Relationship of Tumor Radiation-absorbed Dose to Survival and Response in Hepatocellular Carcinoma Treated with Transarterial Radioembolization with Y in the SARAH Study.

Background Little is known about factors that influence the efficacy of transarterial radioembolization (TARE). Purpose To determine the relationship between tumor radiation-absorbed dose and survival and tumor response in locally advanced inoperable hepatocellular carcinoma treated with TARE. Materials and Methods This was a secondary analysis of prospectively acquired data (between December 2011 and March 2015) from participants who received TARE in the Sorafenib versus Radioembolization in Advanced Hepatocellular Carcinoma (SARAH) trial (ClinicalTrials.gov identifier: NCT01482442). Tumor-absorbed dose was computed using technetium 99m (Tc) macroaggregated human albumin (MAA) SPECT/CT. Visual agreement among CT, Tc-MAA SPECT/CT, and yttrium 90 (Y) SPECT/CT or PET/CT was scored as optimal, suboptimal, or not optimal. Overall survival (OS) and tumor response at 6-month follow-up CT (Response Evaluation Criteria in Solid Tumors, version 1.1) were assessed. OS was evaluated using Kaplan-Meier tests. A propensity score comparing participants receiving a tumor dose greater than or equal to 100 Gy (best cut-off according to the receiver operating characteristic curve and median tumor radiation-absorbed dose values in the study groups) with those receiving sorafenib was calculated. Results One hundred twenty-one participants (median age, 67 years; interquartile range [IQR]: 61-73 years; 110 men) were evaluated in the dose-survival group, and 109 (median age, 66 years; IQR: 61-71 years; 100 men) were evaluated in the dose-tumor response group. In the dose-survival group, median OS was 9.3 months (95% confidence interval [CI]: 6.7 months, 10.7 months), and median tumor radiation-absorbed dose was 112 Gy (IQR: 68-220 Gy). Participants who received at least 100 Gy ( = 67) had longer survival than those who received less than 100 Gy (median, 14.1 months [95% CI: 9.6 months, 18.6 months] vs 6.1 months [95% CI: 4.9 months, 6.8 months], respectively; < .001), and those with optimal agreement ( = 24) had the longest median OS (24.9 months; 95% CI: 9.6 months, 33.9 months). In the dose-tumor response group, tumor radiation-absorbed dose was higher in participants with disease control versus those with progressive disease (median, 121 Gy [IQR: 86-190 Gy] vs 85 Gy [IQR: 58-164 Gy]; = .02). The highest disease control rate was observed in 31 of 40 participants (78%) with a tumor radiation-absorbed dose greater than or equal to 100 Gy and optimal agreement. Conclusion Higher tumor radiation-absorbed dose computed at technetium 99m macroaggregated human albumin SPECT/CT was associated with better overall survival and disease control in hepatocellular carcinoma treated with transarterial radioembolization with yttrium 90 in the Sorafenib versus Radioembolization in Advanced Hepatocellular Carcinoma trial. © RSNA, 2020 See also the editorial by Sofocleous and Kamarinos in this issue.