[18F]-Fluorodeoxyglucose Positron Emission Tomography Can Contribute to Discriminate Patients with Poor Prognosis in Hormone Receptor-Positive Breast Cancer

BACKGROUND: Patients with hormone receptor-positive breast cancer typically show favorable survival. However, identifying individuals at high risk of recurrence among these patients is a crucial issue. We tested the hypothesis that [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) scans can help predict prognosis in patients with hormone receptor-positive breast cancer. METHODS: Between April 2004 and December 2008, 305 patients with hormone receptor-positive breast cancer who underwent FGD-PET were enrolled. Patients with luminal B subtype were identified by positivity for human epidermal growth factor receptor-2 (HER2) or high Ki67 (≥14%) according to criteria recently recommended by the St. Gallen panelists. The cut-off value of SUV(max) was defined using the time-dependent receiver operator characteristic curve for recurrence-free survival (RFS). RESULTS: At a median follow up of 6.23 years, continuous SUV(max) was a significant prognostic factor with a hazard ratio (HR) of 1.21 (p = 0.021). The cut-off value of SUV(max) was defined as 4. Patients with luminal B subtype (n = 82) or high SUV(max) (n = 107) showed a reduced RFS (p = 0.031 and 0.002, respectively). In multivariate analysis for RFS, SUV(max) carried independent prognostic significance (p = 0.012) whereas classification with immunohistochemical markers did not (p = 0.274). The Harell c-index was 0.729. High SUV(max) was significantly associated with larger tumor size, positive nodes, HER2 positivity, high Ki67 (≥14%), high tumor grade, and luminal B subtype. CONCLUSIONS: Among patients with hormone receptor-positive breast cancer, FDG-PET can help discriminate patients at high risk of tumor relapse.