Cholangiocarcinoma Staging overview

Cholangiocarcinoma Staging Overview

The stage of a cancer describes how far it has spread. The stage of bile duct cancer is one of the most important factors for determining the most beneficial treatment options and estimating a patient’s prognosis (outlook).The stage is determined by the results of the physical exam, imaging and other tests , and by the results of surgery if it has been done.

Nearly all bile duct cancers start in the innermost layer of the wall of the bile duct. Over time they can grow through the wall toward the outside of the bile duct. Cancer can spread in the body in the blood stream or through the lymphatic system. The lymphatic system is part of the body’s defense against infection and disease. A staging system is a standard way for doctors to sum up the extent of a cancer. The main system used to describe the stages of bile duct cancer is the American Joint Committee on Cancer (AJCC) TNM system.

AJCC TNM system for all bile duct cancers contains 3 key pieces of information:

T describes whether the main (primary) tumor has invaded through the wall of the bile duct and whether it has invaded other nearby organs or tissues.

T categories:

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

·         T0: There is no evidence of a primary tumor.

·         Tis: Cancer cells are only 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.

·         T1: There is a single tumor that has grown into deeper layers of the bile duct wall, but it is still only in the bile duct. The cancer has not grown into any blood vessels.

·         T2: Split into 2 groups:

  •               T2a: There is a single tumor that has grown through the wall of the bile duct and into a bloodvessel.
  •               T2b: There are 2 or more tumors, which may (or may not) have grown into blood vessels.

·         T3: The cancer has grown into nearby structures such as the intestine, stomach, common bile duct, abdominal wall, diaphragm (the thin muscle that separates the chest from the abdomen), or lymph nodes around the portal vein.

·         T4: The cancer is spreading through the liver by growing along the bile ducts.

N describes whether the cancer spread to nearby (regional) lymph nodes (bean-sized collections of immune system cells throughout the body).

N categories:

·         NX: Nearby (regional) 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 indicates whether the cancer has metastasized (spread) to other organs of the body. (The most common sites of bile duct cancer spread are the liver, peritoneum [the lining of the abdominal cavity], and the lungs.)

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. 

Stage grouping:
Once the T, N, and M categories have been determined, this information is in a process called stage grouping. The stage is expressed as stage 0 (the least advanced stage) or as Roman numerals up to stage IV (the most advanced stage). Some stages are subdivided with letters.

·         Stage 0 (Tis, N0, M0): The cancer is only growing in the innermost layer of the bile duct (Tis) and has not spread to nearby lymph nodes (N0) or sites (M0).

·         Stage I (T1, N0, M0): The cancer is a single tumor that has grown into deeper layers of the bile duct wall (T1), but it has not grown into any blood vessels. It has not spread to nearby lymph nodes (N0) or distant sites (M0).

·         Stage II (T2, N0, M0): The cancer is either a single tumor that has grown into a blood vessel (T2a) or there are multiple tumors (T2b). 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 III (T3, N0, M0): The cancer has grown into nearby structures such as the duodenum (first part of the small intestine), colon, stomach, abdominal wall, diaphragm, or lymph nodes around the portal vein (T3). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

·         Stage IV: Split into 2 groups:

·         Stage IVA(T4, N0, M0) OR (Any T, N1, M0): Either the cancer is spreading through the liver by growing along the bile ducts (T4), OR the cancer has spread to nearby lymph nodes (N1). It has not spread to distant sites (M0).

·         Stage IVB (Any T, any N, M1): The cancer has spread to distant sites (M1).

You may also hear your doctor talk about the grade of the cancer. The grade of a cancer is a way of measuring how abnormal cancer cells are compared to healthy cells. It also gives an idea of how quickly a cancer may grow and whether it is likely to spread. A low grade tumor is generally slow growing and high grade tumors are generally faster growing. 

Differentiation means how developed or mature a cell is. Cancer cells are not as mature as normal cells. So you may hear your doctor describe grade 1 cancer cells as well differentiated. Grade 2 cancer cells are moderately differentiated. Grade 3 cancer cells are poorly differentiated. Grade 4 cancer cells are undifferentiated.

Grades of intrahepatic bile duct cancer:

·         Grade 1 cancer means the cancer cells look very like normal bile duct cells. This is called low grade cancer.

·         Grade 2 cancer means the cancer cells look a bit abnormal. This is called intermediate grade cancer.

·         Grade 3 cancer means the cancer cells look abnormal and unlike normal bile duct cells. This is called high grade cancer.

·         Grade 4 cancer means the cancer cells look very abnormal and completely different to normal bile duct cancer cells. This is also called high grade cancer.