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).
This is a major operation which involves removing the pancreatic head and the curve of the duodenum together ("pancreato-duodenectomy"), making a bypass for food from the stomach to the jejunum ("gastro-jejunostomy") and attaching a loop of jejunum to the cystic duct to drain bile ("cholecysto-jejunostomy"). It can be performed only if the person is likely to survive major surgery and if the cancer is localized without invading local structures or metastasizing. It can, therefore, be performed only in a minority of cases. Cancers of the tail of the pancreas can be resected using a procedure known as a distal pancreatectomy, which often also entails removal of the spleen. Nowadays, this can often be done using minimally invasive surgery.Although curative surgery no longer entails the very high death rates that occurred until the 1980s, a high proportion of people (about 30–45%) still have to be treated for a post-operative sickness that is not caused by the cancer itself. The most common complication of surgery is difficulty in emptying the stomach. Certain more limited surgical procedures may also be used to ease symptoms (see Palliative care): for instance, if the cancer is invading or compressing the duodenum or colon. In such cases, bypass surgery might overcome the obstruction and improve quality of life but is not intended as a cure. Chemotherapy
After surgery, adjuvant chemotherapy with gemcitabine or 5-FU can be offered if the person is sufficiently fit, after a recovery period of one to two months.