Patients with hepatocellular carcinoma (HCC) awaiting liver transplantation may benefit from noninvasive treatment with external-beam radiotherapy (EBRT) but are rarely given this therapy, according to a new analysis of U.S. national data. Findings were presented by Nima Nabavizadeh, MD, at the 2021 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 2078).
“EBRT is a proven, established, safe, and effective treatment option for patients with unresectable liver cancer, yet its underutilization within this population—fewer than 4% of patients—highlights a real-world gap in treatment options available for patients with HCC,” said Dr. Nabavizadeh, Associate Professor of Radiation Oncology and Residency Program Director at Oregon Health & Science University.
Nima Nabavizadeh, MD
Liver Transplant and Use of Bridging Therapy
For patients with localized liver cancer and advanced cirrhosis (roughly 90% of patients with HCC also have cirrhosis), “liver transplantation is the best and only chance for long-term survival,” according to Dr. Nabavizadeh. However, the supply of organs available for transplant is limited, and candidates often wait months or more than a year for a transplant. In addition, if a patient's cancer spreads outside of transplantable size criteria or to another part of the body while they are waiting for a new liver, they are no longer eligible for transplant. Many patients, therefore, receive liver-directed bridging therapy, which is treatment to prevent the growth or spread of tumors during the waiting period.
Liver-directed treatment options for patients awaiting transplant include thermal ablation procedures; catheter-based treatments, including transarterial chemoembolization (TACE) and Y-90 radioembolization; and EBRT, which aims high doses of targeted radiation at tumor sites using noninvasive techniques.
Dr. Nabavizadeh and his team analyzed data from the United Network for Organ Sharing (UNOS), a nonprofit organization that operates the U.S. transplant system under contract with the federal government, to see which bridging therapies were prescribed most often. Of the 18,477 patients with HCC awaiting transplant since 2013, 85.4% received some type of bridging therapy. However, just 3.6% of those patients were treated with EBRT, either alone (1.2%) or in combination with another type of therapy (2.4%).
Dr. Nabavizadeh said he expected the number to be much higher. “Using our own institutional experience, more than 4% of our patients get EBRT at some point, so 3.6% was a surprising figure to us,” he said. He added, “Especially because radiation is the only noninvasive option and has not been shown to be inferior to the other treatments.”
The analysis also found the use of EBRT has increased over the past several years but remains well below utilization for other therapies. TACE was the most-utilized therapy, used for 39.6% of patients, while thermal ablation was used for 12.8% and radioembolization was used for 8.7%. Nearly a quarter of patients (22.2%) received a combination of non-EBRT therapies.
Because there are no data supporting one treatment over another, said Dr. Nabavizadeh, institutional and regional practice patterns are often the key factor driving treatment decisions. Indeed, EBRT usage varied by geographic region, from a high of 8.7% of patients in the Great Lakes states (Michigan, Ohio, and Indiana) receiving this type of bridging therapy to a low of 1.7% of patients in the Southeast (Florida, Georgia, Mississippi, Alabama, Louisiana, and Arkansas; P < .001). EBRT utilization did not differ by clinical parameters such as the number of tumors, tumor diameter, or bilirubin levels.
While the study did not explore why patients were prescribed one treatment over another, Dr. Nabavizadeh suggested it could be a result of which type of doctor a patient consulted. “Radiation oncologists are often left out of the management discussions for these patients,” he said. “When presented with choices, many patients want the noninvasive approach. They understand this treatment could really impact their quality of life. Radiation needs to be part of treatment discussions much more frequently than it is now.”
Disclosure: For full disclosures of the study authors, visit redjournal.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.