Epidemiology and prevention of pancreatic cancer.

Pancreatic cancer is an uncommon tumor, but because the mortality rate approaches 100%, this form of cancer has now become a common cause of cancer mortality. In the United States it is the fourth most frequent cause of cancer mortality; in Japan it ranks as the fifth commonest cause of death from cancer. Smoking is the major known risk factor for pancreatic cancer, accounting for approximately 25-30% of all cases. Some of the time-dependent changes in the frequency of pancreatic cancer can be explained by smoking trends. Aggressive public health measures to control smoking would substantially reduce the burden of pancreatic cancer. Dietary factors are less important for pancreatic cancer than for other digestive tract tumors, but consumption of a diet with adequate quantities of fruits and vegetables, plus control of calories either by dietary measures or by exercise will help to prevent this lethal tumor. There are more than a dozen inherited germline mutations that increase the risk of pancreatic cancer. Of these, hereditary pancreatitis confers the greatest risk, while BRCA2 mutations are the commonest inherited disorder. In addition to germline defects, there are several common polymorphisms in genes that control detoxification of environmental carcinogens that may alter the risk of pancreatic cancer. More research will be needed in this area, to explain and to clarify the interaction between genes and environmental factors.