80 Selective internal radiotherapy (SIRT) versus Hepatic artery embolization (HAE) for the treatment of neuroendocrine liver metastases

Abstract Introduction Liver-directed therapies are an important component of palliative control of disease burden and carcinoid syndrome for unresectable liver metastases of neuroendocrine tumours. Hepatic artery embolization (HAE) and selective internal radiotherapy (SIRT) are both available loco-regional therapies however there is currently no consensus on which should be offered. We looked to compare HAE against SIRT and their impact on survival. Methods This retrospective cohort study compared patients who had SIRT to a historical cohort receiving HAE (2006-2024). Kaplan-Meier plots and cox regression was used to compare survival. Results Our cohort included n=18 SIRT and n=31 HAE patients. There was no difference in survival between HAE and SIRT (log-rank P=0.55). This was also seen when patients with G3 disease were excluded (log-rank P=0.27). In a cox regression model adjusting for age and grade, SIRT was not associated with a survival difference (aHR=1.266, 95% CI:0.534-2.999, P=0.592). Increasing age and grade were associated with worse survival. Radiological response rate was numerically higher with SIRT (82.4%) compared to HAE (62.1%), but this was not statistically significant (Fisher’s P= 0.19). There was missing data on symptomatic response, with only 55.6% on SIRT and 83.9% HAE patients having complete data. However, of those, 10/10 of SIRT patients had symptomatic improvement compared to 17/26 with HAE (Fisher’s P=0.039). Conclusions There was no difference in survival between the HAE and SIRT cohort despite some suggestion of improved radiological and symptomatic response. This information can be used to guide palliative management of liver metastases from neuroendocrine tumours.