Chemotherapy +/- vitamin supplementation in advanced Oesophagogastric cancer

INTERVENTION: Group A: patients will be treated with gemcitabine 1250 mg/m2 IV on days 1 and 8 in combination with Cisplatin 80 mg/m2 on day 1 with vitamin supplementation (Folic acid 450 ug/24 hours PO, starting at least one week prior to chemotherapy and finishing at least 3 weeks after the last treatment dose. Vitamin B12 1000 ug approximately every 9 weeks, starting 1 week before chemotherapy and finishing at least 3 weeks after the last treatment dose). Group B: patients will be treated with gemcitabine 1250 mg/m2 on days 1 and 8 in combination with Cisplatin 80 mg/m2 on day 1 without vitamin supplementation. Cycles will be administered every 21 days. A maximum of 6 cycles will be administered to every patient, although this number could be increased if the patient may benefit from it, based on investigator's criteria. CONDITION: Oesophagogastric cancer ; Cancer ; Malignant neoplasm of stomach PRIMARY OUTCOME: Response rate SECONDARY OUTCOME: 1. Time to progression; 2. Overall survival INCLUSION CRITERIA: 1. Patients must have histologically or cytologically confirmed metastatic or locally advanced unresectable advanced oesophagogastric carcinoma (squamous or adenocarcinoma), not amenable for curative treatment 2. Patients may have received prior surgery, and chemotherapy and/or radiotherapy in neo‐adjuvant or adjuvant setting as long as the chemotherapy was completed at least 6 months prior to study entry 3. Patients should have measurable disease according to RECIST criteria 4. Age of at least 18 5. Performance status (ECOG) 0, 1 or 2 6. Life expectancy of at least 12 weeks 7. Adequate bone marrow function, defined by a neutrophil count above 1.5 x 10^9/l, platelet count above 100 x 10^9/l and hemoglobin above 5.6 mmol/l 8. Adequate renal and hepatic function, defined by bilirubin <1.5 x upper limit of normal (ULN), alkaline phosphatase (AP), aspartate transaminase (AST) and alanine transaminase (ALT) <3 x ULN (<5 x ULN is acceptable in case of