RT Journal Article SR Electronic T1 Efficacy of Radioembolization with 166Ho-Microspheres in Salvage Patients with Liver Metastases: A Phase 2 Study JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 582 OP 588 DO 10.2967/jnumed.117.197194 VO 59 IS 4 A1 Jip F. Prince A1 Maurice A.A.J. van den Bosch A1 Johannes F.W. Nijsen A1 Maarten L.J. Smits A1 Andor F. van den Hoven A1 Stavros Nikolakopoulos A1 Frank J. Wessels A1 Rutger C.G. Bruijnen A1 Manon N.G.J.A. Braat A1 Bernard A. Zonnenberg A1 Marnix G.E.H. Lam YR 2018 UL http://jnm.snmjournals.org/content/59/4/582.abstract AB Radioembolization of liver malignancies with 166Ho-microspheres has been shown to be safe in a phase 1 dose-escalation study. The purpose of this study was to investigate the efficacy of 166Ho radioembolization. Methods: In this prospective single-arm study, 56 patients were enrolled, all with liver metastases refractory to systemic therapy and ineligible for surgical resection. The primary outcome was a response by 2 target lesions on triphasic liver CT scans 3 mo after therapy, as assessed using RECIST, version 1.1. Secondary outcomes included overall tumor response, time to imaging progression, overall survival, toxicity, quality of life, and quantification of the microspheres on SPECT and MRI. Results: Between May 2012 and March 2015, 38 eligible patients were treated, one of whom was not evaluable. In 27 (73%) of 37 patients, the target lesions showed complete response, partial response, or stable disease (disease control) at 3 mo (95% confidence interval [CI], 57%–85%). The median overall survival was 14.5 mo (95% CI, 8.6–22.8 mo). For colorectal cancer patients (n = 23), the median overall survival was 13.4 mo (95% CI, 8.2–15.7 mo). Grade 3 or 4 toxic events after treatment (according to the Common Terminology Criteria for Adverse Events, version 4.03) included abdominal pain (in 18% of patients), nausea (8%), ascites (3%), fatigue (3%), gastric stenosis (3%), hepatic failure (3%), liver abscesses (3%), paroxysmal atrial tachycardia (3%), thoracic pain (3%), upper gastrointestinal hemorrhage (3%), and vomiting (3%). On SPECT, 166Ho could be quantified with high accuracy and precision, with a mean overestimation of 9.3% ± 7.1% in the liver. Conclusion: Radioembolization with 166Ho-microspheres induced a tumor response with an acceptable toxicity profile in salvage patients with liver metastases.