(Please note – this page is for the experts only!! You really don’t need to know this.)
Cancers of the pancreas are divided into groups according to the type of cell that the cancer has started from. The most common cancers (80-90%) start from the cells in the inner lining of the ducts and are “exocrine tumours”. Most of these tumours are called a “Pancreactic Ductal Adenocarcinoma” (PDAC). Other exocrine tumours of the pancreas are rarer, and include “Adenosquamous Carcinomas” and undifferentiated carcinomas.
There are other uncommon tumours that can affect the pancreas. These include:
- a group of conditions called “neuroendocrine tumours” (pNETs) that arise from the cells in the pancreas that normally produce hormones such as insulin or glucagon. These tumours may or may not continue to produce hormones as they develop;
- a type of lymphoma – a cancer arising from the lymphatic tissue in the pancreas; and
- “pancreatic sarcoma” which develops in the tissue that holds the pancreatic cells together; and
- various cystic tumours.
Cancers can sometimes arise from existing benign tumours within the pancreas. The benign tumours are most commonly cystic tumours where the benign but abnormal cells make an excessive amount of mucin (a jelly-like substance) which accumulates within the pancreas, creating a cyst. There are two types of mucinous tumour:
- a “mucinous cystadenoma” and
- tumour cells that arise from the ductal lining – an “intraductal papillary mucinous neoplasm” (IPMN).
Both have the potential to develop cancers within them, but may be detected by scanning when at a benign stage, when excision is potentially curative.
Tumours arise from tissues close to the pancreas, such as the bile duct (cholangiocarcinoma), Ampulla of Vater, (Ampullary adenocarcinoma), or duodenum (duodenal adenocarcinoma). These may cause symptoms similar to pancreatic cancer, but have different treatments and, importantly, a different prognosis.
80-85% of tumours arise in the head of the pancreas, with the remainder arising in the body (10%) and tail (5%).