e23215 Background: FDG-PET/CT is widely used for the detection of primary breast cancer and metastasis, although its clinical significance is somewhat restricted to appropriate higher-risk populations. We attempted to apply maximum uptake values (SUVmax) of FDG-PET/CT to assess the malignant potential of breast cancer before surgery. Methods: We retrospectively reviewed 187 consecutive patients with invasive breast cancer and no distant metastasis recruited from 2009 to 2011 in our hospital who underwent PET/CT before surgery, and determined the representative PET imaging features by SUVmax. Correlation of SUVmax with several clinicopathological factors was evaluated by regression analysis. Relapse-free survival (RFS) and overall survival (OS) were compared among these factors and SUVmax using univariate and multivariate Cox analysis, Kaplan-Meier curves, and log-rank tests. Results: All patients were women of median age 60 years. The median follow-up period was 72 months. A logarithmic transformation was applied to SUVmax, which resulted in exclusion of 32 patients with no FDG uptake on PET/CT. Regression analysis revealed that SUVmax significantly correlated with ER (P = 0.0138), HER2 (P = 0.0153), lymph node metastasis (P < 0.0001), and tumor size (P < 0.0001). Multivariate analysis showed that tumor size was a significant independent factor. As regression analysis showed a strong correlation between SUVmax and tumor size < 5 cm (P < 0.0001), the 11 patients with tumor > 5 cm were excluded. Concerning the malignant potential of tumors, RFS was evaluated by univariate analysis whereby the median log SUVmax (0.6) was the only significantly independent factor to predict recurrence (P = 0.045). Patients with log SUVmax > 0.6 showed poor RFS (11 patients with recurrence) compared with log SUVmax < 0.6 (2 patients with recurrence) (P = 0.0064). OS showed no significant correlation. Conclusions: PET/CT is potentially a valuable modality to predict tumor recurrence in patients with breast cancer whose tumor size is < 5 cm and demonstrates uptake before surgery.
The Clinical Significance of Diffuse Thyroid Uptake That is Incidentally Identified by F-18 FDG PET/CT Imaging in Patients with Breast Cancer