Age and HER2 expression status affect MRI accuracy in predicting residual tumor extent after neo-adjuvant systemic treatment

Abstract

Background: Although recent studies suggest high accuracy of breast magnetic resonance imaging (MRI) in predicting residual tumor extent after neo-adjuvant systemic treatment (NST), its use is still controversial. In this study, we aimed to identify predictive factors of MRI accuracy after NST to determine a subgroup of patients in whom the use of MRI provides best additional benefit. Materials and methods:Clinicopathologic and molecular profiles of breast cancer patients were investigated and their relationships with MRI accuracy were analyzed. predicted residual tumor extent with higher accuracy than ultrasonography. Triple-negative (TN) tumors showed highest correlation between MRI-measured and pathologic tumor size (r = 0.781) when compared with other subtypes. Multivariate analysis showed age and HER2 expression status as independent factors predicting MRI accuracy. When patients were classified based on their age and HER2 status, relatively older patients (>45) with HER2-negative tumors showed highest MRI accuracy. This finding was further validated using an independent cohort of 63 consecutive patients.Conclusion: Age and HER2 status independently affected MRI accuracy after NST. This observation may guide more tailored approach in using MRI in breast cancer patients undergoing NST.

Diagnostic Performance of Magnetic Resonance Imaging for Assessing Tumor Response in Patients With HER2-Negative Breast Cancer Receiving Neoadjuvant Chemotherapy is Associated With Molecular Biomarker Profile

“…9,13,22 For HER2 positive cancer, which is very sensitive to the targeted therapy trastuzumab and chemotherapy, and generally highly proliferative, the treatment is more likely to eliminate the scattered residual cancer cells, leading to a higher negative predictive value of MRI. 28 For HER2 negative cancer, there is no effective targeted regimen, and the residual disease is likely to present as scattered cells and difficult to diagnose by MRI.…”

“…9-11 Despite superior accuracy when compared with other modalities, MRI can over- or under- estimate residual tumor extent. This inaccurate assessment may be influenced by tumor response (some tumors shrink concentrically down to a single focus of residual tumor cells, while others break apart into scattered tumor cells in patchy patterns 4 ), chemotherapeutic agent, or NAC-induced reactive changes within the tumor.…”

Breast Cancer Subtype Influences the Accuracy of Predicting Pathologic Response by Imaging and Clinical Breast Exam After Neoadjuvant Chemotherapy

“…Previously published datasets have shown that MRI most accurately predicts the amount of residual pathologic disease in HR-negative subtypes rather than HR-positive subtypes (11,(16)(17)(18)(19). The concept of variation in clinical response evaluation accuracy by breast cancer subtype is important for the design of future response-guided NACT trials.…”

“…Recent studies have shown that the accuracy of imaging in clinical response evaluation varies by breast cancer subtype according to HR and HER2 status (11)(12)(13)(14)(15)(16)(17)(18)(19). Specifically, MRI more accurately predicts pathologic response in HR-negative subtypes rather than HRpositive stubtypes (11,(16)(17)(18)(19).…”

Clinically Meaningful Tumor Reduction Rates Vary by Prechemotherapy MRI Phenotype and Tumor Subtype in the I-SPY 1 TRIAL (CALGB 150007/150012; ACRIN 6657)

“…[34][35][36][37] Although some have reported the highest accuracy of MRI for Her2-disease, not knowing HR status and differences in rates of traztuzumab use could potentially account for the disparate results. 38 Benign proliferative processes can enhance on MRI and are difficult to differentiate from low-grade, ER? DCIS lesions.…”