What is secondary breast cancer?
This page tells you about secondary breast cancer. There is information about
What secondary breast cancer is
A cancer is made up of millions of cancer cells. These form a tumour. The original cancer is known as a primary tumour or the primary cancer. Some cells may break away and spread to another part of the body and form a new tumour. The new tumour is called a metastasis or a secondary cancer. So a secondary breast cancer is when a cancer that started in the breast spreads to another part of the body.
Cancer cells spread either in the bloodstream or through the lymphatic system. They do not always form a secondary cancer as soon as they have settled in a new place in the body. They may stay inactive (dormant) for many years before growing into a new tumour.
Where breast cancer cells can spread to
Breast cancer cells are more likely to spread to certain parts of the body than others. They most commonly spread to the lymph nodes, the bones, or the liver. They may also spread to the lung or, rarely, the brain. Secondary breast cancer may only affect one area of the body. But it may affect more than one place at a time.
You can view and print the quick guides for all the pages in the Secondary breast cancer section.
A cancer is made up of millions of cancer cells. These form a tumour. The original cancer is known as a primary tumour or the primary cancer. Some cells may break away and spread to another part of the body and form a new tumour. This is called a metastasis or a secondary cancer.
So a secondary breast cancer is when the cancer that started in the breast spreads to another part of the body. The secondary cancer is made of breast cancer cells.
The symptoms of secondary breast cancer depend on which part of the body the breast cancer has spread to. For example, a woman with secondary breast cancer cells in the bone will have different symptoms from a woman with secondary breast cancer in the liver.
Cancer cells can spread from a primary breast cancer to another part of the body through the bloodstream or in the lymph fluid which flows through the lymphatic system.

When the cancer cells are in the bloodstream or lymphatic system, they can get trapped in different organs and tissues. Often they die. Sometimes they stay inactive (dormant) for many years. But sometimes they may grow and divide to form a secondary breast cancer many years later. No one knows why some cancer cells stay inactive or what sometimes makes them form a secondary cancer. Researchers are trying to find out.
Breast cancer cells are more likely to spread to certain parts of the body than others. Breast cancer cells travelling in the lymphatic system can spread to lymph nodes anywhere in the body. The most common lymph nodes affected are those close to the breast, such as in the neck, or under or above the collarbone.
Cancer cells travelling in the bloodstream are most likely to settle in
The cancer cells may also spread to the brain but this is not common.
Secondary breast cancer may only affect one part of the body but it is common for it to affect more than one place at a time.
There are books and booklets about secondary breast cancer, some of which are free. Look at the breast cancer reading list. We have information about coping with secondary breast cancer in this section.






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