Efficacy and safety of chemotherapy in older versus non-older patients with advanced gastric cancer: A real-world data, non-inferiority analysis.

OBJECTIVE: Advanced gastric cancer (AGC) is a common neoplasm in older adults. Nevertheless, there are few specific management data in the literature. The aim of this study was to assess non-inferiority of survival and efficacy-related outcomes of chemotherapy used in older vs non-older patients with AGC.

MATERIALS AND METHODS: We recruited 1485 patients from the AGAMENON registry of AGC treated with polychemotherapy between 2008-2017. A statistical analysis was conducted to prove non-inferiority for overall survival (OS) associated with the use of chemotherapy schedules in individuals ≥70 vs.<70years. The fixed-margin method was used (hazard ratio [HR]<1.176) that corresponds to conserving at least 85% efficacy.

RESULTS: 33% (n=489) of the cases analyzed were ≥70 years. Two-agent chemotherapies and combinations with oxaliplatin (48% vs. 29%) were used more often in the older patients, as were modified schedules and/or lower doses. Toxicity grade 3-4 was comparable in both groups, although when looking at any grade, there were more episodes of enteritis, renal toxicity, and fatigue in older patients. In addition, toxicity was a frequent cause for discontinuing treatment in older patients. The response rate was similar in both groups. After adjusting for confounding factors, the non-inferiority of OS associated with schedules administered to the older vs. younger subjects was confirmed: HR 1.02 (90% CI, 0.91-1.14), P (non inferiority)=0.018, as well as progression-free survival: HR 0.97 (90% CI, 0.87-1.08), P(non-inferiority)=0.001.

CONCLUSION: In this AGC registry, the use of chemotherapy with schedules adapted to patients ≥70 years provided efficacy that was not inferior to that seen in younger cases, with comparable adverse effects.