Comparison of cisplatin+capecitabine and oxaliplatin+capecitabine in the first line treatment of metastatic gastric cancer in terms of effectiveness and side-effect profile

Aim: Gastric cancer is one of the cancer group that have high mortality rates. Most of the patients are diagnosed at later stages of the disease and so, prognosis is generally worse. This study aimed to compare retrospectively the efficacy and side-effect profile of the platinum based therapies combined with flouropyrimidine based chemotherapies (cisplatin + capecitabine and oxaliplatin + capecitabine) which are used as first line therapy in metastatic gastric cancer. Material and method: 103 patients with metastatic gastric cancer who were followed in Karadeniz Technical University Faculty of Medicine- Department of Oncology between January 2010 and December 2015 were included in this study. Patients' records were analysed retrospectively. 66 patients were treated with cisplatin + capecitabine, while 37 patients were treated with oxaliplatin + capecitabine. Two groups were compared for side-effect profiles, progression-free survival (PFS), overall survival rates (OS) and response to therapy. The factors affecting overall survival and progression-free survival were also evaluated. Results: 103 patients included in this study were composed of 74 (71,8%) male and 29 (28,2%) female patients. Mean value of age was 58,3 ± 10,7 (min:29 - max:80). Adenocarcinoma was diagnosed as histopathologically in 100 (97,1%) patients. Liver was the common site of metastasis (26,2%). Objective response rates were 24,3% in cisplatin + capecitabine group and 37,8% in oxaliplatin + capecitabine group (p=0,232). OS were found as 11 months in cisplatin + capecitabine group and 13 months in latter group (p=0,166). PFS were also analysed as 7 months in cisplatin + capecitabine group and 9 months in latter group (p=0,063). Elevated creatinine levels, neutropenia and anemia were diagnosed more common as therapy related side effects in cisplatin + capecitabine group (p=0,003; 0,048; 0,038) but elevated AST ratios were more common in oxaliplatin + capecitabine group (p=0,018). Overall survival rates were found to be related to ECOG scores, operational status for curative or palliative purposes and second-line therapy (p=0,004; 0,004; 0,001). Overall survival rates were found to be related also with ALP, GGT, CRP values at diagnosis and also CA19-9 levels after 3 month therapy (p=0,001; 0,041; 0,001; 0,009). Progression-free survival rates were related to leukocyte counts, GGT and CRP levels at diagnosis (p= 0,043; 0,028; 0,016). Conclusion: No statistically relevant difference was found between oxaliplatin + capecitabine group and cisplatin + capecitabine group for first-line chemotherapy in advanced gastric cancer. Oxaliplatin was found to be safer than cisplatin for adverse effects. Oxaliplatin + capecitabine treatment, which has fewer side effects and is better tolerated, is non-inferior to the standard treatment cisplatin + capecitabine at the beginning of our study and can be used safely instead of cisplatin + capecitabine. Overall survival rates were found to be related to operational status, ECOG scores, second-line chemotherapy, CRP, ALP, GGT and CA19-9 levels after 3 month therapy. Progression-free survival status were affected by leukocyte counts, CRP, GGT at diagnosis. Key Words: Metastatic gastric cancer, Advanced stage, Cisplatin, Oxaliplatin, Capecitabine.