Metastatic Breast Cancer
What is Metastatic Breast Cancer?
Breast cancer is a threat to life because it can spread to other parts of the body. When breast cancer has spread beyond the breast to other parts of the body, it is said to have metastasized. A deposit of breast cancer located beyond the breast is a metastasis. Metastasis (pronounced met-TAS-ta-sis) is a Greek word meaning 'away from the original place.'
Why Is Metastatic Breast Cancer A Threat To Life?
Breast cancer growing in another organ - such as the lungs, the liver, or the brain - can damage that organ. Damaged lungs can result in breathing problems and pneumonia. A damaged liver can cause life-threatening chemical imbalances in the blood. Breast cancer that has spread to the brain may cause symptoms similar to a stroke. This direct damage to other organs is one way metastatic breast cancer can threaten life. Organs commonly involved by metastatic breast cancer include bones, the lungs, the liver, and the brain.
Metastatic breast cancer can also threaten life indirectly. Metastatic breast cancer, like many cancers, can produce abnormal proteins that flow into the patient's bloodstream. These abnormal proteins can cause total-body problems such as weight loss, an increased vulnerability to infection, blood clots, and other similar problems. Many of these total-body problems can be life-threatening.
How Does Breast Cancer Spread (Metastasize) To Other Organs?
The origin of every cancer is damage to DNA, the 'brains' of the cell. When DNA is damaged in a certain way, the cell may grow uncontrollably, creating similar 'offspring' cancer cells that also grow uncontrollably.
An important feature of cancer is progression. Progression refers to a cancer's natural tendency to change and become more aggressive over time. Most cancers will gradually 'learn' to do things they should not do. If a breast cancer progresses (changes) enough, it may eventually 'learn' how to spread beyond the breast and grow in other organs.
Most cancers use blood vessels or lymph channels to leave the breast. These are tiny tubes that cancer cells can use like a highway to spread to other organs. Once in another organ, a breast cancer cell may learn (progress) enough to thrive and grow in that organ, eventually causing organ damage and illness.
All lymph channels feed into lymph nodes. Lymph nodes are collections immune system cells that interrupt lymph channels much like toll booths interrupt an interstate highway. The main purpose of the immune system cells inside lymph nodes is to detect and respond to germs; most germs in the body will soon land in the lymph fluid and travel lymphatic channels, so lymph nodes are well placed to detect such germs. But cancer cells can become 'stuck' in these lymph nodes, and may grow within the lymph node, forming a small (or large) cancer mass within (or even replacing) the lymph node.
When doctors inspect the armpit lymph nodes in a breast cancer patient and find cancer there, they refer to such breast cancers as 'node positive.' However, it is important to understand that breast cancer cells may flow through the lymph nodes without becoming 'stuck' in the node. Breast cancer cells may also spread through the veins, which lack lymph nodes to catch traveling cancer cells.The ability to bypass the lymph nodes and spread beyond the breast means that patients whose armpit lymph nodes are uninvolved by breast cancer ('node negative' breast cancers) are still at risk for metastatic breast cancer.
How is Metastatic Breast Cancer Diagnosed?
Metastatic breast cancer is diagnosed when breast cancer tissue is confidently found in another organ of the body. Metastatic breast cancer may be strongly suggested by finding an abnormal lump in another part of the body during physical examination. Often a CAT scan or other type of test may raise the concern that the cancer has metastasized. A biopsy is often done to confirm the diagnosis of metastatic breast cancer.
A biopsy is a minor surgical procedure in which a piece of the suspected cancer is removed and examined under a microscope. Examination of a biopsy under a microscope is the only way to absolutely confirm the presence of metastatic breast cancer.
How is Metastatic Breast Cancer Treated?
The main treatment of metastatic breast cancer includes some form of drug therapy. These include estrogen-blocking drugs, chemotherapy, and the so-called targeted or biologic drugs.
Radiation therapy and surgery may provide benefit for many patients with metastatic breast cancer. For example, radiation therapy is effective in reducing the pain of breast cancer that has metastasized to bones and may help prevent fractures of weakened bones. Radiation therapy is also the main treatment for patients with metastatic breast cancer that has spread to the brain.
Most experts will agree that metastatic breast cancer cannot be completely cured: that is, it cannot be permanently removed from the patients body using surgery, radiation therapy, or drug therapy.
The goal of metastatic breast cancer treatment is to prolong the duration and quality of life of the patient. Some patients cancers are resistant to treatment and progress rapidly to a life-threatening state. Many patients can be successfully treated for years with excellent quality of life.