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Key Points
The breast receives its principal blood supply from perforating branches of the internal mammary artery, lateral branches of the posterior intercostal arteries, and branches from the axillary artery, including the highest thoracic, lateral thoracic, and pectoral branches of the thoracoacromial artery.
The axillary lymph nodes usually receive >75% of the lymph drainage from the breast, and the rest flows through the lymph vessels that accompany the perforating branches of the internal mammary artery and enters the parasternal (internal mammary) group of lymph nodes.
Breast development and function are initiated by a variety of hormonal stimuli, with the major trophic effects being modulated by estrogen, progesterone, and prolactin.
Benign breast disorders and diseases are related to the normal processes of reproductive life and to involution, and there is a spectrum of breast conditions that ranges from normal to disorder to disease (aberrations of normal development and involution classification).
To calculate breast cancer risk using the Gail model, a woman’s risk factors are translated into an overall risk score by multiplying her relative risks from several categories. This risk score is then compared with an adjusted population risk of breast cancer to determine the woman’s individual risk. This model is not appropriate for use in women with a known BRCA1 or BRCA2 mutation or women with lobular or ductal carcinoma in situ.
Routine use of screening mammography in women ≥50 years of age reduces mortality from breast cancer by 25%. Magnetic resonance imaging (MRI) screening is recommended in women with BRCA mutations and may be considered in women with a greater than 20% to 25% lifetime risk of developing breast cancer.
Core-needle biopsy is the preferred method for diagnosis of palpable or nonpalpable breast abnormalities.
When a diagnosis of breast cancer is made, the surgeon should determine the clinical stage, histologic characteristics, and appropriate biomarker levels before initiating local therapy.
Sentinel node dissection is the preferred method for staging of the regional lymph nodes in women with clinically node-negative invasive breast cancer. Axillary dissection may be avoided in women with one to two positive sentinel nodes who are treated with breast conserving surgery, whole breast radiation, and systemic therapy.
Local-regional and systemic therapy decisions for an individual patient with breast cancer are best made using a multidisciplinary treatment approach. The sequencing of therapies is dependent on patient and tumor related factors including breast cancer subtype.
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A BRIEF HISTORY OF BREAST CANCER THERAPY
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Breast cancer has captured the attention of surgeons throughout the ages. The Smith Surgical Papyrus (3000–2500 B.C.) is the earliest known document to refer to breast cancer. The cancer was in a man, but the description encompassed most of the common clinical features. In reference to this cancer, the author concluded, “There is no treatment.”1 There were few other historical references to breast cancer until the first century. In De Medicina, Celsus commented on the value of operations ...