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

Facilitation by partial hepatectomy of tumor growth within the rat liver following intraportal injection of syngeneic tumor cells

The effects of both mechanical trauma and regeneration on the growth of intraportally injected tumor in the rat liver were investigated using two-thirds partial hepatectomy (PH). Tumor grew at the excision scar when PH was performed less than 2 days before tumor injection (34/34 animals). However, when the PH was performed 4-7 days before injection, tumor developed within the regenerating lobe, but not at the scar (50/51). Injecting the same cell dose into rats with intact livers caused few tumors to develop in 12/30 animals. Intraportally injected 51Cr-labelled tumor cells distributed uniformly in the liver irrespective of the time after PH. Patterns of tumor take seen at different times after PH were not due to selective trapping of the injected cells. Liver extracts showed that epidermal growth factor-like activity was unaltered by PH, while heparin-binding growth factor activity peaked at 2 days post-PH, before the incidence of tumor growth in the parenchyma increased. We observed two peaks of DNA synthesis at days 1 and 4 post-PH by pulse labeling with [125I]deoxyuridine and bromodeoxyuridine. Bromodeoxyuridine immunohistochemistry showed the first peak to be confined to hepatocytes. The second peak involved non-hepatocytes and coincided with the beginning of enhanced tumor take in the regenerating lobe.

Importance of the omentum in the development of intra-abdominal metastases

Areas of trauma are preferred sites for metastatic tumour growth. In extensive intra-abdominal tumour recurrence the omentum is invariably involved. The importance of the omentum in the development of tumours at sites of intra-abdominal trauma has been investigated. Colonic anastomoses were performed in Hooded-Lister rats with and without omentectomy. Animals received intraluminal or intraperitoneal injections of a syngeneic tumour. With intraluminal injection, tumour occurred at the anastomosis and in the omentum in 38 and 43 per cent of animals respectively but following omentectomy the values were 14 and 9 per cent (omental remnant). With intraperitoneal administration tumour occurred in 53 per cent at the anastomosis and in 79 per cent in the omentum compared with 16 and 29 per cent (in omental remnant) following omentectomy. In this model a reduced ability of an anastomosis to support 'seeded' tumour following removal of the omentum is demonstrated and the development of local recurrence from spilled tumour cells during operation may be enhanced by, or be dependent on, the proximity of the omentum.

Blood transfusion and recurrence of colorectal cancer: the role of platelet derived growth factors

Efforts to explain the possible effects of blood transfusion on the recurrence of colorectal cancer have been based entirely on the immunosuppressive effects of blood transfusion. However, the relationship between solid tumour development and the immune system is inconclusive. We have investigated an alternative mechanism involving the potential role of growth factors in this phenomenon. Using a human fibroblast: [125I]deoxyuridine uptake mitogenesis assay, the relative amounts of growth factor in the plasma of stored blood were measured. There was a progressive increase in mitogenesis from day 0 (n = 6) to day 28 (n = 6; P less than 0.001, Mann-Whitney U test). The effect of growth factors on the development of liver and intraperitoneal metastases was studied in Hooded Lister rats. Following an intraportal injection of 10(5) MC28 tumour cells, the experimental group (n = 25) received 2 ml of syngeneic serum intravenously for 4 days. Likewise, colonic anastomoses were performed on omentectomized rats and the peritoneal cavity seeded with 10(3) cells. The experimental groups (n = 20) received either 2 ml serum intravenously repeatedly or 3 ml serum intraperitoneally (n = 19). There was no significant increase in liver metastases or peritoneal disease following intravenous infusion of serum but serum delivered intraperitoneally resulted in a significant increase in tumour from 22 per cent in the controls to 89 per cent in the study group (P less than 0.01). Growth factors released from platelets following blood loss into the peritoneal cavity may be important in enhancing local recurrence of colorectal cancer.