Causes of Gall Bladder Cancer

Your gallbladder is a small, pear-shaped organ on the right side of your abdomen, just beneath your liver. Its main function is to store bile, a bitter, yellow-green fluid that's produced in the liver cells. Bile is essential for the proper digestion of fats and is one of the main ways your body eliminates drugs, cholesterol and waste products of metabolism. It flows from your liver through a thin tube called the common hepatic duct and enters your gallbladder through another small tube (cystic duct).

When you eat, your gallbladder releases a highly concentrated form of bile into the common bile duct, a continuation of the hepatic and cystic ducts. The bile flows through this duct to the upper part of your small intestine (duodenum), where it begins to break down the fat in your food.

How gallbladder cancer begins?
Healthy cells grow and divide in an orderly way — a process that's controlled by DNA, the genetic material that contains the instructions for every chemical process in your body. When DNA is damaged, changes occur in these instructions. One result is that cells may begin to grow out of control and eventually form a malignant tumor — a mass of cancerous cells.

Although the exact cause of gallbladder and bile duct cancers isn't clear, researchers believe that DNA in the cells of your biliary tract may be damaged by toxins that are routinely metabolized by your liver. These toxins are released into bile so that they can be eliminated from your body. But if bile empties more slowly than normal, it increases the amount of time your cells are exposed to cancer-causing substances (carcinogens).

Most gallbladder tumors develop in the cells that line the inner surface of the gallbladder. These tumors are most commonly adenocarcinomas — a term that describes the way the cancer cells look when viewed under a microscope.

Gallbladder adenocarcinoma is highly invasive and can quickly penetrate deep into the gallbladder wall, moving through layers of tissue from the inner surface to the outside of the gallbladder. Eventually the cancer may spread to nearby lymph nodes, obstruct the bile duct or invade other organs such as the liver. Cancer cells may also travel through the bloodstream to more remote parts of the body.

Bile duct cancer (cholangiocarcinoma)
Cancer can develop in any part of the bile duct that stretches from your liver to your small intestine. Many tumors occur in the hepatic duct just as it leaves the liver (perihilar tumors). Other tumors may develop in the bile duct near your small intestine (distal tumors) or inside the liver itself (intrahepatic tumors).

The majority of bile duct cancers are adenocarcinomas that originate in the mucous glands lining the inside of the ducts. By the time these cancers are diagnosed, they often have spread to other tissues and organs.