Pre-operative MRI exhibits limited utility in axillary staging for breast cancer

Abstract

IntroductionMagnetic resonance imaging (MRI) is commonly utilized in treatment planning of breast cancer patients. While axillary lymph node findings are routinely reported in these studies, the utility of these findings remains unclear. MethodsIn this retrospective study from 2008–2014, women diagnosed with invasive breast cancer who did not undergo neoadjuvant therapy were reviewed. MRI characteristics of axillary findings were compared to the final pathologic results. Results210 of 338 female patients met inclusion criteria and comprised our patient cohort. MRI was found to have a sensitivity and specificity of 45% and 84%, respectively. The negative predictive value was 78% with an accuracy of 72% and a false negative rate of 14%. MRI was more often accurate in younger patients (p<0.04, CI 0.52–1.19) and those whom had a larger number of lymph nodes harvested (p<0.0001, CI −10.8 to −0.2). True positives had significantly larger primary tumors and a larger number of positive lymph nodes on final pathology. ConclusionMRI of the axilla is not a reliable tool for axillary staging in women with breast cancer. MicroabstractThe significance of magnetic resonance imaging (MRI) findings of the axilla after routine preoperative imaging is poorly understood. We evaluated the perioperative course including axillary findings on MRI and compared them to the final axillary pathology of 210 women with invasive breast cancer. MRI did not show adequate predictive capability in determining women with invasive cancer progression to the axilla. Clinical practice pointsPreoperative magnetic resonance imaging of the breast is often obtained for women diagnosed with breast cancer. Findings in the axilla are often commented on in the radiology reports of these studies. There is limited data evaluating the significance of axillary finding in breast cancer imaging. The current literature differs in two important ways from the findings revealed in this study. First, the majority of the current literature focuses on imaging obtained using axillary specific protocols. These findings to not contribute transferable information for the typical clinical practice as these protocols are not commonly ordered or performed. Second, currently available studies have small cohorts, typically less than one hundred patients, or are systematic reviews. This study provides analysis of 210 patients over 6 years and represents the largest single study cohort that evaluates the clinical significance of axillary findings obtained during preoperative MRI of the breast.The findings reported here will aid clinicians when completing the preoperative work up for women diagnosed with breast cancer. Further, the subgroup analysis of our true positives presents an opportunity to potentially identify a new set of breast cancer patients that would have a greater benefit from neoadjuvant chemotherapy and thus spare them the morbidity of axillary lymph node dissection.