New research finds that an advanced radiotherapy technique known as radiation segmentectomy could prove effective against very early to early-stage hepatocellular carcinoma (HCC). In a multidisciplinary study published in Lancet Gastroenterology and Hepatology, researchers from the Icahn School of Medicine at Mount Sinai explored the technique's efficacy and outcomes treating HCC, which cannot be treated surgically or thermally (2022; https://doi.org/10.1016/S2468-1253(22)00091-7).
As the authors explained, radiation segmentectomy is a treatment option that delivers radioactive yttrium-90 bound microspheres transarterially to a segment of liver. Radiation segmentectomy relies on a microcatheter to administer beads of high-dose yttrium-90 radioactive isotopes directly to the tumor through the hepatic artery.
The radiation has a maximum radius of 3 millimeters, which enables gradual destruction of the tumor without causing damage to the surrounding tissue, they noted, adding that the aim of this study "was to assess the safety and efficacy of radiation segmentectomy in patients with unresectable hepatocellular carcinoma deemed unfavorable for ablation," the investigators wrote.
Study Details
The Radiation Segmentectomy for Curative Intent of Unresectable Very Early to Early-Stage Hepatocellular Carcinoma (RASER) study was a single-center, single-arm study that included 29 adults with solitary hepatocellular carcinoma with unfavorable location for ablation, without metastasis or macrovascular invasion.
Eligibility criteria included measurable disease 3 cm or less in diameter, Child-Pugh score A-B7, an Eastern Cooperative Oncology Group score of 0, and adequate hematological and organ function. The primary endpoint was a target tumor response measured by mRECIST. Patients were followed up with imaging and office visits for up to 24 months. Patients underwent treatment and were monitored through follow-up sessions over a 2-year period to assess factors such as tumor response, lung metastasis, and adverse effects.
The team of researchers found that all of the patients participating in the study had an objective response to radiation segmentectomy, with 24 of them (83%) demonstrating a complete response rate. In addition, 26 patients (90%) had a sustained complete response after one treatment.
Four patients (14%) had Grade 3 leukopenia and two had Grade 3 thrombocytopenia. The authors reported two non-laboratory-related Grade 3 adverse events-one arterial injury and one ascites. The most frequent Grade 1 or 2 adverse events (experienced by less than 10% of patients) were fatigue; nausea, vomiting, or anorexia; abdominal discomfort; leukopenia; thrombocytopenia; increased alkaline phosphatase; increased alanine or aspartate aminotransferase; increased bilirubin; and decreased albumin. There was one death that was not related to treatment.
Overall, "radiation segmentectomy was efficacious, with a low proportion of high-grade adverse events in patients with unresectable very early to early-stage hepatocellular carcinoma with suboptimal location for ablation," the researchers wrote. "These results suggest that radiation segmentectomy should be further investigated as a potential curative treatment option for well-selected patients."
Mount Sinai was an early adopter of radiation segmentectomy and has been using the technique in clinical practice "for years," noted lead study author Edward Kim, MD, FSIR, Professor of Diagnostic, Molecular, and Interventional Radiology and Surgery at Icahn Mount Sinai, and Director of Interventional Oncology at Mount Sinai Health System.
"We also generated retrospective data from our experience [with radiation segmentectomy], but prospective data generates a more robust level of evidence," said Kim, adding that the hypothesis heading into the study was that radiation segmentectomy can provide similar outcomes to other therapies, such as ablation and surgery, in terms of curative intent with imaging outcomes while minimizing adverse events.
"Radioembolization allows the deposition of tiny spheres embedded with radiation, Yttrium-90, within a target area through the arteries. This radiation has a radius of 3 mm and thus allows a high dose of radiation that is safe if confined to a select region of the liver with tumor," Kim stated. "This high dose of radiation is difficult to achieve from an external beam source and so allows destruction of the intended target with minimal effect to the surrounding area, as evidenced by the small number of adverse events, which were mostly Grade 1."
The results of this study suggest that radiation segmentectomy can indeed be used with curative intent in a well-selected population of patients.
"And, with the long transplant wait times in the United States, this can provide a durable therapy for patients with HCC, as the duration of response was close to the 2-year follow-up that patients had in the study," Kim noted. "This is longer than any study for chemo embolization, which has been used for decades as a means to bridge individuals to transplantation. This can also rival other curative options such as ablation and resection."
Mark McGraw is a contributing writer.