Correlation between (18)F-FDG uptake on PET/CT and prognostic factors in triple-negative breast cancer

The purpose of this study was to investigate whether a correlation exists between (18)F-fluorodeoxyglucose (FDG) uptake and prognostic factors in triple-negative breast cancer (TNBC).

Between January 2009 and December 2013, 103 patients (mean age, 50.6 years) with primary TNBC (mean, 2.6 cm; range, 1.0-6.5 cm) underwent (18)F-FDG PET/CT for initial staging. Correlations between maximum standardized uptake value (SUVmax) on PET/CT and prognostic factors including tumour size, nodal status, histological grade, Ki-67 proliferation index, tumour suppressor p53, and 'basal-like' markers (epidermal growth factor receptor and CK 5/6) were assessed.

The mean SUVmax of the 103 tumours was 10.94 ± 5.25 (range: 2-32.8). There was a positive correlation between SUVmax and Ki-67 (Spearman's rho = 0.29, P = 0.003) and tumour size (Spearman's rho = 0.27, P = 0.006), whereas this relationship was not observed in the nodal status, histological grade, p53 status and 'basal-like' phenotypes. In a multivariate regression analysis, Ki-67 (P < 0.001) and tumour size (P = 0.009) were significantly associated with SUVmax in TNBCs.

Increased (18)F-FDG uptake on PET/CT was correlated with a high Ki-67 proliferation index and larger tumour size in TNBC. These results suggest a potential role of (18)F-FDG PET/CT in identifying TNBC with more aggressive behaviour.

• A wide range of FDG uptake reflected heterogeneity of cancer metabolism. • FDG uptake was correlated with the Ki-67 proliferation index in TNBC. • FDG uptake was correlated with tumour size in TNBC. • FDG uptake was not correlated with 'basal-like' phenotype.