The effects of
radiotherapy on
hepatocellular carcinoma (HCC) were studied clinically. Involved-field
radiotherapy was employed in the treatment of 27 cases with HCC (irradiation of primary
tumor in 12 cases and
tumor embolism in 15 cases). Adverse effects of radiation on hepatic functions were minimum, as fluctuations in
choline-
esterase, prothrombin time and T-
bilirubin were insignificant. Changes in ICGR-15 were assessed from the aspects of radiation dose and treatment field. Aggravation was minimum when Time-Dose-Fractionation factor (TDF) was 80 and the involved filed was not more than 8 x 8 cm, but moderate pathologic changes were noted when these levels were exceeded. Clinical effect of the
radiotherapy was monitored by medical imagings was remarkable, as
tumor regression was evident in 82% of the primary
tumors and in 92% of the
tumor emboli irradiated. Histologically, improvement of at least clinical stage IIA as described by Ohboshi and Shimosato were observed in 88% of the primary
tumors and 80% of
tumor emboli treated. When TDF exceeded 80, improvements observed were at least IIA in all cases treated. From these results, it is clear that a TDF80 or higher dose is required for the effective
radiation treatment of HCC, and that a treatment field of not more than 8 x 8 cm is safe for the TDF80 dose. As for prognosis of the cases treated with
radiotherapy, significant prolongation of the survival period was achieved in the cases with nonresected HCC involved
tumor emboli. Thus,
radiotherapy for HCC is effective not only for the primary
tumor but for
tumor embolism as well, and this is a particularly useful modality for the latter.