Older adults with resectable gastric cancer undergoing perioperative chemotherapy or preoperative chemoradiotherapy plus perioperative chemotherapy: A secondary analysis of the AGITG TOPGEAR phase III trial.

PURPOSE: To evaluate treatment adherence, adverse events, and survival in older (≥70 years) adults undergoing perioperative treatment for gastric cancer. METHODS: Patients with resectable gastric/gastro-esophageal junction adenocarcinoma (ECOG 0-1) enrolled in the phase III TOPGEAR trial were randomized to perioperative chemotherapy (ECF/ECX or FLOT) alone or perioperative chemotherapy plus preoperative chemoradiotherapy (45 Gy in 25 fractions with concurrent fluoropyrimidine). In this exploratory analysis, treatment completion, grade ≥ 3 adverse events (CTCAE v3.0), surgical outcomes, overall survival (OS) and progression-free survival (PFS) were compared between older and younger adults. RESULTS: Of the 574 patients enrolled, 135 (24%) were ≥ 70 years. Older adults more frequently required preoperative chemotherapy dose reductions, omissions, or delays (chemoradiotherapy: 55% vs 35%, p = 0.004; chemotherapy: 60% vs 48%, p = 0.087). Rates of grade ≥ 3 adverse events were comparable between older and younger patients (chemoradiotherapy: 66% vs 67%, p = 0.874; chemotherapy: 68% vs 59%, p = 0.220), but older adults more often had hematologic toxicity and grade ≥ 3 diarrhea in the chemotherapy group (56% vs 37%, p = 0.006; 21% vs 6%, p < 0.001). Resection rates, grade 3/4 surgical complications, number of removed lymph nodes, and 30-/90-day mortality were similar by age. OS and PFS were comparable across age groups, with numerically favorable outcomes for older adults (OS: HR 0.86, 95% CI 0.58-1.26 [chemoradiotherapy]; HR 0.75, 95% CI 0.51-1.11 [chemotherapy]; PFS: HR 0.78, 95% CI 0.53-1.15 [chemoradiotherapy]; HR 0.70, 95% CI 0.47-1.03 [chemotherapy]). CONCLUSIONS: Older adults with gastric cancer achieved comparable oncologic outcomes to younger patients, despite more frequent treatment modifications and higher hematologic toxicity.