Influence of obesity on the serum carcinoembryonic antigen value in patients with colorectal cancer.
BACKGROUND
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.


METHODS
We analyzed the association between BMI and CEA concentration in a group of 2,845 patients who underwent surgical treatment for colorectal adenocarcinoma from 1995 to 2009. Multivariate linear regression analysis was applied to adjust for clinicopathologic confounding factors to analyze main outcome measures. The association of BMI with plasma volume, CEA concentration, and total circulating CEA mass was assessed by determining P values for trends. We also developed a regression formula to calculate the effect of obesity on the serum CEA levels.


RESULTS
Increased BMI was linearly correlated with higher plasma volume (P < 0.001 for trend) and lower adjusted CEA concentrations after controlling for potentially confounding factors (P ≤ 0.005 for trend in stage II and III tumors). Our theoretical model suggests that a CEA value of 7.0 ng/mL in patients of normal weight corresponds to 6.1 ng/mL in obese patients.


CONCLUSIONS
The hemodilution effect from increased plasma volume may account for the decreased CEA concentrations observed in patients with higher BMI.


CONCLUSIONS
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.
Park
Jun Seok
JS
Department of Surgery, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea.
Choi
Gyu-Seog
GS
Jang
You Seok
YS
Jun
Soo Han
SH
Kang
Hyun
H
D000230:Adenocarcinoma / Q000097:blood* / Q000453:epidemiology / Q000473:pathology; D015992:Body Mass Index; D002272:Carcinoembryonic Antigen / Q000097:blood*; D015179:Colorectal Neoplasms / Q000097:blood* / Q000453:epidemiology / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000453:epidemiology / Q000473:pathology; D010953:Plasma Volume / Q000502:physiology; D011379:Prognosis; D012189:Retrospective Studies
D002272:Carcinoembryonic Antigen