Breast cancer
Description
An in-depth report on the causes, diagnosis, treatment, and prevention of breast cancer.
Alternative Names
Mammograms; Mastectomy
Treatment
The three major treatments of breast cancer are surgery, radiation, and drug therapy. No one treatment fits every patient, and combination therapy is usually required. The choice is determined by many factors, including the age of the patient, menopausal status, the kind of cancer (ductal vs. lobular), its stage, and whether or not the tumor contains hormone-receptors.
Breast cancer treatments are defined as local or systemic:
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Local Treatment.
Surgery and radiation are considered local therapies because they directly treat the tumor, breast, lymph nodes, or other specific regions. Surgery is usually the standard initial treatment.
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Systemic Treatment.
Drug treatment is called
systemic
therapy, because it affects the whole body.
Any or all of these therapies may be used separately or, most often, in different combinations. For example, radiation alone or with chemotherapy or hormone therapy may be beneficial before surgery, if the tumor is large or not easily removed at prevention. The optimal sequence for these therapies is being investigated. (Specific treatments and combinations are discussed in the sections below.)
Stage 0
This stage is also called noninvasive carcinoma or carcinoma in situ.
Treatment Options for Lobular Carcinoma in Situ.
These are abnormal cells that pose a long-term risk for invasive cancer. (1) Careful monitoring with or without preventive use of tamoxifen or other selective estrogen-receptor modulators (SERMs). (2) In selected cases, consideration of removal of both breasts, since if the cancer does develop, it tends to do so in both breasts or to be invasive. In one study, chance for invasive cancer over a 25-year period was 25%.
Treatment Options for Ductal Carcinoma in Situ.
These are cancer cells in the lining of a duct that have not invaded the surrounding breast tissue. (1) Mastectomy previously was the commonly recommended treatment. (2) Breast-sparing surgery (typically without lymph-node removal) followed by radiation therapy is reasonable for many women. The risk for recurrence with a more invasive cancer is higher in women under 45 than in older women with this approach. (3) Use of tamoxifen or other SERMs after surgery and radiation to prevent recurrence in selected patients.
Stage I and Stage II
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Stage I. Cancer cells have not spread beyond the breast, and the tumor is no more than 2 cm (about 3/4 of an inch) across.
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Stage II. One of the following conditions apply: the tumor is less than 2 cm across, and the cancer has spread to the lymph nodes under the arm; the tumor is between 2 and 5 cm (about 3/4 inch to 2 inches) with or without spreading to the lymph nodes under the arm; the tumor is larger than 5 cm but has not spread to the lymph nodes under the arm.
Primary Treatment Options for Stage I and II Breast Cancers.
Choice of (1) Breast-sparing surgery (typically lumpectomy, usually with lymph node sampling) followed by external beam radiation therapy. (2) Modified or radical mastectomy with or without breast reconstruction. (3) Removal or radiation of lymph nodes. Choice between (1) and (2) depends mostly on the size and location of the tumor, the size of the breast, certain features of the cancer, and how the woman feels about preserving her breast. Considerations by tumor size are as follows:
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Tumors under 2 cm: Women can generally choose lumpectomy followed by radiation.
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Tumors between 2 cm and 5 cm. Even if tumors are up to 5 cm, a 2000 international study suggested that lumpectomy and mastectomy offer equivalent survival rates (about 66%) and time to metastasis at 10 years. In the study, however, local recurrence occurred in 20% of lumpectomy and 12% of mastectomy patients.
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Tumors over 5 cm: Women generally choose mastectomy.
Other considerations: If women choose breast-sparing procedures, the risk for recurrence is lower with removal of as much breast tissue as possible. In women who experience a local recurrence after treatment, those who have chosen lumpectomy and radiation tend to have a better outlook than women who chose mastectomy, since cancers in the latter case would develop in the chest wall.
Adjuvant and Neoadjuvant Treatment Options.
Adjuvant therapy is administered in addition to surgery or radiation therapy to prevent recurrence.
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Hormone receptor-negative cancers. Combination chemotherapy is often used. Trastuzumab (Herceptin) plus standard chemotherapy has shown outstanding promise in increasing disease-free survival for patients with lymph-node positive cancer.
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Hormone receptor-positive cancers. Tamoxifen is the standard drug and is administered for about 5 years. Aromatase inhibitors (letrozole, anastrozole, and exemestane) are showing promise in adjuvant treatment. Some studies indicate that they are more effective than tamoxifen. Ovarian ablation using goserelin alone or in combination with tamoxifen plus goserelin is also showing specific benefits.
Assessing Risk of Recurrence.
