Abstracts
2000 Digestive Disease Week

# 2398 Can Laparoscopic Surgery Enhance Colorectal Cancer Spread?
Xavier Bessa, Antoni Castells, Antonio M Lacy, Loreto Boix, J. Ignasi Elizalde, Laura Gargallo, Virginia Pinol, Josep M. Pique, Barcelona, Spain

Prognosis of colorectal cancer patients depends on the occurrence of preoperative or perioperative dissemination of tumor cells. In that sense, it has been suggested that laparoscopic surgical techniques may favor malignant cell spread, mainly due to the peritoneal insuflation. The recent possibility of detecting neoplastic cells in human biological samples allowed us to evaluate the effect of surgery on tumoral dissemination, by comparing laparoscopic-assisted colectomy (LAC) versus open colectomy (OC). Methods: 49 consecutive non-metastatic colorectal cancer patients were randomly assigned to LAC (n=26) or OC (n=23). Peripheral venous blood samples were obtained before (baseline), immediately after, and 24 hours after surgery. In a subgroup of 18 patients (LAC=9 and OC=9), portal blood and peritoneal fluid samples were also obtained both at the initiation and the end of surgery. Neoplastic cells were detected by means of reverse transcriptase- polymerase chain reaction targeted to carcinoembryonic antigen (CEA) mRNA (Br J Cancer 1998; 78:1368). Results: Both groups were similar with respect to demographic, clinical and tumoral characteristics. Before surgery, CEA mRNA expression was detected in peripheral blood from 35 patients (LAC=20 (77%), OC=15 (65%); ns). In preoperatively negative patients, CEA mRNA expression was detected at the end of surgery in 4 out of 6 LAC-operated patients as well as in 2 out of 8 OC-operated cases. While conversion persisted 24 hours after surgery in all OC-operated patients, that only happened in 2 cases from the LAC group (25% vs 33%, respectively; ns). On the other hand, before tumor mobilization, portal blood CEA mRNA expression was detected in 7 (78%) patients from the LAC group and in 8 (89%) from the OC group. Only one LAC-operated patient underwent portal blood conversion after surgery, although he remained negative at peripheral level. Finally, while baseline peritoneal fluid CEA mRNA expression was not detected in any patient, one case from each group (11%) became positive after surgery. Conclusion: These results confirm that preoperative and perioperative dissemination of tumor cells is a frequent event in colorectal cancer, but the surgical approach (laparoscopic-assisted vs open colectomy) seems not to be a determining factor. Long term follow-up of these patients will provide data on the prognostic relevance of detecting circulating neoplastic cells in colorectal cancer patients.