Updated September 27, 2010
The goal of chemotherapy is to kill cancer cells that are growing or dividing quickly. It is a powerful tool to fight cancer and protect you from a recurrence.
Every case is unique, so whether you receive chemotherapy depends on many factors.
- The specific type of cancer cells
- Your age and whether you have gone through menopause
- The size of the primary tumor
- Whether you have cancer in your lymph nodes
- The details (or prognostic factors) of the breast cancer, as explained by pathology tests and, sometimes, genomic tests.
Some of the important features in deciding whether you should receive chemotherapy include the tumor’s estrogen and progesterone receptor status, HER2 status, the proliferation index and the tumor grade.
How Chemotherapy Works
Chemotherapy involves taking anti-cancer medicines by injection into a vein (intravenously) or in pill form. These medicines travel throughout the body, where they destroy cancer cells that may have entered the bloodstream. Even in early-stage breast cancer, tiny cancer cells can break away from the original tumor. Typically, these cells are so small that they do not show up on any tests. Chemotherapy lowers the risk of recurrence (the cancer coming back).
Two or more chemotherapy medicines are often given together. Intravenous chemotherapy is given in cycles, with a day (or days) of treatment followed by a period of “off” days. The exact schedule varies depending on the medicines used; most breast cancer chemotherapy regimens are given every two or three weeks. An entire course of chemotherapy for breast cancer usually takes from three to six months.
How Do I Know if I Need Chemotherapy?
Your doctor will recommend chemotherapy if the cancer has a significant risk of developing outside your breast or has traveled outside the breast already. Chemotherapy is given if you have a large tumor, cancer in the lymph nodes or a tumor with features that make it aggressive.
Sometimes it is unclear whether you should receive chemotherapy, and your doctor may order a genomic test. Genomic tests look at groups of genes in breast cancer cells to see whether they are present, absent or too active. These factors help to predict how likely it is that the cancer will come back after treatment.
Genomic tests are used only for certain kinds of early-stage breast cancers. Your doctor may ask for a genomic test if the tumor is small, has not traveled to the lymph nodes, has hormone receptors on it and does not have too many HER2 receptors on it.
If the genomic tests shows it is very likely the cancer will return, your doctor will recommend you have chemotherapy and hormonal therapy. If the chances are very low that the cancer will return, your doctor will recommend hormonal therapy only.
How Is Chemotherapy Given?
Chemotherapy for breast cancer can be given before or after surgery, and it may be given as a single therapy or in various combinations.
Most chemotherapy is given as adjuvant therapy, after and in addition to surgery. Therapy usually begins about a month after surgery, once you have a chance to heal.
Your doctor also may offer you the option of neoadjuvant treatment, which means chemotherapy before surgery. The goal of neoadjuvant therapy is to shrink the cancer, making it easier to remove with surgery. Most of the time, neoadjuvant therapy is done to avoid a mastectomy. After neoadjuvant therapy, you still may need a mastectomy, or you may be able to have breast conservation therapy.
There are many different types of chemotherapy medicines. These may be given alone, called single-agent therapy, or together, called combination therapy. Some chemotherapy medicines do a better job of fighting the cancer when they are given together.
Your doctor will determine the best chemotherapy treatment for the cancer based on the cancer’s traits and your treatment goals.
What Happens at Treatment?
Chemotherapy is put directly into your bloodstream, usually through an IV (intravenously) but sometimes by mouth as pills or capsules.
Chemotherapy can irritate the small veins in your arms, so some surgeons put in a mediport or port-a-cath, a small device under the skin that allows easy access to your veins. Once you complete treatment, the port is removed.
Your doctor will determine how often and how much chemotherapy you receive. Chemotherapy may be given weekly, every two weeks, every three weeks or monthly. Some treatments, mostly pills taken by mouth, are taken daily.
Chemotherapy medicines are organized into classes. Each class has a specific mechanism and attacks a cell at a certain point as the cell rests, grows or divides.
Classes of Chemotherapy
Classes, and some common breast cancer medicines within them, include:
- Antitumor antibiotics: doxorubicin (Adriamycin) and epirubicin (Ellence)
- Alkylating agents: cyclophosphamide (Cytoxan)
- Antitubulins: paclitaxel (Taxol), docetaxel (Taxotere), vinorelbine (Navelbine) and ixabepilone (Ixempra)
- Antimetabolites: gemcitabine (Gemzar) and capecitabine (Xeloda)
Chemotherapy medicines are often given in combinations.
Some common combinations given for breast cancers that have a relatively low risk for recurrence include:
- AC (Adriamycin and Cytoxan)
- TC (Taxotere and Cytoxan)
Some common combinations given for breast cancer that have a relatively high risk for recurrence include:
- CAF (Cytoxan, Adriamycin and fluorouracil)
- TAC (Taxotere, Adriamycin and Cytoxan)
- AT (Adriamycin and Taxotere)
Read more about different types and combinations of chemotherapy in our the article " Understanding Chemotherapy for Early and Advanced Breast Cancer" in our spring 2008 national newsletter.
Many of us have scary images of chemotherapy, based on rumor, “movie-of-the-week” melodramas and stories from friends or family members treated many years ago. We associate cancer and sickness with chemotherapy’s side effects— hair loss, nausea and vomiting, weight gain or loss, fatigue and insomnia, dry mouth, dry skin, mouth sores and even something called “chemo brain,” problems with memory and concentration.
Other side effects associated with chemotherapy include low blood counts and diarrhea.
The truth is that while some people have a rough time with chemotherapy, others manage quite well. Many continue to work, and others report feeling only mild discomfort. Each person has her own individual response.
If you become uncomfortable during treatment, there are many medicines and methods to help you. Let your doctors and nurses know about your concerns before you start treatment. Ask which side effects could occur with the chemotherapy you are receiving.
If your doctor prescribes a medicine to prevent nausea, do not wait to take it until you feel upset to your stomach. Take it, as prescribed, for several days after each treatment.
If you have a new side effect or a side effect gets worse, do not hesitate to discuss it with your doctor or oncology nurse. You do not have to suffer!
Learn more about side effects in our section Beyond the Basics: Symptoms and Side Effects.