Metastasis occurs when cancer spreads from the primary tumor to other parts of the body through the bloodstream or lymphatic system. The new tumors develop in organs or tissues away from the place where the cancer first started.
Even when cancer spreads to another organ, the metastatic tumors are still made up of cells from the original cancer. For example, if breast cancer spreads to the lungs, the cancer cells in the lungs are still breast cancer cells and are treated as breast cancer.
Treatment for metastasis is determined by an oncologist based on the primary cancer, where it has spread, and overall health. Treatment may include chemotherapy, radiation therapy, or immunotherapy to control the disease and relieve symptoms, although metastatic cancer can be difficult to cure.
Common symptoms
The main symptoms of metastasis include:
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Excessive fatigue
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Bone pain or frequent fractures
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Difficulty breathing or shortness of breath
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Severe, persistent headaches, seizures, or frequent dizziness
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Yellowing of the skin and eyes or abdominal swelling
According to the National Cancer Institute (NCI), metastatic cancer does not always cause symptoms, and when symptoms occur, they vary depending on the size and location of the metastatic tumors.
Metastases are a sign of malignant cancer, meaning that abnormal cancer cells have spread and are multiplying uncontrollably in the body.
How metastasis occurs
Metastasis occurs when cells from the primary tumor break away and invade nearby healthy tissue or travel through the bloodstream or lymphatic system to other parts of the body.
Once they reach a new organ or tissue, the cancer cells continue to multiply uncontrollably until they form a tumor similar to the original tumor.
When cancer cells are present in large numbers, they can stimulate the body to form new blood vessels that supply the tumor with more blood. This allows more cancer cells to grow and contributes to continued tumor growth.
Confirming a diagnosis
Metastasis is diagnosed by an oncologist using imaging tests that may be performed during routine cancer follow-up. These tests can include X-rays, CT scans, PET scans, and/or MRI scans.
Imaging tests can confirm whether metastasis is present and help determine its location and extent. This information directly affects which treatment options may be recommended.
Common sites of metastasis
Although metastases can develop in any part of the body, the lungs, liver, and bones are among the most commonly affected areas.
The main sites of metastasis include:
According to the National Cancer Institute (NCI), cancer can spread to almost any part of the body, but the bones, liver, and lungs are the most common sites of metastasis overall.
Cancer can also spread to nearby lymph nodes, as may occur with breast cancer, head and neck cancer, lung cancer, or gastrointestinal cancers.
Treatment options
Treatments for metastasis that may be recommended by an oncologist include:
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Chemotherapy
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Radiation therapy
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Surgery
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Hormone therapy
The type of treatment used for metastasis should always be determined by an oncologist. Treatment depends on the type of primary tumor, the organs affected, treatments the person has already received, and their overall health.
Can metastasis be cured?
Metastatic cancer can be difficult to cure because the disease is already at a more advanced stage and cancer cells may be present in several parts of the body.
In more advanced cases, it may not be possible to eliminate all metastases. In these situations, treatment may include palliative care to relieve symptoms and improve quality of life.
