Staging Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma develops in the smaller bile duct branches inside the liver. It can sometimes be confused with cancer that starts in the liver cells,

Intrahepatic cholangiocarcinoma, meaning within the bile ducts that are within the liver.

Intrahepatic cholangiocarcinoma develops in the smaller bile duct branches inside the liver. It can sometimes be confused with cancer that starts in the liver cells, which is called hepatocellular carcinoma (HCC). Only about 1 in 10 cholangiocarcinomas are intrahepatic.

After a person is diagnosed with intrahepatic 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 intrahepatic bile duct cancers are stage 0 (also called carcinoma in situ, or CIS).

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 intrahepatic 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 tumour (T): How large has the cancer grown? Has the cancer reached nearby structures or organs?
The spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes?
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)?

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced.

Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. For more on this, see Cancer Staging.

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

Cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.

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

T Categories for Intrahepatic Bile Duct Cancer

TX

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

T0

There is no evidence of a primary tumour.

Tis

Cancer cells are only growing in the mucosa (the innermost layer of the bile duct) and have not grown into deeper layers of the bile duct. This stage is also known as intramucosal carcinoma and was previously called carcinoma in situ.

T1

Split into 2 groups:

T1a
The tumour is no more than 5cm (2 inches) in diameter and has not invaded any nearby blood vessels.

T1b
The tumour is larger than 5cm (2 inches) in diameter and has not invaded any nearby blood vessels.

T2

A single tumour that has grown into nearby blood vessels OR 2 or more tumours, which may (or may not) have grown into nearby blood vessels

T3

The tumour has grown through the visceral peritoneum (the outer lining of organs in the abdomen)

T4

The cancer has grown directly into nearby structures outside of the liver such as the intestine, stomach, common bile duct, abdominal wall, or diaphragm.

N Categories

NX

Regional (nearby) lymph nodes cannot be assessed.

N0

The cancer has not spread to nearby lymph nodes.

N1

The cancer has spread to nearby lymph nodes.

M Categories

M0

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

M1

The cancer has spread to tissues or organs far away from the bile duct such as lungs, bone, and/or brain.

Stage Grouping

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 IA

(T1a, N0, M0)

The cancer is a single tumour that is no more than 5cm (2 inches) in diameter and it has not grown into any nearby blood vessels (T1a).

The cancer has not grown into any nearby organs or structures. It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage 1B

(T1b, N0, M0)

The cancer is a single tumor that is more than 5cm (2 inches) in diameter and it has not grown into any nearby blood vessels (T1b).

The cancer has not grown into any nearby organs or structures. It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage IB

(T1b, N0, M0)

The cancer is a single tumour that is more than 5cm (2 inches) in diameter and it has not grown into any nearby blood vessels (T1b).

The cancer has not grown into any nearby organs or structures. It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage II

(T2, N0, M0)

The cancer is either a single tumour that has grown into a blood vessel or there are multiple tumours that may or may not have grown into nearby blood vessels (T2).

The cancer has not grown into any nearby organs or structures. It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage IIIA

(T3, N0, M0)

The cancer has grown through the outer lining of organs in the abdomen without growing into any nearby organs or structures. (T3).

It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage IIIB

Split into 2 groups

(T4, N0, M0)
The cancer has grown directly into any nearby organs or structures. (T4). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

(Any T, N1, M0)
The cancer is of any size and might or might not be growing outside the bile duct (Any T) and it has spread to nearby lymph node (N1). It has not spread to distant sites (M0).

Stage IV

(Any T, any N, M1)

The cancer is of any size and might or might not be growing outside the bile duct or into nearby blood vessels (Any T).

It might or might not spread to nearby lymph nodes (Any N). It has spread to distant sites such as lungs, bone, or brain (M1).

Click to enlarge. Tumour 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 and play video. Many cancer deaths are caused when cancer moves from the original tumour 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 cancer.gov