THE OUTCOME OF LIVER-TRANSPLANTATION AT VARIOUS TIMES (70, 120, AND 134 DAYS) AFTER THE INITIATION OF CARCINOGENESIS IN RATS

The therapeutic results of liver transplantation for primary liver can cer have not been satisfactory. The high rate of recurrence appears to be due to the inadequate care taken in selecting the most appropriate candidates for orthotopic liver transplantation (OLT), the presence o f circulating hepatocellular carcinoma (HCC) cells and micrometastases at the time of liver transplantation, and the tumor growth-promoting effects of immunosuppressive agents, We believe that HCC patients must be carefully staged in order to identify those most suitable for OLT, We therefore induced HCC in pure-strain rats by the oral administrati on of diethylnitrosamine (DEN) and studied the outcomes of liver trans plantation at various time points (70, 120, and 134 days) after the in itiation of carcinogenesis. The mean survival time (MST +/- SD) of the non-OLT control group (N = 14) was 18.2 +/- 5 days after Day 120. The survival time of the four rats in the OLT Day 120 group was 81.3 +/- 20.6 days after transplantation. One rat showing full weight recovery soon after transplantation survived for 97 days after transplantation and then succumbed to recurrence. The survival time of the four rats i n the OLT Day 134 group was 7.3 +/- 5.0 days after transplantation. Th e survival time of the three rats in the OLT Day 70 group was 145.3 +/ - 70.0 days after transplantation, with a maximum survival of 221 days until death. Significantly prolonged survival, as compared with that in the non-OLT group, was observed in the OLT Day 70 and OLT Day 120 g roups (p < 0.01), while there was no significant prolongation in the O LT Day 134 group (NS). The timing of liver transplantation is a very i mportant factor. Preoperative assessment of factors potentially affect ing recurrence in HCC patients is imperative for selecting the most ap propriate candidates for OLT. Careful selection of candidates for OLT should always be considered the key to successful liver transplantatio n (i.e., long-term survival) for patients with liver cancer.