In about 46,000 people per year in the U.S., pancreatic cancer will arise, grow, and spread, often before it's ever discovered. As with many types of cancer, the causes of pancreatic cancer are mysterious. Although certain risk factors have been identified, the story is far from complete.
Pancreatic cancer develops when a cell in the pancreas acquires damage to its DNA that causes it to behave and multiply abnormally. A single cancer cell grows and divides rapidly, becoming a tumor that does not respect normal boundaries in the body. Eventually, cells from the tumor travel elsewhere in the body (metastasize) through the blood or lymphatic system.
No one knows exactly how the process of DNA damage leading to pancreatic cancer occurs. Analyzing pancreatic cancers removed by surgery shows certain mutations that occur in nearly all cases, and others that vary between people.
Some of these mutations occur randomly. Others occur in response to things we do or experience in the environment. Some mutations may be inherited. When enough mutations accumulate, a cell becomes malignant and a tumor begins to grow.
Pancreatic Cancer Risk Factors
No one understands the underlying causes of pancreatic cancer, but certain risk factors have been identified. These factors are present more often in people who get pancreatic cancer than in people who don't.
There are multiple pancreatic risk factors, although most are only weakly associated with the disease. Many people with pancreatic cancer don't have any one specific risk factor.
About one in 76 people will develop pancreatic cancer. This represents the average risk of the condition. People with any of the risk factors are at slightly higher risk than the general population:
Genetics. Five percent to 10% of people with pancreatic cancer have an immediate family member who also had it. Several different genes have been associated with the increased risk, although no "pancreatic cancer gene" has yet been identified.
Diabetes. People with diabetes are not necessarily more likely to get pancreatic cancer but the two have been linked.
Smoking. Cigarette smoking is well known to increase the risk for pancreatic cancer. The more a person smokes, the higher the risk. Ten years after quitting smoking, the risk returns to about that of someone who never smoked.
Obesity and inactivity. In a study of 88,000 nurses, those who were obese (body mass index higher than 30) were more likely to develop pancreatic cancer. Those who exercised frequently were about half as likely to get pancreatic cancer, compared to those who did not exercise at all.
Diet. A diet high in fat and meat (especially smoked or processed meat) has been linked to pancreatic cancer in animal studies. Eating a healthy diet rich in fruits and vegetables decreased pancreatic cancer risk in other studies. Still other studies suggest there's no identifiable link between diet and pancreatic cancer.
Lycopene and selenium. Studies have shown low levels of these nutrients in some people who developed pancreatic cancer. That's not proof that low levels of lycopene and selenium cause pancreatic cancer, though. Any diet that includes lean meat and red or yellow vegetables should provide adequate lycopene and selenium.
Eliminating your risk factors for pancreatic cancer won't reduce your risk entirely. But eating a healthy diet, keeping a healthy weight, and exercising frequently will improve overall health, and reduce your risk of other health problems.