Secondary breast cancer is breast cancer that has spread from the breast to other parts of the body.
Breast cancer starts as a lump in the breast - this is primary breast cancer. In many women, primary breast cancer does not come back after treatment. However, in some women, cancer cells break away from the primary breast cancer and spread to other parts of the body through the bloodstream or lymphatic system.
These cancer cells go on dividing and form a new cancer, known as a secondary cancer or metastasis. The secondary cancer is made up of breast cancer cells. This means that, for example, a secondary breast cancer in the liver behaves as - and is treated as - breast cancer, not a primary liver cancer.
Secondary breast cancer may be diagnosed years after primary breast cancer. Very occasionally, for some women, secondary breast cancer is their first diagnosis of breast cancer.
Where breast cancer may spread to
Less commonly, breast cancer can spread to other parts of the body, such as the bone marrow or ovaries.
Local and regional recurrence
Breast cancer that comes back in the skin of the breast where the cancer was first removed, or in the operation scar, is known as a local recurrence.
Breast cancer may also come back in the lymph nodes in the armpit, behind the breast bone, or in the lower part of the neck. This is called regional recurrence. If cancer cells are blocking the lymph nodes in the armpit, fluid can build up in the arm causing swelling known as lymphoedema.
Local and regional recurrences are not secondary breast cancer, as the cancer has not spread to another organ in the body.
These recurrences are usually less serious than secondary breast cancer. But you will usually have tests to find out if the cancer has spread to other parts of the body.
A local or regional recurrence that hasn't spread anywhere else in the body may be treated with surgery, if possible, or with radiotherapy. Your treatment will depend on the treatments you received to remove and treat the primary breast cancer.
Symptoms of secondary breast cancer
The symptoms of secondary breast cancer depend on the part of the body the cancer has spread to. In this section we explain the general symptoms, and some of the more specific symptoms you may experience.
All the symptoms mentioned here can be caused by other conditions. But if you have any of these symptoms it's important to get them checked out by your doctor or specialist nurse. Always let them know if you develop any new symptoms, especially if they last more than a week or two.