Clinical feasibility and efficacy of stereotactic body radiotherapy for hepatocellular carcinoma: A systematic review and meta-analysis of observational studies

Background and purpose: Stereotactic body radiotherapy (SBRT) is an emerging ablative modality for hepatocellular carcinoma (HCC). This study aimed to synthesize available evidence to evaluate the clinical feasibility and efficacy of SBRT for HCC. Materials and methods: A systematic search was performed of the PubMed, Medline, Embase, and Cochrane Library databases. Primary endpoints were overall survival (OS) and local control (LC), and the secondary endpoint was grade ≥3 complications. Results: Thirty-two studies involving 1950 HCC patients who underwent SBRT were included. Pooled 1-, 2-, and 3-year OS rates were 72.6% (95% confidence interval [CI]: 65.7–78.6), 57.8% (50.9–64.4), and 48.3% (40.3–56.5), respectively. Pooled 1-, 2-, and 3-year LC rates were 85.7% (95% CI: 80.1–90.0), 83.6% (77.4–88.3), and 83.9% (77.6–88.6), respectively. The median value of median tumor sizes among studies was 3.3 cm (range: 1.6–8.6). Median radiation doses, calculated in dose equivalent with 2 Gy per fraction, ranged from 48 to 114.8 Gy ₁₀ (median 83.3 Gy ₁₀ ). Subgroup comparison regarding tumor size showed significant differences for 1- and 2-year OS rates and 1-, 2-, and 3-year LC rates, and that regarding radiation dose showed no difference for OS and a marginal difference for 1-year LC rate. Pooled rates of hepatic and gastrointestinal grade ≥3 complications were 4.7% (95% CI: 3.4–6.5) and 3.9% (2.6–5.6), respectively. Child-Pugh class was significantly correlated with hepatic complication of grade ≥3 in meta-regression analysis (p = 0.013). Conclusion: SBRT for HCC was a feasible option conferring excellent LC persisting up to 3 years. Both OS and LC were affected by tumor size, and radiation dose marginally affected LC. Severe complications rarely occurred, but liver function should be considered to avoid serious hepatic toxicity.