Complete Metabolic Response on Interim 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography to Predict Long-Term Survival in Patients with Breast Cancer Undergoing Neoadjuvant Chemotherapy

Abstract

Abstract Background This study aims to investigate the prognostic role of complete metabolic response (CMR) on interim 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in patients with breast cancer (BC) receiving neoadjuvant chemotherapy (NAC) according to tumor subtypes and PET timing. Patients and Methods Eighty-six consecutive patients with stage II/III BC who received PET/CT during or following NAC were included. Time-dependent receiver operating characteristic analysis and Kaplan-Meier analysis were used to determine correlation between metabolic parameters and survival outcomes. Results The median follow-up duration was 71 months. Maximum standardized uptake value (SUVmax) on an interim PET/CT independently correlated with survival by multivariate analysis (overall survival [OS]: hazard ratio: 1.139, 95% confidence interval: 1.058–1.226, p = .001). By taking PET timing into account, best association of SUVmax with survival was obtained on PET after two to three cycles of NAC (area under the curve [AUC]: 0.941 at 1 year after initiation of NAC) and PET after four to five (AUC: 0.871 at 4 years), while PET after six to eight cycles of NAC had less prognostic value. CMR was obtained in 62% of patients (23/37) with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2−) BC, in 48% (12/25) triple-negative BC (TNBC), and in 75% (18/24) HER2-positive (HER2+) tumors. Patients with CMR on an early-mid PET had 5-year OS rates of 92% for ER+/HER2− tumors and 80% for TNBC, respectively. Among HER2+ subtype, 89% patients (16/18) with CMR had no relapse. Conclusion CMR indicated a significantly better outcome in BC and may serve as a favorable imaging prognosticator.