Early operations were compromised partly because of mistaken beliefs that people would die if their duodenum were removed, and also, at first, if the flow of pancreatic juices stopped. Later it was thought, also mistakenly, that the pancreatic duct could simply be tied up without serious adverse effects; in fact, it will very often leak later on. In 1907–1908, after some more unsuccessful operations by other surgeons, experimental procedures were tried on corpses by French surgeons.In 1912 the German surgeon Walther Kausch was the first to remove large parts of the duodenum and pancreas together (en bloc). This was in Breslau, now Wrocław, in Poland. In 1918 it was demonstrated, in operations on dogs, that it is possible to survive even after complete removal of the duodenum, but no such result was reported in human surgery until 1935, when the American surgeon Allen Oldfather Whipple published the results of a series of three operations at Columbia Presbyterian Hospital in New York. Only one of the patients had the duodenum entirely removed, but he survived for two years before dying of metastasis to the liver. The first operation was unplanned, as cancer was only discovered in the operating theater. Whipples success showed the way for the future, but the operation remained a difficult and dangerous one until recent decades.
The disease occurs most often in the developed world, where about 70% of the new cases in 2012 originated. Pancreatic adenocarcinoma typically has a very poor prognosis; after diagnosis, 25% of people survive one year and 5% live for five years. For cancers diagnosed early, the five-year survival rate rises to about 20%. Neuroendocrine cancers have better outcomes; at five years from diagnosis, 65% of those diagnosed are living, though survival considerably varies depending on the type of tumor. Types
The many types of pancreatic cancer can be divided into two general groups. The vast majority of cases (about 95%) occur in the part of the pancreas that produces digestive enzymes, known as the exocrine component. Several subtypes of exocrine pancreatic cancers are described, but their diagnosis and treatment have much in common. The small minority of cancers that arise in the hormone-producing (endocrine) tissue of the pancreas have different clinical characteristics and are called pancreatic neuroendocrine tumors, sometimes abbreviated as "PanNETs". Both groups occur mainly (but not exclusively) in people over 40, and are slightly more common in men, but some rare subtypes mainly occur in women or children. Exocrine cancers
The exocrine group is dominated by pancreatic adenocarcinoma (variations of this name may add "invasive" and "ductal"), which is by far the most common type, representing about 85% of all pancreatic cancers. Nearly all these start in the ducts of the pancreas, as pancreatic ductal adenocarcinoma (PDAC).