Original Study Hypervascularity Predicts Complete Pathologic Response to Chemotherapy and Late Outcomes in Breast Cancer Enida Bufi, 1 Paolo Belli, 1 Marialuisa Di Matteo, 1 Michela Giuliani, 1 Mariavalentina Tumino, 1 Pierluigi Rinaldi, 1 Luigia Nardone, 2 Gianluca Franceschini, 3 Antonino Mulé, 4 Lorenzo Bonomo 1 Abstract Asymmetric increase in breast vascularity (AIBV) is an emerging marker in magnetic resonance imaging-based evaluation of breast cancer. We analyze herein the largest series so far aimed at elucidating the potential role of AIBV in predicting the early and late outcomes of locally advanced breast cancer. We observed that, despite more aggressive pathologic profile of tumors associated with AIBV, they also present greater sensitivity to neoadjuvant chemotherapy. Nonetheless, the persistence of AIBV after neoadjuvant chemotherapy is asso- ciated with worse late prognosis and might be used to tailor additional treatments. Background: Our objective was to investigate the relationship between asymmetric increase in breast vascularity (AIBV) and pathologic profiles of breast cancer. We also addressed the prognostic performance of AIBV and of vascular maps reduction after neoadjuvant chemotherapy (NAC) in predicting pathologic complete response (pCR) at surgery and outcome at follow-up. Materials and Methods: Two hundred nineteen patients with unilateral locally advanced breast cancer (LABC) underwent magnetic resonance imaging before and after NAC. Axial, sagittal, and coronal maximum intensity projections were obtained in a subjective comparative evaluation. Asymmetrical versus symmetrical breast vascularity was defined through number of vessels, diameter, and signal intensity. Kaplan-Meier methodology was employed for late survival (31.4  18 months follow-up). Results: AIBV ipsilateral to LABC occurred in 62.5% (P < .001). AIBV was significantly associated with invasive ductal carcinoma, G3, triple-negative, HER2þ, and hybrid phenotypes (P < .001). pCR was more frequent among patients with AIBV (24%) (P ¼ .001). After NAC, the vascular map was significantly reduced, particularly in patients with pCR (P < .001). At follow-up, the recurrence rate was 22% (6.1% mortality). AIBV after NAC was associated with worse late survival (P ¼ .036). A trend towards worse late survival existed among patients with AIBV before NAC. We did not observe statistically different survival according to the variation of vascularity after NAC. Conclusion: LABC with ipsilateral AIBV before NAC is associated with more aggressive pathologic profiles. Nonetheless, it is more sensitive to NAC and shows a higher frequency of pCR. The persistence of AIBV after NAC entails a worse late prognosis and should prompt more aggressive therapeutic strategies. Clinical Breast Cancer, Vol. -, No. -, --- ª 2016 Elsevier Inc. All rights reserved. Keywords: Breast tumor, Increased vascularization, Magnetic Resonance Imaging, Neoadjuvant chemotherapy, Prognosis Introduction Magnetic resonance imaging (MRI) is an established tool for lesion characterization and for the evaluation of response to neo- adjuvant chemotherapy (NAC) in patients with breast cancer. 1-4 Since breast carcinomas rely on the process of neoangiogenesis and on the development of blood microvessels for their growth, increased breast vascularity in the whole ipsilateral breast may indicate the presence of disease. Nonetheless, the impact of such 1 Department of Radiological Sciences 2 Department of Radiotherapy 3 Department of Surgery, Breast Unit 4 Department of Pathology, Catholic University, Rome, Italy Submitted: Mar 25, 2016; Revised: May 30, 2016; Accepted: Jun 9, 2016 Address for correspondence: Enida Bufi, MD, Department of Radiological Sciences, Catholic University, Largo A. Gemelli, 8, 00168 Rome, Italy E-mail contact: reagandus@alice.it 1526-8209/$ - see frontmatter ª 2016 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clbc.2016.06.007 Clinical Breast Cancer Month 2016 - 1