Hepatocellular carcinoma converted from atezolizumab and bevacizumab combination therapy: a case report.

Hepatectomy is the curative treatment for hepatocellular carcinoma (HCC), with targeted therapy used when resection is difficult. In this rare case, the tumor shrank with targeted therapy, enabling radical treatment through conversion surgery. The patient, a man in his 70s, developed an 11.5-cm HCC (T3N0M0 Stage III) in the posterior hepatic zone after being virologically negative for hepatitis C. The tumor was near the right portal vein branch, making the liver lobe unresectable due to poor liver function. Upon tumor enlargement, he was treated with atezolizumab and bevacizumab. After 5 courses, the tumor significantly shrank, allowing for complete resection with posterior segment removal. The surgery revealed mostly necrotic tumors with no active cancer cells remaining.