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Every year some 34,200 people die from pancreatic cancer, making it the fourth leading cause of cancer death in the United States.
What is the Pancreas?
The pancreas is a glandular organ in the digestive and endocrine system which is responsible for producing many important hormones such as insulin, somatostatin (growth hormone inhibiting hormone) and glucagen (important for carbohydrate metabolism).
As an exocrine gland (secretes hormones into ducts), the pancreas excretes juices which contain digestive proteins that pass into portions of the small intestine and breakdown carbohydrates, fats and proteins in the chyme (half-digested food).
What is Pancreatic Cancer?
The endocrine and exocrine glands of the pancreas form different types of tumors:
The most common type of pancreatic cancer. Cystadenomas are benign (non-cancerous) cysts and tumors, however, most types of exocrine tumors are cancerous. Around 95% of the cancer of the exocrine gland in the pancreas are cancerous. Cancers which develop from the cells that release pancreatic enzymes are called acinar cell carcinomas. The less common forms of ductal cancers of the exocrine pancreas include the following; adenosquamous carcinomas, squamous cell carcinomas and giant cell carcinomas. The type of cancer presenting can only be distinguished by examination under a microscope. A less common form of cancer in the pancreas is called ampullary cancer or cancer of the ampulla of Vater. The location where the bile duct and pancreatic duct joins, and empties into the duodenum is called the ampulla of Vater.
While uncommon, tumors of the endocrine gland can happen. Tumors of the endocrine gland as a group are called neuroendocrine tumors or islet cell tumors. There are several subtypes of islet cell tumors and each is named according to the type of hormone cell from which it originates. This includes the following:
- Insulinomas: originate in insulin making cells
- Glucagonomas: come from cells that make glucagon
- Gastrinomas: happen in cells that manufacture gastrin
- Somatostatinomas: occur in cells that make somatostatin
- VIPomas: occur from cells that produce vasoactive intestinal peptides (VIP)
Endocrine tumors are referred to as “functioning,” if they make hormones, and “non-functioning” if they do not. For the most part, functioning islet cell tumors are usually benign, while non-functioning tumors are likely to be malignant. Malignant pancreatic endocrine tumors are called islet cell cancers or islet cell carcinomas.
What are the Risk Factors Associated with Pancreatic Cancer?
Each type of cancer has its own risk factors, which means a person has an increased risk of getting the disease. Researches have determined that there are many risk factors associated with a persons chance of developing pancreatic cancer, which include the following:
- Age increases a persons likelihood of developing pancreatic cancer. Most patients diagnosed are around the age of 45, 90% are over the age of 50 and 70% are older than 70 years old. The median age for diagnosis is 72 years old.
- Males are more likely to develop pancreatic cancer than females, this may be a result of males having higher rates of tobacco use.
- African Americans are more prone to developing pancreatic cancer than Caucasians. The reasons for the increase of risk factors in race are unknown, but researchers speculate it could be because of higher rates of tobacco use and diabetes in males and the higher obesity rate among females.
- People who smoke cigarettes are 2-3 times more likely to develop pancreatic cancer, and scientists attribute this to the cancer-causing chemicals found in cigarettes. Around 20-30% of pancreatic cancer diagnosed are believed to be caused directly by cigarette smoking.
- Obese people are more likely to develop pancreatic cancer and the increased risk is also associated with people who do not get enough exercise.
- The risk of pancreatic cancer increases in people with diabetes, however, the reason is unknown. The risk factors increase with people who have type II diabetes, in some cases pancreatic cancer can actually cause people to get diabetes.
- People who have cirrhosis (scarring of the liver due to drinking or hepatitis) have a higher risk of developing pancreatic cancer.
- Pancreatic cancer does have the propensity to run in families, some people at high risk have what is called genetic syndromes (caused by abnormality of the genes or chromosomes), in some cases the gene which causes the increased risk is unknown.
- Having chronic stomach infections caused by Helicobacter pylori (H. pylori) also increases the risk of developing pancreatic cancer. It is thought that the increase of stomach acid is the culprit.
- Some scientific studies have found a definitive link between a diet high in fat and an increased risk of pancreatic cancer. On the other end of the spectrum, diets higher in fruits and vegetables seem to lower the risk factors for pancreatic cancer. Ongoing research is being done to find the exact role that diet plays in relation to pancreatic cancer.
- Occupational exposure to certain types of pesticides, chemicals and dyes used in metal refineries has been associated with an increased risk of developing pancreatic cancer.
- Heavy alcohol use can raise the risk of developing diabetes and chronic pancreatitis, which are factors that relate directly to the development of pancreatic cancer.
What Causes Pancreatic Cancer?
While scientists have not identified the exact cause of pancreatic cancer, several risk factors have been discovered, and these factors increase the chance of a person developing the disease. Recent scientific research has uncovered some of the risk factors involved can affect the deoxyribonucleic acid (DNA) in pancreatic cells which in turn causes abnormal cellular growth and results in tumors.
Science has also discovered several cancer family syndromes in inherited DNA, which puts a person at higher risk. Most commonly, DNA mutations of tumor suppressor genes related to the formation of pancreatic cancer occur after birth, not because of something inherited.