Local peritonectomy highly attracts free floating intraperitoneal colorectal tumour cells in a rat model.

BACKGROUND/AIMS Intraperitoneal free cancer cells are associated with a higher risk of recurrence and a poorer prognosis in colorectal surgery. Tumour recurrence may occur early after surgery. One potential mechanism is the ability of peritoneal lesions to attract tumour cells. METHODS In Wag-Rija rats, the parietal peritoneum was resected on a defined area, a corresponding control area was marked in the same rat and colorectal tumour cells (CC531) were applied into the abdomen after surgery. Tissue was harvested 6 or 9 days after surgery to evaluate intra-abdominal tumour growth. Additionally tumour cells were applied 2 weeks after peritoneal resection to investigate tumour growth in a healed area of peritonectomy. Specimens were evaluated for macroscopic tumour spread, weight of the abdominal wall and maximal tumour thickness. RESULTS Macroscopic tumour spread, weight of the abdominal wall and maximal tumour thickness were significantly increased within the area of peritonectomy after both 6 and 9 days compared to the control area. However, only macroscopic tumour expansion was significantly increased in the healed area of peritonectomy. CONCLUSION Peritoneal defects may play an important role in the pathogenesis of tumour implantation and might have some impact on tumour recurrence. The peritoneal damage should be kept as low as possible.