The disease is more common in men than women, though the difference in rates has narrowed over recent decades, probably reflecting earlier increases in female smoking. In the United States the risk for African Americans is over 50% greater than for whites, but the rates in Africa and East Asia are much lower than those in North America or Europe. The United States, Central, and eastern Europe, and Argentina and Uruguay all have high rates. PanNETs
The annual incidence of clinically recognized PanNETs is low (about 5 per one million person-years) and is dominated by the non-functioning types. Somewhere between 45% and 90% of PanNETs are thought to be of the non-functioning types. Studies of autopsies have uncovered small PanNETs rather frequently, suggesting that the prevalence of tumors that remain inert and asymptomatic may be relatively high. Overall PanNETs are thought to account for about 1 to 2% of all pancreatic tumors. The definition and classification of PanNETs has changed over time, affecting what is known about their epidemiology and clinical relevance. History
Recognition and diagnosis
The earliest recognition of pancreatic cancer has been attributed to the 18th-century Italian scientist Giovanni Battista Morgagni, the historical father of modern-day anatomic pathology, who claimed to have traced several cases of cancer in the pancreas. Many 18th and 19th-century physicians were skeptical about the existence of the disease, given the similar appearance of pancreatitis.
If these lesions become large, cause symptoms, or have suspicious features, they can usually be successfully removed by surgery.A fourth type of cancer that arises in the pancreas is the intraductal tubulopapillary neoplasm. This type was recognised by the WHO in 2010 and constitutes about 1–3% of all pancreatic neoplasms. Mean age at diagnosis is 61 years (range 35–78 years). About 50% of these lesions become invasive. Diagnosis depends on histology, as these lesions are very difficult to differentiate from other lesions on either clinical or radiological grounds. Invasive cancer
The genetic events found in ductal adenocarcinoma have been well characterized, and complete exome sequencing has been done for the common types of tumor. Four genes have each been found to be mutated in the majority of adenocarcinomas: KRAS (in 95% of cases), CDKN2A (also in 95%), TP53 (75%), and SMAD4 (55%). The last of these is especially associated with a poor prognosis. SWI/SNF mutations/deletions occur in about 10–15% of the adenocarcinomas. The genetic alterations in several other types of pancreatic cancer and precancerous lesions have also been researched. Transcriptomics analyses and mRNA sequencing for the common forms of pancreatic cancer have found that 75% of human genes are expressed in the tumors, with some 200 genes more specifically expressed in pancreatic cancer as compared to other tumor types. PanNETs
The genes often found mutated in PanNETs are different from those in exocrine pancreatic cancer. For example, KRAS mutation is normally absent.