Breast Cancer: Evaluation of Response to Neoadjuvant Chemotherapy with 3.0-T MR Imaging

Abstract

Purpose:To assess how the molecular biomarker status of a breast cancer, including human epidermal growth factor receptor 2 (HER2), hormone receptors, and the proliferation marker Ki-67 status, affects the diagnosis at 3.0-T magnetic resonance (MR) imaging. Materials and Methods:This study was approved by the institutional review board and was HIPAA compliant. Fifty patients (age range, 28-82 years; mean age, 49 years) receiving neoadjuvant chemotherapy were monitored with 3.0-T MR imaging. The longest dimension of the residual cancer was measured at MR imaging and correlated with pathologic fi ndings.Patients were further divided into subgroups on the basis of HER2, hormone receptor, and Ki-67 status. Pathologic complete response (pCR) was defi ned as when there were no residual invasive cancer cells. The Pearson correlation was used to correlate MR imaging-determined and pathologic tumor size, and the unpaired t test was used to compare MR imaging-pathologic size discrepancies. Results:Of the 50 women, 14 achieved pCR. There were seven false-negative diagnoses at MR imaging. The overall sensitivity, specifi city, and accuracy for diagnosing invasive residual disease at MR imaging were 81%, 93%, and 84%, respectively. The mean MR imaging-pathologic size discrepancy was 0.5 cm 6 0.9 (standard deviation) for HER2-positive cancer and 2.3 cm 6 3 .5 for HER2-negative cancer ( P = .009). In the HER2-negative group, the size discrepancy was smaller for hormone receptor-negative than for hormone receptor-positive cancers (1.0 cm 6 1.1 vs 3.0 cm 6 4.0, P = .04). The size discrepancy was smaller in patients with 40% or greater Ki-67 expression (0.8 cm 6 1.1) than in patients with 10% or less Ki-67 expression (3.9 cm 6 5.1, P = .06). Conclusion:The diagnostic accuracy of breast MR imaging is better in more aggressive than in less aggressive cancers. When MR imaging is used for surgical planning, caution should be taken with HER2-negative hormone receptor-positive cancers.q RSNA, 2011Supplemental material : http://radiology.rsna.org/lookup /suppl

Imaging Features of HER2 Overexpression in Breast Cancer: A Systematic Review and Meta-analysis

“…No DCE-MRI study excluded patients based on receptor expression. Restricting the meta-analysis to three studies with sub-mm in plane resolution and smaller than 2-mm slice thickness (68,69,79) showed that rim enhancement also increased the chance of HER2 overexpression (pOR, 2.92; 95% CI, 1.42-6.02; P < 0.01; 2 studies; Supplementary Figs. S76-S80).…”

Response monitoring of breast cancer patientsreceiving neoadjuvant chemotherapy using breast MRI – a review of current knowledge

“…For example, it was observed that MRI was able to predict pCR more accurately in patients having HER2-positive tumours when compared to HER2-negative tumours. In the latter case, a higher falsenegative rate was observed, especially when receiving anti-angiogenic drugs [40,45]. It was also observed that the average size discrepancy between MRI and pathology was greater in tumours demonstrating limited Ki-67 staining when compared to tumours demonstrating increased Ki-67 staining [40].…”

“…In the latter case, a higher falsenegative rate was observed, especially when receiving anti-angiogenic drugs [40,45]. It was also observed that the average size discrepancy between MRI and pathology was greater in tumours demonstrating limited Ki-67 staining when compared to tumours demonstrating increased Ki-67 staining [40]. In addition, Loo et al, concluded that response monitoring using breast MRI is accurate in patients having triple-negative or HER2-positive tumours.…”

Whole-body PET/MRI in oncology: current status and clinical applications

“…4). In breast cancer, MRI and fMRI have proven to be sensitive to early therapy response [73], and FDG PET/CT is capable of predicting early response to neoadjuvant therapy [74]. The potential of integrated PET/MRI must be fully explored, since this hybrid methodology will likely play a key role in evaluating recurrence and therapy response in breast cancer patients.…”