Neoadjuvant Chemotherapy for Breast Cancer: Functional Tumor Volume by MR Imaging Predicts Recurrence-free Survival—Results from the ACRIN 6657/CALGB 150007 I-SPY 1 TRIAL

Abstract

).q RSNA, 2015 Purpose:To evaluate volumetric magnetic resonance (MR) imaging for predicting recurrence-free survival (RFS) after neoadjuvant chemotherapy (NACT) of breast cancer and to consider its predictive performance relative to pathologic complete response (PCR). Materials and Methods:This HIPAA-compliant prospective multicenter study was approved by institutional review boards with written informed consent. Women with breast tumors 3 cm or larger scheduled for NACT underwent dynamic contrastenhanced MR imaging before treatment (examination 1), after one cycle (examination 2), midtherapy (examination 3), and before surgery (examination 4). Functional tumor volume (FTV), computed from MR images by using enhancement thresholds, and change from baseline (DFTV) were measured after one cycle and before surgery. Association of RFS with FTV was assessed by Cox regression and compared with association of RFS with PCR and residual cancer burden (RCB), while controlling for age, race, and hormone receptor (HR)/ human epidermal growth factor receptor type 2 (HER2) status. Predictive performance of models was evaluated by C statistics. Results:Female patients (n = 162) with FTV and RFS were included. Conclusion:Breast tumor FTV measured by MR imaging is a strong predictor of RFS, even in the presence of PCR and RCB class. Models combining MR imaging, histopathology, and breast cancer subtype demonstrated the strongest predictive performance in this study.q RSNA, 2015

MRI predicts pathologic complete response in HER2-positive breast cancer after neoadjuvant chemotherapy

“…Our findings are supported by results of the I-SPY study, showing an association with tumour volume at end-of-treatment MRI and recurrence-free survival [23]. The prognostic value of rCR is an exploratory finding and must be confirmed in independent series.…”

Identifying relations between imaging phenotypes and molecular subtypes of breast cancer: Model discovery and external validation

“…Previous studies have shown that smaller functional tumor volume and lower BPE around the tumor are associated with superior survival (38) and lower risk of recurrence in breast cancer (26), respectively. As luminal A cancer is known to have the best prognosis among all four subtypes, this lends support for our findings here.…”

“…This is different from previous studies (26,27) that calculate the absolute signal enhancement or its ratio of background parenchyma, which may be prone to MR signal artifacts or variations in image acquisition protocols. We believe that volume-based measurements are more robust to such variations (38) and that they are more closely related to how radiologists observe and interpret BPE on MR imaging, as suggested in BIRADS (29). …”

Current Practices in Breast Magnetic Resonance Imaging: a Survey Involving the Korean Society of Breast Imaging

“…Breast magnetic resonance imaging (MRI) combined with mammography has been reported to be 90% to 100% sensitive in detecting breast cancer. Its usefulness has been reported not only in high-risk screening but also in pre-operative examination, evaluation of neoadjuvant chemotherapy response, and post-operative screening (2)(3)(4)(5). The use of breast MRI has been rapidly growing in Korea for the last 10 years.…”