Breast cancer: influence of tumour volume estimation method at MRI on prediction of pathological response to neoadjuvant chemotherapy

Objective:Does method of tumour volume measurement on MRI influence prediction of treatment outcome in patients with primary breast cancer undergoing neoadjuvant chemotherapy (NAC)?Method:The study comprised 136 women with biopsy-proven breast cancer scheduled for MRI monitoring during NAC treatment. Dynamic contrast-enhanced images were acquired at baseline (pre-NAC) and interim (post 3 NAC cycles) timepoints. Functional tumour volumes (FTV), automatically derived using vendor software and enhancing tumour volumes (ETV), user-derived using a semi-automated thresholding technique, were calculated at each timepoint and percentage changes calculated. Response, assessed using residual cancer burden (RCB) score on surgically resected specimens, was compared statistically with volumetric changes and ROC analysis performed.Results:Mean volumetric differences for each RCB response category were (FTV/ETV): pCR 95.5/96.8%, RCB-I 69.8/66.7%, RCB-II 64.0/65.5%, RCB-III 25.4/24.0%. Differences were significant betwee...