Is a mammogram (mammography) recommended after neoadjuvant chemotherapy for breast cancer?

Mammography After Neoadjuvant Chemotherapy for Breast Cancer

Mammography is recommended after neoadjuvant chemotherapy for breast cancer, but with a rating of 7 out of 9 (usually appropriate), while MRI is the preferred imaging modality with a rating of 9 out of 9. 1

Imaging Recommendations After Neoadjuvant Chemotherapy

Primary Recommended Imaging Modalities

• MRI breast without and with IV contrast is the most highly recommended imaging modality (rating: 9/9) after neoadjuvant chemotherapy, as it provides the most accurate assessment of residual disease 1
• Breast ultrasound is the second most recommended modality (rating: 8/9), especially reliable for determining tumor size when residual tumor is >7mm 1
• Mammography is recommended (rating: 7/9) particularly for masses well seen on pretreatment mammogram 1
• Digital breast tomosynthesis (DBT) is an alternative to standard mammography with the same rating (7/9) 1

Limitations of Mammography After Neoadjuvant Chemotherapy

• Assessing response to treatment with mammography may be challenging because changes in tumors can be variable after chemotherapy 1
• Mammography correctly estimates residual tumor size in only 38% of cases, compared to 63% for MRI 2
• Dense breast tissue in up to 50% of women may limit evaluation of disease extent on mammography 1
• Mammography is less accurate for invasive lobular cancers and higher grade lesions 1

Benefits of MRI Over Mammography

• MRI correctly identifies response to chemotherapy in all cases of complete response and in the majority of partial or non-response cases 2
• MRI is superior to mammography in detecting multifocal or multicentric disease (83% vs 33%) 3
• MRI plus mammography correctly predicts breast conservation surgery eligibility in 92% of cases after neoadjuvant chemotherapy 4
• MRI is particularly useful for invasive lobular cancer, where it more accurately defines disease extent than mammography 1

Clinical Algorithm for Post-Neoadjuvant Chemotherapy Imaging

1. Baseline imaging before starting neoadjuvant chemotherapy:

   • Obtain diagnostic mammography/DBT, breast ultrasound, and breast MRI with contrast 1
   • These serve as baseline for comparison after treatment 1

2. After completion of neoadjuvant chemotherapy:

   • Perform MRI with contrast as the primary imaging modality 1
   • Follow with breast ultrasound, particularly if the tumor was well visualized on ultrasound before treatment 1
   • Perform diagnostic mammography, especially if the tumor was well visualized on mammography before treatment 1

3. Interpretation considerations:

   • Compare post-treatment imaging with pre-treatment studies 5
   • Recognize that no imaging modality is entirely accurate in determining pathologic complete response 1
   • Surgical excision of the area of biopsy-proven malignancy remains indicated after neoadjuvant chemotherapy 1

Important Caveats

• Despite advances in imaging, no single modality can reliably detect all residual disease after neoadjuvant chemotherapy 1
• Mammography may miss microfoci of ductal carcinoma in situ (DCIS) or invasive lobular carcinoma 3
• Mammography may be particularly important when extensive microcalcifications are present, as these may indicate need for mastectomy despite MRI suggesting suitability for breast conservation 4
• After neoadjuvant chemotherapy, locoregional treatment should follow the same principles as first-line locoregional treatment 6