Brown Adipose Tissue in Breast Cancer Evaluated by [¹⁸F] FDG-PET/CT

Recently brown adipose tissue (BAT) activation has been proposed to have a possible role in breast cancer. The aim of this study was to evaluate BAT activation in patients with breast cancer and its relationship with molecular characteristics of tumor.

The study group comprised 79 patients with histologically proven ductal breast carcinoma (51 ± 13 years). Data on distribution, intensity (SUVmax), and total metabolic activity (TMA) of BAT were obtained from [¹⁸F] FDG-PET/CT. Clinical and biochemical data were obtained from the database.

BAT activation was present in 12 of the 79 patients (15.2 %). Patients with BAT activation were younger and had a lower body mass index (BMI) (p < 0.05 and p < 0.0005, respectively) and showed less frequently metastasis (p < 0.05). No significant differences were found in estrogen receptor (ER), progesterone receptor (PgR), Ki67, grade, and in molecular subtypes. In patients younger than 55 years and with a BMI < 26, no significant differences were observed between patients with and without BAT activation. In the 12 patients with BAT activation, a significant inverse correlation was observed between TMA and BMI (r = - 0.64, p < 0.05). TMA and SUVmax were higher in grade 2 than in grade 3 patients. No significant differences were found in both TMA and SUVmax between patients with and without lymph node metastases. A significant difference in both TMA and SUVmax was observed among different molecular types, with luminal B patients showing higher values.

In conclusion, the present study suggests a relation between BAT activation and positive known prognostic factor in breast cancer, such as intermediate tumor grade and luminal B cancer type.