Breast Cancer Risk Factors

Study Notes

5-10% of breast cancers are hereditary, increasing risk if:
- Parent/sibling/child have breast/ovarian cancer, especially under 50 years old
- Multiple close relatives are affected by breast or ovarian cancer
- Relatives have both breast and ovarian cancer
- Relatives were diagnosed with breast cancer before menopause
- Relatives have bilateral breast cancer
- Are of Ashkenazi (Eastern European) Jewish ancestry
BRCA gene: hereditary, Ashkenazi (Eastern European) Jewish ancestry, mutation of the tumor-suppressing gene

BI-RADS (Breast Imaging Reporting and Data System) levels of breast density:
- A: Almost entirely fatty (1 in 10 women)
- B: Scattered areas of fibroglandular tissue (4 in 10 women)
- C: Heterogeneously dense (4 in 10 women)
- D: Extremely dense (1 in 10 women)

CC:
- Medial aspect shown
- As much axillary tail as possible
- Pectoral muscle shadow at chest wall
MLO:
- Pectoral muscle shadow to nipple level
- Pectoral muscle at appropriate angle
- Nipples in profile
- Infra-mammary angle clearly demonstrated
Additional views:
- Lateral: better localize medial or lateral lesions, shows effects of gravity on air-fluid levels
- Extended view: for imaging axillary tail
- Cleavage view: for imaging medial and posterior breast tissue
- Compression spot views: provides better tissue separation and visualization
- Magnification views: similar to spot views, but with additional platform to reduce SID
- Tomosynthesis: 2D views taken at multiple angles to provide a 3D view
- Push back views: for breast implants

Screening:
- Every 2 years for females aged 45-69
- Have not had a mammogram within the previous 12 months
- Not pregnant or breastfeeding
- Free from cancer
- Asymptomatic
- Eligible for public health services in NZ
Diagnostic:
- For males or females who are symptomatic, of any age
- Referred by GP
- Additional imaging used initially
- Under 35 will have U/S first

Cooper's ligaments: help maintain structure and shape of breast, connecting lobules to skin surface
Montgomery glands: protrusions on the surface of the areola, providing lubrication during lactation

Ultrasound:
- For women under 35
- Assess lesions for size, shape, density
- Useful for helping to diagnose cancer in people with dense breast tissue
- Best modality for looking at lesions and localized areas
Appearance on U/S:
- Benign:
  - Cysts: fluid accumulation inside gland/s in the breast
  - Fibroadenoma: lumps from excess proliferation of connective tissue
- Malignant:
  - DCIS: ductal carcinoma in situ, cells lining milk ducts become cancerous
  - Lobular carcinoma: starts in milk-producing glands (lobules) of the breast
  - Inflammatory breast cancer: rare, aggressive, occurs in younger women, worse prognosis
  - Triple-negative breast cancer: a type of breast cancer where cells lack receptors for estrogen and progesterone hormones and the HER2 protein

First lymph node to receive lymphatic fluid from the breast
Sentinel node is biopsied (sentinel node biopsy) and tested to determine breast cancer staging

kVp range: 24-35 kVp
Tube angle: 20-24 degrees
Tube heads: tilted to cover entire image field, utilize anode heel effect, and get tube parallel to chest wall
Filters: commonly made of Molybdenum (Mo) or Rhodium (Rh)
Target material: made of Molybdenum (Mo) or Rhodium (Rh)
Ideal target/filter combinations: Rhodium/Rhodium or Tungsten/Rhodium
AEC: positioned behind the detector to reduce OID and improve spatial resolution
Detector: composed of Cesium Iodide crystals (Indirect) or Amorphous silicon (Direct)
Preferred detector composition: Direct
Focal spot sizes: 0.1mm or 0.3mm
Face shield: to ensure no artifacts from the head in the x-ray beam and to reduce dose to the eyes and thyroid