CT-based compartmental quantification of adipose tissue versus body metrics in colorectal cancer patients

While obesity is considered a prognostic factor in colorectal cancer (CRC), there is increasing evidence that not simply body mass index (BMI) alone but specifically abdominal fat distribution is what matters. As part of the ColoCare study, this study measured the distribution of adipose tissue compartments in CRC patients and aimed to identify the body metric that best correlates with these measurements as a useful proxy for adipose tissue distribution. In 120 newly-diagnosed CRC patients who underwent multidetector computed tomography (CT), densitometric quantification of total (TFA), visceral (VFA), intraperitoneal (IFA), retroperitoneal (RFA), and subcutaneous fat area (SFA), as well as the M. erector spinae and psoas was performed to test the association with gender, age, tumor stage, metabolic equivalents, BMI, waist-to-height (WHtR) and waist-to-hip ratio (WHR). VFA was 28.8 % higher in men (p_VFA<0.0001) and 30.5 % higher in patients older than 61 years (p_VFA<0.0001). WHtR correlated best with all adipose tissue compartments (r_VFA=0.69, r_TFA=0.84, p<0.0001) and visceral-to-subcutaneous-fat-ratio (VFR, r_VFR=0.22, p=<0.05). Patients with tumor stages III/IV showed significantly lower overall adipose tissue than I/II. Increased M. erector spinae mass was inversely correlated with all compartments. Densitometric quantification on CT is a highly reproducible and reliable method to show fat distribution across adipose tissue compartments. This distribution might be best reflected by WHtR, rather than by BMI or WHR. (orig.)