Imaging & screening Flashcards
Risk Factors for Breast Cancer
Exposure to steroid hormones (early menache, nulliparity/late age of first child, oral contraception/HRT)
Age (50% >65YRS) Weight/height FH
Carcinogens or radiation exposure
Male Breast Cancer
<1% of all breast cancers
peak age 71
Many have unusual causative agent, particularly in africa
Risk factors for male breast cancer
Work in hot environments (testicular failure). Men taking estrogens (transsexuals or prostate Ca). Undescended testis (relative risk 12)
Mumps over the age of 20 (relative risk 2.5). Obesity
Is male gynaecomastia as risk factor for breast cancer?
No
was once treated with radiotherapy which is a risk factor
Genetic risk factors for Male breast cancer
4-40% due to BRCA2 mutations–> only important risk gene in men
Men with Klinefelter’s have a similar risk of breast cancer to women
Protective Factors for Breast Cancer
Pregnancy –> age of first pregnancy-> major determinant
Oophorectomy Lactation
Late menache or early menopause
Oophorectomy as breast cancer protection
At age of 30 it reduces risk by 2/3 but by 50 there is no protective effect
Oral contraception and Breast cancer risk
Current use increases risk by 25% (from 0.006 to 0.007%) –> this returns to normal between 5 and 10 years after
HRT and Breast cancer risk
Increases risk by between 10% (1yr) and 50% (15yrs) –> still very low risk
But it slightly reduces the mortality of cancer and decreases the grade at detection
Radiation and Breast cancer risk
Increases risk by 2-8 times depending on dose
Hiroshima and Nagasaki had a 2x increase in breast cancer after bombing
Smoking and Breast cancer risk
Smoking has anti-estrogenic effects, inducing early menopause and gives lower risk of endometrial cancer but higher risk of osteoporosis
But any reduction in ER+ve breast cancers will be offset by increases in ER-ve cancers. Smokers may also have a worse prognosis
Alcohol and Breast cancer risk
A solvent for carcinogens and modulates oestrogen metabolism which increases free estrogen (E2)
Can increase risk up to 50% depending on dose
Fat intake and Breast cancer risk
Highly significant relationship between fat intake and breast cancer incidence across countries–> but at individual levels difficult to prove
Obesity and Breast cancer risk
Obesity is protective in premenopausal women but increases risk for postmenopausal women, who also have worse prognosis if fat
Height and Breast cancer risk
Much argument but probably explaining by other factors which effect both (calorie intake or genetics)
Some studies found taller women at more risk
Gamma GT and Breast cancer risk
Elevated levels are associated with liver damage
GGT >72u/l increased risk 3-4x–> GGT is related to organic pollutants, lead and cadmium which are carcinogens–> argument to monitor these women more closely
Family history and genetics in breast cancer
5% of breast cancers are genetic in basis–> only people with multiple relatives with early onset breast cancer should be worried
BRCA genes and Breast cancer risk
BRCA1 –> 65% lifetime risk of breast Ca and 40% for ovarian Ca
BRCA2 –> 45% lifetime risk of Breast Ca and 20% for ovarian Ca
Also 14% of prostate, 6% of male breast cancer and 3% pancreatic
Molecular classification of Breast cancer
Basal-like –> ER neg, HER2 neg, grade III 84%
Luminal A (high differentiation) –> ER pos, HER2 neg, grade III 19%
Luminal B (poor differentiation) –> ER pos, HER2 neg, grade III 53%
HER2-like —> ER 50/50, HER2 pos, grade III 74%
DCIS
Was rare, now 20% of screening detected cancers because of microcalcification –> major RF for invasion
Breast Imaging
Mammography–> X rays in two views converted into 3D only method valid for screening. USS–> Dynamic study which assess vascularity and elastography–> can be combined with MRI. good for young, dense breasts. MRI–>contrast to assess enhancement of lesions
PET/CT–> useful in staging
BI-RAD grading system
A way of reporting breast imaging. 1- Normal. 2- Benign finding. 3- Probably benign. 4- suspicious of malignancy. 5- highly suggestive of malignancy. 6- Biopsy proven cancer
Initial Screening of a breast lump
Under 35yrs–> USS, possibly a mammogram after,
Over 35yrs–> Mammogram, possibly an USS
If abnormality detected proceed to FNA or core biopsy
Breast cysts on imaging
Well circumscribed –> smooth, round lumps on mammogram (will not tell you if solid or cystic) USS is diagnostic
Fibroadenoma on imaging
A smooth, round or oval solid mass. Similar appearance on both mammogram and USS
Calcification on mammograms
Clustered, linear or branching calcification is characteristic of DCIS, while coarse, generalised calcification is usually benign (‘popcorn’)
Mammographic, but not palpable lesions
Stellate lesions –> starlike–> complex sclerosing lesion
Spiculated lesion–> sharp pointed body with irregular margins–> infiltrating carcinoma
Rounded lesions–> oval with smooth borders –> FA or lymph node
Definition of Breast cancer screening
Evaluation of a population asymptomatic women who have no overt signs or symptoms in an effort to detect unsuspected disease at a time when cure is still possible
Why screen for breast cancer?
1/3 of all female Ca–>most common female Ca,
Most common cause of Ca deaths worldwide
Incidence is 50-60 per 100,000–>41,000 cases/yr–>15,000 deaths/yr
RFs well known, but not cause–> Forrest report 1986 showed 30% mortality reduction
NHS breast cancer screening programme (NHSBSP) – History
set up in 1988–> originally invited 50-64yos for a single view (MLO) every three years–> 2 view mammogram at first screen (1995)–> extended to 50-70 yos
NHS breast cancer screening programme (NHSBSP) – stats
Each year–> 1.6m women screened–. 13,500 cancers detected, 1400 lives saved
1 life saved for every 8 women diagnosed
Costs 96million per year
NHS breast cancer screening programme (NHSBSP) – Aims
To detect–> Grade I tumours <10mm and high or intermediate DCIS
NHS breast cancer screening programme (NHSBSP) – Quality assuarance
Aim to detect 90% of cancers
Actually detect 80%
Why use Mammography?
Because it is the only screening tool which has been shown to reduce mortality
Only 5% of mammograms are equivocal–> most benign lesions are clearly benign and most malignant lesions are clearly malignant
NHS breast cancer screening programme (NHSBSP) — Impact
~35% reduction in breast cancer mortality among women involved
between the ages of 40-49 there is limited evidence of reduction in mortality due to false positives in this group –> cause of significant anxiety
NHS breast cancer screening programme (NHSBSP) – stages
Invitation by letter–> basic screen (two views) of each breast –> Assessment (pt may be called back for further evaluation –> Treatment if abnormality is detected
NHS breast cancer screening programme (NHSBSP) — secondary evaluation
If recalled the pt may undergo–> clinical examination, extramammographic views, ultrasounds of breasts and possibly an Xray or USS guided biopsy
NHS breast cancer screening programme (NHSBSP) — Sensitivity
Some false negatives and positives are unavoidable
Mammograms over-diagnose grade I and low grade DCIS
Over 20yrs screening saves 5.7/1000, but puts 2.3/1000 through unnecessary treatment
MRI screening of High-risk women
High-risk if–> BRCA1/2 carrier, related to 1 or strong other FH (or previously tx with radiotherapy)
MRI is able to detect smaller, earlier tumours ( combination of MRI & mammogram most sensitive
Only offered to high risk women under age of 50yrs
Disadvantages of MRI screening
Expensive
High false positive rate and require MRI biopsy to investigate
Use of Urgent Breast lump referrals
All lumps in over 30yr olds and any lump with worrying features in under 30yr olds.
