CIO 2021-37 Use of Y90 Radioembolization Outside of the Liver

Purpose: Radioembolization using Y90 microsphere is a powerful treatment option typically used for primary and metastatic liver cancers. This literature review summarizes the safety and efficacy of Y90 radioembolization sites outside of the liver, such as the brain, kidney, spleen, and lungs.

Material and Methods: PubMed and Cochrane Library Database were used to perform a search of all full-text articles published anytime before January 2021, using the following search terms: “yttrium”, “y-90”, “radioembolization”, “brain”, “kidney/renal”, “spleen”, “lungs/pulmonary” and “prostate”. A total of 9 papers were selected.

Results: In 1995, Zimmermann et al. demonstrated successful Y90 radioembolization of the kidney using a porcine model. This study noted complications such as arterial necrosis and arteritis, but did not utilize a control group. Subsequent studies on porcine kidney were conducted by MacKie et al. in 2011 and de Silva et al. in 2016. Comparing Y90 resin beads with a bland bead control group, they reported successful results in the target zone. MacKie et al. demonstrated a dose-dependent toxicity, with nephron-sparing effects below 0.3GBq. Hamoui et al. utilized Y90 in a metastatic sarcomatoid renal cell carcinoma of a 76 year-old woman in 2012. Renal tumor size remained stable up to 9 months and the patient lived well beyond the median survival for this pathology. Becker et al. and Muylle et al. reported successful use of Y90 to treat splenomegaly with thrombocytopenia. After treatment, a steady decrease in splenic volume and an increase in platelets were observed in both cases. Ricke et al. published 2 cases of Y90 treatment for diffuse lung metastasis. Lung nodules targeted with Y90 showed partial remission, whereas non-targeted nodules showed disease progression. In 2020, Pasciak et al. published a study using Y90 for treatment of canine brain tumors. All five patient animals showed a reduction in tumor mass at 1 month post-therapy, with only one animal experiencing remission at 5 months. Finally, Shukla et al. showed Y90 to be effective in treating advanced prostate cancer in a sample of 31 patients who were unresponsive to alternative therapies. Efficacy was demonstrated using PSA levels and scintigraphy.

Conclusions: Y90 radioembolization appears to be technically feasible and effective in various extrahepatic sites. Additional clinical studies are necessary to address its complete safety profile at these novel sites of usage.