Most extrahepatic malignancies of the bile duct arise at the union of the right and left hepatic ducts (hilar cholangiocarcinoma); a smaller number arise in the distal bile duct (periampullary malignancy) or mid bile duct.
History
Presenting Complaint
Jaundice is the most common presenting feature, usually painless unless cholangitis has developed (20%). This is in contrast to intrahepatic cholangiocarcinoma which may also present with jaundice but is often found incidentally. Advanced cases will develop symptoms of weight loss, anorexia and those related to metastatic sites.
Past History
Sclerosing cholangitis and ulcerative colitis are significant risk factors for the development of the disease. Exposure to Thoratrast was a risk factor historically. Unlike gallbladder malignancy, choledocholithiasis is not an important risk factor.
In Asia, chronic infection with liver flukes promotes inflammatory reactions within the biliary tree and predisposes to carcinoma of both intra- and extra-hepatic bile ducts.
Social History
Occupation exposure may play a role, particularly exposure to the usual suspects (dioxin, asbestos, nitrosamines).
Examination
Examination may be unremarkable aside from jaundice, or may demonstrate hepatomegaly. Advanced cases with liver failure may have the usual signs (ascites, splenomegaly, bruising).
Imaging
Ultrasound may show dilated intrahepatic bile ducts and is particularly useful at assessing the level of obstruction. Proximal tumours may only show dilated intrahepatic ducts; distal tumours cause dilatation of the entire biliary tree and gallbladder. CT provides improved detail as to the extent of local and nodal (and metastatic) disease but may be normal aside from the dilated duct system; MRI suffers from similar problems. MRCP may allow for the best delineation of the biliary tree and identification of tumour level.
ERCP is frequently used for:
- Identification of the level of the stricture
- Biopsy
- Placement of palliative stent
Placement of stent is a controversial topic - although it provides palliation, it has also been shown to cause infection and delay discharge from hospital. If patients have impending hepatic failure, placement of the stent allows for effective palliation and should be performed.
Histological Diagnosis
Diagnosis may be difficult without ERCP as identifying the tumour mass can be difficult.
Staging
Staging is through the TNM system. There are separate systems for proximal and distal bile duct tumours.
Proximal Bile Duct
T Stage
T1: Confined to bile duct
T2a: Invades fat outside bile duct
T2b: Invades liver outside bile duct
T3: Invades either right or left hepatic artery / portal vein
T4: Invades both right and left hepatic artery / portal vein, or either whole vessel, or second-order biliary radicals bilaterally
N Stage
N1: Involvement of adjacent regional nodes (porta hepatis)
Distal Bile Duct
T Stage
T1: Confined to bile duct
T2: Outside bile duct but not adjacent organs
T3: Invades adjacent organs but not coeliac axis or SMA
T4: Involves coeliac axis or SMA
N Stage
N1: Regional node involvement (common hepatic artery, portal vein, pancreatoduodenal, coeliac and SMA nodes)
Overall Stage
Stage | T | N | M |
---|---|---|---|
IA | T1 | N0 | M0 |
IB | T2 | N0 | M0 |
IIA | T3 | N0 | M0 |
IIB | T1-3 | N1 | M0 |
III | T4 | Nany | M0 |
IV | Tany | Nany | M1 |
Stage I and II are resectable disease; Stage III is unresectable and Stage IV is metastatic. Most patients with perihilar disease have stage III disease, whereas the stage is usually lower for distal bile duct disease.