A new genetic test (Onco
type
DX) can help determine the likelihood of late recurrence (for example, recurrence in 5 or 10 years) in newly diagnosed patients whose breast cancer is Stage I or II, node negative, estrogen receptor positive, and who will be treated with tamoxifen. Knowing whether their tumor has a low, moderate, or high risk of recurrence may help women determine the best course of treatment. Importantly, it may help those with low-risk tumors avoid overly aggressive treatment.
Stage III (Locally Advanced)
In this stage, the tumor in the breast is more than 5 cm across, and:
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It has spread (sometimes extensively) to the underarm lymph nodes.
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It has spread to other lymph nodes or tissues near the breast.
A condition called inflammatory breast cancer is also treated as a Stage III cancer.
Treatment Options for Stage III.
(1) Standard therapy is mastectomy usually with radiation therapy and systemic treatment (combination chemotherapy, hormonal therapy, or both). (In very advanced Stage III, systemic drug therapy, radiation, or both sometimes achieve a response that allows a woman to avoid mastectomy, although this approach does not increase survival rates.) (2) Radiation after surgery is now recommended for women with four or more involved lymph nodes or an extensive primary tumor. It is not yet clear if radiation would benefit women with one to three involved lymph nodes. (3) Clinical trials: high-dose chemotherapy and stem cell transplantation; new chemotherapeutic, hormonal, or biologic drugs; neoadjuvant therapies using taxanes alone or concurrent taxane and radiation treatment; post surgical radiation for women with one to three involved lymph nodes.
Stage IV (Metastasized Cancer)
In Stage IV the cancer has spread from the breast to other parts of the body. In about 75% of cases, the cancer has spread to the bone. The cancer at this stage is considered to be chronic and incurable, and the usefulness of treatments is limited. The goals of treatment for Stage IV are a complete or partial response, stabilization of the disease, or slowing disease progression.
Treatment Options for Stage IV.
(1) Surgery or radiation for any localized tumors in the breast. A 2006 study indicated that surgical removal of the primary tumor immediately after metastatic cancer diagnosis can dramatically improve survival.
(2) Chemotherapy, hormonal drugs, or both are appropriate for most patients (durable and complete remission possible in 10 - 20% of cases but cure is very rare). Chemotherapy in patients with hormone receptor-negative disease or who have extensive metastasis that requires rapid tumor shrinkage. Ovarian ablation (in premenopausal women) or other hormonal therapies in patients with hormone receptor-positive cancer and no or minimal organ involvement. (Aromatase inhibitors, taxanes, and other drugs used in combination or in innovative schedules are improving results.) In 2004, the cancer drug gemcitabine (Gemzar) was approved for use in combination with paclitaxel (Taxol) as a first-line treatment option for women with metastatic breast cancer.
(3) Metastasis to the brain may require radiation and high-dose steroids.
(4) Metastasis to the bone (which occurs in 75% of cases) may be helped with radiation and bisphosphonates. Such treatments can relieve pain and help prevent bone fractures.
(5) Clinical trials: Standard hormonal or chemotherapy drugs used as initial treatment, newly developed chemotherapeutic or hormonal drugs, monoclonal antibodies, total hormone blockade using surgery, high-dose chemotherapy with stem-cell support, immune cell transplant.
Recurrent Breast Cancer
Recurrent breast cancer is considered to be an advanced cancer. In such cases, the disease has come back in spite of the initial treatment. Most recurrences appear within the first 2 - 3 years after treatment, but breast cancer can recur many years later. Treatment options are based on the stage at which the cancer reappears, whether the tumor is hormone responsive or not, and the age of the patient. Between 10 - 20% of recurring cancers are local. Most are metastatic at presentation. All patients with recurring cancer are candidates for clinical trials.
The Effects of Emotions and Psychological Support
Recent evidence has not supported early reports of survival benefits for women with metastatic breast cancer who engage in support groups. However, studies have suggested that psychotherapy, group support, or both can relieve pain and reduce stress, particularly in women who are suffering emotionally.
Stress has been ruled out as a risk factor either for breast cancer itself or for recurrence. The role of depression, however, is unclear. A 2000 study suggested that women who had a history of major depression were four times as likely to develop breast cancer as those without clinical depression. One expert suggested the association may be based on common hormonal factors that affect both conditions. A 2003 study, however, reported a slightly higher risk for a poorer outcome in patients with breast cancer who had pre-existing depression. Those with bipolar disorder had the highest risk. Such findings are unlikely to be related to hormonal issues. More research is needed to determine if treating depression in such women will improve their prognosis.
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Review Date: 4/3/2007
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Reviewed By: Editorial Team: Greg Juhn, M.T.P.W., David R. Eltz, Kelli A. Stacy. Previously reviewed by Harvey Simon, M.D., Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital (10/2/2006).
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