Abstract: Objective To evaluate the effects of stereotactic conformal therapy（SCT）in the treatment of patients with hepatocellular carcinoma with tumor thrombus in inferior vena cava. Methods 66 hepatocellular carcinoma patients with tumor thrombus in inferior vena cava were reviewed and analyzed by Kaplan-Meier and Cox regression analysis. 36 patients with tumor thrombus in inferior vena cava with hepatocellular carcinoma were treated with stereotactic conformal therapy（body gamma knife），and 30 patients did not receive stereotactic conformal therapy. The planned target volume was encompassed by 50% to 70% isodose line，and tumor dose was 3Gy to 4Gy per fraction，with total dose ranging from 30Gy to 48Gy. Results In 36 patients with stereotactic conformal therapy，12（33.3％）were in complete remission，10（27.8％）in partial remission，13（36.1％）were in no change， and 1（2.8％）showed disease progression. The remission rate of tumor thrombus in inferior vena cava was 61.1％ and one-year survival rate was 27.8% with the median survival of 9.8 months. In the non-SCT-treated 30 patients，one-year survival rate was 11.5% and the median survival was 3.5 months. Cox proportional hazards model analysis showed that the number of tumors and Child-Pugh class were the independent prognostic factor for the survival probability of the patients. Conclusion The stereotactic conformal radiotherapy is an effective method for treatment of tumor thrombus in inferior vena cava in patients with hepatocellular carcinoma.

Key words: Hepatocellular carcinoma, Stereotactic conformal therapy, Inferior vena cava, Thrombus