Immune-related adverse events and prognosis in patients with upper gastrointestinal cancer treated with nivolumab.

Background: Immune checkpoint inhibitors (ICIs) are increasingly being used for the treatment of upper gastrointestinal cancers [esophageal cancer and gastric cancer (GC)]. They cause imbalances in immunological tolerance, resulting in immune-related adverse events (irAEs). Although irAEs have been reported to be associated with the efficacy of ICIs in some cancers, the relationship between irAEs and prognosis of upper gastrointestinal cancers remains unknown. This study aimed to investigate the prognostic impact of irAEs in patients with advanced or recurrent upper gastrointestinal cancer treated with nivolumab. Methods: We retrospectively divided the patients (n=96) who received nivolumab into two groups: the irAEs group (n=41) and non-irAEs group (n=55), according to the Common Terminology Criteria for Adverse Events ver. 5.0. Results: irAEs were significantly associated with good performance status and high serum albumin levels (all P<0.05). The irAEs group had a significantly longer overall survival (OS) than the non-irAEs group [log-rank P=0.003; univariate hazard ratio (HR) =0.36, 95% confidence interval (CI) =0.21-0.65, P<0.01; multivariate HR =0.47, 95% CI =0.26-0.88, P=0.018]. Importantly, in both esophageal cancer and GC, the irAEs group experienced favorable clinical outcomes compared with the non-irAEs group. In the multivariate analysis, male sex (P<0.01), presence of irAEs (P=0.018), and good pretreatment performance status (P<0.01) were independent prognostic factors. Conclusions: Among patients with upper gastrointestinal cancer treated with nivolumab, the prognosis of patients who developed irAEs was better than that of patients who did not develop irAEs. Long-term continuation of nivolumab by early detection of irAEs and an appropriate response to irAEs are important.