Quantitative Detection Of Disseminated Cancer Cells In The Peritoneal Cavity Of Colorectal Carcinoma Patients With Real-Time RT-PCR And Its Clinical Significance

The purpose of this study is to detect the free cancer cells in peritoneal cavity of colorectal cancer patients by quantitative Real-time RT PCR method and investigate its clinical significance. From May 2003 to Jan. 2004, peritoneal wash was obtained from 81 patients with colorectal cancer in Aichi cancer center. cDNA was synthesized from mRNA extracted from peritoneal washes by 2 kinds of primers ( Random primer and Oligo primer). Quantification of CEA and CK-20 mRNA was performed on a LightCycler instrument with hybridization probe. A part of each peritoneal wash was also examined by conventional cytology. All patients were followed up with a median follow-up period of 12 months. The results indicated: Both CEA mRNA and CK-20 mRNA positive rates and values were significantly correlated with depth of tumor invasion, tumor stage, lymph node status. Sensitivity and specificity of CEA and CK-20 real-time RT-PCR with an appropriate cutoff value were 100%, 100%. and 100%. 100%. respectively, whereas those of conventional cytology were 33%. and 100%, respectively. These results suggest that both CEA and CK-20 mRNA quantifications are sensitive and specific methods for detection of micrometastases in the peritoneal washes of colorectal cancer. Abnormality of CEA and CK-20 mRNA in peritoneal washes is correlated with disease free survival for colorectal cancer patients. Further follow-up study is needed to demonstrate the clinical significance of CEA and CK-20 mRNA in peritoneal washes.