Systemic Therapy for Breast Cancer

Chemotherapy for breast cancer may be the most commonly known systemic therapy, but there are several treatments like hormone therapy and molecularly-target therapy. Systemic therapies for breast cancer are administered to the patient as medicines. They can be given through an IV, taken as a pill, and sometimes received as an injection. Breast cancer patients at Siteman might have one or more of these treatments.

Chemotherapy for breast cancer

Chemotherapy involves the administration of drugs, either orally or through an IV, to kill cancer cells. There are many different chemotherapy drugs, and patients usually receive several in combination.

Chemotherapy is intended to prevent the cancer from recurring. Patients can receive chemotherapy before or after surgery. If a patient undergoes chemotherapy before surgery, it’s called neoadjuvant chemotherapy. It’s used to shrink tumors that are either too large or too difficult to remove surgically. Sometimes, this can even allow patients to receive breast-conserving surgery instead of a mastectomy.

When chemotherapy is given after surgery, it’s called adjuvant chemotherapy. If surgery reveals that the cancer has spread to the lymph nodes, or you have other high risk features, your doctors might recommend adjuvant chemotherapy.

Some patients with metastatic breast cancer receive chemotherapy as a primary treatment. In these cases, the chemotherapy can stop the cancer from spreading further.

Because chemotherapy is taxing on the body, it is given in cycles of two to three weeks, with a break in between. Some patients will receive chemotherapy once a week.  If you’re having chemotherapy as an adjuvant or neoadjuvant treatment, the cycles will probably continue for three to 6 months. Chemotherapy can be a major commitment, and your team at Siteman will do everything they can to help you through the process. Click here to learn more about support services available to cancer patients, and don’t hesitate to mention any issues you are struggling with to your physicians and nurses.

Chemotherapy is the treatment that can cause cancer patients to lose their hair. The drugs used to treat breast cancer are even more likely to provoke hair loss. Click here to learn more about scalp cooling, an innovative treatment available to Siteman patients that can reduce or even prevent the loss of hair during chemo.

Hormone therapy for breast cancer

Most breast cancers are “hormone sensitive.” This means that they harness the hormones estrogen and/or progesterone as additional fuel. Hormone therapy (also called endocrine therapy) prevents the cancer cells from obtaining the hormones they need, either by blocking the delivery of hormones to the cells or decreasing the amount of hormones in the body.

The purpose of hormone therapy is to reduce the likelihood that breast cancer will recur, especially when it is administered after surgery. However, patients with later-stage or metastatic breast cancer are sometimes given hormone therapy as a second-line, or even a first-line, treatment. In these cases, it can slow or even halt the progression of the cancer.

Patients receive hormone therapy as either pills or injections. You’ll probably have to continue the therapy for a minimum of five years.

Hormone therapy is not the same thing as hormone replacement therapy, a common treatment for menopause symptoms. Hormone replacement therapy gives the body extra hormones to compensate for naturally-falling hormone levels during menopause. Breast cancer patients who are undergoing hormone replacement therapy are asked to discontinue the treatment because the additional hormones could accelerate the growth of their cancer.

Molecularly-targeted therapy for breast cancer

Cancer cells multiply without stopping because they have undergone certain molecular changes or harbor specific mutations. These changes occur in cellular components called proteins, which control the behavior of the cell.

Molecularly-targeted therapies target the dysfunctional proteins. They don’t kill cancer cells, but they stop them from dividing and spreading, slowing the progression of the cancer. They are one of the latest, most exciting innovations in the treatment of breast cancer.

Patients can receive molecularly-targeted therapy as IV infusions or pills. These drugs still have side effects, but they are often much less severe than the side effects from chemotherapy.

Physicians at Siteman will recommend targeted therapies according to the distinct features of your disease. There are therapies available for patients with BRCA mutations, PIK3Ca mutations, hormone-sensitive cancers, and metastatic cancer. In addition, a number of molecularly-targeted therapies are in clinical trials that Siteman Cancer Center investigators are leading.