Comparison of radiation therapy modalities for hepatocellular carcinoma with portal vein thrombosis: A meta-analysis and systematic review

Purpose: We performed a meta-analysis and systematic review to compare the radiotherapy (RT) modalities for hepatocellular carcinoma (HCC) with portal vein thrombosis (PVT). Materials and methods: We searched the PubMed, EMBASE, Medline, and Cochrane library databases. The primary endpoint was the 1-year overall survival (OS), and response rate (RR), local control (LC), 2-year OS, and grade ≥3 toxicity incidence were evaluated as secondary endpoints. Results: Thirty-seven studies comprising 2513 patients were included. The pooled 1-year OS rates for the 3-dimensional conformal RT (3DCRT), selective internal RT (SIRT), and stereotactic body RT (SBRT) groups were 43.8% [95% confidence interval (CI): 37.6–50.2], 46.5% (95% CI: 37.7–55.6), and 48.5% (95% CI: 39.4–57.8). These inter-group differences were not statistically significant (p = 0.635). The pooled response rates were 51.3% (95% CI: 45.7–57.0), 33.3% (95% CI: 18.0–53.2), and 70.7 (95% CI: 63.7–76.8) for 3DCRT, SIRT, and SBRT groups, respectively; p = 0.001 and 0.031 for 3DCRT vs. SBRT and SIRT, respectively. The most common grade ≥ 3 complications were lymphocytopenia and bilirubin abnormalities in the 3DCRT and SIRT groups, respectively. Grade ≥ 3 complication was rare in SBRT group. Conclusions: OS did not differ among the modalities, although the response rates vary among modalities.