Superparamagnetic iron oxide sentinel lymph node biopsy in early breast cancer: an analysis of artefacts on post-operative breast imaging

Abstract

Page 1 of 9© Annals of Breast Surgery. All rights reserved. Ann Breast Surg 2021 | https://dx.doi.org/10.21037/abs-21-110 Original Article Superparamagnetic iron oxide sentinel lymph node biopsy in early breast cancer: an analysis of artefacts on post-operative breast imaging Vivian Man1^, Michelle Cheung2, Christine Lo3, Tina Poy Wing Lam2, Ava Kwong1 1Division of Breast Surgery, Department of Surgery, The University of Hong Kong Li Ka Shing Faculty of Medicine, Queen Mary Hospital, Hong Kong, China; 2Department of Radiology, Queen Mary Hospital, Hong Kong, China; 3Department of Diagnostic Radiology, Hong Kong Sanatorium & Hospital Medical Group, Hong Kong, China Contributions: (I) Conception and design: V Man, M Cheung; (II) Administrative support: M Cheung, TPW Lam; (III) Provision of study materials or patients: V Man, A Kwong; (IV) Collection and assembly of data: V Man, M Cheung; (V) Data analysis and interpretation: V Man, M Cheung, C Lo; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Ava Kwong. Division of Breast Surgery, Department of Surgery, The University of Hong Kong Li Ka Shing Faculty of Medicine, Queen Mary Hospital, K1401, Hong Kong, China. Email: avakwong@hku.hk. Background: Superparamagnetic iron oxide (SPIO) has been shown to be a feasible alternative in sentinel lymph node (SLN) localization for early stage breast cancer. It allows simpler administrative logistics but is associated with post-operative breast magnetic resonance imaging (MRI) void artefacts and skin discoloration. The aim of this prospective study is to evaluate the clinical significance of SPIO-associated artefacts in post-operative breast imaging. Methods: Nine patients with breast conservative surgery and SPIO-guided SLN localization were invited to obtain a followup breast MRI at 18 months supplementary to the routine cancer surveillance mammography and breast ultrasonography. Intensity and maximum dimension of post-operative skin discoloration were recorded in every followup visit. Results: Signal void artefacts were encountered in every performed MRI study at post-operative 18 months and MRI interpretation was impaired at a variable degree in 66.7% of patients. There was no obvious association between the extent of MRI interference and post-operative skin discoloration. One patient experienced SPIO-associated abnormality in post-operative mammography and breast ultrasonography. Conclusions: Post-operative breast MRI void artefacts and skin discoloration were common after SPIO- guided sentinel lymph node biopsy (SLNB) and they persisted at 18 months post-injection. Future studies should focus on the reduction of breast imaging artefacts in order to extend the application of SPIO in breast cancer patients.