Does Obesity-Related Hemodilution of Carcinoembryonic Antigen Exist in Non-Small Cell Lung Cancer Patients?

BACKGROUND: Previous investigations reported inverse relationship between prostate-specific antigen concentration and body mass index (BMI). These results have been explained by a hemodilution effect among obese men. However, the hemodilution of serum carcinoembryonic antigen (CEA) concentration in obese patients with non-small cell lung cancer (NSCLC) has not been ever reported. METHODS: Consecutive 381 NSCLC patients were enrolled. A body surface area (BSA)-based and a hematocrit (HCT)-based equations were applied for plasma volume (PV) estimation. The relationship between BMI and PV, serum CEA concentration and CEA amount, representing the total amount of CEA protein within the circulation, were examined. RESULTS: Higher BMI was significantly associated with higher PV (P < 0.001). However, serum CEA concentration was not significantly associated with increasing BMI. Furthermore, there was no significant association between BMI and CEA amount. The 5-year survival rate of patients with a high serum CEA concentration was significantly lower than that of patients with a normal CEA. There was no difference in the prognostic significance of serum CEA concentration and CEA amount. CONCLUSIONS: We failed to find the association between BMI and CEA, suggesting no or small hemodilution effect of CEA in NSCLC patients. Furthermore, the measurement of the CEA amount could not provide any additional information.