What are the next steps for mammography findings categorized using the Breast Imaging-Reporting and Data System (BI-RADS)?

Management of Mammography Findings Based on BI-RADS Categories

The appropriate next steps for mammography findings depend directly on the BI-RADS category assigned, with specific management protocols for each category ranging from routine screening to immediate biopsy.

BI-RADS Categories and Definitions

• Category 0: Incomplete Assessment - Needs additional imaging evaluation and/or comparison with prior mammograms. Typically used in screening situations when additional views or ultrasound are needed 1
• Category 1: Negative - No abnormalities found, breasts are symmetric with no masses, architectural distortion, or suspicious calcifications 2, 1
• Category 2: Benign Findings - Negative mammogram with benign findings such as calcifying fibroadenomas, oil cysts, lipomas, intramammary lymph nodes, vascular calcifications, implants, or architectural distortion clearly related to prior surgery 2
• Category 3: Probably Benign - Findings have less than 2% likelihood of malignancy 2, 1
• Category 4: Suspicious Abnormality - Findings warrant biopsy consideration, risk of malignancy is variable but greater than category 3 and less than category 5 2
• Category 5: Highly Suggestive of Malignancy - Findings have a high probability (≥95%) of being cancer, examples include spiculated masses or malignant-appearing pleomorphic calcifications 2
• Category 6: Known Biopsy-Proven Malignancy - Lesions confirmed to be malignant through biopsy but before definitive therapies 2

Management Algorithm by BI-RADS Category

BI-RADS 0 (Incomplete Assessment)

• Proceed with additional imaging evaluation including comparison with prior films and/or diagnostic mammogram with or without ultrasound scan 2
• Complete the assessment to assign a definitive BI-RADS category 2

BI-RADS 1-2 (Negative or Benign)

• Return to routine screening mammography in 1 year 2
• No additional imaging or intervention needed 1

BI-RADS 3 (Probably Benign)

• Perform short-interval follow-up with diagnostic mammograms at 6 months, then every 6-12 months for 1-2 years 2, 1
• At first 6-month follow-up, perform unilateral mammogram of the index breast 2
• At 12-month follow-up, perform bilateral mammography in women aged 40 years and older 2
• If the lesion remains stable or resolves, resume routine screening 2, 1
• If any interval mammogram shows increased size or changed characteristics, proceed to biopsy 2
• Consider initial biopsy instead of short-term follow-up if:
  • Patient follow-up is uncertain 2
  • Patient has high anxiety 2
  • Patient has strong family history of breast cancer 2

BI-RADS 4-5 (Suspicious or Highly Suggestive of Malignancy)

• Perform tissue diagnosis using core needle biopsy (preferred) or needle localization excisional biopsy with specimen radiograph 2, 1
• Ensure concordance between pathology report and imaging findings 2
• If pathology and imaging are discordant:
  • Repeat breast imaging 2
  • Sample or excise additional tissue 2
  • If discordance persists, perform surgical excision 2
• For benign results with pathology/image concordance:
  • Follow up with mammography every 6-12 months for 1-2 years before returning to routine screening 2
• For atypical hyperplasia, LCIS, or other potentially pathologic conditions:
  • Perform surgical excision 2
  • Consider risk-reduction therapy 2

BI-RADS 6 (Known Malignancy)

• Manage according to breast cancer treatment guidelines 2

Important Clinical Considerations

• The overall BI-RADS assessment is based on the most worrisome findings when multiple abnormalities are identified 2, 1
• When both mammography and ultrasound are performed, the BI-RADS categories represent the cumulative findings of both imaging modalities 2
• For women aged 30 years or older with a dominant breast mass, begin with bilateral diagnostic mammogram, not observation 2
• For solid lesions that are suspicious (BI-RADS 4-5) on ultrasound, tissue biopsy should be obtained using core needle biopsy (preferred) or surgical excision 2
• Recent research suggests that patients should undergo diagnostic biopsy instead of follow-up imaging if they are 50 years or older or exhibit calcification, nonparallel orientation of mass, non-circumscribed margin, or posterior shadowing 3
• Studies have shown that appropriate use of BI-RADS category 3 can save many patients from unnecessary biopsies of benign lesions without decreasing cancer detection rates 4, 5

Pitfalls to Avoid

• Do not assign BI-RADS category 3 in a screening study without completing a comprehensive diagnostic evaluation 5
• Ensure proper use of BI-RADS descriptors to avoid inappropriate categorization 4
• Do not overrely on negative ultrasonographic findings when assigning BI-RADS categories 4
• Avoid discordance between pathology and imaging findings by ensuring thorough correlation 2
• Remember that the PPV of BI-RADS categories varies: category 3 has approximately 2% risk of malignancy, category 4 about 30%, and category 5 approximately 97% 6