Cancer is considered metastatic when it spreads from the area in which it originates to a different part of the body. For many types of cancer, this is considered stage 4 cancer.
Metastasis is not always the same as “locally advanced cancer,” often considered stage 3 cancer, which is cancer that spreads to nearby tissues or lymph nodes, but has not spread throughout the body.
Any type of cancer can metastasize (spread) depending on:
- How fast the cancer is growing
- The type of cancer: some cancers have a higher risk of metastasizing
- Other factors about the behavior of the cancer
What Are Symptoms of Metastatic Cancer?
Metastatic cancer may not cause symptoms.
General signs and symptoms of metastatic cancer may include:
- Tiredness
- Weakness
- Weight loss without trying
- Pain
- Trouble breathing
- Yellow eyes or skin (jaundice)
Other symptoms of metastatic cancer depend on the size and location of the metastatic tumors and may include:
- Headache, dizziness, or seizures when cancer has spread to the brain
- Shortness of breath, when cancer has spread to the lung
- Pain and broken bones (fractures), when cancer has spread to the bone
- Yellow skin and eyes (jaundice) or swelling in the belly, when cancer has spread to the liver
Where in the Body Can Cancer Metastasize?
Cancer can metastasize (spread) to nearly any body part. Some types of cancer have a tendency to spread to certain parts of the body. For example:
- Melanoma (skin cancer) tends to spread to the bones, brain, liver, lungs, skin, muscles
- Lung cancer tends to spread to the brain, bones, liver, adrenal glands, and the other lung
- Colon, rectal, stomach, ovarian, and pancreatic cancers tend to spread to the liver, lungs, and peritoneum
- Breast cancer tends to spread to the bones, liver, lungs, chest wall, and brain
- Prostate cancer tends to spread to the adrenal glands, bones, liver, and lungs
- Bladder and thyroid cancers tend to spread to the bones, liver, and lungs
- Kidney cancer tends to spread to the adrenal glands, bones, brain, liver, and lungs
- Uterine cancer tends to spread to the bones, liver, lungs, peritoneum, and vagina
How Is Metastatic Cancer Treated?
Metastatic cancers usually cannot be cured. The goal of treatment for metastatic cancers is to slow growth, reduce symptoms, and prolong a patient’s life with as much quality as possible.
The treatment for metastatic cancer depends on:
- The original cancer and where it started
- How much the cancer has metastasized and where it is located
- How quickly the cancer is spreading
- The patient’s age and health
Treatment for metastases may not be the same as treatment for the original tumor. Treatments for metastatic cancers may include one or more of the following:
- Chemotherapy
- Radiation therapy
- Targeted therapy
- Immunotherapy
- Hormone therapy
- Surgery
- Palliative care
- To help reduce side effects of treatment
- To improve quality of life
The goals of treatment of metastatic cancer may change during a patient’s care, depending on how a person reacts to the treatment and how the cancer responds to the treatment.
From 
https://www.cancer.net/coping-with-cancer/managing-emotions/coping-with-metastatic-cancer
https://www.cancer.gov/types/metastatic-cancer
https://www.cancer.org/treatment/understanding-your-diagnosis/advanced-cancer/what-is.html