Risk stratification in patients with advanced-stage breast cancer by pretreatment [¹⁸F]FDG PET/CT

BACKGROUND The objective of the current study was to investigate the prognostic value of pretreatment [¹⁸F] fluorodeoxyglucose position emission tomography/computed tomography ([¹⁸F]FDG PET/CT) in patients with advanced-stage breast cancer. METHODS Pretreatment PET/CT scans from 240 consecutive patients with American Joint Committee on Cancer stage III or stage IV BC were analyzed retrospectively. Clinicopathological factors and metabolic parameters of the primary tumor including maximum standardized uptake value (SUV_max), metabolic tumor volume, and total lesion glycolysis (TLG) with a range of thresholds were compared to predict progression-free survival (PFS) and overall survival (OS) using a time-dependent receiver operating characteristic curve and Cox proportional hazards regression analyses. RESULTS SUV_max with a cutoff value of 6.0, TLG_30% with a cutoff value of 158 g, and phenotype associated with PFS and OS were analyzed using multivariate analysis. The mean TLG_30% of primary tumors for patients with stage III and stage IV disease was 405 g and 750 g (P =.010), respectively. Patients with triple-negative breast cancer or a TLG_30% >158 g or with both were categorized as being at high risk, and those with non-triple-negative breast cancer and a primary tumor with a TLG_30% ≤158 g were defined as low risk. The 5-year PFS rates for stage III disease among patients with low-risk versus high-risk BC were 85% and 67.5%, respectively. For patients with stage IV disease, the 5-year PFS rates were 45% and 9%, respectively, for patients with low-risk versus high-risk disease. Patients with stage III and high-risk BC had OS rates that were similar to those for patients with stage IV and low-risk BC (P =.552). CONCLUSIONS The TLG_30% from pretreatment PET/CT was found to independently correlate with survival outcomes and appears to be able to effectively stratify both patients with stage III and those with stage IV BC. Cancer 2015;121:3965-3974.