The pancreas is a small gland located in the abdomen between the stomach and the intestines. It is mainly composed of exocrine cells, which make digestive enzymes. A very small portion of the pancreas is made of endocrine (islet) cells, which make hormones such as insulin, which controls blood sugar levels.
The vast majority of pancreatic cancers start in exocrine cells found in the pancreas ducts (small channels) that carry digestive enzymes to the intestines. These cancers are often adenocarcinomas that begin in the tissue lining the pancreas, although as many as 20 different types of tumors can be found in the pancreas. As a pancreatic tumor grows, it can invade nearby organs – such as the bile duct, intestine, or stomach – or adjacent blood vessels. Tumor cells can break away and spread to the lymph nodes or liver, or elsewhere in the abdomen.
According to the National Cancer Institute, approximately 43,000 people in the United States are diagnosed with pancreatic adenocarcinoma each year. Although the tumor is relatively uncommon, it is the fourth-leading cause of cancer death in the United States. Because the disease does not cause symptoms in its early stages, this type of pancreatic cancer is usually diagnosed only after it has metastasized (spread) from the pancreas to other parts of the body.
The following factors may increase your risk of developing pancreatic cancer:
Smoking is a major risk factor for pancreatic cancer. Pancreatic adenocarcinoma is two to three times more common in heavy smokers than in nonsmokers. However, a significant number of pancreatic cancers arise in nonsmokers.
Pancreatic cancer usually occurs in people older than age 55. However, pancreatic cancer can occur in younger people as well.
African Americans are more likely to develop pancreatic cancer than white, Hispanic, or Asian Americans.
Approximately 10 percent of people with pancreatic cancer have one or more inherited genetic mutations that can also cause other diseases, including familial atypical multiple mole melanoma syndrome, familial breast cancer, Peutz-Jeghers syndrome, and hereditary pancreatitis. Mutations in the genes BRCA1 and BRCA2 – which increase the risk of breast, prostate, and certain gynecologic cancers – have been found in some families with a history of pancreatic cancer. Other inherited genetic factors have been identified, but do not greatly increase an individual’s risk of pancreatic cancer.
Many pancreatic tumors contain cells that have genetic mutations. More than 90 percent of people with pancreatic cancer have an abnormal copy of a gene called KRAS. Inactivation of genes that normally suppress tumor development, such as p16 and p53, also may lead to pancreatic cancer.
Family History of Pancreatic Cancer
An estimated 5 to 10 percent of people with pancreatic cancer have one or more family members who have had the disease. According to the National Cancer Institute, people with a strong family history of pancreatic cancer are nine times more likely to develop pancreatic cancer than others.
If you have a family history of pancreatic cancer, doctors on our Clinical Genetics Service can help assess your personal risk for the disease. Our specialists may also refer you to Memorial Sloan Kettering Cancer Center’s Familial Pancreatic Tumor Registry, a research center that is investigating the causes of pancreatic cancer in people with a family history of the disease.
Evidence suggests that people with a body mass index of 30 or greater have a higher risk of pancreatic cancer. Researchers are studying whether physical activity and a low-fat diet can lower this risk.
Having type II diabetes may increase a person’s risk of pancreatic cancer. In some people, the sudden onset of type II diabetes can be caused by pancreatic cancer.
Chronic inflammation of the pancreas, especially in people who smoke, may increase the risk of pancreatic cancer. However, most people with pancreatitis do not develop pancreatic cancer.
Exposure to carcinogens such as asbestos, pesticides, dyes, and petrochemicals may be linked to pancreatic cancer.
Advances in imaging technology have dramatically increased the number of small abnormalities that are found in the pancreas. Most of these abnormalities are identified during imaging for another condition. Many of them are benign (noncancerous), fluid-filled cysts and are unlikely to cause symptoms or shorten a person’s life. Others are precancerous and have the ability to turn into pancreatic cancer.
Researchers at Memorial Sloan Kettering are working to identify biomarkers – measurable substances such as proteins and genes – that clearly distinguish between benign and precancerous lesions. Biomarkers will also help to determine whether a precancerous lesion may become cancerous. This information could help guide treatment decisions and eliminate unnecessary removal of benign cysts. Learn more about our approach to the diagnosis and treatment of pancreatic cysts.
There are no early-warning signs for pancreatic cancer. Symptoms may be so nonspecific that they are ignored.
Some people notice the following symptoms as pancreatic cancer evolves:
- severe pain in the upper abdomen and back
- nausea, vomiting, and unintended weight loss
- burning feeling in the stomach
- inability to digest fatty foods, which can result in large, greasy stools
- jaundice (a yellowing of the skin or whites of the eyes) and itchiness, which can be caused when a tumor blocks the common bile duct
Many of these symptoms can also be caused by other health problems that are more common than pancreatic cancer. For example, hepatitis, gallstones, and other liver problems can block the bile duct and are much more typical causes of jaundice. Tell your doctor if you have any of these symptoms to ensure proper diagnosis and treatment.
Other signs of pancreatic cancer, such as an enlarged gallbladder or the sudden onset of type II diabetes, may be detected by a physician during a medical examination – even if there are no other noticeable symptoms.