Safety and efficacy of neoadjuvant S-1 and oxaliplatin therapy for gastric cancer in the elderly: combined phase II trials of KSCC1601 and KSCC1801.

BACKGROUND

The efficacy of neoadjuvant chemotherapy in elderly patients with locally advanced gastric cancer remains unclear. We evaluated neoadjuvant S-1 plus oxaliplatin (SOX) therapy in elderly patients using patient data from two phase II trials.

METHODS

Patient data from KSCC1601 and KSCC1801 phase II trials were integrated. Patients were divided into an elderly group (age ≥75 years) and a non-elderly group (age <75 years). Adverse events, postoperative complications, and outcomes were compared. Overall survival (OS) and recurrence-free survival (RFS) were calculated from treatment initiation.

RESULTS

Among the 73 patients enrolled in trials, 66 (90.4%) underwent surgery and 65 (89.0%) achieved R0 resection. Neoadjuvant SOX therapy was administered to 69 patients (94.5%). Among those with R0 resection, 22 were aged ≥75 years and 43 were aged <75 years. PS 1 was significantly more common in the elderly group, with no other baseline differences. Postoperative complications developed in 11 patients (16.9%), including 1 (4.5%) in the elderly group and 10 (23.3%) in the non-elderly group (p = 0.12). Grade III or higher complications occurred only in the non-elderly group. OS and RFS did not differ significantly between the age groups (OS: Hazard ratio (HR) = 0.78, 95% Confidence Interval (CI) 0.27-2.21, p = 0.64; RFS: HR = 1.12, 95% CI 0.51-2.44, p = 0.79). Undifferentiated histology, stage III disease, and poor pathological response were associated with worse survival.

CONCLUSIONS

Neoadjuvant SOX therapy is feasible in selected elderly patients with locally advanced gastric cancer and yields survival comparable to those of younger patients.