Purpose: There are an estimated four million breast cancer survivors in the US. They are at risk of having recurrence and early diagnosis improves survival. Therefore, imaging surveillance is needed for women with breast conserving surgery (BCS). Contrast enhanced mammogram (CEM) is a form of mammography that contains both the traditional morphologic data with the addition of physiological information from the contrast injection and dual energy subtraction. Our aim is to retrospectively review the performance of CEM in this population including lesion location and histopathology findings.
Materials and Methods: In an IRB approved, HIPAA compliant retrospective study included women who underwent CEM exams post BCS at 4 outpatient imaging sites from February 2019 to October 2022. Medical records were reviewed for age, exam indication, short-term recommendations, biopsies and cancers detected. A total of 265 exams in 198 women were interpreted by 9 subspecialized radiologists. Breast Imaging Reporting and Data System (BI-RADS) outcomes, cancer detection rate (CDR), sensitivity and specificity, positive predicted value of screening (ppv1) and biopsy (ppv3) and negative predictive value were calculated. The performance of low energy (LE) vs recombined images on cancers were evaluated.
Results: Among the 198 women, the mean age was 56.1 ± 10.7 (standard deviation) and 65% (173/265) had dense breast tissue. The 265 exams resulted in final BI-RADS scores of 1 or 2 in 233 exams (87.9%), score of 3 in 12 exams (4.5%), and score 4 or 5 in 20 exams (7.5%). Twenty-two biopsies on nineteen women resulted in 8 (36%) cancers and 14 (64%) benign lesions. CDR 30/1000 (8/265) when utilizing CEM in this population. One year follow up was available on 250 women, no interval cancers. The ppv1 was 25% (8/32), ppv3 was 42% (8/19), specificity was 100% (8/8) and specificity was 91.32% (221/242). Of the 8 cancers, the 7 invasive cases were found on both LE and recombined images, one DCIS with calcifications was visible only on contrast images. Of the 14 benign cases, 7 (50%) were found on LE only and 7 (50%) were found on both LE and recombined images.
Conclusion: Our preliminary results indicate that among women undergoing BCS surveillance, CEM is effective in identifying breast cancer recurrence in this high-risk population. Additional evaluation of long-term patient outcomes is warranted.
Clinical Relevance Statement: Contrast enhanced mammography is a promising technique for the surveillance of women after breast conserving surgery finding more cancers and fewer false positives than the low energy FFDM exams.
