Chemotherapy (chemo) is treatment with cancer-killing drugs that may be given intravenously (injected into a vein) or by mouth. The drugs travel through the bloodstream to reach cancer cells in most parts of the body. Chemo is given in cycles, with each period of treatment followed by a recovery period. Treatment usually lasts for several months.

When is chemotherapy used?

There are several situations in which chemotherapy may be recommended.

Adjuvant chemotherapy: Systemic therapy given to patients with no evidence of cancer after surgery is called adjuvant therapy. While surgery is used to remove all of the cancer that can be seen, adjuvant therapy is used to kill any cancer cells that may have been left behind that can't be seen. Adjuvant therapy after breast-conserving surgery or mastectomy reduces the risk of breast cancer coming back. Both chemotherapy and hormone therapy can be used as adjuvant treatments.

Even in the early stages of the disease, cancer cells may break away from the primary breast tumor and spread through the bloodstream. These cells don't cause symptoms, they don't show up on imaging tests, and they can't be felt during a physical exam. But if they are allowed to grow, they can establish new tumors in other places in the body. The goal of adjuvant chemotherapy is to kill undetected cells that have traveled from the breast.

Neoadjuvant chemotherapy: Chemotherapy given before surgery is called neoadjuvant therapy. Often, neoadjuvant therapy uses the same chemo that is used as adjuvant therapy (only it is given before surgery instead of after). In terms of survival, there is no difference between giving chemo before or after surgery. The major benefit of neoadjuvant chemotherapy is that it can shrink large cancers so that they are small enough to be removed by lumpectomy instead of mastectomy. Another possible advantage of neoadjuvant chemotherapy is that doctors can see how the cancer responds to chemotherapy. If the tumor does not shrink, your doctor may try different chemotherapy drugs.

Chemotherapy for advanced breast cancer: Chemotherapy can also be used as the main treatment for women whose cancer has already spread outside the breast and underarm area at the time it is diagnosed, or if it spreads after initial treatments. The length of treatment depends on whether the cancer shrinks, how much it shrinks, and how a woman tolerates treatment.

How is chemotherapy given?

In most cases (especially for adjuvant and neoadjuvant treatment), chemotherapy is most effective when combinations of more than one drug are used. Many combinations are being used, and it's not clear that any single combination is clearly the best. Clinical studies continue to compare today's most effective treatments against something that may be better.

Some of the most commonly used drug combinations are:

• CMF: cyclophosphamide (Cytoxan), methotrexate (Amethopterin, Mexate, Folex), and 5-fluorouracil (Fluorouracil, 5-FU, Adrucil)

• CAF (FAC): cyclophosphamide, doxorubicin (Adriamycin), and 5-fluorouracil

• AC: doxorubicin (Adriamycin) and cyclophosphamide

• EC: epirubicin (Ellence) and cyclophosphamide

• TAC: docetaxel (Taxotere), doxorubicin (Adriamycin), and cyclophosphamide

• AC → T: doxorubicin (Adriamycin) and cyclophosphamide followed by paclitaxel (Taxol) or docetaxel (Taxotere) (Herceptin may be given with the paclitaxel or docetaxel for HER2/neu positive tumors.)

• A → CMF: doxorubicin (Adriamycin), followed by CMF

• CEF (FEC): cyclophosphamide, epirubicin, and 5-fluorouracil (this may be followed by docetaxel)

• TC: docetaxel (Taxotere) and cyclophosphamide

• TCH: docetaxel, carboplatin, and Herceptin for HER2/neu positive tumors

Other chemotherapy drugs used for treating women with breast cancer include cisplatin (Platinol), vinorelbine (Navelbine), capecitabine (Xeloda), pegylated liposomal doxorubicin (Doxil), gemcitibine (Gemzar), mitoxantrone, ixabepilone (Ixempra), and albumin-bound paclitaxel (Abraxane). The targeted therapy drugs Herceptin and Tykerb may be used with these chemo drugs for tumors that are HER2/neu-positive (these drugs are discussed in more detail in the "Targeted therapy" section).

Doctors give chemotherapy in cycles, with each period of treatment followed by a rest period. The chemotherapy begins on the first day of each cycle, and then the body is given time to recover from the effects of chemotherapy. The chemotherapy drugs are then repeated to start the next cycle. The time between giving the chemotherapy drugs is generally 2 or 3 weeks and varies according the specific chemotherapy drug or combination of drugs. Some drugs are given more often. These cycles generally last for a total time of 3 to 6 months when given as adjuvant therapy, depending on the drugs used. Treatment may be longer for advanced breast cancer.

