Chemotherapy - Treating Breast Cancer: Breast Cancer

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Chemotherapy

Chemotherapy, or treatment with anticancer medications, is a systemic therapy; the drugs travel through the bloodstream to reach cancer cells anywhere in the body. It is often used as adjuvant treatment, to kill cancer cells throughout the body that can't be removed with surgery. For cases in which cancer is widespread, chemotherapy may be the main form of treatment. Chemotherapy may also be used as neoadjuvant treatment, to shrink a large tumor before surgery.

The study of chemotherapy began as early as 1948 after it became clear that breast surgery alone did not cure all cancers. In fact, about 30% of women with node-negative cancers and 75% of women with node-positive cancers experienced recurrence and death from breast cancer when treated by surgery alone. Controlled studies of modern chemotherapy regimens began in the 1970s. The results of more than 100 studies over three decades showed that chemotherapy and other adjuvant therapies have significantly improved survival rates of patients with breast cancer.

Cancer cells usually grow more rapidly than normal cells, and chemotherapy drugs work against them by interfering with their growth and reproduction. Some normal cells also are rapid growing, however, and these, too, can be killed by chemotherapy.

Damage to these normal cells results in side effects. For example, hair loss, one of the most common side effects of chemotherapy, is caused by damage to the rapidly growing cells in hair follicles. Similarly, gastrointestinal and bone marrow side effects may also occur, due to the rapidly dividing cells that line the intestinal contents and the blood cells that are made in the bone marrow. Lowering of the blood counts may be one of the most serious side effects of chemotherapy because lowered blood counts may lead to an increased incidence of bleeding and infection.

Side effects of chemotherapy are generally temporary, and most can be managed with a combination of medications and self-help techniques until the treatment is done.

If you or someone you know is taking chemotherapy treatment, be aware that patients and doctors sometimes reduce the chemotherapy dosage in order to lessen side effects. Researchers at the University of Rochester cautioned against this practice after their 2003 study of 20,000 women found that more than half of them did not receive the full recommended schedule of chemotherapy. Reducing the dose or the schedule of treatment may put women at risk of the disease worsening or coming back, researchers said.

Choosing a chemotherapy regimen

How do you know if you will need chemotherapy, and if so, which regimen of medications is right for you? Your medical oncologist (a doctor who specializes in the treatment of cancer with chemotherapy, hormonal therapy, and immunotherapy) will evaluate your situation based upon your pathology report as well as information obtained from your medical history and physical examination. Such factors include

• lymph node status

• size of the primary tumor

• presence or absence of aggressive characteristics of the cancer cells (called differentiation)

• evidence of cancer cells in the blood or lymph vessels of the breast or surrounding skin

• presence or absence of cancer cells at the outer edges of the tissue removed in surgery

• estrogen and progesterone receptor status

• HER2/neu receptor status

• your age

• your menopausal status

• your overall health status

• the results of staging studies, such as a bone scan and CT scans.

If you and your doctor determine that chemotherapy is a good choice for you, the next step will be to decide which regimen is the best choice. Chemotherapy drugs are given in pill form or intravenously (infused into a vein). The drugs are usually taken in cycles, with each period of treatment followed by a rest period. This rest period is usually necessary for the bone marrow cells to recover, thus minimizing the possibility of bleeding or infection. The selection of particular drugs depends on the many characteristics of the cancer.

Chemotherapy for early-stage non-metastatic disease. In this case, the goal is to cure the disease. Drugs are commonly given in combinations such as:

• doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan), together called AC (Taxol or Taxotere might be added if lymph nodes are involved)

• cyclophosphamide, doxorubicin, and fluorouracil, together called CAF

• cyclophosphamide, methotrexate, and fluorouracil, together called CMF.

Chemotherapy for advanced or metastatic cancer. For this treatment the oncologist usually recommends a single drug, perhaps once a week, until there is evidence that the disease is again progressing. Then that drug is discontinued and another is started. This type of chemotherapy schedule can be daily, weekly, or every three to four weeks, depending on the drug and the patient's tolerance for any side effects.

