Immune-related adverse events not associated with survival in advanced or metastatic gastroesophageal cancers.

Immune checkpoint inhibitors (ICIs) have shown promise in the treatment of gastric and oesophageal cancers (GEC). Despite their promising efficacy, ICIs have been associated with unique side effects known as immune-related adverse events (IRAEs). Several studies have shown improved treatment responses in patients with IRAEs compared to those without IRAEs in various cancer types such as melanoma and non-small cell lung cancer. We performed a single-institution retrospective study to characterize IRAE incidence and association with treatment response in advanced GEC. We identified 70 patients with GEC who received ICI therapy; 20 (29%) developed an IRAE of any magnitude. The most common were colitis (35%) hypothyroidism (25%) and pneumonitis (20%). Median PFS and OS were not statistically different between IRAE and nonIRAE groups (10.4 vs. 11.3 months  = 0.6 and 11.0 vs. 12.9 months  = 1.0, respectively). This is in contrast to studies in other cancer types that have suggested association between IRAE and improved outcomes.