Metastasis means that cancer spreads to a different body part from where it started. When this happens, doctors say the cancer has “metastasized.” Your doctor may also call it "metastatic cancer," "advanced cancer," or "stage 4 cancer." But these terms can have different meanings. For example, a cancer that is large but has not spread to another body part can also be called advanced cancer or locally advanced cancer. Ask your doctor to explain where the cancer has spread.
How metastases develop
Metastases is the plural form of metastasis. Metastases most commonly develop when cancer cells break away from the main tumor and enter the bloodstream or lymphatic system. These systems carry fluids around the body. This means that the cancer cells can travel far from the original tumor and form new tumors when they settle and grow in a different part of the body.
Metastases can also sometimes develop when cancer cells from the main tumor, typically in the belly, or abdominal cavity, break off and grow in nearby areas, such as in the liver, lungs, or bones.
Any type of cancer can spread. Whether this happens depends on several factors, including:
The type of cancer. Some cancers are more likely to spread than others.
How fast the cancer is growing
Other factors about the behavior of the cancer that your doctor may find
Where in the body cancer can spread
Cancer can spread to almost every part of the body. Some types of cancer tend to spread to certain parts of the body. For example:
Breast cancer tends to spread to the bones, liver, lungs, chest wall, and brain
Lung cancer tends to spread to the brain, bones, liver, and adrenal glands
Prostate cancer tends to spread to the bones
Colon and rectal cancers tend to spread to the liver and lungs
Less frequently, cancer can spread to the skin, muscle, or other organs in the body. Cancer cells can also spread to the lining around the lungs called the pleural cavity. It can also spread to the space around the belly called the peritoneal cavity. When these cancer cells cause fluid to build up in these areas, it is called malignant pleural effusion and malignant ascites.
Is a metastasis the same type of cancer as before?
Yes, a cancer that has spread to another area is given the same name as the original cancer. For example, a breast cancer that spreads to the liver is called metastatic breast cancer, not liver cancer. This is because the cancer started in the breast and the treatment used is for breast cancer.
How do doctors diagnose metastasis?
If you already had cancer treatment for non-metastatic cancer, you probably have a follow-up care plan. You will see your doctor for regular checkups. Specific tests may be done to look for metastases.
Alternatively, some people already have metastases when they are first diagnosed with cancer. In this situation, the metastases are usually found during the initial tests to stage the cancer.
Cancer may cause symptoms such as pain or shortness of breath. Sometimes these symptoms will lead your doctor to do necessary tests to find the metastases.
How do doctors treat metastasis?
Treatment depends on:
The original cancer and where it started
How much the cancer has spread and where it is located
Your age and health
Your personal treatment choices
Researchers are learning more about how metastases may differ from the original tumor at the molecular and genetic level. This is why treatment for metastasis is often different from the treatment used for the original tumor.
Treatment may include chemotherapy or hormone therapy. Surgery and radiation therapy may also be options for some types of cancer. Doctors might try one type of treatment and then switch to another when the first treatment no longer works. Or you might have a combination of treatments.
Types of treatment
The main types of treatment for metastasis include:
Treatment that affects your entire body. Doctors call this systemic therapy. It includes chemotherapy and other medications, such as targeted therapy, hormone therapy, and immunotherapy.
Treatment for the area with cancer. Doctors call this local therapy. It includes surgery, radiation therapy, and some other treatments.
When you choose a treatment, talk with doctors who have experience treating metastatic cancer. Doctors can have different opinions on the best treatment plan. Learn more about getting a second opinion.
Does treatment cure metastatic cancer?
In some situations, metastatic cancer can be cured, but most commonly, treatment does not cure the cancer. But doctors can treat it to slow its growth and reduce symptoms. It is possible to live for many months or years with certain types of cancer, even after the development of metastatic disease.
How well any treatment works depends on:
The type of cancer
How far the cancer has spread and where it is located
How much cancer there is
If the cancer is growing quickly or slowly
The specific treatment
How the cancer responds to treatment
It is important to ask your doctor about the goals of treatment. These goals may change during your care, depending on whether the cancer responds to the treatment. It is also important to know that pain, nausea, and other side effects can be managed with the help of your health care team. This is called palliative care and should be a part of any treatment plan.
Research shows that palliative care can improve the quality of your life and help you feel more satisfied with the treatment you receive. Learn more about palliative care, or supportive care.
Treatment in clinical trials
Clinical trials offer treatments that are not yet available to the public. A clinical trial might be the main treatment for metastases, or just one of the options. Only 3% to 5% of adults with cancer take part in clinical trials. The clinical trial treatment may or may not help. But even if it does not, it gives researchers information that could help future patients. Learn more about clinical trials and talk with your health care team if you are interested in participating in one.
When you live with metastatic cancer
When you live with cancer for many months or years, doctors often treat it like a chronic, or long-term, illness. Like someone with any chronic illness, such as diabetes or heart failure, treatment is important.
It is important to follow your treatment plan so it works as well as possible. You also need support for the physical, emotional, and social effects of living with cancer.
Dealing with Cancer Recurrence
National Cancer Institute: Metastatic Cancer
American Cancer Society: Advanced Cancer, Metastatic Cancer, and Bone Metastasis