Objective To retrospectively analyze the role of 3-dimensioual conformal radiotherapy (3-DCRT) after percutaneous transhepatic portal vein stenting and transcatheter arterial chemoembolization (PTPVS-TACE) in the treatment of patients with hepatocellular carcinoma (HCC) complicated by main portal vein tumor throw.bus (MPVTT).Methods Between July 2002 and July 2007,45 patients with HCC complicated by MPVTT were treated by PTPVS-TACE.Among them,3-DCRT were undertaken for MPVTT in 16 patients (group A),the other 29 patients were not treated with 3-DCRT(group B).The clinical effects,complication,stent patency rates,cumulative survival rates were evaluated among groups.The Kaplan-Meier method and log-rank test were used for survival analysis.Results No patient died during stent placement or within the preceding first 24 hours.No severe procedure-related complications were observed.The 60--,180--,360--day cumulative stent patency rates were 100.0%,62.2% and 34.6% in group A,and 58.6%,21.7% and 10.8% in group B,respectively,showing significant difference between the two groups (X2 =9.672,P <0.01).The mean patency time was(475±137) and (200±61)days,respectively.The 60--,180--,and 360--day cumulative survival rates were 93.8%,81.3% and 32.5% for group A,86.2%,13.8% and 6.9% for group B,respectively.There were significant statistical differences between the two groups(X2=9.672,14.596,P < 0.01).Conclusion Treatment with PTPVS-TACE-3-DCRT is a more effective modality than PTPVS-TACE for HCC complicated by MPVTT.