[Facilitation of hepatic metastasis by surgical stress in mice]

An experimental model for hepatic metastasis with a transplantation route of free-pedicled subcutaneous-embedded spleen was established in BALB/c mice. Colon-26 tumor cells to produce hepatic metastasis were inoculated into the spleen and the influence of surgical stress by means of a 20-min exposure of the abdominal cavity on the incidence of hepatic metastasis was examined. Hepatic metastasis was more promoted by the surgical stress in order when it was given on the same day, the 7th day and the 3rd day of the inoculation. Administration, without surgical stress, of ASGM 1, a specific inhibitor of the natural killer activity, also facilitated the hepatic disease. Administration of OK-432 prior to the surgical stress or ASGM 1 was at least partly effective for prevention of the hepatic metastasis and prolonged the survival of the inoculated mice. Preoperative immunotherapy utilizing OK-432 might be a possible means to prevent hepatic metastasis triggered in colorectal surgery for cancer.