Enhanced growth of tumour cells in healing colonic anastomoses and laparotomy wounds.

In the past, it has been noted that experimental tumour cells inoculated into the peritoneal cavity or into the lumen of the bowel will grow at a recently formed colonic anastomosis. However, it has previously been unclear whether the healing process enhances tumour growth or whether the presence of a suture line merely allows the tumour cells to gain access to the tissues. In the present study, using the hooded Lister rat, we have confirmed these findings by showing that growth of the syngeneic MC28 sarcoma and OES5 breast carcinoma occurs preferentially at colonic anastomoses and laparotomy wounds after intraperitoneal injection, and at colonic anastomoses after intraluminal injection. In previous studies using the MC28 sarcoma and the OES5 breast carcinoma injected by the intracardiac route (so that tumour cells reach normal and healing tissues in approximately equal numbers) we have shown that tumour growth is enhanced in healing wounds but not in the surrounding normal tissues when cells reach a healing colonic anastomosis or laparotomy wound within 2 h of its formation. Furthermore, by studying the distribution of radiolabelled tumour cells after intracardiac injection, we have calculated that the probability of a tumour cell leading to a deposit in a healing anastomosis or laparotomy wound is increased 1,000 fold compared to normal tissue. No previous studies have combined the data for intracardiac, intraluminal and intraperitoneal injection of tumour cells using the same animal model. We conclude that the same phenomenon of tumour growth enhancement in colonic anastomoses and laparotomy wounds reported after intracardiac injection of tumour cells may well be enhancing tumour growth after intraperitoneal and intraluminal injection.(ABSTRACT TRUNCATED AT 250 WORDS)