# Yttrium-90 Selective Internal Radiation Therapy for Neuroendocrine Liver Metastases: An Institutional Case Series, Updated Systematic Review, and Meta-Analysis

## TL;DR

This study evaluates the effectiveness and safety of yttrium-90 radiation therapy for liver metastases from neuroendocrine tumors, combining institutional data with a meta-analysis of existing studies.

## Contribution

The study provides updated survival data and symptom improvement outcomes for Y-90 SIRT in neuroendocrine liver metastases, integrating new institutional results with a comprehensive meta-analysis.

## Key findings

- Median overall survival was 33.3 months and hepatic progression-free survival was 15.3 months in the institutional cohort.
- Meta-analysis showed pooled 1-, 2-, 3-, and 5-year overall survival rates of 82%, 66%, 52%, and 34%, respectively.
- Symptom improvement was reported in 77% of symptomatic patients with minimal grade ≥ 3 toxicities.

## Abstract

Background/Objectives: To evaluate the efficacy, safety, and symptom impact of yttrium-90 selective internal radiation therapy (Y-90 SIRT) for neuroendocrine liver metastases (NELM) through an updated systematic review and meta-analysis integrated with our institutional data. Methods: We retrospectively analyzed 12 patients with NELM treated with Y-90 resin microspheres between 2019 and 2024. Outcomes included overall survival (OS), hepatic progression-free survival (HPFS), symptom improvement, and adverse events. Concurrently, a systematic review and meta-analysis of 43 studies (including our institutional cohort; total n = 2221; 2008–2025) was conducted following PRISMA guidelines. Pooled estimates for survival, tumor response, symptom improvement, and adverse events were derived using random- or fixed-effects models, with publication bias assessed by standard methods. Results: In our cohort, the median OS and HPFS were 33.3 and 15.3 months; 71.4% of symptomatic patients reported improvement, with no grade ≥ 3 toxicities. In the meta-analysis, pooled OS rates were 82%, 66%, 52%, and 34% at 1, 2, 3, and 5 years, and HPFS rates were 64%, 41%, and 29% at 1, 2, and 3 years. The pooled objective response rate (ORR) and disease control rate (DCR) were 40% and 87% by RECIST, and 56% and 91% by mRECIST. Patients treated with resin microspheres (ORR 38%, DCR 86%) and glass microspheres (ORR 39%, DCR 83%) showed comparable responses. Symptom improvement was observed in 77% of symptomatic patients, while reported grade ≥ 3 toxicities for individual adverse events were each below 5%. Conclusions: Y-90 SIRT is associated with promising survival outcomes, high disease control rates, and substantial symptom improvement in NELM with acceptable toxicity, suggesting its potential value as a liver-directed therapy option.