← Back to Browse
Ask AleraHome
XRAY
BreastDemonstration data

Mammography (Screening)

Screening mammography is a low-dose X-ray examination of the asymptomatic breast performed to detect early, clinically occult breast cancer and reduce breast cancer mortality. Standard two-view digital mammography (with digital breast tomosynthesis increasingly used) is the internationally validated screening tool, and findings are communicated using the standardised BI-RADS lexicon. Effective screening depends on high-quality technique, comparison with prior studies and structured interpretation.

Indications

  • Routine breast cancer screening in average-risk women, typically from age 40-50 depending on the national programme
  • Annual or biennial screening intervals per programme guidelines
  • Earlier and/or supplemental screening (often with MRI) in high-risk women (BRCA carriers, strong family history, prior chest radiotherapy)
  • Baseline imaging before hormone therapy or as part of surveillance
  • Continued screening in women with prior breast cancer (surveillance rather than diagnostic when asymptomatic)

Contraindications & Cautions

  • Screening mammography is for asymptomatic women; a symptomatic patient (palpable lump, nipple discharge, skin change) requires diagnostic work-up, not screening
  • Pregnancy and lactation are relative contraindications for screening (defer or use targeted diagnostic imaging with justification)
  • Very low radiation dose (mean glandular dose ~0.4 mSv for a two-view study); benefit outweighs risk in the screening age group
  • Recent breast surgery/biopsy may warrant deferral until healing
  • Apply ALARA; balance benefits and harms (false positives, overdiagnosis) when counselling

Patient Preparation

  • Schedule (in premenopausal women) during the first half of the cycle when breasts are less tender
  • Advise no deodorant, talc or lotion on the breasts/axillae, as these can mimic calcifications
  • Take a history of prior surgery, biopsies, implants, symptoms, hormone use and family history
  • Obtain and load prior mammograms for comparison
  • Explain the compression and its purpose (reduces dose, spreads tissue, reduces motion)
  • Position the patient and mark any scars, moles or palpable areas

Technique & Parameters

  • Standard two views per breast: craniocaudal (CC) and mediolateral oblique (MLO)
  • Full-field digital mammography; digital breast tomosynthesis (3D) increasingly added to improve cancer detection and reduce recall in dense breasts
  • Low kVp (~26-32 kVp) with molybdenum/rhodium or tungsten targets and appropriate filtration; automatic exposure control
  • Firm compression to reduce thickness, spread tissue, lower dose and reduce motion blur
  • MLO should include the pectoral muscle to the level of the nipple and the inframammary fold; CC should include posterior/medial tissue
  • Additional diagnostic views (spot compression, magnification, true lateral) are performed at recall, not at screening
  • Adhere to quality-control standards for exposure, positioning and image quality

Systematic Review

  • Confirm identity, laterality, adequate positioning and image quality (PGMI criteria)
  • Compare CC and MLO of each breast and compare with prior studies for change
  • Assess overall breast density (BI-RADS a-d categories)
  • Search systematically for masses: shape, margin, density
  • Search for calcifications: morphology and distribution
  • Assess for architectural distortion and asymmetries (focal, global, developing)
  • Evaluate the retroglandular/retroareolar regions, axillary tail and lymph nodes
  • Check skin, nipple and trabecular pattern for thickening or retraction

Key Findings & Significance

  • A spiculated or irregular mass with ill-defined margins is highly suspicious for malignancy
  • Fine pleomorphic or fine linear/branching calcifications in a linear or segmental distribution suggest DCIS or invasive cancer
  • Architectural distortion without a central mass is suspicious for malignancy (or radial scar)
  • A developing or enlarging focal asymmetry compared with priors warrants recall
  • Round/oval circumscribed masses are usually benign (cyst, fibroadenoma) but may need ultrasound correlation
  • Coarse 'popcorn' calcifications suggest an involuting fibroadenoma; rim/eggshell calcifications suggest cysts or fat necrosis
  • Skin or nipple retraction and skin thickening may indicate underlying malignancy or inflammatory change
  • Dense breast tissue reduces sensitivity and may warrant supplemental imaging

Differential Considerations

  • Spiculated mass: invasive carcinoma, radial scar/complex sclerosing lesion, post-surgical scar, fat necrosis
  • Circumscribed mass: cyst, fibroadenoma, phyllodes tumour, papilloma, circumscribed carcinoma (e.g. mucinous, medullary)
  • Pleomorphic/segmental calcifications: DCIS, invasive carcinoma
  • Benign calcifications: vascular, secretory (plasma cell mastitis), milk of calcium, skin, fibroadenoma, fat necrosis
  • Architectural distortion: carcinoma, radial scar, post-surgical change, sclerosing adenosis
  • Asymmetry: normal overlapping tissue, developing asymmetry from carcinoma, hormonal change
  • Axillary lymphadenopathy: benign reactive, metastatic disease, lymphoma, systemic causes

Pearls & Pitfalls

  • Always compare with prior mammograms - a stable finding over years is reassuring, while any interval change lowers the threshold for recall
  • Cancers are commonly missed in dense tissue, at the film edges, in the retroglandular/axillary tail and behind the nipple - review these areas deliberately
  • Correlate any palpable lump with imaging; a normal mammogram does not exclude cancer in a symptomatic patient - proceed to diagnostic work-up and ultrasound
  • Deodorant and skin lesions can simulate suspicious calcifications; note skin markers and confirm on true lateral
  • Architectural distortion is subtle and one of the most frequently overlooked signs of malignancy
  • Tomosynthesis reduces the masking effect of overlapping tissue and lowers recall rates
  • Assess both views together; a real lesion should be identifiable on orthogonal projections

Structured Report

  • State the examination type (2D/tomosynthesis), views, laterality and comparison
  • Report breast density category (BI-RADS a-d)
  • Describe any mass, calcifications, asymmetry or distortion using the BI-RADS lexicon with location and size
  • Assign a final BI-RADS assessment category (0 incomplete, 1-2 negative/benign, 3 probably benign, 4-5 suspicious/highly suspicious, 6 known malignancy)
  • Give a clear management recommendation matched to the category (routine screening, short-interval follow-up, recall for diagnostic work-up, or biopsy)
  • Include audit-relevant data and communicate significant findings appropriately

References

  • ACR BI-RADS Atlas (Breast Imaging Reporting and Data System), 5th Edition
  • ACR Practice Parameter for the Performance of Screening and Diagnostic Mammography
  • NHS Breast Screening Programme Guidance / European Guidelines for Quality Assurance in Breast Cancer Screening
  • US Preventive Services Task Force (USPSTF) Breast Cancer Screening Recommendations
  • Kopans DB. Breast Imaging, Wolters Kluwer

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.