Diagnostic Tests:
       Laboratory Tests

 Laboratory tests of the blood may aid in the diagnosis of both cancers. The most important one is the test for elevated bilirubin levels in the bloodstream. Elevated levels of other enzymes may also point to obstruction of the biliary tract.

Carcinoma of the bile duct produces certain compounds that can be detected in the bloodstream. These tumor markers, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9), are especially useful in diagnosing carcinoma of the bile duct associated with primary sclerosing cholangitis.

        Imaging Tests

When symptoms, physical signs, and blood tests are concerning for an abnormality of the biliary tract, the next step involves imaging tests. The tests useful for carcinoma of the gallbladder and bile duct are similar. The objective is to determine the size and location of the tumor, as well as the extent of spread to nearby structures.  

Noninvasive tests can supply much anatomic information in rapid fashion. Both ultrasound and computed tomography (CT) can detect the actual tumor and the extent to which it has spread. Dilatation of the gallbladder or bile ducts can be seen. CT adds the ability to detect enlarged lymph nodes throughout the abdominal cavity. Magnetic resonance imaging (MRI) has also been used to determine the involvement of bile ducts and blood vessels.

If these tests indicate the presence of a tumor, then cholangiography usually follows. This procedure involves injecting dye into the biliary tract to obtain anatomic images of the bile ducts and the tumor. The biliary tract is accessed directly through the skin or endoscopically (through the intestine via the mouth.) The specialist that performs this test can obtain samples of cells from the tumor to allow diagnosis under the microscope. Small tubes, or stents, can be placed into a partially obstructed portion of the bile duct to prevent further obstruction by growth of the tumor. This is vitally important since it may be the only intervention that is possible in certain patients. Cholangiography is an invasive test that carries a small risk of infection of the biliary tract.

Angiography can determine if the tumor has spread to blood vessels. This is especially crucial in planning surgical resection of the tumor. If certain blood vessels are encased with tumor, surgical resection may not be possible.

If samples of cells are not obtained by cholangiography, they can be aspirated directly from the tumor under guidance of ultrasound or CT. The treatment of bile duct tumors is usually not affected by the specific type of cancer cells that comprise the tumor. For this reason, some physicians forego biopsy.