What is secondary brain cancer?
Secondary brain cancer is when a cancer that started somewhere else in the body has spread to the brain.
Where a cancer starts is called the primary cancer. If some cancer cells break away from the primary cancer, they can move through the bloodstream or 
to another part of the body forming a new tumour. This is called a secondary cancer. Secondary cancers are also called metastases (pronounced me-tass-ta-sis).
The secondary cancer is made of the same type of cells as the primary cancer.
So, if your cancer started in your lung and has spread to your brain, the areas of cancer in the brain are made up of lung cancer cells.
This is different from having a cancer that first started in the brain (a primary brain cancer). In that case, the cancer is made up of brain cells that have become cancerous. This is important because the primary cancer tells your doctor which type of treatment you need.
This video is about secondary cancer, it lasts for 2 minutes and 42 seconds.
A secondary cancer is a cancer that has spread from where it first started to another part of the body. You might hear people call it a metastasis, metastases or advanced cancer.
Where a cancer starts is sometimes called the primary cancer. A secondary cancer is made up of the same type of cells as the primary cancer. SO, for example a cancer that starts in the bowel may spread to the liver. The cancer cells in the liver are the same type of cells that started in the bowel.
Secondary cancers happen when cancer cells break off the primary cancer and move through the body. This can happen by cancer cells passing through the blood or the lymphatic system.
The lymphatic system is a network of tubes and glands that filters body fluid and fights infection.
The cancer cells can travel through the blood and lymphatic systems to other parts of the body. Most cancer cells die when they are moving through but some don’t and can pass through the blood and lymphatics into another part of the body. They can then grow and develop into another cancer in that part of the body.
Cancer can spread to anywhere in the body but there are places that it is more likely to spread to depending on where your cancer started. So for example bowel cancers are most likely to spread to the liver and lungs and cancers that start in the lungs is more likely to spread to the brain and bones.
Treatment will depend on where your cancer started. This is because the primary and secondary cancer cells are the same and will respond to the same types of treatment. Treatment might include one or more types. You should talk to your doctor to find out how the treatment will work. Once a cancer has spread it can be more difficult to cure.
The aim of treatment may be to control the growth of the cancer and any symptoms you have for as long as possible or sometimes the aim might be to get rid of the cancer completely.
For more information about secondary cancer go to cruk.org/secondary-cancer. For more information about your cancer type go to cruk.org/cancer-type
Which cancers spread to the brain?
Any cancer can spread to the brain. Some of the cancers that do are:
- lung cancer
- breast cancer
- kidney cancer
- melanoma skin cancer
- bowel cancer (colorectal cancer)
Symptoms of secondary brain cancer
Symptoms depend on where the cancer is in your brain. The cancer can cause pressure on the surrounding brain tissue and the symptoms will depend on what this part of the brain does.
Symptoms can include:
- headaches
- feeling or being sick
- weakness of a part of the body
- seizures (fits)
- personality or mood changes
- changes to your eyesight such as blurred vision or loss of vision
- confusion and difficulty understanding
- difficulty speaking
Remember other conditions can cause these symptoms. They don't necessarily mean that you have cancer that has spread to the brain. But if you have any of these symptoms, tell your doctor or nurse so that they can check it out.
Tests
You may have one or more of the following tests:
- physical examination by a doctor to test your muscle strength, eyes and reaction times
- CT scan
- MRI scan
- biopsy (removing some or all of the tumour to see if it is cancer)
You may not need to have a biopsy as your medical history and test results can usually give a clear idea about whether you have a secondary cancer.
Treatment
Secondary brain cancer can’t usually be cured. But treatment can control it for some time and help prevent problems developing. Some people may not be able to have treatment for their cancer because they are too unwell.
Survival
Most people worry about their outlook (prognosis) when they have a secondary cancer. Your individual outlook depends on many factors including whether the cancer has spread to more than one part of your body, how quickly it is growing and how it responds to treatment.
It is usually difficult to predict and this uncertainty can be hard to deal with. Speak to your doctor who can give you more information about your outlook.
