DCE-MRI assessment of response to neoadjuvant SABR in early stage breast cancer: Comparisons of single versus three fraction schemes and two different imaging time delays post-SABR

Matthew Mouawad; Heather Biernaski; Muriel Brackstone; Michael Lock; Brian Yaremko; Olga Shmuilovich; Anat Kornecki; Ilanit Ben Nachum; Giulio Muscedere; Kalan Lynn; Frank S. Prato; R. Terry Thompson; Stewart Gaede; Neil Gelman

Clinical and Translational Radiation Oncology (Mar 2020)

DCE-MRI assessment of response to neoadjuvant SABR in early stage breast cancer: Comparisons of single versus three fraction schemes and two different imaging time delays post-SABR

Matthew Mouawad,
Heather Biernaski,
Muriel Brackstone,
Michael Lock,
Brian Yaremko,
Olga Shmuilovich,
Anat Kornecki,
Ilanit Ben Nachum,
Giulio Muscedere,
Kalan Lynn,
Frank S. Prato,
R. Terry Thompson,
Stewart Gaede,
Neil Gelman

Affiliations

Matthew Mouawad: Medical Biophysics, Western University, London, Ontario, Canada; Corresponding author at: 800 Commissioners Road East, Room A4-841, P.O. Box 5010, STN B, London, ON N6A 5W9, Canada.
Heather Biernaski: Lawson Health Research Institute, London, Ontario, Canada
Muriel Brackstone: Medical Biophysics, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; London Health Sciences Centre, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada
Michael Lock: London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
Brian Yaremko: London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
Olga Shmuilovich: Lawson Health Research Institute, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada
Anat Kornecki: Lawson Health Research Institute, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada
Ilanit Ben Nachum: Lawson Health Research Institute, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada
Giulio Muscedere: Lawson Health Research Institute, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada
Kalan Lynn: Lawson Health Research Institute, London, Ontario, Canada; London Health Sciences Centre, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada
Frank S. Prato: Medical Biophysics, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; St. Joseph’s Health Care, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada
R. Terry Thompson: Medical Biophysics, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada
Stewart Gaede: Medical Biophysics, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
Neil Gelman: Medical Biophysics, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada

Journal volume & issue: Vol. 21
pp. 25 – 31

Abstract

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Purpose: To determine the effect of dose fractionation and time delay post-neoadjuvant stereotactic ablative radiotherapy (SABR) on dynamic contrast-enhanced (DCE)-MRI parameters in early stage breast cancer patients. Materials and methods: DCE-MRI was acquired in 17 patients pre- and post-SABR. Five patients were imaged 6–7 days post-21 Gy/1fraction (group 1), six 16–19 days post-21 Gy/1fraction (group 2), and six 16–18 days post-30 Gy/3 fractions every other day (group 3). DCE-MRI scans were performed using half the clinical dose of contrast agent. Changes in the surrounding tissue were quantified using a signal-enhancement threshold metric that characterizes changes in signal-enhancement volume (SEV). Tumour response was quantified using Ktrans and ve (Tofts model) pre- and post-SABR. Significance was assessed using a Wilcoxin signed-rank test. Results: All group 1 and 4/6 group 2 patients’ SEV increased post-SABR. All group 3 patients’ SEV decreased. The mean Ktrans increased for group 1 by 76% (p = 0.043) while group 2 and 3 decreased 15% (p = 0.028) and 34% (p = 0.028), respectively. For ve, there was no significant change in Group 1 (p = 0.35). Groups 2 showed an increase of 24% (p = 0.043), and Group 3 trended toward an increase (23%, p = 0.08). Conclusion: Kinetic parameters measured 2.5 weeks post-SABR in both single fraction and three fraction groups were indicative of response but only the single fraction protocol led to enhancement in the surrounding tissue. Our results also suggest that DCE-MRI one-week post-SABR may be too early for response assessment, at least for single fraction SABR, whereas 2.5 weeks appears sufficiently long to minimize confounding acute effects. Keywords: Breast cancer, DCE-MRI, Response assessment, Tofts model, SABR

Published in Clinical and Translational Radiation Oncology

ISSN: 2405-6308 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Medicine: Medicine (General): Medical physics. Medical radiology. Nuclear medicine; Medicine: Internal medicine: Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Website: https://www.journals.elsevier.com/clinical-and-translational-radiation-oncology

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