OBJECTIVETo evaluate the possibility of dissemination of lung cancer cells through blood during the operation for lung cancer.

METHODSThe blood samples were taken from 52 patients with non-small cell lung cancer (NSCLC) and 5 patients with benign lung diseases at four different intervals during the operation. The transcription of carcinoembryonic antigen (CEA) messenger ribonucleic acid was assayed by means of nested reverse transcriptase polymerase chain reaction (RT-PCR). A549 (a human adenocarcinoma cell line) served as positive control. The sensitivity has been tested using quantificationally diluted A549 cells.

RESULTSThe CEA mRNA positive rates of all four time spots are as follows: 31% (16/52) at beginning of the operation (sample taken from peripheral vein), 54% (28/52) at ligating the pulmonary vein (peripheral vein), 54% (28/52) at ligating the pulmonary vein (pulmonary vein) and 54% (28/52) at 1 hour after ligating the pulmonary vein (peripheral vein). There is no relationship between the tumor identity and the positive rate of CEA mRNA. The positive rate of CEA mRNA is higher in patients with centrally located lung cancer than that in patients with peripherally located lung cancer, similar phenomenon is also found between patients with advanced lung cancer and the patients with early stage of lung cancer. No negative control samples was found to be positive for CEA mRNA, the sensitivity of our test was 1 x 10(-6).

CONCLUSIONSThe cancer cell dissemination during operation was demonstrated indirectly in our study, the time of pulmonary vein ligation (later or earlier) may affect the quantity of tumor cells released into circulation. Patients with lung cancer of central type and late TNM stage have more possibility of cancer cell dissemination during operation. More effective means may be needed to avoid the dissemination of cancer cells.