Abstract

Introduction: Cachexia reduces considerably quality of life and survival of patients with lung cancer (LC). We aimed to find out whether positron emission tomography / computed tomography (PET/CT) derived brown-adipose-tissue (BAT) activity and body-composition parameters were associated with cachexia and survival.

Methods: Data on patients (n=116, 66% males), tumours, metabolism, and survival were prospectively collected. BAT activity was assessed via fluorine-18 deoxyglucose PET/CT. Mean standardised uptake values (SUV) of supraclavicular fat regions were measured and normalised to liver (L) or cerebellum (C) uptake (SUV ratio [SUVR_L/C]). Bioelectrical impedance analysis (BIA) quantified muscle mass (body cell mass) and body fat. Subcutaneous and visceral adipose tissue (SAT/VAT) plus muscle regions of interest were segmented manually in a transverse CT image (lumbar disc L3/L4). Plasma adipokines were measured via enzyme-linked immunosorbent assay. Statistics included group comparisons, correlations, survival, Cox regression.

Results: Higher SUVR_C was associated with anorexia or cachexia (p<0.05, respectively). SUVR_L correlated negatively with CT-derived SAT (r=-0.36, p<0.01) and VAT (r=-0,57, p<0.01), and BIA-derived body cell mass (r=-0.35, p<0.01) and body fat mass (r=-0.43, p<0.01). Adiponectin correlated positively with SUVR_L (r=0.35, p<0.001), and negatively with SAT (r=-0.26, p<0.01) and VAT (r=-0.44, p<0.01). Higher SUVR_L increased the risk for shorter median overall survival (100 versus 630 days, hazard ratio 2.42, p=0.01).

Conclusions: Enhanced BAT activity increased the risk for cachexia and shorter survival in LC patients suggesting a potential role for the workup of cachexia.