Effects of S-1 and Capecitabine on Coronary Artery Blood Flow

Patients diagnosed with adenocarcinoma of the gastroesophageal tract are randomly assigned to receive two 3-weekly cycles of either XELOX (intravenous oxaliplatin 130 mg/m2 d.1 followed by oral capecitabine 2000 mg/m2/day divided in 2 daily doses d1-14) or SOX (intravenous oxaliplatin 130 mg/m2 d. 1 followed by oral S-1 25 mg/m2/day BID d1-14). A cross-over between the 2 arms is carried out after the first 2 cycles; patients allocated to XELOX will receive 2 cycles of SOX (cycles 3 and 4), and those allocated to SOX will receive XELOX (cycles 3 and 4). Monitoring of the coronary artery flow, cardiac arrythmias, cardiac symptoms and blood biochemistry is done at baseline, during each chemotherapy cycle (cycles 1 to 4) and after treatment.Study treatment will continue until all patients have discontinued from treatment or maximum 24 weeks from the date of the first day of treatment, whichever occurs first. At that point, treatment may continue at the discretion of the Investigator. Each patient will be followed for survival status for a minimum of 12 months after first dose of study medication. Tumor assessments will be performed throughout the study period and analyzed using Response Evaluation Criteria in Solid Tumors (RECIST) criteria (Version 1.1, 2009). Computed tomography (CT) scans will be performed at the end of every 2 cycles. Cardiac assessments will be performed and analyzed using non-invasive transthoracic Doppler echocardiography, 24-h Holter registration, and plasma troponin concentration.