Breast Cancer Screening Flashcards
sensitivity
Percentage of patients with disease who will be correctly identified by a screening test
specificity
Percentage of patients without disease who will be correctly identified as disease free by a screening test
PPV
Probability of having the disease given one has a positive test result
NPV
Probability of not having the disease given one has a negative test result
Prevalence
Probability of having the disease for a patient sample simulated in a 2x2 table
Most common breast cancer screening modalities
digital mammography, the clinical breast exam (lesions greater than 1 cm), and the self-breast exam
Interventions according to basic, limited, enhanced, and maximal levels of resources
Basic:
Breast health awareness (education + self-examination)
Clinical history and CBE
Limited:
Targeted outreach/education encouraging CBE for at risk groups
Diagnostic breast US +/- diagnostic mammography in women with positive CBE
Enhanced:
Diagnostic mammography
Opportunistic mammographic screening
Maximal:
Population based mammographic screening
Other imaging technologies as appropriate for high-risk groups
Mammography
- low dose radiographs of breast
- 2 views of each breast in perpendicular planes (medio-lateral and cranio-caudal views)
- 2 indications are screening and diagnostic
- Breast composition graded on a 4 point scale (A-D)
- breast cancers appear white on mammograms, but denser breast tissue is also white: makes lesion identification more difficult. (younger women= denser breasts)
A-D scale and description for mammogram
A:The breasts are almost entirely fatty (10%)
B: There are scattered areas of fibroglandular density (40%)
C: The breasts are heterogeneously dense, which may obscure small masses. (40%)
D: The breasts are extremely dense, which lowers the sensitivity of mammography. (10%)
BI-RADS Assessment categories
Categories 0-6
0: incomplete
- Need additional imaging/info
1: negative (~0% malignant)
2: benign (~0% malignant)
3: probably benign (0-2% likelihood of malignancy)
- shorter interval for follow up or next mammogram
4: suspicious (low, moderate, high) (2-95% chance of malignancy)
- Need tissue diagnosis
5: highly suggestive of malignancy (95% likelihood of malignancy)
- Tissue dx
6: known biopsy-proven malignancy
- surgical excision
Breast self-exam vs being breast aware
BSE: regular, repetitive monthly palpation to a rigorous set method performed by the woman at the same time each month
Breast aware:
a woman becoming familiar with her own breasts and the way that they will change.
-to know how their own breasts look and feel normally so that they gain confidence about noticing any change which might help detect breast cancer early
Changes in breasts that should be looked out for
- Size – if one breast becomes larger, or lower.
- Nipples – if a nipple becomes inverted (pulled in) or changesposition or shape.
- Rashes – on or around the nipple.
- Discharge – from one or both nipples.
- Skin changes – puckering or dimpling.
- Swelling – under the armpit or around the collarbone (where the lymph nodes are).
- Pain – continuous, in one part of the breast or armpit.
- Lump or thickening – different to the rest of the breast tissue.
Clinical breast exam
- examination of a patient’s breast tissue by a trained examiner
- examining the entire breast and its lymphatic drainage, palpating the breast tissue at multiple depths, and examining the breast tissue for three minutes each.
- Characterize lesions by mobility, consistency, regularity, size (is it fixed? hard? irregular? how big?)
When are MRIs appropriate? 3D mammography?
MRIs
- for pts at very high risk of developing breast cancer (like BRCA carriers)
- expensive
3D mammography
- newest
- more suitable for women with more dense breasts
American Cancer Society recommendations for women at average risk
- Women ages 40 to 44 should have the choice to start annual breast cancer screening with mammograms
- Women age 45 to 54 should get mammograms every year.
- Women age 55 and older should switch to mammograms every 2 years, or have the choice to continue yearly screening.
- Screening should continue as long as a woman is in good health and is expected to live 10 more years or longer
US preventive services task force recommendations
- individual choice to start biennial screening mammography before age 50
- biennial screening for women between 50-74 y
Personal history risk factors for breast cancer
a prior of breast cancer, ductal carcinoma in situ, and / or lobular carcinoma in situ; history of a breast biopsy showing atypical ductal hyperplasia; moderate alcohol consumption; and exposure to ionizing radiation.
Leading RF:
being a woman
Another RF:
older age (women under 40 rarely screened)
Estrogen exposure and risk for breast cancer
younger age at menarche; nulliparity; older age at first pregnancy (age above 23 yrs often cited); older age at menopause; combined hormone replacement therapy for postmenopausal women and increased weight, especially in postmenopausal women. Breastfeeding is protective.
-oral contraceptive pills have not been shown to increase risk.
Genetic/familial risk factors
- breast cancer in first degree relative
- BRCA 1 or 2 gene carrier
Determining Breast cancer risk in general population
- good tool is The Breast Cancer Risk Assessment Tool
- takes less than 1 minute
- based on Gail model
- estimates risk of developing invasive BC in next 5 years and age up to 90
8 questions:
- med hx (BC, DCIS, LCIS, radiation)
- BRCA 1 or 2 or other genetic syndrome (there are better assessment tools for these women)
- age
- age at 1st period (increased risk if before age 12 y)
- age at 1st live birth of child
- number of first degree relatives with BC
- breast biopsy
- race/ethnicity
Location of BRCA 1 and 2
- BRCA1 on chrom 17
- BRCA2 on chrom 13
BRCA1: 35-85% risk for BC development; 10-50% risk of ovarian cancer by 70y
Key determinants of risk for carrying BRCA mutation:
Ashkenazi Jewish descent, the number of relatives with cancer, the relationship of those family members to the patient, the genders of the relatives affected, the ages at which family members were diagnosed, and the types of cancer diagnosed.
Models for the Patient-Physician relationship: Paternalistic model
Paternalistic Model:
ensures that patients receive interventions that best promote their health and well-being. (Physician identifies tests/tx most likely to restore the patient’s health. Physician then shares selected info that will encourage patient to consent to the intervention.)
-limited pt participation
Informative model
objective of the physician-patient interaction is for the physician to provide the patient with all relevant information, for the patient to select the medical interventions he or she wants, and for the physician to execute the selected interventions
interpretive model
The aim of the physician-patient interaction is to elucidate the patient’s values and what he or she actually wants and to help the patient select the available medical interventions that realize these values
deliberative model
The aim of the physician-patient interaction is to help the patient determine and choose the best health related values that can be realized in the clinical situation
- The physician’s objectives include suggesting why certain health-related objectives are more worthy and should be aspired to.
- the physician indicates what the patient should do, what decision making regarding medical therapy would be admirable.
