The efficacy of adjuvant cytostatic therapy after organ transplantation for malignancy: an experimental study with a combined transplantation/tumor model

New data show that perioperative cytostatic therapy is beneficial in the ca se of liver transplantation for hepatic cancer. However. it has not been es tablished clearly whether chemotherapy interferes with graft rejection. We therefore studied the interactions between tumor growth and graft rejection , especially with regard to chemotherapy, using a combined tumor/transplant ation model. As a tumor model, we used the Novikoff hepatoma. a malignant h epatoma that was injected subcutaneously into the backs of rats. Heterotopi c heart grafting served as the transplantation model. In a first step (a), we studied the effect of cytostatic therapy on tumor growth: tumor cells we re injected, and in four groups epirubicin, cyclosporinel epirubicin + cycl osporine, and placebo were applied, in corresponding groups, transplantatio n was additionally performed. Tumor growth was measured and the resected tu mors were examined by histology and immunohistology. In a second step (b). we studied the effect of chemotherapy on graft rejection: transplantation w as performed and the above-mentioned drugs were applied; in corresponding g roups, a solid tumor was additionally induced and resected immediately befo re transplantation. The results of these procedures were as follows: (a) Ep irubicin decreased tumor growth and diminished the volume-increasing effect of cyclosporine significantly. After transplantation, tumor growth was sim ilar. (b) Epirubicin prolonged graft survival significantly, and the combin ation with cyclosporine had an augmenting effect. In the corresponding grou ps, graft survival was similar. In conclusions. chemotherapy diminishes the tumor-increasing effect of cyclosporine and does not interfere negatively with graft survival. It might therefore be beneficial after transplantation for malignancy.