RADIATION TOLERANCE OF THE TRANSPLANTED LIVER - A HISTOPATHOLOGIC STUDY OF 3 CASES

Three patients with multifocal recurrence of hepatocellular carcinoma following liver transplantation received palliative irradiation. Hyper fractionated irradiation (150 cGy/fraction b.i.d.) was delivered in tw o cases to the entire liver using parallel opposed oblique portals to a total dose of 30 Gy. Conventional irradiation (180 cGy/fraction) tot aling 45 Gy was administered to the liver hilus with concomitant infus ional 5-fluorouracil chemotherapy in the third case. Clinicopathologic correlations were performed. At autopsy all patients had massive tumo r burden within the liver. Veno-occlusive changes were observed in two patients 1 and 2 months following completion of conventional and hype rfractionated irradiation, respectively. Liver transplantation in thes e 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 hyper fractionated radiation, which was delivered 6 months following liver t ransplantation. No significant differences in prior immunosuppressive therapy were identified among patients. Veno-occlusive changes are not spared by hyperfractionated radiation. Transplanted livers exhibit re sponses to radiation similar to those normally observed.