SIR 2024
Interventional Oncology
Kurt Pianka, BS (he/him/his)
Medical Student
University of California San Diego
Financial relationships: Full list of relationships is listed on the CME information page.
Mark Barahman, MD, PhD
Resident Physician, Radiology
University of California San Diego
Disclosure information not submitted.
Claudio B. Ghetti, BS
Medical Student
University of California San Diego
Disclosure information not submitted.
Jeet Minocha, MD
Division of Interventional Radiology
University of California San Diego
Financial relationships: Full list of relationships is listed on the CME information page.
Jonas Redmond, MD
Associate Professor of Clinical Radiology
UCSD
Financial relationships: Full list of relationships is listed on the CME information page.
Gabriel Schnickel, MD
Faculty hepatobiliary and transplant surgery physician
University of California San Diego
Disclosure information not submitted.
Zachary Berman, MD
Assistant Clinical Professor
University of California, San Diego
Disclosure information not submitted.
Ablative transarterial radioembolization (TARE) plays a key role as a bridge to transplant for hepatocellular carcinoma (HCC) patients. Post-transplant outcomes are improved with complete tumor necrosis on explant pathology. A LEGACY study (Local radioEmbolization using Glass Microspheres for the Assessment of Tumor Control with Y‐90) analysis showed that single compartment absorbed doses >400 Gy increased the likelihood of complete necrosis compared to the previous benchmark of 205 Gy {1}. This study examined the real-world impact of this analysis on explant pathologic outcomes.
Materials and Methods:
The new dosimetry standard was established in August 2020. All patients with HCC treated with TARE between 2015 – June 2023 who underwent liver transplantation were eligible. Patients for whom Medical Internal Radiation Dose (MIRD) or explant pathology could not be determined were excluded. A complete response was assigned if explant pathology showed complete necrosis and the patient did not undergo additional treatments to the same lesion after the index TARE based on multidisciplinary evaluation of residual viability. Dose, patient, and tumor characteristics were compared by t-test or chi-squared test. Logistic regression was done to model response as a function of dose.
Results:
Forty-four patients were included (59 HCC lesions). Twenty-four patients (34 lesions) underwent TARE prior to the change in dosimetry standards, while 20 patients (25 lesions) were treated post-change. There was no difference in tumor size, patient demographics, or baseline laboratory evaluations pre/post-change (p >0.05). The mean predicted MIRD dose was higher post-change (449 versus 341 Gy, p=0.04) and lesions were more likely to meet criteria for complete response (88% versus 26%, p < 0.0001). Mean dose on index TARE was 176 Gy for the six lesions that underwent repeat treatment. Based on explant pathology alone, lesions treated post-change were more likely to meet criteria for complete response (88% versus 38%, p < 0.001).
A multivariable logistic regression demonstrated that only MIRD dose was associated with complete response (p=0.003), while albumin-bilirubin (ALBI) grade 2/3 was negatively associated (p=0.04).
Conclusion:
The LEGACY study had an impact on this institution’s practice with predicted mean doses increasing significantly after its publication. In concordance with the LEGACY study, higher MIRD doses (mean 449 Gy) were associated with a threefold higher rate of complete pathologic response. This provides real world evidence validating the LEGACY results.