Supplementary Material for: Multicenter Study on the Safety and Efficacy of First-Line Nivolumab-Combination Chemotherapy in Patients Aged 75 years and Older with Unresectable Advanced or Recurrent Gastric Cancer

Introduction: Nivolumab combined with chemotherapy has been approved as the first-line treatment for HER2-negative, unresectable, advanced, or recurrent gastric cancer. Patients aged ≥ 75 years more often have impaired organ function and comorbidities that increase the risk of adverse events, including immune-related adverse events, than younger patients, potentially limiting the continuation of treatment. In this multicenter study, we aimed to evaluate the safety and efficacy of first-line nivolumab chemotherapy in older patients. Methods: We retrospectively analyzed data from 103 patients treated with first-line nivolumab combination chemotherapy for unresectable, advanced, or recurrent gastric cancer at 12 institutions between November 2021 and January 2023. The participants were divided into groups A (