Benign Breast Disease and Breast Cancer

• Breast cancer is the most common malignancy in women in the United States (except for skin cancers), representing approximately 30% of female cancers and 230,000 new diagnoses each year in the United States
• Breast cancer is the second most common cause of cancer deaths in women (after lung cancer deaths), accounting for some 40,000 deaths per year
• A woman has a one in eight chance (12%) of developing invasive breast cancer over her lifetime
• The cause of breast cancer remains unknown
• As many as 50% of women will have benign breast lesions over their lifetime
• Obstetrician-gynecologists, primary care providers, and surgeons perform evaluations of breast pain, nipple discharge, and breast masses and also screen for breast cancer
• Breast parenchyma


  • Divided into segments containing mammary glands that consist of 20 to 40 lobules drained by lactiferous ducts that open individually into the nipple
  • Fibrous bands spanning between two fascia layers—called Cooper suspensory ligaments-support the breast
  • Breast is divided into four quadrants for ease of description: upper outer quadrant (UOQ), lower outer quadrant, upper inner quadrant (UIQ), and lower inner quadrant (LIQ)
• Blood supply to the breast

  • Major blood supply is from the internal mammary and lateral thoracic arteries
  • Medial and central aspects are supplied by the anterior perforators of the internal mammary artery, and the UOQ is supplied by the lateral thoracic
• Lymph drainage of the breast

  • Axillary lymph nodes drain up to 97% of the ipsilateral breast, and secondarily drain the supraclavicular and jugular nodes
  • Internal mammary nodes are responsible for 3% of drainage, mainly of the UIQ and LIQ
  • Interpectoral nodes (Rotter nodes) lie between the pectoralis major and pectoralis minor muscles
• Innervation of the breast

  • Nerves at risk of injury include the intercostobrachial nerve, the long thoracic nerve (of Bell), the thoracodorsal nerve, and the lateral pectoral nerve
• Breast development


  • Classified into Tanner stages 1 to 5
  • Responds to cyclic hormones, as well as to changes during pregnancy and menopause
  • Estrogen promotes ductal development and fat deposition
  • Progesterones promote the lobular-alveolar (stromal) development that makes lactation possible
  • Prolactin is involved in milk production, whereas oxytocin from the posterior pituitary causes milk letdown
  • In postmenopausal women, the hypoestrogemic state is associated with tissue atrophy, loss of stroma, and replacement of atrophied lobules with fatty tissue
• Components of breast cancer screening for women at average risk

  • Clinical breast examination
  • Breast self-examination
  • Screening mammography
• Clinical breast examination


  Careful inspection of the skin for contour or color changes, dimpling, and retractions with the patient in upright and supine positions, followed by palpation of the axilla for lymphadenopathy and the breast for masses, nipple discharge, or pain
• Breast self-examination


  Emphasis has moved from the monthly breast self-examination toward general "breast self-awareness" which encourages women to become familiar with their breasts and to report any changes from baseline
• Screening mammography


  Current guidelines by the American Cancer Society include a mammogram every year starting at age 40 and continuing for as long as a woman is in good health
• Women at high risk of breast cancer

  • Those who have a known BRCA1 or BRCA2 gene mutation
  • Those with a first-degree relative (mother, sister, or daughter) with either mutation
  • Those deemed to be at high risk based on a validated risk assessment tool (e.g., Gail or Claus model)
  • Those who underwent radiation to the chest between the ages of 10 and 30
  • Those with a hereditary syndrome associated with multiple cancer diagnoses (e.g., Li-Fraumeni, Lynch II syndrome)
• Screening recommendations for women at high risk

  • Teaching of breast self-awareness
  • Clinical breast examination every 6 to 12 months
  • Annual mammography starting at age 25 or 5 to 10 years before the age of the youngest cancer diagnosis in the family
  • Interval breast MRIs along with the annual screening mammogram
• Women at moderate risk of breast cancer

  • Those deemed to be at moderate risk based on a validated screening tool
  • Those with a personal history of breast cancer or its precursor lesions
  • Those who have particularly dense breast tissue on mammogram
• Ultrasonography


  Useful in the evaluation of uncertain mammographic findings, in women younger than 40, in women with dense breast tissue, and as a tool to guide a needle for breast biopsies
• Digital mammography


  Better imaging modality in women with dense breasts, women younger than 50, and premenopausal or perimenopausal women
• Breast pain (mastalgia, mastodynia)

  • Typically mild and may be cyclic (67%) or noncyclic (33%) in nature
  • Can be a normal physiologic response to hormonal fluctuations, or a pathologic response to trauma or malignancy
  • Only 1% to 7% of women with breast pain will have underlying malignancy
• Nipple discharge


  • As many as 50% to 80% of women will have nipple discharge at some point during their reproductive years
  • The vast majority of nipple discharge is due to normal physiology or benign processes, and only 5% is associated with underlying malignancy
  • The most concerning discharge is spontaneous, bloody or serosanguineous, unilateral, persistent, from a single duct and associated with a mass
  • Bilateral, nonbloody, multiductal secretion is usually benign regardless of color
• Breast masses


  • The most common causes are fibroadenomas and breast cysts
  • Worrisome lumps are dominant, discrete, and dense
  • Malignant masses are classically single, firm, nontender, and immobile with irregular borders
  • Lymph nodes are worrisome if larger than 1 cm, fixed, irregular, firm, or multiple
• Mammography


  • Up to 10% to 15% of new breast cancers are not seen or detected via mammography
  • A suspicious mass should never be dismissed just because the mammogram is negative
• Breast masses


  The most common causes are fibroadenomas and breast cysts
• Evaluating a breast mass

  1. Ascertain manner of discovery

  2. Associated tenderness or trauma

  3. Relationship to menstrual cycle

  4. Location, size, shape, consistency, mobility

  5. Overlying skin changes
• Worrisome lumps


  • Dominant, discrete, dense
• Malignant masses


  • Single, firm, non-tender, immobile with irregular borders
• Worrisome lymph nodes


  • Larger than 1 cm, fixed, irregular, firm, or multiple
• Evaluating abnormal breast masses

  1. Ultrasound for women <30 years

  2. Mammography for women ≥30 years

  3. Biopsy to obtain pathologic diagnosis
• BI-RADS


  Collaborative scoring system to standardize mammogram reporting and categorize findings
• Mammographic findings most suggestive of malignancy

  • Spiculated mass
  • Architectural distortion with retraction
  • Asymmetric localized fibrosis
  • Microcalcifications with linear, branched patterns
  • Increased vascularity
  • Altered subareolar duct pattern
• Evaluating palpable mass or abnormality on imaging

  1. Mammography (if not previously performed)

  2. Biopsy to obtain pathologic diagnosis
• Evaluating palpable cystic mass

  Needle aspiration to drain and sample for diagnosis
• Evaluating palpable solid mass in women <30 years

  Fine-needle aspiration
• Evaluating palpable solid mass in women ≥30 years

  Core-needle biopsy
• Evaluating nonpalpable abnormal mammogram finding

  Wire-guided excisional biopsy
• Benign breast symptoms and findings are common, occurring in approximately 50% of women
• Two-thirds of tumors in reproductive-age women are benign, whereas half of palpable masses in perimenopausal women and the majority of lesions in postmenopausal women are malignant
• Fibrocystic breast changes


  Spectrum of clinical findings due to exaggerated stromal response to hormones and growth factors