What is metastasis?
Metastasis is when cancer has spread to other parts of the body, beyond where it started. It happens when cancerous cells have broken off the original tumor and spread, via the lymphatic system or bloodstream.
Usually, metastatic cancer can’t be cured, but treatment can be given to manage the symptoms. Metastasis is also referred to as metastatic cancer, secondary cancer or stage IV cancer.
When does cancer metastasize?
Most types of cancer are able to metastasize. The most common types of metastatic cancer include:
However, metastasis is dependent on certain factors, such as the location of the original (primary) tumor, its location and its size.
Where the cancer spreads to will depend on where the primary tumor is located.
What causes metastasis?
Metastasis happens when cancer cells spread from the original tumor to other parts of the body. This can happen in three ways:
- Through the blood stream to reach locations such as your organs or bones.
- Through the lymphatic system to reach lymph nodes.
- Growing into surrounding tissue.
Metastasis can be triggered by different factors, such as:
- Autophagy (cell death)
- Hypoxia (decreased oxygen in our tissues)
- Lactic acidosis (lactic acid buildup in the blood)
- Weakened immune system.
What are the symptoms of metastasis?
Metastasis doesn’t always have symptoms. Cancer cells sometimes spread slowly over a long period of time and go unnoticed.
In general, metastasis symptoms include extreme tiredness, weight loss and night sweats.
The symptoms of metastasis may also depend on where the cancer has spread. For example:
- Bone metastases: Pain in the bones or fractures.
- Brain metastases: Headaches, seizures and dizziness.
- Liver metastases: May cause swelling in the abdomen, jaundice and a reduced appetite.
- Lung metastases: Shortness of breath.
How is metastatic cancer diagnosed?
Metastatic cancer may be detected during diagnostic testing, or it may be found during routine follow-ups in people who have developed it after treatment for non-metastatic cancer (recurrence).
The following tests may be used to diagnose metastasis:
- Blood tests
- Biopsy
- Ultrasound
- Bone scans
- CT, MRI or PET scans
- Tumor marker tests
- X-rays.
How is metastatic cancer treated?
Metastatic cancer treatment will depend on where the cancer originates. For example, if lung cancer has spread to the liver, then you will be treated for lung cancer, as the cancer cells are the same, just in a different place.
Treatment for metastatic cancer may include:
- Chemotherapy
- Radiation therapy
- Immunotherapy
- Hormone therapy
- Targeted therapy.
Can metastasis be prevented?
If cancer is detected early, and surgery and adjuvant therapy (chemotherapy, immunotherapy, targeted therapy) are given, it may lower the risk of metastasis. However, it is not always possible to prevent cancer from spreading.
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