Intra-luminal tumour cells and peri-anastomotic tumour growth in experimental colonic surgery

Most loco-regional tumour recurrences following colorectal cancer surgery are extra-luminal. This study was designed to determine the conditions necessary for viable intra-luminal tumour cells to give rise to extra-luminal tumour growth in an experimental animal model. When carcinoma cells were injected into the colonic lumen in the absence of a colonic wound, tumour growth was rare (1 of 24 animals). However, when tumour cells were injected intra-luminally either in the presence of an apparently watertight colotomy repair or prior to the transmural insertion of interrupted sutures, peri-anastomotic +/- widespread peritoneal tumour growth was consistently observed. Tumour growth did not occur on the mucosa of the bowel. These findings suggest that viable intra-luminal tumour cells can migrate across a clinically intact experimental large bowel anastomosis or along transmural suture tracts to give rise to extra-luminal tumour growth.