FDG uptake in breast cancer and Quantitative Assessment of Breast Parenchymal Uptake on 18F-FDG PET/CT: Association with Histopathological, Hormonal status, and Clinical Features

To evaluate the predictive value of the 18F-FDG PET/CT parameters on the histopathological features, receptor expression status, and molecular proliferation markers in breast cancer. Also, to assess the effect of the normal breast parenchymal uptake (BPU) on primary breast cancer.

287 patients were included, 198 patients with breast cancer (BC) and 89 patients with the healthy breast control group (CG). The metabolic parameters of breast carcinoma were compared with immunohistochemical subtypes, Ki-67 expression status, tumor size, axillary nodal involvement, and distant organ metastasis. We also analyzed the BPU using a 1.5 cm3 volume of interest (VOI) in the BC and CG groups.

There was a positive correlation between primary tumor SUVmax and tumor size (p=0.001), high Ki-67 expression (p<0.001), axillary nodal involvement (p<0,001), distant organ metastases (p=0.026), ER and PR negativity, and HER2 positivity (p=0.000, 0.001, and 0.021, respectively). Furthermore, the change in mean SUVmax in molecular subtypes was statistically significant (p<0.001). In addition, the SUVmax measured 0.5 cm from the tumor in the same quadrant is higher than the opposite quadrant and contralateral breast, suggesting that the distance to the tumor increases, the FDG uptake decreases (p<0.001 and 0.001, respectively).

Strong relationships were detected between the ER and PR negativity, HER2-positivity, high Ki-67 expression, tumor size, axillary lymph node involvement, distant organ metastases, and SUVmax values. Therefore, we believe that metabolic parameters obtained with 18F-FDG PET/CT may provide relevant information about breast cancer tumor biology and suggest a potential role in identifying more aggressive behavior.