Significant response to atezolizumab plus bevacizumab treatment in unresectable hepatocellular carcinoma with major portal vein tumor thrombus: a case report

BACKGROUND: Hepatocellular carcinoma (HCC) with major portal vein tumor thrombus (Vp4 PVTT) is an extremely advanced tumor with limited treatment options. Systemic chemotherapy is the only recommended treatment option, and atezolizumab plus bevacizumab has recently emerged as a first-line treatment option. CASE PRESENTATION: We describe the case of an 82-year-old man with unresectable advanced HCC with Vp4 PVTT who achieved a significant response to atezolizumab plus bevacizumab treatment. A single administration of atezolizumab plus bevacizumab ensured significant anti-tumor effects (regression in the tumor size and PVTT, portal vein recanalization, and serum alfa-fetoprotein levels decreased from 90,770 to 89 ng/mL). The patient continued with atezolizumab monotherapy, and after nine consecutive regimens, there was no apparent sign of residual tumor. CONCLUSIONS: This case demonstrates the powerful anti-tumor effect of atezolizumab plus bevacizumab treatment for advanced HCC with Vp4 PVTT, suggesting that these agents can be a promising treatment option for such refractory tumors.