ISGACA, the international study group on non-pancreatic peri-ampullary cancer.
Periampullary cancer is a widely used term to define a heterogeneous group of neoplasms in and around the Ampulla of Vater, the structure from the confluence of the common bile duct and the pancreatic duct to its protrusion into the duodenum. Pancreatic ductal adenocarcinoma (PDAC) is the most frequently diagnosed periampullary cancer and also has the worst prognosis with 5-year overall survival of 5-22% after surgical resection. Other peri-ampullary tumors are ampullary adenocarcinoma and duodenum adenocarcinoma and distal cholangiocarcinoma which are commonly classified as non-pancreatic peri-ampullary (NPPC) tumors. Despite anatomic similarities, there are fundamental and biological differences between the NPPC subgroups what is associated with a variety of reported 5-year survival, ranging between 30% to 70% for ampullary cancer, 18% to 40% for distal cholangiocarcinoma, and 46% to 71% for duodenal cancer.
In more detail, the ampullary adenocarcinoma can be divided in subtypes. Using immuno-phenotyping, it is shown that the ampullary adenocarcinoma can be classified in three main histopathological subtypes, the intestinal (IT), pancreaticobiliary (PB) and the mixed subtype (m). The intestinal subtype shows histological similarities with intestinal cancer, the pancreaticobiliary subtype shows histological similarities with the distal bile duct and distal pancreatic duct epithelia and the mixed subtype is a combination of the IT and PB type.
Compared with other peri-ampullary cancers, ampullary adenocarcinoma and distal cholangiocarcinoma often present at an earlier time point, due to early biliary obstruction and therefore earlier symptoms of the disease. Therefore, these subtypes are more amendable to resection at the time of diagnosis. Resection rates of ampullary tumors are reportedly higher compared with other peri-ampullary cancers (50% vs 10%). Moreover, patients with AAC have a better prognosis with 5-year survival rates varying from 30% to 70% after resection. Despite this more favorable profile, the majority of patients with AAC will eventually succumb to recurrent disease.
As there is still a lack of knowledge regarding the diagnosis, definitions and treatment of non-pancreatic peri-ampullary adenocarcinoma and therefore, we proposed to form an International Study Group with the aim of improving outcomes by working on standardising the diagnosis and treatment of non-pancreatic peri-ampullary adenocarcinoma, with a special interests on the classification of the subtypes in comparison with other peri-ampullary tumors, possible treatment strategies, and future RCTs in the field.
In this group, we will have renowned surgeons and a representations from renowned oncologists and gastroenterologists word wide. Only with the collaboration of all the experts in the field, both surgeons and oncologist, we can find answers for these rare but aggressive types of cancer.