The Evolving Application of Radiation Segmentectomy for the Treatment of Hepatic Malignancy

Transarterial radioembolization (TARE) is an image-guided cancer treatment that delivers microspheres carrying radiation-emitting isotopes, such as yttrium 90 (⁹⁰Y), to liver malignancy via the hepatic arteries. Historically a palliative therapy for advanced liver cancer, TARE with ⁹⁰Y has evolved via the segmental delivery of ⁹⁰Y microspheres with ablative intent, known as radiation segmentectomy. The purpose of radiation segmentectomy is to deliver high radiation doses to targeted hepatic segments, limiting the volume of normal hepatic parenchyma exposed to radiation. Radiation segmentectomy is characterized by high, sustained response rates and high rates of explant necrosis. Currently, radiation segmentectomy is a recognized treatment option for patients with Child-Pugh class A liver function and solitary hepatocellular carcinoma that is 8 cm or smaller in size. It can be applied for hepatic metastases not amenable to resection or thermal ablation. Advancements in patient selection, technique, and radiation dosimetry for radiation segmentectomy have redefined the goal of TARE as a curative therapy. With improved dosimetry and patient selection, it has become more common to observe early responses at posttreatment imaging after radiation segmentectomy, even complete response within the first month of treatment. This article reviews the history of radiation segmentectomy, its expanding applications, and future directions.