Noninvasive Bridging Therapy Underutilized Versus More Invasive Options in Transplant-Eligible Hepatocellular Carcinoma

External-beam radiation therapy may be underused compared with other liver-directed therapies in patients with hepatocellular carcinoma awaiting liver transplants, study results demonstrated.

Findings from the study, which was presented at the American Society for Radiation Oncology Annual Meeting, may highlight a gap in treatment offerings for patients with hepatocellular carcinoma. Improving utilization of external-beam radiation therapy may improve the care of these patients who require liver transplantation.

“Our team overall was quite surprised at the low utility rate of external-beam radiation therapy for these patients,” said Dr. Nima Nabavizadeh, an associate professor of radiation medicine and director of the medical residency program at Oregon Health & Science University School of Medicine in Portland, in an interview with CURE®. “Our institutional experience is that a fair number of patients are given the option, and a fair number (of patients) proceed with the option of noninvasive radiation therapy for their liver cancer.”

In particular, of the 18,477 patients with hepatocellular carcinoma who were waiting for a transplant since 2013, 85.4% received bridging therapy (used to stop tumor progression). Although most patients received bridging therapy, 3.6% were treated with external-beam radiation therapy compared with other liver-directed therapies.

Nabavizadeh explained that liver-directed therapy is a generic term for the type of treatment delivered to treat a liver tumor before transplantation. They can come in several forms including:

• thermal ablation, usually performed percutaneously with general anesthesia and is considered a minimally invasive procedure;
• transarterial chemoembolization, a catheter-based treatment performed under some sedation, where catheterization is performed through the arteries to find blood vessels that feed the tumor, which are then used to deliver chemotherapy and an embolic compound to the tumor;
• Y90 radioembolization, which is similar to transarterial chemoembolization but instead of chemotherapy, a radioactive embolic agent is delivered to the tumor; and
• external-beam radiation therapy, a noninvasive therapy where high doses of radiation are delivered using daily image guidance.

Despite the options available for patients, more research is needed to determine which may be the best option.

“It’s our duty in our field to gather the evidence to compare the treatment options because currently, we’re kind of flying blind,” Nabavizadeh noted. “We really don’t know if one treatment is better than the other.”

Results from the study also demonstrated that the use of external-beam radiation therapy increased an average of 14% per year from 2013 to 2020, although it has not increased as much as other bridging therapy options.

“As expected, the prevalence of chemoembolization for liver cancer has decreased over time but seemed to be largely supplanted with another type of catheter-related therapy, which is Y90 radioembolization,” Nabavizadeh said. “The year-to-year increase in (the) prevalence of Y90 (radioembolization) definitely surpassed that of external-beam (radiation therapy). That is not totally evidence-based, as there’s no real data supporting the use of one treatment over the other. It’s clear to us that largely institutional practice paradigms, as well as the type of physicians that patients see, has largely dictated the type of treatment they’re getting rather than patient desires and evidence.”

Nabavizadeh added that physicians need to improve on how they discuss options not only with their patients, but also their colleagues.

“I think radiation oncologists in general need to do a better job being at the table … advocating for their noninvasive treatment modality,” he said. “Just as patients are given the option to decide on surgery or radiation therapy for localized prostate cancer, we should start thinking the same for the treatment options available for our patients with (hepatocellular carcinoma).”

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