Radiation tolerance of the transplanted liver. A histopathologic study in three cases

Three patients with multifocal recurrence of hepatocellular carcinoma following liver transplantation received palliative irradiation. Hyperfractionated irradiation (150 cGy/fraction b.i.d.) was delivered in two cases to the entire liver using parallel opposed oblique portals to a total dose of 30 Gy. Conventional irradiation (180 cGy/fraction) totaling 45 Gy was administered to the liver hilus with concomitant infusional 5-fluorouracil chemotherapy in the third case. Clinicopathologic correlations were performed. At autopsy all patients had massive tumor burden within the liver. Veno-occlusive changes were observed in two patients 1 and 2 months following completion of conventional and hyperfractionated irradiation, respectively. Liver transplantation in these two patients had been performed 18 and 16 months prior to palliative hepatic irradiation. In the third patient, no veno-occlusive changes were pathologically observed at autopsy 1 month after completing hyperfractionated radiation, which was delivered 6 months following liver transplantation. No significant differences in prior immunosuppressive therapy were identified among patients. Veno-occlusive changes are not spared by hyperfractionated radiation. Transplanted livers exhibit responses to radiation similar to those normally observed.