摘要AIM: To establish a more sensitive method for detection of free cancer cells in peritoneal washes from gastric cancer patients during surgery and to evaluate its clinical significance.METHODS: The carcinoembryonic antigen (CEA) mRNA levels in peritoneal washes from 65 cases of gastric cancer were detected by real-time RT-PCR. Peritoneal lavage cytology (PLC) was applied simultaneously to detection of free cancer cells. Negative controls included peritoneal washes from 5 cases of benign gastric disease and blood samples from 5 adult healthy volunteers.RESULTS: There was no CEA mRNA in peritoneal washes from benign gastric disease patients and in blood of adult healthy volunteers. The positive percentage of free cancer cells detected by real-time RT-PCR was 47.7% and only 12.3% by PLC. The positive rate of CEA mRNA was significantly related with serosa invasion between peritoneal metastasis and stage of gastric cancer.CONCLUSION: Real-time RT-PCR is a sensitive and rapid method for the detection of free cancer cells in peritoneal washes. The presence of free cancer cells in peritoneal washes is related to the pathologic stage of gastric cancer.