CIO 2021-20 Efficacy of Transarterial Bland Embolization with Everolimus (EveroEmbo) for Hepatic Metastatic Neuroendocrine Tumors

Purpose: Current guidelines recommend liver directed therapies for progressive or symptomatic neuroendocrine liver metastases, however there is controversy regarding the optimal technique of bland embolization (TAE), chemoembolization (TACE), or radioembolization (TARE). Median hepatic progression-free survival (hPFS) following TAE is reported at 11 months, TACE at 20 months, and TARE at 18 months while new studies suggest long term hepatotoxicity of TARE. RADIANT-3 & 4 reported everolimus to result in median progression free survival of 11 months. Everolimus is typically held 2-4 weeks prior to and after embolization to minimize toxicity. We hypothesize that the concurrent use of everolimus with TAE (EveroEmbo) would result in prolonged local tumor control compared to either therapy alone after demonstrating safety of EveroEmbo.

Material and Methods: Review of all consecutive patients who underwent EveroEmbo between 9/2016 and 6/2021 at the University of Kentucky. Inclusion criteria included systemic everolimus for ≥ 1 month prior to embolization. For median hPFS analysis, only patients with > 12 months post-TAE imaging study were included. An independent radiologist reviewed all baseline and subsequent post-therapy studies and performed hepatic specific treatment response assessment according to RECIST 1.1.

Results: 65 concurrent EveroEmbo procedures in 38 consecutive patients were performed. Females represented 58% (22/38) of the population while males represented 42% (16/38), with mean age of 57.8 ± 12.8 years. 51 procedures had sufficient post-procedural imaging to apply RECIST 1.1 criteria, showing 7.8% with complete response, 74.5% with partial response, 13.7% with stable disease, and 3.9% with disease progression. The percentage change in tumor burden was -57.2% ± 21.7% (-18% to -100%). Among the 65 procedures, 44 had 12+ months follow-up imaging. Two of these patients progressed to date and the median hPFS was 28 months.

Conclusions: Concurrent EveroEmbo is a promising approach for local hepatic disease control with median hPFS of 28 months, exceeding the reported hPFS for everolimus alone or TAE, TACE, and TARE alone. Longer follow up is needed to assess for true median hPFS and overall survival.