TNM system for bile duct cancer
The American Joint Committee on Cancer (AJCC) TNM system, also accepted by the International Union Against Cancer (UICC), is the most widely accepted method for staging bile duct cancer. This system bases the staging criteria on the evaluation of three primary factors:
- Tumor (T) describes the number and size of the original tumor.
- Lymph Node (N) indicates whether the cancer is present in the regional (nearby) lymph nodes.
- Metastasis (M) refers to whether cancer has spread to distant parts of the body.
A number (0-4) or the letter X is assigned to each factor. A higher number indicates increasing severity. For instance, a T1 score indicates a smaller tumor than a T2 score. The letter X means the information was insufficient and could not be adequately assessed.
Once the T, N and M scores have been assigned, the overall bile duct cancer stage is determined.