Combining stereotactic radiotherapy with anti-PD-1 for advanced hepatocellular carcinoma patients with portal vein tumor thrombus.

Abstract

e16121 Background: Immunotherapy has attracted extensive attention in advanced hepatocellular carcinoma. For unselected patients, the efficacy of PD-1 monotherapy is less than 20%. The addition of radiotherapy to local lesions can significantly enhance the effectiveness of PD-1. However, the efficiency of SBRT combined with PD-1 in the treatment for portal vein tumor thrombus in patients with hepatocellular carcinoma remains unclear. Methods: This phase II study enrolled 17 patients with advanced liver cancer with portal vein tumor thrombus after 1-line or multi-line treatment in our single center, between June 2018 and June 2021. SBRT was delivered to the carcinoma thrombus with or without primary intrahepatic tumor，with a median total dose of 60Gy/10fx (range of 50Gỹ70Gy). Camrelizumab was administered within 2 weeks after SBRT, in cycles of every 3 weeks, until disease progression or patient intolerance. The primary endpoints were overall survival (OS), progression-free survival (PFS) and overall response rate (ORR). Results: At 3 months after SBRT, 6 patients had complete responses (35.3%) and 11 patients had partial responses (64.7%), with an ORR of 100%. The 1-year OS rate was 100%, and 1-year PFS was 84.8%. None of the patients had radiation response. Four patients (23.5%) were unable to tolerate immunotherapy, with one patient stopping after 12 cycles due to frequent preventricular phase contraction (in a double couplet rhythm) and 3 owing to upper gastrointestinal bleeding. Conclusions: SBRT combined with immunotherapy can improve local control and bring survival benefit, suggesting that SBRT could be considered in patients with portal vein tumor thrombus in hepatocellular carcinoma after 1-line or multi-line treatment. Moreover, the adverse reactions were mild. Clinical trial information: ChiCTR1900026188.