Dose-dense chemotherapy: Doctors have found that giving the cycles of chemo closer together can lower the chance that the cancer will come back and improve survival in some women. This usually means giving the same chemo that is normally given every 3 weeks (such as AC → T), but giving it every 2 weeks. In addition, a drug (growth factor) to help boost the white blood cell count is given after the chemo to make sure the white blood cell count returns to normal in time for the next cycle. This approach can lead to more side effects and be harder to take, so it is only used for adjuvant treatment in women with a higher chance of the cancer coming back after treatment. Recently, this approach was also used for neoadjuvant therapy. The patients getting treated more often had their tumors shrink more, were less likely to have the cancer come back, and lived longer than the patients treated every 3 weeks.

Possible side effects

Chemotherapy drugs work by attacking cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow, the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemotherapy, which can lead to side effects. Some women have many side effects while other women may have few.

The side effects of chemotherapy depend on the type of drugs, the amount taken, and the length of treatment. Some of the most common possible side effects include:

• hair loss
• mouth sores
• loss of appetite
• nausea and vomiting
• increased chance of infections (due to low white blood cell counts)
• easy bruising or bleeding (due to low blood platelet counts)
• fatigue (due to low red blood cell counts and other reasons)

These side effects are usually short-term and go away after treatment is finished. It's important to let your health care team know if you have any side effects, as there are often ways to lessen them. For example, drugs can be given to help prevent or reduce nausea and vomiting.

Several other side effects are also possible. Some of these are only seen with certain chemotherapy drugs. Your cancer care team will give you information about the possible side effects of the specific drugs you are getting.

Menstrual changes: For younger women, changes in menstrual periods are another possible side effect of chemotherapy. Premature menopause (not having any more menstrual periods) and infertility (not being able to become pregnant) are possible permanent complications of chemotherapy. Some chemotherapy drugs are more likely to do this than others. The older a woman is when she receives chemotherapy, the more likely it is that she will become infertile or menopausal as a result. When this happens, it can also lead to rapid bone loss from osteoporosis. Again, there are medicines that can help prevent this possible side effect.

You cannot depend on chemotherapy to prevent pregnancy, and getting pregnant while receiving chemotherapy could lead to birth defects and interfere with treatment. For this reason, it is important that pre-menopausal women who are sexually active discuss using birth control with their doctor. It is safe to have children after chemotherapy, but it's not safe to get pregnant while on treatment. If you are pregnant when you get breast cancer, you still can be treated. Chemotherapy can be safely given during the last 2 trimesters of pregnancy.

Neuropathy: Several drugs used to treat breast cancer, including the taxanes (docetaxel and paclitaxel), platinum agents (carboplatin, cisplatin), and ixabepilone, can damage nerves outside of the brain and spinal cord. This can sometimes lead to symptoms (mainly in the hands and feet) such as numbness, pain, burning or tingling sensations, sensitivity to cold or heat, or weakness. In most cases this goes away once treatment is stopped, but it may be long-lasting in some women.

Heart damage: Adriamycin (doxorubicin), epirubicin, and some other drugs may cause permanent heart damage if used for a long time or in high doses. For this reason, doctors often check the patient's heart function before starting one of these drugs. They also carefully control the doses and use echocardiograms or other heart tests to monitor heart function. If the heart function begins to decline, treatment with these drugs will be stopped. Still, in some patients, heart damage takes a long time to develop. They may show signs of poor heart function months or years later.

Chemobrain: Another possible side effect of chemotherapy is "chemobrain." Many women who get chemotherapy for breast cancer report a slight decrease in mental functioning. There may be some problems with concentration and memory, which may last a long time. Still, most women do function well after chemotherapy. In studies that have found chemobrain to be a side effect of treatment, the symptoms most often go away within a few years. For more information, see the American Cancer Society document, Chemobrain.

Increased risk of leukemia: Very rarely, certain chemotherapy drugs may cause acute myeloid leukemia, a life-threatening cancer of white blood cells. When this happens it is usually within 10 years after treatment. In most women, chemotherapy's benefits in preventing breast cancer from coming back or in extending life are likely to far exceed the risk of this serious but rare complication.

Feeling unwell or tired: Many women do not feel as healthy after receiving chemotherapy as they did before. There is often a residual feeling of body pain or achiness and a mild loss of physical functioning. These are very subtle changes that are only revealed by closely questioning women who have undergone chemotherapy.

Fatigue is another common (but often overlooked) problem for women who have received chemotherapy. This may last up to several years. It can often be helped, so it is important to let your doctor or nurse know about it. For more information on what you can do about fatigue, see the American Cancer Society document, Fatigue in People with Cancer. Exercise, naps, and conserving energy may be recommended. If there are sleep problems, these can be treated. Sometimes there is depression, which may be helped by counseling and/or medicines.

Last Medical Review: 09/18/2009
Last Revised: 09/18/2009