IntroductionTransarterial radioembolisation (RE) using yttrium-90 (Y-90) microspheres is a widely used locoregional therapy for a broad spectrum of HCC given its favourable safety profile. We evaluated the real-world outcomes of unresectable HCC treated with resin Y-90 RE and the relationship between tumour absorbed dose and subsequent curative therapy with survival.Methods Included were consecutive patients treated with Y-90 resin microspheres RE for unresectable HCC between January 2008 and May 2019 at the National Cancer Centre Singapore /Singapore General Hospital. The outcomes were stratified by tumour burden, distribution, presence of portal vein invasion (PVI) and liver function to improve prognostication. Results The median overall survival (OS) evaluated on 413 included patients was 20.9 months (95% CI 18.2 – 24.0). More than half of the patients (214/413, 51.8%) had HCC beyond up-to-seven criteria, and 37.3% had portal vein invasion (154/413, 37.3%). Majority (71.7%) had dosimetry calculated based on the partition model. Patients who received ≥150 Gy to tumour had significantly better outcomes (OS 32.2 months, 95% CI 18.3 – 46.4) than those who did not (OS 17.5 months, 95% CI 13.7 – 22.7, p < 0.001). Seventy patients (17%) received curative therapies after tumour was downstaged by Y-90 RE and had better OS of 79.7 months (95% CI 40.4 – NE) compared to those who did not receive curative therapies (OS 17.1 months; 95% CI 13.5 – 20.4, p < 0.001). Radioembolisation-induced liver injury was observed in 5.08% of the patients while 3.2% of the patients had possible radiation pneumonitis but none developed Grade 3-4 toxicity. For HCC without PVI, overall survival differed significantly with performance status, ALBI grade, tumour distribution, and radiation dose; for HCC with PVI, Child-Pugh class and AFP were significant predictors of survival. Conclusions Treatment outcomes for unresectable HCC using Y-90 RE were favourable. Incorporating tumour burden and distribution improved prognostication. Patients who received tumour absorbed dose above 150 Gy had better OS. Patients who subsequently received curative therapies after being downstaged by Y-90 RE had remarkable clinical outcomes.

IntroductionTransarterial radioembolisation (RE) using yttrium-90 (Y-90) microspheres is a widely used locoregional therapy for a broad spectrum of HCC given its favourable safety profile. We evaluated the real-world outcomes of unresectable HCC treated with resin Y-90 RE and the relationship between tumour absorbed dose and subsequent curative therapy with survival.Methods Included were consecutive patients treated with Y-90 resin microspheres RE for unresectable HCC between January 2008 and May 2019 at the National Cancer Centre Singapore /Singapore General Hospital. The outcomes were stratified by tumour burden, distribution, presence of portal vein invasion (PVI) and liver function to improve prognostication. Results The median overall survival (OS) evaluated on 413 included patients was 20.9 months (95% CI 18.2 – 24.0). More than half of the patients (214/413, 51.8%) had HCC beyond up-to-seven criteria, and 37.3% had portal vein invasion (154/413, 37.3%). Majority (71.7%) had dosimetry calculated based on the partition model. Patients who received ≥150 Gy to tumour had significantly better outcomes (OS 32.2 months, 95% CI 18.3 – 46.4) than those who did not (OS 17.5 months, 95% CI 13.7 – 22.7, p < 0.001). Seventy patients (17%) received curative therapies after tumour was downstaged by Y-90 RE and had better OS of 79.7 months (95% CI 40.4 – NE) compared to those who did not receive curative therapies (OS 17.1 months; 95% CI 13.5 – 20.4, p < 0.001). Radioembolisation-induced liver injury was observed in 5.08% of the patients while 3.2% of the patients had possible radiation pneumonitis but none developed Grade 3-4 toxicity. For HCC without PVI, overall survival differed significantly with performance status, ALBI grade, tumour distribution, and radiation dose; for HCC with PVI, Child-Pugh class and AFP were significant predictors of survival. Conclusions Treatment outcomes for unresectable HCC using Y-90 RE were favourable. Incorporating tumour burden and distribution improved prognostication. Patients who received tumour absorbed dose above 150 Gy had better OS. Patients who subsequently received curative therapies after being downstaged by Y-90 RE had remarkable clinical outcomes.