Differences in radiotherapy application according to regional disease characteristics of hepatocellular carcinoma

Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines

This systematic review and meta-analysis reports on outcomes and hepatic toxicity rates after stereotactic body radiation therapy (SBRT) for liver-confined hepatocellular carcinoma (HCC) and presents consensus guidelines regarding appropriate patient management. Using the Preferred Reporting Items for Systemic Review and Meta-Analyses guidelines, a systematic review was performed from articles reporting outcomes at ≥5 years published before October 2022 from the Embase, MEDLINE, Cochrane, and Scopus databases with the following search terms: ("stereotactic body radiotherapy" OR "SBRT" OR "SABR" OR "stereotactic ablative radiotherapy") AND ("hepatocellular carcinoma" OR "HCC"). An aggregated data meta-analysis was conducted to assess overall survival (OS) and local control (LC) using weighted random effects models. In addition, individual patient data analyses incorporating data from 6 institutions were conducted as their own subgroup analyses. Seventeen observational studies, comprising 1889 patients with HCC treated with ≤9 SBRT fractions, between 2003 and 2019, were included in the aggregated data meta-analysis. The 3- and 5-year OS rates after SBRT were 57% (95% confidence interval [CI], 47%-66%) and 40% (95% CI, 29%-51%), respectively. The 3- and 5-year LC rates after SBRT were 84% (95% CI, 77%-90%) and 82% (95% CI, 74%-88%), respectively. Tumor size was the only prognostic factor for LC. Tumor size and region were significantly associated with OS. Five-year LC and OS rates of 79% (95% CI, 0.74-0.84) and 25% (95% CI, 0.20-0.30), respectively, were observed in the individual patient data analyses. Factors prognostic for improved OS were tumor size <3 cm, Eastern region, Child-Pugh score ≤B7, and the Barcelona Clinic Liver Cancer stage of 0 and A. The incidence of severe hepatic toxicity varied according to the criteria applied. SBRT is an effective treatment modality for patients with HCC with mature follow-up. Clinical practice guidelines were developed on behalf of the International Stereotactic Radiosurgery Society (ISRS).

Will the collaboration of surgery and external radiotherapy open new avenues for hepatocellular carcinoma with portal vein thrombosis?

Portal invasion of hepatocellular carcinoma (HCC) occurs in 12.5%-40% of patients diagnosed with cancer and yields poor clinical outcomes. Since it is a common cause of inoperability, sorafenib was regarded as the standard treatment for HCC in the Barcelona Clinic of Liver Cancer guidelines. However, the median survival of the Asian population was only approximately 6 mo, and the tumor response rate was less than moderate (< 5%). Various locoregional modalities were performed, including external beam radiotherapy (EBRT), transarterial chemoembolization, hepatic arterial infusion chemotherapy, and surgery, alone or in combination. Among them, EBRT is a noninvasive method and can safely treat tumors involving the major vessels. Palliative EBRT has been commonly performed, especially in East Asian countries, where locally invasive HCC is highly prevalent. Although surgery is not commonly indicated, pioneering studies have demonstrated encouraging results in recent decades. Furthermore, the combination of neo- or adjuvant EBRT and surgery has been recently used and has significantly improved the outcomes of HCC patients, as reported in a few randomized studies. Regarding systemic modality, a combination of novel immunotherapy and vascular endothelial growth factor inhibitor showed results superior to that of sorafenib as a first-line agent. Future clinical trials investigating the combined use of these novel agents, surgery, and EBRT are expected to improve the prognosis of HCC with portal invasion.