Postoperative immunocompetence and immunosuppressive effect of rat liver tumors

To investigate the kinetics of postoperative immunocompetence and immunosuppressive effects of rat liver tumors, we examined natural killer cell cytotoxicity and blastogeneses to phytohemagllutinin-P, concanavalin A, and lipopolysaccharide on 1-, 2-, 3-, 5-, 7-, 9- and 14- postoperative days (-POD) after partial hepatectomy in tumor-bearing or healthy rats. The immunosuppressive effects of the tumor were observed on all the parameters examined, particularly from 1- to 3-POD and on 14-POD. Surgical stress induced immunosuppression in the early postoperative stage which lasted over 1 week, and the immunosuppression was seriously affected by the presence of the tumor. The present study suggests that surgery without curability is closely related to enhancement of the growth of the remaining or occult cancer, leading to worse survival.