PT - JOURNAL ARTICLE AU - Ahmed A. Alsultan AU - Caren van Roekel AU - Maarten W. Barentsz AU - Maarten L. J. Smits AU - Britt Kunnen AU - Miriam Koopman AU - Rutger C.G. Bruijnen AU - Bart de Keizer AU - Marnix G.E.H. Lam TI - Dose-response and dose-toxicity relationships for yttrium-90 glass radioembolization in patients with colorectal cancer liver metastases AID - 10.2967/jnumed.120.255745 DP - 2021 Mar 01 TA - Journal of Nuclear Medicine PG - jnumed.120.255745 4099 - http://jnm.snmjournals.org/content/early/2021/03/19/jnumed.120.255745.short 4100 - http://jnm.snmjournals.org/content/early/2021/03/19/jnumed.120.255745.full AB - Purpose Radioembolization based on personalized treatment planning requires established dose-response and dose-toxicity relationships. The aim of this study was to investigate dose-response and dose-toxicity relationships in patients with colorectal liver metastases (CRLM) treated with glass yttrium-90 (90Y)-microspheres. Methods All CRLM patients treated with glass 90Y-microspheres in our institution were retrospectively analyzed. The tumor-absorbed dose was calculated for each measurable metastasis (i.e., 18F-FDG-positive and >5 ml tumor volume) on post-treatment 90Y-PET. Metabolic tumor response was determined on 18F-FDG-PET/CT by measuring the total lesion glycolysis at baseline and at three months post-treatment. Response was categorized according to the PERCIST criteria. The relationship between tumor-absorbed dose and metabolic response was determined on a per lesion and per patient basis using a linear mixed-effects regression model. Clinical and laboratory toxicity were correlated with healthy liver-absorbed dose. Results Thirty-one patients were included. The median tumor-absorbed dose of 85 measurable metastases was 133 Gy (range 20-1001 Gy). Per response category this was 196 Gy for complete response (CR), 177 Gy for partial response (PR), 72 Gy for stable disease, and 95 Gy for progressive disease (PD). A significant dose-response relationship was found on a tumor level with a significantly higher tumor-absorbed dose in metastases with CR (+94%) and PR (+74%) compared to metastases with PD, p<0.001. A similar relationship was found on a patient level, with PR having a higher tumor-absorbed dose compared to PD (+58%, p=0.044). A tumor-absorbed dose of >139 Gy predicted three-month metabolic response with the greatest accuracy (89% specificity, 77% sensitivity), while a tumor-absorbed dose of >189 Gy predicted response with 97% specificity and 45% sensitivity. The median healthy liver-absorbed dose was 63 Gy (range: 24-113 Gy). Toxicity was mostly limited to grade 1-2, with one case of radioembolization-induced liver disease who received the highest healthy liver-absorbed dose. A positive trend was seen for most laboratory parameters in our dose-toxicity analysis. Conclusion A significant relation was observed between dose and response in CRLM patients treated with glass 90Y-radioembolization.