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

Abstract

Background: 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. Methods: 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. Results: 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 %). Conclusions: 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.