When the cancer has advanced fully, it spreads out to other organs. The process of spreading out from the original site is called metastasis, and the stage is referred to as metastatic breast cancer. Sometimes, all cancer cells do not die even after treatment for cancer, and these cells can break out from the original site and travel to other organs through blood vessels and lymphatic vessels, and develop tumors in other organs. This recurrence of cancer in other organs is called metastatic breast cancer, too.

Metastatic breast cancer can either recur, that is, the treatment for breast cancer may have completed, but the cancer cells that escaped from being killed make the cancer recur, or may happen during the course of treatment, when the cancer is so aggressive that it spreads out despite of the treatments, or, in some cases when diagnosis is very late, and the cancer has spread out, metastatic might be the very first diagnosis.

Unfortunate as it may be, breast cancer has the maximum chances of metastasizing. When this happens, bones, and organs like the lungs and brain starts showing abnormal changes, which means they're starting to develop cancer cell growth. If you get lung cancer or liver cancer or any other cancer after getting breast cancer, it is probably just breast cancer metastasis and not a new cancer. This is good news, since breast cancer has low mortality rates and can be treated. However, if the new cancer if in the breast which did not have cancer previously, it may be a new cancer.

Metastatic breast cancer develops in almost thirty out of hundred women who have had breast cancer, which makes knowledge about it so necessary. When the cancer has not metastasized to organs like the lungs and brain, or when there is a presence of estrogen and progesterone hormones in cancer tissues, the cancer is treatable. Also, if you have already not undergone many treatments for your previous cancer, and the malignant cells show some change after therapies, your treatment can be successful.

Metastatic breast cancer, owing to its nature, requires extensive treatment. Therapies like chemotherapy, hormonal treatment, immune therapy alone with regular mammograms, ultrasounds, CT scans, MRIs, bone scans etc. are necessary. The treatments can be purpose-specific. For treating the whole body, systemic therapies have to be implemented; for treatment of specific organs, local treatments like mastectomy and lumpectomy are done, and for alleviating pain, therapies along with oral aspirin intake are adopted.

A lot of research is going into slowing down and completely stopping further advancement of metastatic breast cancer. Even though this is the worst phase of your cancer, it is important that you know that many women with the metastatic disease have lived happily and normally while taking their treatment. You will have to decide when to end your treatment, for the higher the number of treatments you take, the higher the side-effects. This decision is the hardest to take, but you will know you have tried everything, prolonged your life as much as you could have. Spend the rest of your life being happy, and taking regular medication. Happiness is known for prolonging life, too.