Metastatic breast cancer is also known as Stage IV breast cancer or advanced breast cancer. This is the most advanced stage of breast cancer, where the cancerous cells have spread to the other parts of the body and are no longer present only in the breast region. In most cases of metastatic breast cancer, the cancerous cells have spread to the brain, liver, bones, or lungs. Despite spreading to the rest of the body, it is treated under metastatic breast cancer treatments.

Nearly 154,000 people have been diagnosed with metastatic breast cancer in the US. It has been observed that metastatic breast cancer reoccurs a few years after the completion of treatment for early stages of breast cancer.

No metastatic breast cancer treatment ensures a complete cure for cancer. All treatments are aimed at improving the quality and length of life of the patient. The goal of every type of metastatic breast cancer treatment is to slow down the progress of cancer with minimal pain and side-effects.

The type of metastatic cancer treatments depends on the characteristics of the cancerous cells, the extent to which the cancer cells have spread, general health of the patient, age, the symptoms of the disease, and previous treatments of breast cancer.

Hormonal therapy
This type of metastatic breast cancer treatment is used in cases of hormone receptor-positive breast cancer. This is usually the first treatment for this type of metastatic cancer. In this treatment, hormone therapy drugs are administered to prevent cancer cells from receiving estrogen required for their growth. Depending on their menopausal status and previous hormonal treatment for early stages of breast cancer, women can choose the type of hormonal therapy they want. Hormone therapy drugs can be either injected into the body or taken orally.

For premenopausal women, ovarian suppression is done at the beginning of any hormonal therapy treatment. This lowers the levels of estrogen in the body, which prevents the cancerous cells from getting estrogen necessary for their growth. Surgery can be done to remove the ovaries or drugs are used to prevent the ovaries from producing estrogen. For post-menopausal women, hormonal therapy involves the administration of inhibitors or anti-estrogen drugs. Ovarian suppression is not done since estrogen is not produced by the ovaries in post-menopausal women.

For metastatic breast cancer treatment, consecutive sessions of hormonal therapy may be required. However, hormonal therapy might not be effective in the long run. In such cases, doctors may recommend chemotherapy.

Chemotherapy
This metastatic breast cancer treatment is recommended for cancers that are hormone receptor-negative, hormone receptor-positive, or HER2-positive. The advantage of chemotherapy is its effectiveness as compared to hormonal therapy. Chemotherapy is quicker in shrinking cancerous tumors. In this metastatic breast cancer treatment, chemotherapy drugs disable or destroy the cancerous cells. The type of chemotherapy drugs used for treatment depends on factors such as symptoms and the general health of the patient.

Chemotherapy treatment with one type of drug is referred to as a line of treatment. If a drug does not work, another set of chemotherapy drugs or another line of treatment is used to combat the cancer cells. A chemotherapy treatment lasts for about 3 to 6 months with short breaks of a few days or weeks in between. The schedule of treatment depends on the set of chemotherapy drugs used. Patients with metastatic breast cancer often go through multiple chemotherapy treatments (four or more). The probability of cancer shrinking decreases with each line of treatment.

Although chemotherapy is the most effective metastatic breast cancer treatment, it also has more intense side effects. Some of the common side effects of chemotherapy include fatigue, nausea, and hair loss. Most of these symptoms are short-term that are experienced during the treatment and go away once the treatment is done. However, some symptoms are long-term and can possibly last for few months and even years.

Targeted therapy
Anti-HER2 drugs are used in this type of metastatic breast cancer treatment. HER2 is a protein that is found on the surface of breast cancer cells. This type of cancer is called HER2-positive breast cancer. In this type of breast cancer, the HER2 protein is used by the cancer cells to grow and multiply.

In this type of metastatic breast cancer treatment, drugs containing antibody are used to target the HER2-positive cancer cells. The antibody drugs in targeted therapy are administered through the veins. The antibody attaches to the HER2 protein and slows down or stops the growth of the cancerous cells. When combined with chemotherapy treatment, targeted therapy shrinks the cancerous tumors and destroys them.

Unlike chemotherapy, targeted therapy does not have many side effects. There is no hair loss or any effect on the bone marrow. However, some antibody drugs may cause nausea, headache, dry skin, or rashes.