Breast Cancer Flashcards
Proto-oncogenes
Promote cell growth and reproduction
Mutated —> oncogenes (cancer causing)
Tumour suppressor genes
Inhibit cell division
Mutation —> divide in uncontrolled manner
Tumour/neoplasm
Expanding mass of abnormal cells
Benign tumour grows locally —> cannot spread by invading surrounding cells or metastasis
Malignant cells —> invade surrounding cells, enter blood vessels and metastasis
Individual risks
Macro env —> chemicals, viruses, radiation, physical agents
Micro env —> oxyradicals, hormones, growth factors
Gatekeeper genes —> cell cycle control, programmed cell death
Caretaker genes —> carcinogen metabolism, DNA repair
BRCA
Starts in milk ducts or lobules
Spreads to lymph nodes near armpit
Surgical biopsy to remove 1 or more nodes to determine cancer
Receptors
HR: Hormone receptors —> ER: estrogen receptor ; PR: progesterone receptor
HER2: Human epidermal growth factor receptor 2
Patients with ER and PR+ tumours have better survival than HR- —> HR+ tumours more responsive to endocrine therapy
In situ (in original place)
Non invasive
Ductal carcinoma in situ (DCIS) —> may or may not progress to invasive cancer
Lobular carcinoma in Situ (LCIS) —> not considered true cancer but a risk factor for developing invasive cancer in long run
Invasive
Luminal A (HR+ / HER2-) —> majority of invasive BRCA ; most favourable prognosis ; more responsive to hormonal tax ; least aggressive, grow slowly
Luminal B (HR+/HER2+)
HER2-enriched (HR-/HER2+)
Triple negative (HR-/HER2-) —> currently no targeted therapies
Metastasis
Via blood/lymphatic vessels
Establish new tumour at other sites
Signs and symptoms
Breast lump
Nipple puckered (indrawn) or bleeding
Swelling of breast skin
Dimpling of breast skin — texture similar to orange peel
Nipple discharge
Breast pain
Enlarged lymph nodes of armpit
Risk factors
Gender —> female
Increased age
Genetic factors —> family history of BRCA / ovarian CA ; personal history of breast cancer — prior history in 1 breast have increased risk in other
BRCA1, BCRA2 gene mutations —> originally produce tumour suppressor proteins ; occur in approx half of families with history of breast or ovarian CA
Factors associated with estrogen exposure —> reproductive factors (early menarche/ 1st menstruation, late menopause, have 1st child at older age, never been pregnant) ; prolonged hormone replacement therapy ; high bone mineral density
Postmenopausal obesity — fat largest source of estrogen
Alcohol consumption
Exposure to ionizing radiation
Tobacco use
Primary prevention
Maintain childhood dietary intake of veg, fruits, whole grains and reduce animal protein
Increase and maintain physical activity through childhood, adolescence and adult years
Reduce weight gain during adult years
Reduce alcohol intake btw menarche and 1st birth / throughout life course
Reduce hormone therapy
Drugs targeted to reduce BRCA risk
Selective Estrogen Receptor Modulators (SERMs)
Tamoxifen competes with estrogen for binding to receptor
2.53 x greater risk of endometrial cancer
3x greater risk pulmonary embolism
2x risk stroke
Aromatase inhibitors
Exemestane
Inhibit testosterone conversion to estrogen
Hot flashes, fatigue
Not FDA approved
Prophylactic mastectomy
Surgical removal of 1 or both breasts
Prophylactic oophorectomy / ovarian ablation
Removing ovaries and fallopian tubes
Eliminate source of estrogen
Abrupt onset of menopausal symptoms — sleep disturbances, mood changes, anxiety, depression
Secondary prevention
Screening —> earlier the detection ,greater chances of survival
Mammography
X ray of breast
May miss some (False negatives)
Cancer is present when not (false positives)
Overdiagnosis —> treatment of insignificant cancers
Clinical breast examination
Performed by physician
Breast self examination
Empower women to take responsibility for own health
Raise awareness rather than as screening
Tumour grading
- Low grade: Well differentiated —> spread more slowly ; look like normal cells
- Intermediate grade: Moderately differentiated
- High grade: poorly differentiated —> more aggressive
TNM staging system
T: Tumour (0,1,2,3,4) —> size of primary tumour, extent of spread to nearby tissue
N: Node status (0,1,2,3) —> extent of spread to lymph nodes
M: Metastasis (0,1) —> extent of spread to parts beyond breast
Higher numbers more advanced cancer
Stage 0
Limited to inside of milk duct
Non invasive
E.g. DCIS
Stage 1
Small and have not spread to nodes
Tiny area of cancer spread in sentinel lymph node
