Background

Carcinoembryonic antigen (CEA) is a glycoprotein on cellular surface, which is highly condensed in embryonic tissue and tumor of various kinds. Previous study found out that CEA may grow with various cancer or other diseases other than cancer as well. Besides, it is widely known that smoking also influences the rise in CEA. Among the same smokers, some of them show high CEA figures in serum when others remain in normal range. There are those whose pulmonary function is not influenced by smoking when that of others are susceptible to it. Therefore, this study was undertaken with an aim to study the relationship between serum CEA and pulmonary function by investigating how the change in pulmonary function caused by smoking influences serum CEA.

Methods
From Nov, 1997 to Feb, 2001, this study carried out tests on adult male smokers ages 35 to 64 who visited a hospital located in Kang Nung city. The subjects were divided into two groups: one group of 29 subjects with high CEA with over 6.0 ng/ml with normal colon study; the other group, which is the CEA normal group, consisted of 58 subjects selected through age adjusted random sampling. Data on personal information, smoking and clinical history was collected from a questionnaire. CEA was tested using radioimmunoassay of Abott. Pulmonary function was examined using Analyzer assembly Vmax 20C from Sensormedics Company. These examinations was limited to those who have been screened not to have cancer by chest X-ray, abdominal ultrasonography, and duodenofibroscopy.

Results
Smoking per day for the group with high serum CEA was 1.3 pack (±0.4 pack), which was found to be significantly higher compared to that of normal group (P＜0.01). Pack-years with high serum CEA group was 32.6±13.5 which was also comparatively higher than that of the normal group with 22.4±10.9 (P＜0.01). Pulmonary function test indicated that FEV₁ for the group with high serum CEA was 3.0±0.5 L, which marked lower than that of the normal group with 3.4±0.5 L (P＜0.05). After compensating for age and pack years, FEV1 decreased in proportion to the rise in CEA.

Conclusion
This study has established a link between serum CEA and daily smoking, pack years, and pulmonary function and found that FEV₁ was inversely proportionate to the rise in CEA regardless of corrected pack years and daily smoking. Consequently, serum CEA alone is thought to be related to the pulmonary function. Therefore, it is advised that smokers with high serum CEA need to take heed of the influence on pulmonary function.