Types of Pancreatic Tumour
Pancreatic tumours can arise from the endocrine cells in the pancreas that normally produce hormones, or from the exocrine tissues that produce digestive enzymes. On rare occasions, they can arise from other tissues within the pancreas, such as the lymphatic system.
Tumours can be benign or malignant. Benign tumours can grow locally to a large size, but do not generally destroy surrounding structures or spread to distant sites. They cause symptoms either by producing an excess of hormones that disrupts the body’s normal balance (metabolic effect), or by pressing on neighbouring anatomical structures (mass effect). Malignant tumours, on the other hand, can invade and destroy surrounding tissues (invasion), and travel through the lymphatic and blood circulation to spread to distant sites (metastasis); sometimes, they can also produce aberrant hormones or excessive hormone levels.
Benign tumours are uncommon, but carry an excellent prognosis if managed appropriately. About 90% ofmalignant pancreatic tumours arise from the cells that line the ducts of the pancreas, which collect the enzymes produced in the pancreas and deliver them to the intestine; this type of tumour is called pancreatic ductal adenocarcinoma. The cells that produce digestive enzymes are arranged around the branching pancreatic ducts like bunches of berries around a vine, an arrangement known as an acinus, after the Latin word for berry; malignant tumours arising from these cells are called acinar cell carcinoma, and account for less than 5% of pancreatic malignancies. Pancreatic neuroendocrine tumours or islet cell tumours, arising from the hormonal cells of the pancreas in the islets of Langerhaans, account for 2 – 3% of pancreatic tumours, and may be either benign or malignant. A number of other tumour types – such as solid cystic pseudopapillary (Franz) tumour, cystadenocarcinoma, pancreatoblastoma, and lymphoma – constitute the remainder of tumour types.
Characteristics of Patients with Pancreatic Tumours
Approximately 80% of patients present with advanced disease, beyond the stage at which it is possible to be cured. Pancreatic ductal adenocarcinoma remains an aggressive disease, and without treatment, 90% of patients will die within 12 months. Of the 20% who are diagnosed early enough to be treated, and who undergo successful treatment, approximately one-third will survive beyond five years.
Patients with other pancreatic tumour types usually have a much better prognosis, and respond well to treatment, with high numbers achieving a sustained cure.