Contrast-Enhanced Mammography vs. MRI: Neoadjuvant Therapy Response in Breast Cancer

According to a new study appearing in the American Journal of Roentgenology (AJR), contrast-enhanced mammography (CEM) may be a useful alternative test for neoadjuvant therapy (NAT) response assessment in patients with breast cancer who are unable to undergo MRI.

“After NAT for breast cancer, contrast-enhanced mammography and MRI yielded comparable assessments of lesion size (both slightly overestimated vs pathology) and RECIST categories, and no significant difference in specificity for pathologic complete response,” writes corresponding author Rubina Manuela Trimboli, a PhD student at IRCCS Humanitas Research Hospital in Milan, Italy. 

Noting that MRI had higher sensitivity for pathologic complete response, Trimboli says “delayed contrast-enhanced mammography acquisition may help detect residual ductal carcinoma in situ (DCIS).”

Trimboli and her team’s prospective study included 51 patients (mean age, 46 years) with biopsy-proven breast cancer from May 2015 to April 2018, who were candidates for NAT. Patients underwent both contrast-enhanced mammography and MRI before, during, and after NAT: pre-NAT, mid-NAT, and post-NAT, respectively. Post-NAT contrast-enhanced mammography included a 6-minute delayed acquisition. One breast radiologist with experience in contrast-enhanced mammography reviewed contrast-enhanced mammographyexaminations; one breast radiologist with experience in MRI reviewed MRI examinations.

Compared with pathology, post-NAT contrast-enhanced mammography, MRI, and delayed contrast-enhanced mammography systematically overestimated residual tumor size by 0.8 mm, 1.9 mm, and 1.2 mm, respectively. For detecting pathologic complete response by post-NAT imaging, sensitivity and specificity were 81% and 83% for contrast-enhanced mammography, 100% and 86% for MRI, and 81% and 89% for delayed contrast-enhanced mammography

“While MRI remains the preferred test for NAT monitoring,” the authors of this AJR article conclude, “the findings support contrast-enhanced mammography as a useful alternative when MRI is contraindicated or not tolerated.”