TNM system for liver cancer
The American Joint Committee on Cancer (AJCC) TNM system is the most widely accepted method for liver cancer staging. 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. (The most common sites of liver cancer spread are the lungs and bones).
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 could not be assessed.
Once the T, N, and M scores have been assigned, an overall liver cancer stage is assigned.
Other liver cancer staging systems have been developed that also take into account other factors, such as the function of the liver. However, the staging guidelines described here are based on the current AJCC TNM system.
Other staging systems for lung cancer
Unlike other cancers, liver cancer is complicated by the fact that most patients have liver damage that limits the function of the liver. The liver provides a very important function for the body, aiding in digesting and detoxification. Reduced liver function could result in severe and, even, life-threatening conditions. Reduced liver function may also have implications when choosing treatment options.
Several other liver cancer staging systems have been developed that take into account how the function of the liver may affect the prognosis:
- The Barcelona-Clinic Liver Cancer (BCLC) system
- The Cancer of the Liver Italian Program (CLIP) system
- The Okuda system
The Child-Pugh score is part of the BCLC and CLIP staging systems, and gives the measure of liver function in people with cirrhosis. The system looks at 5 factors including: levels of bilirubin and albumin in the blood, prothrombin time, accumulation of fluid (ascites) in the abdomen, and impact of liver disease on brain function.
Patients with normal liver function are classified as class A, those with mild abnormalities as class B, and those with severe abnormalities as class C. Liver cancer patients with class C cirrhosis are generally not fit to receive treatment.