New research demonstrates that a lack of calcifications on post-neoadjuvant chemotherapy (NAC) magnetic resonance imaging (MRI) scans is significantly associated with higher pathologic complete response (pCR) for patients being treated for human epidermal growth factor receptor 2 (HER2)-positive breast cancer.
For the retrospective study, recently reported in Radiology, researchers reviewed mammography and breast MRI data from 732 patients (mean age of 51.9 years) with HER-2-positive breast cancer who had NAC and underwent surgery. The study authors noted that 64.8 percent of the cohort had calcifications on post-NAC MRI.
The researchers found that the lack of calcifications on post-NAC MRI was associated with a 65 percent higher likelihood of pCR.
For patients without calcifications on MRI, the study authors also noted a higher pCR rate (48.4 percent vs. 37.1 percent) and higher positive predictive value (PPV) (73.1 percent vs. 60 percent) of radiologic complete response (rCR) in contrast to those with breast MRI calcifications.
“Persistent calcification after NAC may warrant surgical removal to ensure complete DCIS (ductal carcinoma in situ) elimination. Considering these factors in surgical decision-making may lead to optimal treatment strategies and improve oncologic outcomes in patients with HER2-positive breast cancer,” wrote lead study author Eun Sook Ko, M.D., Ph.D., who is affiliated with the Department of Radiology at the Samsung Medical Center at the Sungkyunkwan University School of Medicine in Seoul, Korea, and colleagues.
When employing the ypTO/Tis definition (no remaining invasive cancer with some possible remaining in situ cancer) for pCR, the study authors noted no difference with the pCR rate between those with and without calcifications on MRI (62 percent vs. 58.5 percent).
Three Key Takeaways
- Absence of calcifications on post-NAC MRI is a strong predictor of higher pCR rates. In patients with HER2-positive breast cancer, the lack of calcifications on breast MRI was linked to a 65 percent increased likelihood of pCR compared to those with calcifications.
- Persistent calcifications after NAC are associated with residual DCIS. This highlights the importance of surgical removal to ensure complete disease elimination and optimize oncologic outcomes.
- Radiologic complete response (rCR) is more predictive of true pCR in patients without calcifications. Researchers noted higher PPV and NPV compared to those with calcifications, suggesting that MRI findings should be carefully integrated into surgical planning.
However, they also pointed out that residual DCIS appeared to be more prevalent among those with calcifications, noting that 24.9 percent of this cohort was reclassified with the ypTO/Tis definition of pCR in comparison to 10.1 percent in the group without calcifications.
“(This) suggests a higher frequency of residual DCIS in patients with calcifications. Accordingly, both sensitivity and NPV were lower in this group, likely because DCIS was classified as pCR. The lower PPV observed in patients with calcifications under the ypT0 definition indicates that many patients who appeared disease-free at MRI still had residual DCIS or invasive cancers,” posited Ko and colleagues.
(Editor’s note: For related content, see “Breast Reconstruction: Current Principles and Emerging Concepts in Imaging,” “Possible Real-Time Adaptive Approach to Breast MRI Suggests ‘New Era’ of AI-Directed MRI” and “Can Mid-Treatment MRI Help Predict Neoadjuvant Chemotherapy Response for Patients with Breast Cancer?”)
Beyond the inherent limitations of a single-center retrospective study, the authors acknowledged the grouping of PR-positive only cancers with ER-high tumors, the lack of axillary response evaluation with the pCR definition utilized in the study, and the study’s focus on the presence or absence of residual disease without considering residual cancer burden.
