Study shows obese patients have lower CEA levels

http://cebp.aacrjournals.org/content/19/10/2461.full

 Prior studies suggest that obesity is inversely associated with tumor marker concentration and may reduce diagnostic precision. This study was undertaken to evaluate the association between body mass index (BMI) and serum carcinoembryonic antigen (CEA) concentrations in colorectal cancer patients.

Obesity might be one of the factors that affect CEA value, leading to loss of sensitivity and diagnostic accuracy in the CEA test. The BMI status of patients should be taken into account during assessment of serum CEA during the surveillance of colorectal cancer.

Based on the above, we hypothesized that the diagnostic precision of the CEA test was affected by body mass index (BMI) status. This theory was examined in the context of colon cancer, and we explored whether large plasma volumes in obese patients were associated with lower CEA concentrations.

Patients with BMI of ≥27.5 displayed 15% to 20% lower mean CEA concentrations relative to normal-weight patients.  Based on this theoretical formula, the observed CEA concentration of 7.0 ng/mL in normal-weight patients corresponded to 6.1 ng/mL in obese patients.