Detection of colorectal cancer cells in mesenteric venous blood in comparison to peripheral blood samples

Background: Pre- and postoperative hematogenic dissemination of tumor cells in patients with colorectal cancer may play an important role in tumor pro gression. The tumor cells probably reach the systemic circulation through t he mesenteric venous blood. Therefore the central lymphovascular bundle is ligated in oncological colon surgery before mobilisation of the tumor. Purp ose of this study was the detection of colorectal cancer cells in mesenteri c venous blood compared to central venous blood. Methods: For tumor cell detection we used the established CK 20 RT-PCR. Blo od samples (10 ml) were obtained intraoperatively from the tumor draining v ein and from a central venous catheter in the vena cava superior before mob ilisation and after resection of the tumor. Results: 18/18 primary tumor samples showed CK 20-expression. All blood sam ples from 20 healthy volunteers and from 24 patients with benign bowel dise ases tested negative for CK 20. Mesenteric venous blood samples from 4 pati ents with colonic resections for benign disease also tested negative. In se rial dilution experiments with the colon cancer cell-line HT-29 10 tumor ce lls could be detected in 10 mi of blood. We detected tumor cells in 8/13 (6 2%) patients in mesenteric venous blood and in 3/13 (23%) patients in centr al venous blood. After tumor resection 4 of 14 (31%) patients were CK 20-po sitive in central venous blood, whereby 3 of these 4 patients had already s hown CK 20-expression in their mesenteric venous blood. Conclusion: The detection rate for tumor cells of colorectal carcinomas was distinctly higher in mesenteric venous blood compared to central venous bl ood. The lower detection rate in central venous blood may be explained by t he filtering effect of the RES in the liver The high incidence of tumor cel ls in mesenteric venous blood supports the concepts of primary ligature of the tumor draining mesenteric vein ("no-touch isolation technique").