Pancreatic cancer is cancer found in the tissues of the pancreas, an organ located behind the lower part of the stomach. The pancreas extends horizontally across the abdomen, with the head of the pancreas located on the right side of the abdomen, behind the place where the stomach meets the duodenum (the first part of the small intestine).
The pancreas contains two different types of glands: exocrine and endocrine. The exocrine glands produce pancreatic "juice" that is released into the intestines. This juice contains enzymes, such as trypsin, chymotrypsin, pancreatic lipase, and pancreatic amylase, which help digest fats, proteins, and carbohydrates from food. Without these enzymes, food would pass through the intestines without being absorbed. The enzymes are released into tiny tubes called ducts; the tiny ducts form larger ducts that carry the pancreatic juice to the small intestine.
Endocrine cells constitute only approximately five percent of the cells in the pancreas. They are arranged in small clusters called islets or islets of Langerhans, which release two important hormones, insulin and glucagon, directly into the blood. Insulin controls the amount of sugar in the blood, while glucagon raises blood sugar levels.
Cancer of the pancreas is diagnosed in about 30,000 people in the United States each year. Pancreatic cancer is the fourth leading cause of cancer death in the United States. The lifetime risk of developing pancreatic cancer is about one in 79 (1.27%). The National Cancer Institute estimates that there will be 37,680 new cases of pancreatic cancer in 2008 and 34,290 deaths from pancreatic cancer in the United States.
Pancreatic cancer is approximately twice as common in Europe as in the United States. This is attributed to factors such as increased smoking in European countries. Most cases occur in people over the age of 65; however, pancreatic cancer can occur in younger people, particularly those with a family history of the disease. Unfortunately, there are often no symptoms early on, making pancreatic cancer difficult to diagnose in its beginning stages.
Adenocarcinomas, adenosquamous carcinomas, ampulla of Vater, bile, bilirubin, biopsy, chemotherapy, chronic pancreatitis, computerized tomography, CT, cystadenomas, diabetes, distal pancreatectomy, duodenum, endocrine pancreatic tumor, endoscopic retrograde cholangiopancreatiography, endoscopic ultrasound, ERCP, EUS, exocrine pancreatic tumor, gastrin, gastrinomas, giant cell carcinomas, glucagon, glucagonomas, H. pylori, Helicobacter pylori, islet cell carcinomas, jaundice, laproscopy, magnetic resonance imaging, malignant, metastasis, MRI, neuroendocrine tumors, pancreatic enzyme, pancreatoduodenectomy, percutaneous transhepatic cholangiography, PTC, radiation therapy, respectable, somatostatin, somatostatinomas, squamous cell carcinomas, total pancreatectomy, Trousseau sign. ultrasound, vasoactive intestinal peptide, VIP, VIPomas, Whipple procedure.
types of pancreatic tumors
The tumors formed by the exocrine
cells and endocrine
cells are very different. Exocrine and endocrine cancers have distinct risk factors and causes, have different signs and symptoms, are diagnosed using different tests, are treated in different ways, and have different prognoses.
Exocrine tumors: As most of the cells in the pancreas are exocrine glands and ducts, exocrine tumors
are the most common type of pancreatic cancer. Benign or non-cancerous exocrine cysts and tumors are called cystadenomas. Unfortunately, most pancreatic exocrine tumors are malignant or cancerous.
About 95% of cancers of the exocrine pancreas originate in glandular tissues and are called adenocarcinomas. Acinar cell carcinomas develop from the cells that make the pancreatic enzymes.
Ductal cancers are less common and include adenosquamous carcinomas, squamous cell carcinomas, and giant cell carcinomas. Ductal cancers are only distinguishable under a microscope.
As there are far fewer endocrine cells in the pancreas, endocrine tumors are much less common (one per 100,000). Endrocrine tumors are often grouped as neuroendocrine tumors or islet cell tumors. The subtypes of islet cell tumors are named according to the type of hormone-making cell from which they originate. They include: insulinomas, which come from cells that make insulin; glucagonomas, which come from cells that make glucagon; gastrinomas, which come from cells that make gastrin; somatostatinomas, which come from cells that make somatostatin; and VIPomas, which come from cells that make vasoactive intestinal peptide (VIP).
The tumors may be classified as functioning if they make hormones or non-functioning if they do not. Functioning islet cell tumors are usually harmless but non-functioning tumors are typically cancerous. The cancerous tumors are called islet cell cancers or islet cell carcinomas.