Compensatory enlargement of the liver after treatment of hepatocellular carcinoma with carbon ion radiotherapy – Relation to prognosis and liver function

Background and purposeTo examine whether liver volume changes affect prognosis and hepatic function in patients treated with carbon ion radiotherapy (CIRT) for hepatocellular carcinoma (HCC).Material and methodsBetween April 1995 and March 2003, among the cases treated with CIRT, 43 patients with HCC limited to the right hepatic lobe were considered eligible for the study. The left lateral segment was defined as the non-irradiated region. Liver volume was measured using contrast CT at 0, 3, 6, and 12 months after CIRT. We examined serum albumin, prothrombin activity, and total bilirubin level as hepatic functional reserve.ResultsAfter CIRT, the non-irradiated region showed significant enlargement, and enlarged volume of this region 3 months after CIRT ⩾50 cm3 was a prognostic factor. The 5-year overall survival rates were 48.9% in the larger enlargement group (enlarged volume of non-irradiated region 3 months after CIRT ⩾50 cm3) and 29.4% in the smaller enlargement group (as above, <50 cm3). The larger enlargement group showed better hepatic functional reserve than the smaller enlargement group 12 months after CIRT.ConclusionsThis study suggests that compensatory enlargement in the non-irradiated liver after CIRT contributes to the improvement of prognosis.