Breast Cancer: Diagnosis and Treatment

Diagnosis

Breast self-examination and clinical examination by a health care provider are used for screening, although the efficacy remains controversial. Mammography screening clearly decreases mortality for women over 50 years of age. Women usually receive initial screenings at 40 to 50 years of age, but may begin earlier depending on individual risk factors.

Presenting signs and symptoms of breast cancer may include palpable breast mass (most common), dimpling, or pain; nipple inversion or unilateral nipple discharge (especially when bloody or watery); and peau d'orange ("orange peel skin"), erythema, or other skin changes.

All breast lumps should be evaluated thoroughly with mammography, ultrasound, or fine-needle aspiration biopsy (FNAB). Mammography is not usually recommended in women under 35 years of age. FNAB and ultrasound determine whether the lump is a simple cyst or a complex/solid mass.

A suspicious mass on mammogram requires tissue sample, and a mass not certainly benign requires ultrasound (or magnified or spot compression mammography).

An FNAB with bloody aspirate must be cytologically evaluated.

Recurrent/residual lumps must be re-evaluated and may need core or excisional biopsy. Solid cysts may still be diagnosed with cells from the needle. Benign cells require a mammogram and nondiagnostic cells require repeat FNAB, core, or excisional biopsy.

Complex cysts or solid masses on ultrasound need FNAB, core, or excisional biopsy for definitive evaluation.

It is important to follow up all masses that were determined to be benign, using appropriate guidelines.

Treatment

Treatment is based on the TNM staging system: primary tumor, regional lymph nodes, and distant metastasis. Surgery, radiation, and chemotherapy (including hormone therapy) are involved in primary treatment of breast cancer. Many possible algorithms exist, and each patient's presentation should be evaluated to determine the best treatment.

Factors that will affect the prognosis and preferred treatment are the size of the tumor, degree of invasiveness, lymph node involvement, menopausal status, age, hormone receptor status, and other tumor markers. Tumor histology is less important than invasiveness. Invasive disease usually requires surgical and nodal resection and postoperative adjuvant therapy, whereas in situ disease usually only requires surgery. An exception to this rule is inflammatory breast cancer, which typically calls for chemotherapy prior to surgical excision.

The choice of primary therapy often presents difficulties for doctors and patients because of patients' nonmedical priorities. Breast-conserving procedures, such as lumpectomy and segmental mastectomy followed by radiation, may be considered in the case of smaller, unifocal tumors and/or larger breasts where a good cosmetic result is anticipated. Mastectomy virtually eliminates the risk of local recurrence, but does not appear to confer higher overall survival compared with more limited surgery. Occasionally, radiation may be required after a mastectomy, such as in the case of a chest wall recurrence.

Primary treatment of breast cancer also usually includes excision of all or a sample of axillary lymph nodes. When axillary nodes are positive, chemotherapy or hormonal therapy is generally recommended. However, axillary node dissection carries risks of lymphedema. Alternatively, sentinel node biopsy, a newer and increasingly common form of nodal examination, can be performed, reducing the risk of lymphedema. However, discovery of a cancerous node on sentinel node biopsy may still necessitate further axillary lymph node removal or irradiation.

Women with estrogen-receptor-positive or progesterone-receptor-positive cancers may benefit from adjuvant treatment with tamoxifen and/or aromatase inhibitors such as exemestane or anastrozole. Conversely, women who are receptor-negative may benefit from adjuvant chemotherapy, particularly if they are under 50 years of age or premenopausal. Hormonal therapy or chemotherapy is often used in the treatment of recurrent or systemic disease. Women who have aggressive, unresponsive tumors, but who are positive for HER-2/neu gene, frequently respond to trastuzumab, a drug therapy created to target HER-2/neu protein.

Among high-risk women without breast cancer, tamoxifen taken for 5 years decreases the risk of developing breast cancer by 50% or more.²⁷