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Breast Cancer Chemotherapy

Chemotherapy drugs are used to slow or stop cancer cells from reproducing. Drugs can shrink tumors significantly, thereby controlling the disease. They improve quality of life and extend it.

Chemotherapy drugs are given independently or in combination with other medications or therapies. Drug choice depends on cancer type and cell structure, origin and degree of spreading.

Although beneficial, breast cancer chemotherapy can have negative effects such as hair loss, nausea, mouth sores, diarrhea, fatigue and reduced blood cell counts. Side effects depend on the drug used and on the patient's individual response to it.

When is Chemotherapy Used?

Unlike radiation therapy and surgery, chemotherapy reaches diseased cells throughout the body. This effect is particularly important following radiation therapy or surgery where not all affected cells are destroyed; this is known as adjuvant therapy.

Drugs are also used prior to surgery and radiation therapy to reduce tumor size and lessen tumor attachment to healthy tissue. This is called neoadjuvant chemotherapy.

Chemotherapy is also used in palliative care to help shrink the tumor and improve quality of life in metastatic breast cancer. When metastasis has occurred, drugs are often used to destroy large numbers of cells even when the risk of chemotherapy side effects is high.

Breast cancer chemotherapy is typically administered in successive treatments, each one followed by a recovery period. Treatment can last three to six months, depending on patient health, drugs used and extent of the disease.

Breast Cancer Chemotherapy Drugs

Some of the drugs used in breast cancer treatment are: arimidex, doxorubicin, femara, herceptin, tamoxifen, taxol, taxotere, and xeloda. They vary in their effectiveness, toxicity and suitability.

Chemotherapy drugs are administered in different quantities and for different durations depending on the patient's condition and the oncologist's objectives. Typical methods used are intravenous injection and oral administration.

Some current protocols for breast cancer are outlined below. Talk to your oncologist about specifics of the drug treatment options available to you.

Arimidex is a palliative therapy. Arimidex is used in the treatment of advanced disease in postmenopausal women who have failed to respond to other drugs such as tamoxifen.
Doxorubicin is an antibiotic used for locally advanced cancer. It is used to treat inflammatory breast cancer, as adjuvant therapy and in palliative care in cases of metastatic breast cancer.
Femara is used in palliative care. Femara is used to treat postmenopausal patients with advanced cancer.
Herceptin is used in palliative care for patients with metastatic breast cancer. Herceptin is a form of "immunotherapy" in which monoclonal antibodies target cancer cells. Herceptin is used alone or in combination with Taxol as a first line treatment for some metastatic tumors.
Tamoxifen is used in adjuvant chemotherapy to stop or slow the growth of diseased cells. The hormone estrogen is known to stimulate breast cancer cell reproduction by attaching to affected cells at estrogen receptor sites. Tamoxifen interferes with estrogen binding. It is also used in palliative care.
Taxol is used as a follow up to doxorubicin in adjuvant therapy, and in palliative care in cases of metastasis.
Taxotere is used alone or in combination with other treatments in cases of locally advanced or metastatic breast cancer.
Xeloda is used to treat metastatic breast cancer. It enters diseased cells and is metabolized into a cancer-killing drug (5-FU). Xeloda can be taken as oral tablets.

Poor Response to Chemotherapy Does Not Mean Poor Prognosis
In the past it was thought that poor response to chemotherapy was indicative of a poor outcome. New research indicates that this isn't necessarily true. Women with lobular breast cancer, which typically responds poorly to chemotherapy, actually live longer than women with ductal breast cancer, the most common type of invasive breast cancer, that responded well to chemotherapy. All of the women in the study received chemotherapy prior to surgery. Of the women with ductal cancer 66 percent were recurrence-free five years after surgery while 87 percent of women with lobular breast cancer were recurrence-free after five years.

Resources

American Cancer Society. (2004). Chemotherapy for breast cancer.

BC Cancer Agency. (2004). Chemotherapy protocols – Breast.

CancerBACUP. (updated 2004). Chemotherapy.

Cristofanilli, M., Gonzalez-Angulo, A., Sneige, N., Kau, S-W., Broglio, K., Theriault, R., Valero, V., et al. (2005, January 1). Invasive lobular carcinoma classic type: Response to primary chemotherapy and survival outcomes. Journal of Clinical Oncology 23(1), 41-48.