The three ways that cancer spreads in the body are:
- Through tissue. Cancer invades the surrounding normal tissue.
- Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
- Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.
The following stages are used for adult primary liver cancer:
In stage I, there is one tumor and it has not spread to nearby blood vessels.
Pea, peanut, walnut, and lime show tumor sizes.
In stage II, one of the following is found:
- one tumor that has spread to nearby blood vessels; or
- more than one tumor, none of which is larger than 5 centimeters.
Stage III is divided into Stage IIIA, IIIB, and IIIC.
- In stage IIIA, one of the following is found:
- more than one tumor larger than 5 centimeters; or
- one tumor that has spread to a major branch of blood vessels near the liver.
- In stage IIIB, there are one or more tumors of any size that have either:
- spread to nearby organs other than the gallbladder; or
- broken through the lining of the peritoneal cavity.
- In stage IIIC, the cancer has spread to nearby lymph nodes.
In stage IV, cancer has spread beyond the liver to other places in the body, such as the bones or lungs. The tumors may be of any size and may also have spread to nearby blood vessels and/or lymph nodes.
For adult primary liver cancer, stages are also grouped according to how the cancer may be treated. There are 3 treatment groups: