Accuracy and Safety of Scout Dose Resin Yttrium-90 Microspheres for Radioembolization Therapy Treatment Planning: A Prospective Single-Arm Clinical Trial

Abstract

Purpose: To compare the accuracy and safety of 0.56 GBq resin yttrium-90 (90Y) (scout90Y) microspheres with those of technetium-99m macroaggregated albumin (MAA) in predicting the therapeutic 90Y (Rx90Y) dose for patients with hepatocellular carcinoma (HCC).

Materials and methods: This prospective single-arm clinical trial (Clinicaltrials.gov: NCT04172714) recruited patients with HCC. Patients underwent same-day mapping with MAA and scout90Y. Rx90Y activity was administered 3 days after mapping. Using paired t test and Pearson correlation, the tumor-to-normal ratio (TNR), lung shunt fraction (LSF), predicted mean tumor dose (TD), and nontumoral liver dose (NTLD) by MAA and scout90Y were compared with those by Rx90Y. Bland-Altman plots compared the level of agreement between the TNR and LSF of scout90Y and MAA with that of Rx90Y. The safety of scout90Y was evaluated by examining the discrepancy in extrahepatic activity between MAA and scout90Y.

Results: Thirty patients were treated using 19 segmental and 14 nonsegmental (ie, 2 contiguous segments or nonsegmental) therapies. MAA had weak LSF, moderate TNR, and moderate TD linear correlation with Rx90Y. Scout90Y had a moderate LSF, strong TNR, strong TD, and very strong NTLD in correlation with those of Rx90Y. Furthermore, the TNR and LSF of scout90Y had a stronger agreement with those of Rx90Y than with those of MAA. In the nonsegmental subgroup, MAA had no significant correlation with the TD and NTLD of Rx90Y, whereas scout90Y had a very strong correlation with both of these factors. In the segmental subgroup, both MAA and scout90Y had a strong linear correlation with the TD and NTLD of Rx90Y.

Conclusions: Compared with MAA, scout90Y is a more accurate surrogate for Rx90Y biodistribution for nonsegmental therapies.

Conflict of interest statement

N.K. reports grant from Sirtex Medical Ltd, educational grant from Boston Medical, and consulting fees from Sirtex Medical Ltd. None of the other authors have identified a conflict of interest.

Copyright © 2022 SIR. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1.

Study flowchart for each recruited patient. 90Y = yttrium-90; CBCT = cone-beam computed tomography; CT = computed tomography; f/u = follow-up; HCC = hepatocellular carcinoma; MAA = macroaggregated albumin; MR = magnetic resonance; PET = positron emission tomography; SIRT = selective internal radiation therapy; SPECT = single-photon emission computed tomography; Tc99 = technetium-99m; w/ = with.

Figure 2.

Correlation of tumor-to-normal liver ratio (TNR) by yttrium-90 (90Y) mapping and 90Y treatment type: (a) macroaggregated albumin (MAA) versus therapeutic 90Y (Rx90Y) entire cohort, (b) MAA versus Rx90Y nonsegmental treatment, (c) MAA versus Rx90Y segmental treatment, (d) Scout90Y versus Rx90Y entire cohort, (e) Scout90Y versus Rx90Y nonsegmental treatment, and (f) Scout90Y versus Rx90Y segmental treatment.

Figure 3.

The correlation of mean tumor dose by yttrium-90 (90Y) mapping and 90Y treatment type: (a) macroaggregated albumin (MAA) versus therapeutic 90Y (Rx90Y) entire cohort, (b) MAA versus Rx90Y nonsegmental treatment, (c) MAA versus Rx90Y segmental treatment, (d) Scout90Y versus Rx90Y entire cohort, (e) Scout90Y versus Rx90Y nonsegmental treatment, and (f) Scout90Y versus Rx90Y segmental treatment.