The Evolving Application of Radiation Segmentectomy for the Treatment of Hepatic Malignancy Lewandowski RJ, Serhal M, Padia SA, et al. Radiology. 2025;316(1):e240333. https://doi.org/10.1148/radiol.240333.
Transarterial radioembolization (TARE) is an image-guided therapy that enables targeted transarterial delivery of yttrium-90 radioactive microspheres to liver tumors via the hepatic arterial supply. This allows high radiation doses to be delivered to diseased hepatic segments while sparing normal parenchyma. Initially developed as a palliative therapy for advanced liver malignancy, advances in interventional radiology has enabled it to be a potentially curative locoregional treatment in selected patients. The technique is most commonly used for hepatocellular carcinoma (HCC) and is currently recognized as a treatment option for patients with Child-Pugh class A liver function and solitary HCC ≤8cm. Radiation segmentectomy delivers ablative radiation doses to a limited hepatic angiosome with the aim of eradicating both the tumour and a surrounding margin of normal liver tissue. Beyond HCC, TARE has also been applied in selected cases of solitary or oligofocal hepatic metastases that are not amenable to resection or thermal ablation, and more recently in intrahepatic cholangiocarcinoma, although evidence in these settings remains limited. TARE has frequently been compared with the more established locoregional therapy, transarterial chemoembolization (TACE). Several studies have demonstrated longer time to tumour progression, higher imaging response rates, and comparable or improved overall survival with TARE in selected HCC patients. These findings suggest that TARE may represent a viable alternative to TACE in appropriately selected patients, particularly where a targeted segmental approach is feasible. Radiation segmentectomy has also been evaluated against other potentially curative treatments such as thermal ablation and surgical resection. Outcomes in selected cohorts appear comparable, with high local tumour control rates and encouraging long-term survival. TARE may offer advantages over thermal ablation when ablation is technically challenging, such as when tumours are located adjacent to major vessels or bile ducts, are difficult to access percutaneously, or exceed typical ablation size thresholds. Compared with surgical resection, TARE provides a less invasive alternative for patients who are not fit for surgery, with studies suggesting similar oncologic outcomes and fewer complications. Retrospective cohorts have reported median overall survival approaching 6-7 years in carefully selected patients with solitary early-stage HCC who were not candidates for resection or ablation. Treatment effectiveness is strongly dependent on the radiation dose delivered to the tumour. Because microspheres are distributed heterogeneously within the tumour vasculature during vascular brachytherapy, higher radiation doses are required to ensure adequate tumouricidal activity. Studies suggest that tumour doses exceeding 190 Gy are associated with complete pathologic necrosis, while doses greater than 400 Gy are strongly predictive of complete tumour Treatment follow-up typically involves contrast-enhanced CT or MRI at approximately 1, 3, and 6 months following TARE. Imaging assessment focuses on features such as reduction in arterial tumour enhancement and decrease in tumour size. Radiation segmentectomy may demonstrate earlier imaging response compared with conventional radioembolization, with some studies reporting complete response within the first month following treatment. There is increasing interest in combining TARE with systemic therapies, particularly anti-angiogenic agents. Radiation and embolization may stimulate the release of pro-angiogenic factors, potentially contributing to tumour progression in some patients. Combining TARE with systemic agents such as bevacizumab or atezolizumab may therefore improve treatment response and disease control, although further prospective studies are required. This review highlights the evolving role of TARE as a potentially curative treatment in selected patients with liver malignancy. Although early results are promising, the technique remains relatively new and further research is required to better define its role within current treatment algorithms. The topic is of particular relevance to the ESGAR community as radiologists play a central role not only in disease identification but also in patient selection, procedural planning, and post-treatment response assessment. | References
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