Pathologic Complete Response after Chemotherapy with Atezolizumab plus Bevacizumab for Hepatocellular Carcinoma with Tumor Thrombus in the Main Portal Trunk

We report a case of pathologic complete response after successful treatment for advanced hepatocellular carcinoma (HCC) complicated with portal venous tumor thrombus with atezolizumab and bevacizumab followed by radical resection. The patient was a male in his 60s. During follow-up for chronic hepatitis B, abdominal ultrasonography revealed a huge tumor located in the right lobe of the liver with the portal vein thrombosed by the tumor. The tumor thrombus extended to the proximal side of the left branch of the portal vein. The patient's tumor marker levels were elevated (alpha-phetoprotein, 14,696 ng/mL; PIVKA-II, 2,141 mAU/mL). Liver biopsy revealed poorly differentiated HCC. The lesion was categorized as advanced stage according to the BCLC staging system. As systemic therapy, atezolizumab plus bevacizumab was administered. Imaging showed marked shrinkage of the tumor and portal venous thrombus with a remarkable decrease of tumor marker levels after 2 courses of chemotherapy. After 3 additional courses of chemotherapy, radical resection was considered possible. The patient underwent right hemihepatectomy and portal venous thrombectomy. A pathological examination revealed a complete response. In conclusion, we experienced a case in which advanced HCC was curatively treated with atezolizumab plus bevacizumab, which was administered as systemic therapy with a view to conversion surgery.