Breast Cancer Flashcards
Epidemiology
2nd leading cause of cancer mortality in women (1st is lung cancer)
Most common cancer diagnosis in Canadian women
1/9 women in Canada dx in their lifetime
1/27 women will die from breast cancer
Risk factors
BRCA gene
BRCA1 lifetime risk - breast 57-65%, ovarian 39%
BRCA2 lifetime risk - breast 45-55%, ovarian 11-17%
Prevalence 1 in 300-500
1 in 50 in Ashkenazi Jewish
Female 99%
Age - new diagnosis 80% > 50 years old, 28% >70
Prior hx of breast cancer, prior breast biopsy
1st degree relative with breast cancer (risk increases 2x) or relative with BRCA
Unopposed estrogen (nulliparity, first pregnancy >30 y/o, menarche <12, menopause >55 y/o, not breastfeeding, >5 year HRT)
Radiation exposure (ex. Mantle radiation in Hodgkin’s lymphoma)
Hx benign breast disease - moderate/florid hyperplasia 2x, atypical hyperplasia 4x, sclerosing adenosis 1.5x, papilloma 1.5x
Modifiable -
decreased weight, increased activity (RR 30%), decreased EtOH (2-3/day increase risk by 43%), decreased hormone exposure, early pregnancy (OR 0.79 if <35 yo), breastfeeding (RR 4.3% per 12 months)
Reducing fat has not been shown to reduce risk
Screening
Screening mammography
Sens 79%, Spec 94%
40-49 - recommend NOT screening
50-69 - screen q2-3 years based on patient preference
70-74 - screen q2-3 years based on patient preference
No longer recommended to do breast exams or self-breast exams
Risk of mammography
Radiation exposure
Pain
Anxiety
False +
High risk screening
Females 30-69 yo are eligible for annual mammography/MRI if:
known BRCA 1/2 carrier
1st degree relative BRCA 1/2 carrier
Chest radiation <30 yo and at least 8 years ago
>25% lifetime risk using IBIS or BOADICEA tools
MRI picks up extra CA than mammogram + u/s, though mammogram still better for ductal carcinoma in situ
Genetic screening for BRCA 1/2 if breast CA <50 yo, especially <35 ovarian CA bilateral breast CA breast + ovarian CA in same female multiple breast CA on the same side of the family male breast CA Ashkenazi Jewish ethnicity
Prevention in high risk patients
Mastectomy + salpingo-oophorectomy
US preventative task force recommending considering chemoprevention
Ductal carcinoma in situ etiology and presentation
Proliferation of malignant ductal epithelial
80% non-palpable - detected by screening
Lobular carcinoma in situ etiology and presentation
Neoplastic contained within breast lobule
None palpable, not on mammography, usually found on biopsy
Infiltrative ductal carcinoma prevalence, etiology and presentation
Most common 80%
Hard scirrhous, infiltrating tentacles, gritty on cross section
Invasive lobular carcinoma prevalence, etiology and presentation
8-15%, 20% bilateral
Originates from lobular epithelium, hard to detect
Paget’s disease prevalence, etiology and presentation
1-3%
Ductal CA invades nipple with eczema
Inflammatory carcinoma prevalence, etiology and presentation
1-4%
Ductal carcinoma that invades dermal lymphatics
Most aggressive form - erythema, edema, warm, tender
Peau d’orange indicates advanced disease (IIIb-IV)
Investigations
Initial investigation
0-30 u/s
>30 u/s + mammogram
Needle aspiration for palpable cystic lesions
Fine needle aspiration for solid masses
Core needle biopsy
Excisional biopsy
If diagnosed with breast cancer: bone scan, abdo u/s, CXR, head CT
For newly diagnosed stage 1 asymptomatic females, there is little justification for imaging to detect metastasis
Stage 0, tumour description, nodes/metastasis, 5 year survival, treatment
In situ
None
99%
Breast conserving surgery (BCS) +/- radiotherapy, mastectomy
Stage I, tumour description, nodes/metastasis, 5 year survival, treatment
<2 cm
None
94%
BCS + axillary node dissection + radiotherapy
mastectomy +/- chemo
