Efficacy of tumoricidal agents in vitro and in vivo.

Implantation of exfoliated tumour cells can give rise to local recurrence of colorectal cancer and it has been recommended that the bowel lumen be lavaged with a tumoricidal agent. This study identified which tumoricidal agents are currently used in Scotland and investigated their efficacy in vitro and in vivo. Cytotoxic efficacy was tested in vitro by a clonogenic assay and in vivo by a rat model with viable intraluminal tumour cells. Overall 70 per cent of surgeons used a tumoricidal agent during colorectal cancer surgery. Povidone-iodine, sodium hypochlorite and chlorhexidine-cetrimide were all effective at killing tumour cells in vitro but were all inactivated by the presence of 25 per cent whole blood in vitro. With 10(5) cells in vivo povidone-iodine and sodium hypochlorite significantly (P < 0.02) reduced the incidence of tumour growth while chlorhexidine-cetrimide had no significant effect. With 10(6) cells povidone-iodine had no effect on the incidence of tumour growth. Tumoricidal agents have effective cytotoxicity in vitro but are only weakly cytotoxic in vivo.