Intensity-Modulated Proton Therapy for Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis

Patients with hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) have poor outcomes and limited treatment options. Clinical data specifically evaluating the effects of intensity-modulated proton therapy (IMPT) for this population remain scarce. We reported the outcomes of patients with HCC with PVTT treated with IMPT.

We retrospectively reviewed the data of 83 patients with nonmetastatic HCC with PVTT treated with IMPT between March 2019 and June 2023. Survival outcomes were analyzed with Kaplan-Meier analysis, and prognostic factors were identified via multivariable Cox regression. Treatment responses were assessed with the modified Response Evaluation Criteria in Solid Tumors. Toxicities, including liver dysfunction and gastrointestinal events, were documented.

The median overall survival (OS) was 32.4 months, with 1- and 2-year OS rates of 82.6% and 61.0%, respectively. The 2-year local control rate was 88.8%, and the objective response rate was 91.5%. Complete response after IMPT was independently associated with improved OS and liver control, whereas an albumin-bilirubin (ALBI) grade of 2 predicted a greater risk of liver dysfunction. Grade 3 gastrointestinal toxicities occurred in 4.8% of patients, and radiation-induced liver disease occurred in 9.3%. IMPT facilitated curative-intent surgery in 8.4% of patients after treatment.

IMPT offers excellent local control and a favorable safety profile in patients with HCC and PVTT, with the potential to downstage tumors for curative interventions. These findings, though limited by the retrospective design and heterogeneity of systemic therapies, support the integration of IMPT into multidisciplinary treatment strategies and highlight the need for prospective studies to clarify its role alongside systemic therapy.