New research suggests that delayed image acquisition with contrast-enhanced mammography (CEM) may provide improved detection of residual cancer after the use of neoadjuvant chemotherapy (NAC) for breast cancer in comparison to early image acquisition.
For the retrospective study, recently published in European Radiology, researchers compared early-only CEM (images obtained two minutes after contrast injection), delayed-only CEM (images obtained eight minutes after contrast injection) and a combination of the protocols. The cohort was comprised of 202 women (mean age of 54.7) who had pre- and post-NAC CEM, according to the study.1
The study authors found that delayed-only image acquisition with CEM provided an 85.7 percent sensitivity for detecting residual disease in comparison to 68.1 percent for early-only image acquisition, The combination of the protocols offered an 86.8 percent sensitivity, according to the researchers.1
Early-only acquisition had a slightly higher positive predictive value (PPV) (72.9 percent) than delayed-only acquisition (71.3 percent) and combined protocols (69.6 percent). The researchers also noted that early-only image acquisition provided higher specificity than delayed-only image acquisition (63.9 percent vs. 60.6 percent) and significantly higher specificity than the combined protocols (45.8 percent). However, the study authors pointed out that delayed-only acquisition offered a 13 percent higher negative predictive value (NPV) for residual disease in contrast to early-only acquisition.1
“The observed differences between early and delayed CEM acquisitions can be explained by treatment-related changes in tumor vascularity after neoadjuvant chemotherapy. Delayed imaging may improve detection of (residual disease) by allowing progressive contrast accumulation in areas of persistent neo-angiogenesis or low perfusion tumor components, thereby increasing sensitivity and NPV,” noted lead study author Chiara Bellini, MD, who is affiliated with the Breast Imaging Unit in the Department of Radiology at Azienda Ospedaliero-Universitaria Careggi in Florence, Italy, and colleagues.
Could delayed image acquisition be a viable alternative to MRI for detecting residual disease in the post-NAC setting?
Citing a 2013 systematic review on the use of MRI for post-NAC assessment in patients treated for breast cancer, the study authors noted that the pooled MRI specificity rate of 89 percent for pathologic complete response (pCR) paralleled the current study’s finding of 85.7 percent sensitivity for delayed image acquisition with CEM. The researchers also pointed out that the 60.6 percent specificity for delayed image acquisition for CEM was higher than the 42 percent sensitivity for MRI.1,2
“These comparisons suggest that, despite differences in definition and imaging modality, delayed CEM demonstrates diagnostic performance broadly comparable to MRI for response assessment after NAC,” posited Bellini and colleagues.
Three Key Takeaways
• Delayed-phase CEM significantly improves detection of residual invasive disease. Incorporating delayed imaging after neoadjuvant chemotherapy enhances sensitivity and overall accuracy compared to early-phase acquisition alone, making it a critical component of CEM protocols.
• CEM may offer a practical alternative to MRI with comparable diagnostic performance. Delayed image acquisition with CEM may offer similar effectiveness to breast MRI for evaluating residual tumor burden, supporting its use when MRI is unavailable, contraindicated, or less feasible.
• Persistent limitation in underestimation of residual in situ carcinoma.
CEM demonstrates reduced accuracy in detecting residual ductal carcinoma in situ (DCIS), indicating that in situ components may be underestimated and should be carefully considered in post-NAC evaluation.
The researchers cautioned that an in situ component (ypTis) was present in 34.1 percent of false positive cases and 38.1 percent of true negative cases for patients with delayed CEM acquisition.1
“This may be explained by the variable enhancement patterns of DCIS, which can show minimal or absent enhancement in low-grade lesions but more conspicuous enhancement in high-grade forms. As a result, CEM may misclassify some DCIS as residual invasive disease, potentially reducing specificity,” added Bellini and colleagues.
(Editor’s note: For related content, see “Study Affirms Impact of Contrast-Enhanced Mammography for Screening Recalls,” “Video: Stamatia Destounis, MD Discusses the Recent ACP Guidance on Breast Cancer Screening” and “Can Contrast-Enhanced Mammography Offer a Viable Option for Pre-Op Assessment of Pathologic Nipple Involvement?”)
Beyond the inherent limitations of a single-center retrospective design, the authors acknowledged the use of a single system for CEM acquisition, image review by two experienced breast radiologists and the cohort being limited to patients with complete CEM and histopathologic data.
References
- Bellini C, Bicchierai G, Maiello C, et al. Early, delayed, or combined contrast-enhanced mammography for detecting residual disease after neoadjuvant chemotherapy in breast cancer. Eur Radiol. 2026 May 15. doi: 10.1007/s00330-026-12633-1. Online ahead of print.
- Lobbes MBI, Prevos R, Smidt M, et al. The role of magnetic resonance imaging in assessing residual disease and pathologic complete response in breast cancer patients receiving neoadjuvant chemotherapy: a systematic review. Insights Imaging. 2013;4(2):163-75.
