Radiation segmentectomy may be an effective treatment for very early– to early-stage hepatocellular carcinoma (HCC) that cannot be treated surgically or thermally. The findings from a multidisciplinary study by researchers at the Icahn School of Medicine at Mount Sinai were published by Kim et al in The Lancet Gastroenterology & Hepatology. It is the first prospective study to explore the efficacy and outcomes of this technique, and the results suggest it may be a curative treatment for inoperable, early-stage HCC.

Radiation segmentectomy uses a microcatheter to deliver beads of high-dose yttrium-90 radioactive isotope directly to the tumor through the hepatic artery. The radiation has a maximum radius of 3 mm, enabling gradual destruction of the tumor without any damage to the surrounding tissue. Although retrospective studies have found it to be effective, the literature and studies are limited by selection bias and a lack of adverse event follow-up.

“We have used radiation segmentectomy at Mount Sinai for more than a decade, and our patients have benefited tremendously as a result. It is an extremely well-tolerated, easily replicated, and reproducible technique,” said Edward Kim, MD, FSIR, Professor of Diagnostic, Molecular, and Interventional Radiology and Surgery at Icahn Mount Sinai and Director of Interventional Oncology at the Mount Sinai Health System. “The challenge is that there is a general lack of awareness about this technology and how well it works. We decided to undertake the first-ever prospective study because we participated in the initial retrospective study of radiation segmentectomy, and we could generate data that would demonstrate its safety and efficacy.”

RASER Study

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 recruited 29 Mount Sinai patients aged 18 and older who had solitary HCC with an unfavorable location for surgical or thermal treatment, but who did not have cancer spread or macrovascular invasion. 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 researchers found that all of the patients participating in the study had an objective response to radiation segmentectomy, and 24 of them (83%) experienced a complete response. Furthermore, 26 patients (90%) had a sustained complete response after one treatment.

“Those response rates are impressive because they are similar to what we are able to achieve with ablation, or thermal treatment, and they exceed the rates we have historically observed with chemoembolization, which are approximately 55% to 70%,” said Dr. Kim. “It is also notable that the duration of the response was extremely long, which means there was no real progression in the treated area. That is outstanding for this patient population.”

Possible Bridge to Transplant

HCC is the most common type of liver cancer nationwide, and available data show that its prevalence has increased over the past 2 decades due to the increased prevalence of both hepatitis C and nonalcoholic fatty liver disease. Partial liver resection is the standard of care among patients with single HCC and compensated liver disease, but only 20% of these cases are resectable. Transplantation is the only true curative treatment for patients with primary liver cancer. The current median wait time in New York State is more than 2 years, and the risk of dropout due to tumor progression is approximately 20% to 25%.

“Given both the excellent objective response from radiation segmentectomy and the duration of that response among this specific patient population, this technique affords patients with nonresectable and nonablatable cancer an opportunity to remain on that waiting list for a longer period of time. In that way, we believe the radiation segmentectomy provides them with an effective bridge to a true cure, which is transplantation,” said Dr. Kim. “But we also believe, based on our findings, that this technique could be used with curative intent among patients who are eligible for surgical resection.”

Based on the study results, the Mount Sinai team believes that radiation segmentectomy merits larger, investigative studies of its curative potential and validates its inclusion in the Barcelona Clinic Liver Cancer guidelines for all patients with early-stage HCC.

“My hope is that our work will encourage more adoption of this technology not only nationwide but also globally as a curative procedure and as a bridge to transplantation,” Dr. Kim said. “I believe patients everywhere will benefit significantly from this technique and enjoy a better quality of life.”

Disclosure: For full disclosures of the study authors, visit thelancet.com.