What Metastatic Cancer Means

Cancer that spreads from where it started to a distant part of the body is called metastatic cancer. For many types of cancer, it is also called stage 4 cancer. The process by which cancer cells spread to other parts of the body is called metastasis.

Metastatic cancer keeps the name of the original cancer. For example, breast cancer that spreads to the lung is called metastatic breast cancer, not lung cancer. It is treated as stage 4 breast cancer, not as lung cancer.

When doctors look at the cells under a microscope, metastatic cancer cells look like the cells of the original cancer, not like the cells of the place where they are found. That is how doctors can tell the cancer spread from somewhere else.

Sometimes doctors cannot tell where a metastatic cancer started. This is called cancer of unknown primary origin.

Cancer cells spread through the body in a series of steps. These steps include:

1. growing into, or invading, nearby normal tissue
2. moving through the walls of nearby lymph nodes or blood vessels
3. traveling through the lymphatic system and bloodstream to other parts of the body
4. stopping in small blood vessels at a distant place, then moving into the surrounding tissue
5. growing in this tissue until a tiny tumor forms
6. causing new blood vessels to grow, which gives the new tumor a blood supply so it can keep growing

Most of the time, spreading cancer cells die at some point in this process. Only when conditions are right at every step can some of the cells form new tumors. Metastatic cancer cells can also stay inactive at a distant site for many years before they begin to grow again, if they grow at all.

Cancer can spread to almost any part of the body, though different types are more likely to spread to certain areas. The most common sites where cancer spreads are the bone, liver, and lung.

Some examples of common patterns include breast cancer spreading to bone, brain, liver, or lung; colon cancer spreading to the liver, lung, or the lining of the belly; and prostate cancer spreading to the bone, liver, or lung. Your health care team can tell you what is most likely for your type of cancer.

Metastatic cancer does not always cause symptoms. When symptoms do occur, what they are like and how often they happen depend on the size and location of the tumors. Some common signs 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
• yellowing of the skin (jaundice) or swelling in the belly, when cancer has spread to the liver

Tell your health care team about any new or changing symptoms. They can help figure out the cause and how to manage it.

There are treatments for most types of metastatic cancer. Often, the goal of treatment is to control the cancer by stopping or slowing its growth. Some people can live for years with metastatic cancer that is well controlled.

Other treatments may improve quality of life by relieving symptoms. This type of care is called palliative care, and it can be given at any point during treatment for cancer.

The treatment that fits you depends on your type of primary cancer, where it has spread, treatments you have had in the past, and your general health. To learn about your options, including clinical trials, ask your health care team about the treatment information for your specific type of cancer.

For more specific next-step pages, see metastatic breast cancer, stage 4 lung cancer, metastatic colorectal cancer, metastatic prostate cancer, and oligometastatic cancer.

If your cancer can no longer be controlled, you and your loved ones may want to discuss end-of-life care. Whatever you choose about treatment, palliative care remains available to control symptoms and side effects.