Palliative radiotherapy for hepatic tumors: a narrative review of indications and recommendations

Primary and metastatic liver cancer presents heterogeneously. New radiotherapy techniques have reduced toxicity concerns, leading to increased use of liver radiotherapy. This review synthesizes available evidence and offers recommendations for palliative radiotherapy for liver cancer.PubMed, Ovid Medline, Embase, Cochrane Central, and Web of Science were searched from inception to December 28th, 2022. Articles reporting local control (LC), survival, toxicity, symptom control, and response after stereotactic body radiotherapy (SBRT), partial-liver, or whole-liver radiotherapy (WLRT) techniques were reviewed. We also identified nomograms identifying patients who may benefit from radiotherapy.Nine randomized-controlled trials were found, in addition to many retrospective, feasibility, and phase I or II studies. Patients with favorable prognosis may receive SBRT using 30-50 Gray (Gy) in 3-5 fractions for primary cancer and up to 60 Gy for metastases, provided normal-tissue constraints are met. Select patients with multiple (>5) or large (>10 cm) lesions or macrovascular invasion (MVI) may be considered, but with potentially reduced LC and increased toxicity. Lower SBRT doses (i.e., 25 Gy in 5 fractions) can be considered on a cautionary basis for patients with poorer liver function or health. Patients with larger tumor burden, poor performance status (PS), or inability to tolerate SBRT positioning or motion-management can consider partial-liver three-dimensional conformal radiotherapy (3DCRT). For patients with extremely guarded prognosis and/or extremely poor performance, WLRT provides pain and symptom relief over several weeks. Combining radiotherapy and systemic therapy may allow radiotherapy de-escalation while maintaining good outcomes.Radiotherapy has a definite role for palliation of liver cancer with practical research providing guidance in the use of techniques and different regimens in various patient subgroups. Future investigation, including randomized trials, is needed to optimize patient selection, radiotherapy techniques, and integration with other therapies.