Screening Mammography Callback in a Woman with Dense Breasts
A 52-year-old woman presents for routine screening mammography. She has no symptoms and no family history of breast or ovarian cancer. Her last mammogram was 2 years ago and was normal. She is premenopausal. The screening mammogram shows extremely dense breast tissue (BI-RADS category D). There is a new 1.0 cm asymmetry in the upper outer quadrant of the right breast, visible on the mediolateral oblique (MLO) and craniocaudal (CC) views. No associated calcifications or architectural distortion are seen. The patient is notified and returns for additional imaging. Diagnostic mammography with spot compression and magnification views is performed, and the asymmetry persists but becomes less conspicuous. Ultrasound of the right breast is then performed and shows a 0.8 cm hypoechoic mass with irregular margins at the site of the asymmetry, suspicious for malignancy.
1. What is the BI-RADS assessment for the mammographic asymmetry and the ultrasound finding, and what is the next step in management?
Read the worked answer
The screening mammogram showed a new focal asymmetry in a woman with extremely dense breasts. After diagnostic mammography with spot compression, the asymmetry persists, which is suspicious. The ultrasound reveals a 0.8 cm hypoechoic mass with irregular margins, which is highly suspicious for malignancy (BI-RADS 4C or 5). The next step is ultrasound-guided core needle biopsy of the mass. A marker clip should be placed at the biopsy site. The patient should be referred to a breast surgeon for further management. Because the breast is dense, the mammogram may have limited sensitivity; however, the ultrasound identified the lesion. If the biopsy reveals malignancy, staging and treatment planning should follow. The patient should be informed of the findings and the need for biopsy.
2. The biopsy reveals invasive ductal carcinoma, grade 2, ER-positive, PR-positive, HER2-negative. What additional imaging is recommended for staging, and why?
Read the worked answer
For a patient with newly diagnosed early-stage breast cancer (0.8 cm, clinically node-negative), routine staging with systemic imaging (CT, bone scan, PET/CT) is not recommended because the yield of distant metastases is very low and does not improve survival. However, staging imaging may be considered if there are symptoms or laboratory abnormalities suggestive of metastasis. According to NCCN guidelines, for stage I-II breast cancer, only a chest radiograph and possibly liver ultrasound or CT may be considered in select cases. In this patient, a sentinel lymph node biopsy is indicated at the time of surgery to assess nodal status. If the sentinel node is positive, further axillary dissection may be avoided in favor of radiation. The patient should also undergo genetic counseling and testing if appropriate. The role of breast MRI is controversial; it may be considered for preoperative planning in dense breasts or for screening the contralateral breast, but it is not routinely recommended for staging.