Vitamin C to Quality of Life in Patients With Terminal Stage Pancreatic Cancer

Inclusion Criteria: * Ability to understand and the willingness to sign a written informed consent document. * Age ≥ 18 years and ≤ 80 years. * Eastern Cooperative Oncology Group (ECOG) performance status 0-2. * Histologically or cytologically confirmed metastatic pancreas adenocarcinoma. * Tumor progression after two lines of chemotherapy. * Adequate organ performance based on laboratory blood tests. * Presence of at least of one measurable lesion in agreement to Response Evaluation Criteria in Solid Tumours (RECIST) criteria. * The expected survival ≥ 1 months. * Women of childbearing potential and men must agree to use adequate contraception prior to study entry and for the duration of study participation. Exclusion Criteria: * Active second primary malignancy or history of second primary malignancy. * The diagnosis was confirmed by pathology as non-adenocarcinoma of pancreas. * Inflammation of the digestive tract, including pancreatitis, cholecystitis, cholangitis, etc. * Pregnant or nursing women. * Glucose-6-phosphate dehydrogenase (G6PD) deficiency. * Severe and uncontrollable accompanying diseases that may affect protocol compliance or interfere with the interpretation of results. * Renal insufficiency or dialysis * Other serious accompanying illnesses, which, in the researcher's opinion, could seriously adversely affect the safety of the treatment. * Patients who are unwilling or unable to comply with study procedures.