Biweekly And Triweekly S-1 And Oxaliplatin Combination Chemotherapy As A First-line Therapy For Elderly Patients With Advanced Gastric Cancer

BackgroundAlthough the triweekly S-1 and oxaliplatin(SOX3)combination chemotherapy has yielded significant improvements in time to progression,overall survival,and overall response rate,the high incidence of severe adverse events limits the use in elderly patients with advanced gastric cancer(AGC).To overcome this limitation,we evaluated the efficacy and toxicity of the biweekly(SOX2)and triweekly S-1 and oxaliplatin combination for the treatment of elderly AGC patients.MethodChemotherapy-naive elderly patients(?60 years old)with pathologically proven unresectable recurrent or metastatic gastric adenocarcinoma were assessed for eligibility.SOX2: S-1 was administered orally at 80 mg/m~2 on days 1–10,and oxaliplatin at 85 mg/m~2,q2w;SOX3: S-1 was administered orally at 80 mg/m~2 on days 1–14,and oxaliplatin at 130mg/m~2,q3w;intravenously on day 1.Patients received a maximum of 8 cycles or 6 cycles in both groups,respectively.ResultsFrom March 2013 to May 2016,47 patients with KPS?70 were enrolled in this study.The median patient age was 64 years(range,60–79 years).The results showed that 58.3%(14/24)and 52.2%(12/23)patients achieved a partial response,29.2%(7/24)and 30.4%(7/23)patients had a stable disease,12.5%(3/24)and 17.4%(4/23)patients progressed during thecourse of the treatment in SOX2 and SOX3 groups,respectively;and there were no significant differences for response rate(ORR)(p=0.72)and disease control rate(DCR)(p=0.70)between both groups.The disease free survival(PFS)and overall survival(OS)time were 6.6(95%CI4.36-8.84)vs 7.3 months(95% CI 3.53-11.13)(p=0.49)and 16.4(95%CI 12.10-20.70)vs.15.9(95%CI 11.80-20.00)(p=0.12)from the start of the chemotherapy in both groups,respectively.A total of 279 cycles of chemotherapy were assessed for toxicity.Major hematological toxicities included grade 3 leukopenia(0% vs.13.0%,p=0.12);grade 3neutropenia(8.3% vs.26.1%,p=0.14);grade 3/4 anemia(12.5% vs.17.4%,p=0.70),grade 3thrombocytopenia(8.3% vs.13.0%,p=0.67)in SOX2 and SOX3,respectively.The non-toxicities observed were grade 3 vomiting(0% vs.17.4%,p=0.05),grade 3 diarrhea(0.0% vs.8.7%,p=0.23);and grade 3 Hyperbilirubinemia(4.2% vs.13.0%,p=0.35);grade 3Neurotoxicity(4.2% vs.8.7%,p=0.61).ConclusionThese data suggested that the biweekly SOX2 regimen had a non-superior to was promising survival and well tolerated as a first-line therapy for elderly advanced gastric cancer.