Efficacy and safety of S-1 and oxaliplatin combination therapy in elderly patients with advanced gastric cancer

A randomized phase III study of Japanese patients with advanced gastric cancer, the G-SOX trial, revealed that S-1 and oxaliplatin (SOX) combination therapy was noninferior to S-1 and cisplatin (CS) combination therapy. However, it is unclear whether the efficacy and safety in elderly patients were different between the two regimens. A total of 685 patients registered in the G-SOX trial were classified as elderly (70 years or older) or not elderly (younger than 70 years), and 663 patients (SOX therapy, elderly 113 of 333 patients, 34 %; CS therapy, elderly 99 of 330 patients, 30 %) and 673 patients (SOX therapy, elderly 114 of 338 patients, 34 %; CS therapy, elderly 101 of 335 patients, 30 %) were analyzed for efficacy and safety, respectively. Treatment delivery of SOX was also compared between elderly and nonelderly groups. No differences in efficacy were identified between the elderly and nonelderly groups for either regimen. In the elderly groups, SOX therapy showed better trends in progression-free survival (hazard ratio 0.805, 95 % confidence interval 0.588-1.102) and overall survival (hazard ratio 0.857, 95 % confidence interval 0.629-1.167) compared with CS therapy, although there were no significant differences. Grade 3 or worse adverse events were less frequent in the elderly group receiving SOX than in the elderly group receiving CS except for the low incidence of sensory neuropathy (5.3 % vs 0 %), neutropenia (25.4 % vs 42.6 %), anemia (21.1 % vs 42.6 %), febrile neutropenia (1.8 % vs 10.9 %), increased creatinine level (0.9 % vs 3.0 %), and hyponatremia (7.9 % vs 18.8 %). SOX is an effective and feasible therapy in both nonelderly and elderly patients with advanced gastric cancer. In elderly patients, SOX demonstrated favorable efficacy and safety compared with CS.