Radiotherapeutic strategies for hepatocellular carcinoma with portal vein tumour thrombosis in a hepatitis B endemic area

Abstract Background & Aims This nationwide, multicenter study investigated treatment outcomes as well as the optimal radiotherapeutic strategy in patients with hepatocellular carcinoma ( HCC ) and portal vein tumour thrombosis ( PVTT ). Methods We retrospectively reviewed the records of 985 patients who received radiotherapy ( RT ) for PVTT . The median equivalent RT dose was 48.75 Gy. Combined treatment, defined as liver‐directed treatments performed within a month of RT , was administered to 657 patients (66.7%). The PVTT and primary tumour were irradiated in 413 patients (41.9%), and PVTT only was targeted in 572 patients (58.1%). Results The response rate of the PVTT was 51.8%, and RT responders had a significantly longer survival than non‐responders (15.2 vs. 6.9 months). Equivalent RT dose and combined treatment predicted response of PVTT . The median overall survival ( OS ) was 10.2 months. Multivariate analysis revealed the equivalent RT dose ˃45 Gy and combined treatment as significant positive factors for OS . In the propensity score matching analysis, the combined treatment group had better OS than the no combined treatment group, whereas the OS of the PVTT + primary tumour group did not differ significantly from that of the PVTT only group. Conclusion The equivalent RT dose ˃45 Gy, given in combination with other treatments, provided better PVTT control and OS . The optimal RT volume is suggested for either PVTT + primary or PVTT only. Taken together, multimodal treatment with equivalent RT dose higher than 45 Gy is recommended for patients with HCC and PVTT .