The gallbladder is a small pouch that stores and concentrates the bile that is made by the liver. When bile is needed (i.e. when people eat) the gallbladder contracts and bile from the liver passes down the bile ducts into the small intestine where it aids with the digestion of fats. There are several types of gallbladder cancers, named after the type of cell it affects. Gallbladder cancer begins in the mucosal inner layer of the gallbladder and spreads through the outer layers. More than 85% of gallbladder cancer types are adenocarcinomas that start in the gland cells lining the gall bladder. The role of the gland cells is to produce mucous, a thick fluid that coats the lining of the gallbladder tissue.
Bile Duct Cancer (also known as cholangiocarcinoma)
Bile ducts are tubes that transport the bile produced by the liver into the small intestine. There are two bile ducts that come from the liver and one from the gallbladder. These tubes connect to form the common bile duct that connects to the small intestine. When food is being digested, bile stored in the gall bladder is released and passed through the bile ducts into the small intestine. Cholagiocarcinoma can form anywhere along the bile ducts and each sub-type of biliary tract cancer is named after the location where the primary cancer begins. Intrahepatic cancers begin inside the bile duct in the liver. Extrahepatic cancers begin from bile ducts outside the liver. Half of bile duct cancers are Klatskin tumours, which form where the right hepatic duct joins with the left hepatic duct in the liver. Cancers that begin in the common bile duct are called common bile duct cancers. If there are multiple tumours present in different areas of the bile duct this is called multifocal bile duct cancer.
Ampullary cancer develops in the ampulla of Vater, where bile ducts from the liver and pancreas join and enter the duodenum.
Duodenal cancer develops in the duodenum, the first and shortest part of the small bowel (e.g. small intestine), between the stomach and jejunum.
The gallbladder is lined by the same type of cells that line the bile ducts, and gallbladder cancer is therefore similar to bile duct cancer. Despite being most common in patients over the age of 60, both gallbladder cancer and cholangiocarcinoma is diagnosed in an increasing number of 45-60-year-olds. Gallbladder cancer usually occurs in people who have gallstones. Chronic inflammation of the bile ducts (primary sclerosing cholangitis) predisposes a person to bile duct cancer, but it can also occur in the absence of this condition. Gallbladder cancer does not usually cause symptoms until it becomes more advanced. However, it may be discovered at an earlier stage due to pain from the gallstones. Gallbladder cancer is sometimes diagnosed unexpectedly when the gallbladder has been removed to treat gallstones. It’s important to note that gallstones are a very common condition and that the majority of people with gallstones do not develop gallbladder cancer. Bile duct cancers often cause jaundice (a yellowing of the skin and eyes) due to obstruction to the flow of bile out of the liver. Radiology tests, such as a CT scan or an MRI, are done to help diagnose and stage the cancer and determine the best treatment options.
The main treatment for gall bladder and bile duct cancer is surgery. This is only suitable if the cancer has not spread. Other treatments such as chemotherapy and radiotherapy may be used, and blockages of the bile duct can usually be alleviated with stents (a plastic or metal tube inserted through the blocked section). The prognosis depends on the stage and whether or not it is possible to remove the cancer with surgery. In the best circumstances, cure is possible. If cure is not possible, the symptoms caused by the cancer can often be alleviated
Some known risk factors for the different types of biliary cancers are:
Primary sclerosing cholangitis
Family history of gallbladder cancer
Inflammation of the gallbladder, gallstones or gallbladder polyps
Abnormalities of the pancreas and bile duct
Smoking and excessive alcohol
Primary sclerosing cholangitis
Liver fluke infection
Bile duct stones
Hepatitis B or C virus infection
Familial adenomatous polyposis