The main reason that cancer is so serious is its ability to spread in the body. Cancer cells can spread locally by moving into nearby normal tissue. Cancer can also spread regionally, to nearby lymph nodes, tissues, or organs. And it can spread to distant parts of the body. When this happens, it is called metastatic cancer. For many types of cancer, it is also called stage IV (four) cancer. The process by which cancer cells spread to other parts of the body is called metastasis.
When observed under a microscope and tested in other ways, metastatic cancer cells have features like that of the primary cancer and not like the cells in the place where the cancer is found. This is how doctors can tell that it is cancer that has spread from another part of the body.
How Cancer Spreads
Cancer cells spread through the body in a series of steps. These steps include:
- Growing into, or invading, nearby normal tissue
- Moving through the walls of nearby lymph nodes or blood vessels
- Traveling through the lymphatic system and bloodstream to other parts of the body
- Stopping in small blood vessels at a distant location, invading the blood vessel walls, and moving into the surrounding tissue
- Growing in this tissue until a tiny tumor forms
- Causing new blood vessels to grow, which creates a blood supply that allows the tumor to continue growing
Most of the time, spreading cancer cells die at some point in this process. But, as long as conditions are favorable for the cancer cells at every step, some of them are able to form new tumors in other parts of the body. Metastatic cancer cells can also remain inactive at a distant site for many years before they begin to grow again, if at all.
Symptoms of Metastatic Cancer
Metastatic cancer does not always cause symptoms. When symptoms do occur, their nature and frequency will depend on the size and location of the metastatic tumors. Some common signs of metastatic cancer include:
- Pain and fractures, when cancer has spread to the bone
- Headache, seizures, or dizziness, when cancer has spread to the brain
- Shortness of breath, when cancer has spread to the lung
- Jaundice or swelling in the belly, when cancer has spread to the liver
When Metastatic Cancer Can No Longer Be Controlled
If you have been told you have metastatic cancer that can no longer be controlled, you and your loved ones may want to discuss end-of-life care. Even if you choose to continue receiving treatment to try to shrink the cancer or control its growth, you can always receive palliative care to control the symptoms of cancer and the side effects of treatment. Information on coping with and planning for end-of-life care is available in the Advanced Cancer section.
Coping with Advanced Cancer