About 25% of cases are linked to smoking, and 5–10% are linked to inherited genes. Pancreatic cancer is usually diagnosed by a combination of medical imaging techniques such as ultrasound or computed tomography, blood tests, and examination of tissue samples (biopsy). The disease is divided into stages, from early (stage I) to late (stage IV). Screening the general population has not been found to be effective.The risk of developing pancreatic cancer is lower among nonsmokers, and people who maintain a healthy weight and limit their consumption of red or processed meat; however, the risk is greater for men, especially at very high levels of red meat consumption. Smokers chances of developing the disease decrease if they stop smoking and almost return to that of the rest of the population after 20 years. Pancreatic cancer can be treated with surgery, radiotherapy, chemotherapy, palliative care, or a combination of these. Treatment options are partly based on the cancer stage. Surgery is the only treatment that can cure pancreatic adenocarcinoma, and may also be done to improve quality of life without the potential for cure. Pain management and medications to improve digestion are sometimes needed. Early palliative care is recommended even for those receiving treatment that aims for a cure.In 2015, pancreatic cancers of all types resulted in 411,600 deaths globally. Pancreatic cancer is the fifth-most-common cause of death from cancer in the United Kingdom, and the third most-common in the United States.
Pathophysiology
Precancer
Exocrine cancers are thought to arise from several types of precancerous lesions within the pancreas, but these lesions do not always progress to cancer, and the increased numbers detected as a byproduct of the increasing use of CT scans for other reasons are not all treated. Apart from pancreatic serous cystadenomas, which are almost always benign, four types of precancerous lesion are recognized. The first is pancreatic intraepithelial neoplasia (PanIN). These lesions are microscopic abnormalities in the pancreas and are often found in autopsies of people with no diagnosed cancer. These lesions may progress from low to high grade and then to a tumor. More than 90% of cases at all grades carry a faulty KRAS gene, while in grades 2 and 3, damage to three further genes – CDKN2A (p16), p53, and SMAD4 – are increasingly often found.A second type is the intraductal papillary mucinous neoplasm (IPMN). These are macroscopic lesions, which are found in about 2% of all adults. This rate rises to about 10% by age 70. These lesions have about a 25% risk of developing into invasive cancer. They may have KRAS gene mutations (40–65% of cases) and in the GNAS Gs alpha subunit and RNF43, affecting the Wnt signaling pathway. Even if removed surgically,  a considerably increased risk remains of pancreatic cancer developing subsequently.The third type, pancreatic mucinous cystic neoplasm (MCN), mainly occurs in women, and may remain benign or progress to cancer.