EBRT Underutilized as Bridging Therapy to Transplant for Hepatocellular Carcinoma Although Use Increased Over Past Decade

Although the use of external-beam radiation therapy (EBRT) as a bridging therapy to transplant has increased in prevalence over the past decade, the therapy was rarely used and notably underutilized compared with other liver-directed therapies for patients with hepatocellular carcinoma (HCC), according to results from a retrospective study presented at the 2021 American Society for Radiation Oncology Annual Meeting (ASTRO).

Of the 18,447 patients who were included in the study population, EBRT use was prevalent in 3.6% of patients. From 2014 to 2019, the average annual percent change for EBRT use was 11.4% compared with an increase of 23.4% for Yttrium-90 (Y-90) radioembolization (TheraSphere).

“As an established safe, effective, and non-invasive bridging therapy, the low national utilization of external-beam radiation therapy and, in turn, SBRT, highlights a real-world gap in the treatment armamentarium for HCC and an opportunity for us to improve care of [patients with] HCC [who are] in need of liver transplants,” presenter Nima Nabavizadeh, MD, a radiation oncologist and associate professor of radiation medicine at the Oregon Health & Science University, explained in his presentation of the data.

The research retrospectively analyzed patients included in the United Network for Organ Sharing (UNOS) dataset from 2013 to 2020 to determine the national prevalence of liver-directed therapies for patients with HCC who were waiting to receive a liver transplant within the United States. Investigators identified patients with HCC who had applied for waitlist prioritization due to their disease. The study’s primary outcome was period prevalence of EBRT. Clinicopathologic parameters between patients who received and did not receive EBRT were compared.

The prevalence of several common liver-directed therapies were compared included trans arterial chemoembolization alone (39.6%), combination therapy excluding EBRT (22.2%), thermal ablation alone (12.8%), Y-90 radioembolization alone (8.7%), and chemoablation alone (1%). A total of 14.6% of patients did not receive a liver-directed therapy.

Investigators did not observe a statistical difference between patients who received EBRT and those who did not receive EBRT in terms of age, initial MELD score, initial bilirubin, history of portal vein thrombosis, baseline alpha-fetoprotein, tumor diameter, or total number of tumors.

Moreover, EBRT use differed significantly by region of the United States (P <.001). UNOS region 10, comprised of Michigan, Indiana, and Ohio, had the highest prevalence of EBRT use at 8.7%. Comparatively, UNOS region 3, which included Arkansas, Louisiana, Mississippi, Alabama, Georgia, and Florida, had the lowest prevalence of EBRT use at 1.7%.

Other regions by prevalence of EBRT use were as follows: 7.3% in region 1 (Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut), 6.4% in region 6 (Alaska, Washington, Montana, Idaho, and Oregon), 6.2% in region 9 (New York and Vermont), 4.3% in region 2 (New Jersey, Pennsylvania, Delaware, Maryland, and West Virginia), 3.4% in region 11 (Virginia, North Carolina, South Carolina, Kentucky, and Tennessee), 2.5% in region 7 (North Dakota, South Dakota, Minnesota, Wisconsin, and Illinois), 2.3% in region 4 (Texas and Oklahoma), 1.9% in region 5 (California, Nevada, Utah, Arizona, and New Mexico), and 1.8% in region 8 (Wyoming, Colorado, Nebraska, Kansas, Iowa, and Missouri).

Reference

Herman T, Kaempf A, Schlansky B, et al. Bridge-to-transplant external-beam radiation therapy in patients with hepatocellular carcinoma: a utilization analysis of the United Network for Organ Sharing (UNOS) database. Presented at 2021 American Society for Radiation Oncology Annual Meeting; October 25-27, 2021; Chicago, IL. Accessed October 26, 2021. Abstract 2078.