Staging Perihilar (Hilar or Klatskin Tumor) Cholangiocarcinoma

Perihilar (also called hilar) cholangiocarcinomas develop at the hilum, where the hepatic ducts have joined and are just leaving the liver. They are also called Klatskin tumors. These are the most common type of bile duct cancer, making up 6 or 7 of every 10  cholangiocarcinomas. These cancers are grouped with distal bile duct cancers as extrahepatic bile duct cancers.

After a person is diagnosed with perihilar (hilar) bile duct cancer, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes how much cancer is in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use a cancer's stage when talking about survival statistics.

The earliest stage perihilar bile duct cancers are stage 0, also called carcinoma in situ (CIS) or high-grade biliary intraepithelial neoplasia. Stages then range from stages I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter means a lower stage.

Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.

How is the stage determined?

The staging system most often used for perihilar bile duct cancer is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information:

  • The extent (size) of the main tumor (T): Has the cancer grown through the bile duct or reached nearby structures or organs?
  • The spread (metastasis) to distant sites (M): Has the cancer spread to distant lymph nodes or distant organs such as the bones, lungs, or peritoneum (the lining of the abdomen)?

The system described below is the most recent AJCC system, effective January 2018.



Perihilar bile duct cancer is typically given a clinical stage based on the results of a physical exam, biopsy, and imaging tests (described in Tests for Bile Duct Cancer). If surgery is done, the pathologic stage (also called the surgical stage) is determined by examining the tissue removed during the operation.


Click to enlarge. Tumor sizes are often measured in centimeters (cm) or inches. Common food items that can be used to show tumor size in cm include: a pea (1 cm), a peanut (2 cm), a grape (3 cm), a walnut (4 cm), a lime (5 cm or 2 inches), an egg (6 cm), a peach (7 cm), and a grapefruit (10 cm or 4 inches).

Click to enlarge. Millimeters (mm). A sharp pencil point is about 1 mm, a new crayon point is about 2 mm, and a new pencil eraser is about 5 mm.

Metastasis: How Cancer Spreads

Click to enlarge and play video. Many cancer deaths are caused when cancer moves from the original tumor and spreads to other tissues and organs. This is called metastatic cancer. This animation shows how cancer cells travel from the place in the body where they first formed to other parts of the body.

graphics and video courtesy of

T Categories for Distal Extrahepatic Bile Duct Cancer


No description of the tumor’s extent is possible because of incomplete information.


N Categories


Regional (nearby) lymph nodes cannot be assessed.


M Categories


The cancer has not spread to tissues or organs far away from the bile duct.


Stage Grouping

Once a patient’s T, N, and M categories have been determined, this information is combined in a process called stage grouping. The stage is expressed in Roman numerals from stage 0 (the least advanced stage) to stage IV (the most advanced stage). Some stages are subdivided with letters.

Stage 0

(Tis, N0, M0)

The cancer cells are only growing in the mucosa (the innermost layer of the bile duct) (Tis) and have not grown into deeper layers of the bile ducts or any nearby organs or structures. It has not spread to lymph nodes (N0) or distant sites (M0).

Stage I
Stage II
Stage IIIA
Stage IIIB
Stage IIIC
Stage IVA
Stage IVB