Drug selection differs from patient to patient, because responses are individual. However there are now a series of well studied combinations of drugs that are usually tolerated and allow the best response (remission) rates to occur. The treatment usually is continued for a finite period of time. Patients will then undergo staging studies to evaluate the extent of the cancer and the response of the cancer to current treatment. Subsequent treatments are then based upon the results of these staging studies.

Managing chemotherapy side effects

Mention chemotherapy and most women will ask: "Will I lose my hair?" "Will I be nauseated all the time?" "Will I be too tired to live a normal life?" Chemotherapy's reputation for unpleasant side effects goes back several decades, when most patients were hospitalized for their chemotherapy treatments because they vomited so much. Today, if the drug is given intravenously, the patient sits in a comfortable chair, usually for two to three hours, and then goes home. Because chemotherapy attacks quickly dividing cells - including cancer cells, but also some normal cells such as those in hair follicles, bone marrow, and the mouth, stomach, and intestines - side effects may include hair loss, fatigue, mouth sores, nausea, and infertility.

The side effects depend on the drugs being used and the drug schedule. Not all patients have a negative reaction to chemotherapy. Most of the unpleasant effects can be managed, and severe side effects are uncommon. For instance, some chemotherapy drugs do not always cause hair loss. If given orally, the CMF combination produces hair loss in only 50% of patients. With other chemotherapy drugs, you indeed will lose your hair - but it will grow back, although possibly with a different texture. Whether you are nauseated will depend on the drugs and how your body responds. The nausea probably will be mild and alleviated by the antinausea drugs used today. You may or may not be tired; many women make minor changes at work to make their days easier during this period.

Treatment centers today are geared toward making chemotherapy as problem-free as possible. The nurse or medical oncologist will recommend medications and give practical suggestions for alleviating the discomforts of therapy. It's important not to suffer even mild discomfort in silence. Instead, talk to your health care professionals about how to relieve any symptoms you experience. A good rule of thumb is to report every problem - even those that appear minor - to your oncologist.

It is especially important for your oncologist to try and prevent the development of nausea and vomiting associated with the initial cycles of chemotherapy. By doing so, many patients will be able to avoid a later consequence of chemotherapy, called anticipatory nausea and vomiting. This anticipatory situation occurs when the patient revisits the hospital or office where the first chemotherapy was administered that was associated with nausea and vomiting. If the nausea and vomiting is eliminated initially, the anticipatory nausea component may be avoided later.

Allergic reactions. Like many medications, chemotherapy drugs can cause allergic reactions in some people. Facial flushing, itching, a rash, or shortness of breath may all be signs of allergy and should be reported promptly. Changes in the regimen can minimize the possibility of future allergic reactions.

Temporary effects. The short-term effects of chemotherapy depend on the drug, the dosage, the length of treatment, and the individual. Because hair loss is so common, many women buy a wig, scarves, or other head covering before they start therapy. Some side effects, such as nausea, discontinue almost as soon as the treatment stops. Hair begins to grow back within a month of ending treatment. Many women also find that they have trouble concentrating and remembering things (see "Chemotherapy and the brain").

Later effects. A decrease in blood cell counts is likely to occur because the drugs suppress bone marrow growth. A decrease in white blood cells, which fight off infection, may make a person more susceptible to infections. A shortage of red blood cells leads to fatigue, and fewer blood platelets may mean more bleeding or bruising after minor injuries. Blood cell counts usually improve on their own, but if necessary, growth factor drugs can be used to boost bone marrow recovery. These growth factor drugs stimulate the production of important blood cells from the bone marrow.

Potential permanent complications. Chemotherapy can affect fertility: Menstrual cycles may become temporarily irregular or may stop permanently, sometimes making a woman unable to become pregnant. However, pregnancy can still occur during and after chemotherapy. In general, women who are sexually active and wish to prevent pregnancy should use nonhormonal methods of birth control (such as condoms, diaphragms, or a nonhormonal IUD).

Created by the Faculty of the Harvard Medical School

Copyright Harvard Medical School, Harvard University, 2007

Last updated:	April 23, 2007