Where does cancer usually begin in the pancreas?

Where Pancreatic Cancer Starts

When we talk about pancreatic cancer, most cases actually begin in the same place: the lining of the ducts that carry digestive enzymes through the pancreas. These cells are responsible for transporting secretions from the pancreas to the small intestine, and when they become cancerous, the disease is known as pancreatic ductal adenocarcinoma. This form accounts for about 90% of all pancreatic cancers, making it by far the most common type.

The pancreas itself has two main functions—producing digestive enzymes and managing blood sugar through hormone release—so it's made up of different cell types. While most tumors arise in the exocrine (enzyme-producing) part, a smaller number develop in the endocrine cells, which produce hormones like insulin. These rarer forms are called pancreatic neuroendocrine tumors (PNETs), and they tend to grow more slowly and have a better prognosis than their exocrine counterparts.

Because the pancreas is deep within the abdomen, early signs of cancer are often subtle or absent, which is why it’s typically diagnosed at a more advanced stage. Symptoms like jaundice, unexplained weight loss, or abdominal pain can prompt further testing, but they often appear only after the tumor has grown or spread.

Understanding where pancreatic cancer begins helps researchers and doctors tailor treatments and improve early detection. While progress has been slow, growing knowledge about the biology of both exocrine and endocrine tumors offers hope for better outcomes in the future. For now, raising awareness of the disease’s origins and risks remains a crucial step.