breast cancer
A malignant neoplasm (usually an adenocarcinoma) of the breast; the most common malignancy of American women and the leading cause of death in American women aged 40 to 55.
Incidence: In 2024 the American Cancer Society estimated that nearly 314,000 Americans would be newly diagnosed with invasive breast cancer and that approx. 43,000 would die of the disease.
Causes: There are several known risk factors for breast cancer.
SEE: table - Selected Risk Factors for Breast Cancer .
Symptoms and Signs: Breast cancer usually presents as a dominant mass in one breast, although the malignancy may first become evident when nipple discharge, nipple retraction, skin dimpling, or asymmetrical swelling of the breast occurs. In most cases breast cancers are first identified by women performing breast self-examination. A smaller but considerable number are detected by professional examination or mammography. About 1000 men are diagnosed with breast cancer annually. Breast cancer has several pathological variants. Carcinoma in situ, the most localized form of the disease, represents a preinvasive stage confined to a duct or lobule. Other presentations include lobular carcinoma, infiltrating ductal carcinoma, inflammatory carcinoma, and Paget disease of the nipple.
Diagnosis: Regular breast self-examination, professional breast examination, and mammography are the keys to screening for breast cancer. All these screenings identify many more benign lesions than malignant ones, esp. in younger patients, and none of these techniques can definitively exclude breast cancer. Many mammographically detected lesions are benign, and about 15% of the time mammography will fail to detect lesions that are truly malignant. Digital mammography provides significantly better detection in women with dense breasts, those under age 50, and those who are premenopausal or perimenopausal. If a suspicious mass is identified, fine needle aspiration, core biopsy, or excisional biopsy must be used to obtain tissue for analysis. Ultrasonography can be used before biopsy to identify solid masses and cysts. Solid breast masses have a much greater chance of being malignant than cysts. Other imaging techniques used to help identify breast cancers include magnetic resonance imaging, positron emission tomography, and ductal imaging.
SEE: table - Common and Experimental Techniques Used in Breast Imaging.
SEE: breast self-examination; double reading; mammography.
Staging: The size of tumors and their possible metastasis to the chest wall, skin, axillae, or distant sites all determine the stage of breast cancer. Lymphatic mapping during cancer surgery can be used to find metastases to sentinel lymph nodes and guide therapies. Staging provides important information about the need for particular forms of therapy and the prognosis.
SEE: illus..
A biopsy (obtained by fine needle aspiration, with a stereotactic core needle, or by surgical lumpectomy) is usually recommended for any breast mass that does not resolve spontaneously within one or two menstrual cycles and for all postmenopausal women. Negative results from mammography and ultrasonography are not always accurate enough to rule out a malignant diagnosis.Treatment: Combined modalities (including surgery, radiation, or drug therapies) are offered to many women with breast cancer, depending on their menopausal status and the stage of their disease at the time of diagnosis. Patients with stage I or II disease are offered either modified radical mastectomy (removal of the breast and 20 to 30 axillary lymph nodes) or lumpectomy with sentinel node or axillary dissection (as required) and radiotherapy, provided they have no contraindications to either of these choices. A variety of radiotherapy options are available, depending upon the individual patient's cancer. In premenopausal women with tumors larger than a centimeter, adjuvant chemotherapy prolongs survival, probably by eliminating microscopic metastases. Chemotherapeutic regimens commonly used include CMF (cyclophosphamide, methotrexate, and fluorouracil), CAF (cyclophosphamide, doxorubicin [Adriamycin], and fluorouracil), AC (doxorubicin [Adriamycin] and cyclophosphamide), doxorubicin (Adriamycin) followed by CMF, or FEC (fluorouracil, epirubicin, and cyclophosphamide). All of these agents are given several times in cycles of treatment. These same regimens are offered to vigorous postmenopausal women whose cancer has spread to axillary lymph nodes. Hormonal therapies like tamoxifen or raloxifene (two estrogen-receptor blockers) are also beneficial in patients with estrogen-receptor–positive tumors. Aromatase inhibitors (such as letrozole), and monoclonal antibodies (such as trastuzumab) may be prescribed for selected patients. After breast surgery, some women elect to have cosmetic restoration of the breast, either with saline- or silicone-filled implants or with tissue reconstructions made from the abdominal muscles. If breast cancer recurs after treatment, very high-dose chemotherapies are prescribed and peripheral stem cell transplantation is occasionally considered, but only in research settings. Bone metastases may be treated with monthly dosing of intravenous zoledronic acid (Zometa).
SEE: ductal carcinoma in situ of breast.
Patient Care: The patient's feelings and level of knowledge about her disease are determined. She is encouraged to express fears and concerns, and her family, supporters, or health care professionals stay with her during periods of anxiety or anguish. If surgery is planned, the procedure, postoperative care, and expected outcomes are explained.
While undergoing chemotherapy, the patient is monitored for adverse reactions (such as nausea, vomiting, anorexia, stomatitis, gastrointestinal ulceration, anemia, leukopenia, thrombocytopenia, and bleeding), so that they can be managed early. Weight and nutrition status are evaluated. The skin is inspected for redness, irritation, or breakdown if radiation therapy is prescribed, and aloe or a prescribed cream is applied. Bisphosphate drugs (such as alendronate or zolendronic acid) are administered to prevent or treat bone metastases or hypercalcemia, but their use may be associated with osteonecrosis of the jaw.
Comfort measures are used to promote relaxation and rest and to relieve anxiety. If immobility develops late in the disease, careful repositioning, excellent skin care, respiratory toilet, and low-pressure mattresses are used to prevent complications, e.g., skin breakdown, respiratory problems, and pathological fractures. The patient's and family's coping abilities are evaluated, and referral for counseling and support services may be necessary. End-stage disease patients benefit from hospice care. Women judged to be at high risk for breast cancer may have tamoxifen or ralozifene prescribed as preventative therapy.
ABBR: LABC.
Breast cancer that has spread to neighboring tissues but has not widely metastasized. LABC includes large primary tumors (larger than 5 cm in size), tumors that have spread to the skin, inflammatory breast cancer, and tumors that have spread to multiple axillary lymph nodes.