Cancer of the pancreas is diagnosed in more than 37,000 people in the United States each year. Most cases occur in people over the age of 55. 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.
The Pancreas
The pancreas is a gland that serves two basic functions: It produces secretions that help digest food and it produces hormones (one of which is insulin) that regulate how food is stored and used. The pancreas is located in the abdomen and is surrounded by the stomach and intestines. It is about six inches long, wide at the head, and narrow at the tail. Most pancreatic cancers begin in the head of the pancreas, in the ducts that carry the digestive juices.
Types of Pancreatic Cancer
The bulk of pancreatic cells are devoted to producing digestive enzymes, and it is in those cells (the exocrine cells) that 95 percent of pancreatic cancers start. About 5 percent of pancreatic cancers start in the cells that produce hormones (the endocrine cells, or islet cells). This overview focuses on cancers of the exocrine pancreas.
As many as 20 distinct types of tumors are classified under the term “pancreatic cancer,” each with varying responses to treatment. Most pancreatic tumors are adenocarcinomas (malignant tumors whose cells are arranged in a gland-like pattern). As a tumor grows in the pancreas, it may begin to invade nearby organs such as the stomach and intestines. Tumor cells can break away and spread to the lymph nodes, the liver, and sometimes the nerves and blood vessels. Most pancreatic cancers have spread beyond the pancreas at diagnosis.
In most cases, pancreatic cancer is diagnosed when it is advanced and very difficult to treat. However, coordinated care by a multidisciplinary team of clinician-researchers with experience in treating pancreatic cancer and its related symptoms can help ensure quality of life for longer periods than has been possible in the past.
Risk Factors
Smoking is generally accepted as a major risk factor for cancer of the pancreas. Adenocarcinomas — the glandular-cell growths that account for about 95 percent of pancreatic tumors — are two to three times more common in heavy smokers than in nonsmokers.
Genetic alterations involved in pancreatic cancer include activation of the Kras oncogene and inactivation of tumor-suppressor genes such as p16 and p53. Pancreatic cancer has the highest frequency of Kras mutations among all human cancers. This frequency of Kras mutations, which are also linked to bladder and lung cancers, may be associated with smoking.
Other possible risk factors include the following:
- Family History An estimated 7 to 10 percent of patients with pancreatic cancer have a family history of the disease. A few hereditary syndromes, including familial atypical multiple mole melanoma syndrome, familial breast cancer, Peutz-Jeghers syndrome, and hereditary pancreatitis, account for a small percentage of pancreatic cancer cases. Mutations in the breast cancer-susceptibility genes BRCA1 and BRCA2 have been found in some families with familial pancreatic cancer.
- Obesity Research has suggested that obesity (defined as having a body mass index of 30 or greater) is associated with a higher risk of pancreatic cancer. Additional studies are investigating whether physical inactivity and a diet high in meat and fats also may increase the risk of developing this disease.
- Advancing age Nearly 90 percent of patients diagnosed with pancreatic cancer are over age 55. The disease can occur in younger people, and those with early-onset pancreatic cancer may not necessarily have a family history of the disease.
- No Allergies Several studies have found that the risk of developing pancreatic cancer is lower in people with certain types of allergies, particularly hay fever and atopic dermatitis.
- Male Gender More men than women are diagnosed with pancreatic cancer.
- Race African-Americans are more likely to develop pancreatic cancer than Hispanics, Asian-Americans, or white Americans, and currently have the highest pancreatic cancer rates in the world.
- Diabetes There may be an association between pancreatic cancer and diabetes, although it has not been proven. Chronic pancreatitis has also been associated with pancreatic cancer, but the exact nature of the association is still under study.
- Environmental Factors Occupational exposure to carcinogens (such as asbestos, pesticides, dyes, and petrochemicals) has been associated with pancreatic cancer.
- Pancreatic Cysts Intraductal papillary mucinous neoplasm (IPMN), a type of pancreatic cyst, is thought to be a common precursor to pancreatic cancer.
Investigating Risk Factors
Memorial Sloan-Kettering Cancer Center established a Familial Pancreatic Cancer Registry in 2002 to learn more about what causes some people to be at increased risk for pancreatic cancer, and to develop better screening tools for high-risk individuals. The registry enrolls the first-degree relatives (parent, sibling, or child) of patients who were diagnosed with pancreatic cancer before age 50. It also includes people thought to be at high risk for the disease based on its diagnosis in multiple first- or second-degree relatives, as well as people with BRCA1 or BRCA2 mutations who also have a family history of pancreatic cancer.
Participants who are considered at high risk are screened yearly using MRI to look for lesions that can develop into tumors, including intraductal papillary mucinous neoplasms (IPMN). If lesions are detected, physicians can follow up with more extensive testing through endoscopic ultrasound or traditional (fine-needle aspiration) biopsy. If cancer is found, surgery may be recommended to remove part or all of the pancreas.
In addition to the registry, Memorial Sloan-Kettering epidemiologists are investigating risk factors for pancreatic cancer in patients and their family members and collecting DNA in an effort to identify genetic markers for the disease in relatives of patients with the disease.
Symptoms
There are no established early-warning signs for pancreatic cancer. Symptoms often do not appear until the tumor grows large enough to interfere with the function of the stomach, liver, or other nearby organs.
When symptoms occur, they are often so vague and nonspecific that they may be ignored. The first symptoms are typically pain (sometimes severe pain in the upper abdomen that can penetrate to the back) and weight loss. Because about 80 percent of pancreatic cancers occur in the head of the pancreas, where they can block the common bile duct, jaundice (a yellowing of the skin or whites of the eyes, often with general itchiness) is another frequent sign. Hepatitis and gallstones, however, can also obstruct the common bile duct and are much more common causes of jaundice.
Nausea, loss of appetite, unintended weight loss, pain in the upper or middle abdomen, and jaundice may be caused by other problems that are far less serious than pancreatic cancer. The appearance of any of these signs, however, warrants a medical examination.
Related Cancer & Treatment Information
Recommended Links
