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Optimized breast MRI functional tumor volume as a biomarker of recurrence‐free survival following neoadjuvant chemotherapy
Author(s) -
Jafri Nazia F.,
Newitt David C.,
Kornak John,
Esserman Laura J.,
Joe Bonnie N.,
Hylton Nola M.
Publication year - 2014
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.24351
Subject(s) - hazard ratio , breast cancer , medicine , voxel , magnetic resonance imaging , confidence interval , proportional hazards model , biomarker , nuclear medicine , imaging biomarker , radiology , oncology , cancer , chemistry , biochemistry
Purpose To evaluate optimal contrast kinetics thresholds for measuring functional tumor volume (FTV) by breast magnetic resonance imaging (MRI) for assessment of recurrence‐free survival (RFS). Materials and Methods In this Institutional Review Board (IRB)‐approved retrospective study of 64 patients (ages 29–72, median age of 48.6) undergoing neoadjuvant chemotherapy (NACT) for breast cancer, all patients underwent pre‐MRI 1 and postchemotherapy MRI 4 of the breast. Tumor was defined as voxels meeting thresholds for early percent enhancement (PE thresh ) and early‐to‐late signal enhancement ratio (SER thresh ); and FTV (PE thresh , SER thresh ) by summing all voxels meeting threshold criteria and minimum connectivity requirements. Ranges of PE thresh from 50% to 220% and SER thresh from 0.0 to 2.0 were evaluated. A Cox proportional hazard model determined associations between change in FTV over treatment and RFS at different PE and SER thresholds. Results The plot of hazard ratios for change in FTV from MRI 1 to MRI 4 showed a broad peak with the maximum hazard ratio and highest significance occurring at PE threshold of 70% and SER threshold of 1.0 (hazard ratio = 8.71, 95% confidence interval 2.86–25.5, P < 0.00015), indicating optimal model fit. Conclusion Enhancement thresholds affect the ability of MRI tumor volume to predict RFS. The value is robust over a wide range of thresholds, supporting the use of FTV as a biomarker. J. Magn. Reson. Imaging 2014;40:476–482 . © 2013 Wiley Periodicals, Inc .