Efficacy and Safety of Reduced-Dose Chemotherapy Plus Nivolumab in Elderly Advanced Gastric Cancer

Background/Objective: The standard first-line treatment for advanced or recurrent gastric cancer (AGC) includes chemotherapy combined with an immune checkpoint inhibitor or zolbetuximab, but delivering fluoropyrimidine-platinum chemotherapy at standard doses can be difficult in elderly patients. Method: We retrospectively collected clinical data from 70 patients aged 70 years or older with AGC who received first-line chemotherapy plus nivolumab between July 2017 and December 2024. Patients who started treatment without dose reduction were classified as the normal group, whereas those who received a reduced starting dose of fluoropyrimidine and/or platinum were classified as the reduced group. Results: Fifty patients were assigned to the reduced group and 20 to the normal group. The reduced group was older, more frequently received SOX, and more often had PD-L1 combined positive scores ≥ 1. Objective response rate, disease control rate, progression-free survival, and overall survival did not differ significantly between the groups. In contrast, grade ≥ 3 adverse events and any-grade infections were more frequent in the normal group. Conclusions: These findings suggest that reduced-dose chemotherapy plus nivolumab may be an effective and less toxic first-line option for elderly patients with AGC.