Off the Beaten Path in Oncology: Active Brown Adipose Tissue by Virtue of Molecular Imaging

Brown Adipose Tissue (BAT) is considered beneficial in diabetes and obesity, but it can also have negative effects such as its implication in tumours' pathogenesis and the development of Cancer-induced Cachexia. Since ¹⁸F-FDG PET/CT is a common molecular imaging modality used in cancer assessment, we aim to study the ¹⁸F-FDG BAT biodistribution in oncological patients and look for possible correlations between BAT activity and different malignancies as well as the patient's weight status. After analysing the total number of oncological ¹⁸F-FDG PET/CT scans between 2017 and 2021, we selected patients with active BAT. Based on their BMI, the selected patients were divided into nonobese (NO) vs. overweight and obese (OOB). OOB SUV_maxlean body mass(LBM) had the highest mean values in supraclavicular, latero-cervical, and paravertebral vs. mediastinal and latero-thoracic localisations in NO. BMI was positively correlated with latero-cervical and supraclavicular SUV_max(LBM) but negatively correlated with latero-thoracic and abdominal SUV_max(LBM). Considering the age of the patients, SUV_max(LBM) decreases in the latero-cervical, paravertebral, and abdominal regions. In addition, the males presented lower SUV_max(LBM) values. SUV_max(LBM) was not affected by the treatment strategy or the oncological diagnosis. To conclude, it is mandatory to take into consideration the BAT particularities and effects on weight status in order to optimise the clinical management of oncological patients.