Radiotherapy to Patients With CA19-9-elevated Advanced Pancreatic Cancer

Pancreatic adenocarcinoma (PDAC) is a highly lethal malignancy with a 5-year survival less than 10%. Approximately 80% of patients with pancreatic cancer are diagnosed at an advanced stage. Chemotherapy is one of the major treatments for advanced pancreatic cancer. In 2011, the PRODIGE trial has shown that oxaliplatin, irinotecan, fluorouracil, and leucovorin (FOLFIRINOX) was associated with a survival advantage but had increased toxicity. Carbohydrate antigen 19-9 (CA19-9) is the most widely used biomarker in pancreatic cancer. Circulating CA19-9 levels are positively correlated with tumor burden and stage in pancreatic cancer with a diagnostic sensitivity of approximately 80%, suggesting that approximately 20% of patients have normal CA19-9 levels. It is well recognized that Lewis (-) individuals, constituting approximately 10% of the population, have low or no secretion of CA19-9 due to the lack of critical enzyme involved in CA19-9 biosynthesis. Thus, approximately 10% of patients with pancreatic cancer have normal CA19-9 levels regardless of tumor stage. Our previously retrospective study has shown that CA19-9-normal advanced pancreatic cancer may be more sensitive to chemotherapy combined with radiotherapy. The purpose of this study is to evaluate the efficacy of chemotherapy plus radiotherapy to patients with CA19-9-elevated Advanced Pancreatic Cancer who are not refractory to chemotherapy. Progression-free survival (PFS), objective response rate (ORR), overall survival (OS) and disease control rate (DCR) are measured every four weeks.