Pancreatic cancer can start in the head, body or tail of the pancreas. It can start from different types of cell.
Where the cancer is
Cancer can start in the head, body or tail of the pancreas. The wide end of the pancreas is called the head. The thin end is called the tail. The bit in the middle is called the body.
About 75 out of 100 pancreatic cancers (75%) start in the head of the pancreas.
Exocrine pancreatic cancers
Most pancreatic cancers are the exocrine type. This means that they start in cells that produce pancreatic digestive juices.
More than 8 out of 10 exocrine pancreatic cancers are adenocarcinomas. Nearly all of these are ductal adenocarcinomas. They start in the cells lining the ducts of the pancreas.
Rarer types of exocrine pancreatic cancer include:
Cystic tumours cause a cyst or fluid filled sac in the pancreas. Most pancreatic cysts are benign but some are cancerous. Cystic cancers can have a better outlook (prognosis) than other types of exocrine pancreatic cancer.
Cancer of the acinar cells
The acinar cells are at the ends of the ducts that produce pancreatic juices. These tumours are generally diagnosed in people at a younger age than adenocarcinomas. They are slower growing and tend to have a better outlook.
Endocrine pancreatic tumours
Endocrine tumours are uncommon. They start in the endocrine pancreas, where insulin and other hormones are made and released directly into the bloodstream. They are also called pancreatic neuroendocrine tumours (PNETS) or islet cell tumours.
About a third of these tumours produce hormones, which can cause some strange symptoms. Most of these tumours are non cancerous (benign).
They are named after the hormone they produce:
- gastrinomas produce a hormone called gastrin
- insulinomas produce insulin
- somatostatinomas produce a hormone called somatostatin
- VIPomas produce a hormone called VIP
- glucagonomas produce a hormone called glucagon
Two thirds of pancreatic endocrine tumours are called non functioning tumours as they don't produce any hormones or symptoms. Most of these tumours are cancers (malignant).
Endocrine pancreatic tumours are treated differently to exocrine tumours and generally have a much better outlook (prognosis) than adenocarcinoma of the pancreas.
Other rare types of pancreatic cancer
There are other rare types of cancer of the pancreas.
These very rare tumours mainly occur in children. They are sometimes linked with rare genetic conditions called Beckwith-Wiedemann syndrome and familial adenomatous polyposis (FAP).
Sarcomas of the pancreas
These are cancers of the connective tissue that hold together the cells of the pancreas. They are extremely rare.
Lymphoma is a cancer of the lymphatic system. As the lymphatic system runs throughout the body, these tumours can develop in any part of the body.