An advanced radiotherapy technique called radiation segmentectomy may be effective against very early to early-stage hepatocellular carcinoma (HCC), a type of liver cancer 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 in the journal Lancet Gastroenterology and 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 is a liver cancer treatment technique that 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 three millimeters, 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.”
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 ages 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 two-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 percent) had a complete response rate. Furthermore, 26 patients (90 percent) 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 percent to 70 percent,” 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.”
HCC is the most common type of liver cancer nationwide, and available data show that its prevalence has increased over the past two decades due to the increased prevalence of both hepatitis C and nonalcoholic fatty liver disease. A surgical procedure known as partial liver resection is the standard of care among patients with single HCC and compensated liver disease, but only 20 percent of these cases are resectable for a variety of reasons. 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 two years, and the risk of dropout due to tumor progression is approximately 20 percent to 25 percent.
“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.”