Rapid Sequence Bland Embolization in the Treatment of Neuroendocrine Tumors with Large Volume Hepatic Metastatic Disease

Purpose: To assess the safety and efficacy of rapid sequence bland embolization (RSE) in patients with large-volume hepatic metastatic neuroendocrine tumor (mNET).

Materials and Methods: Retrospective review of 19 patients (10 female; mean age 59.0 ±14.4 years) treated with RSE between 2017 and 2024 for large-volume hepatic mNETs (defined as >50% liver volume replaced by tumor). Tumor response was assessed using modified RECIST criteria, and overall survival and progression free survival were calculated using Kaplan Meier analysis.

Results: 10 patients (53%) had 50-70% liver involvement and 9 patients (47%) had >70% liver involvement. 18 patients were on somatostatin analogue therapy prior to RSE. 11 patients had undergone prior treatment with chemotherapy, targeted therapy, surgical resection/ablation, and/or embolotherapy. Patients underwent a median of 2 embolizations (range 1-4), with a median interval of 28 days (range 19-117 days). 15 patients (79%) completed their RSE cycle with all planned embolizations performed. Four patients (21%, 3 with 50-70% tumor burden and 1 with >70% tumor burden) had only 1 embolization and could not complete their RSE cycle due to liver decompensation. The mean follow-up period was 366 +/- 356 days. Adverse effects occurred in 21 of 43 embolizations (49%), of which 9 (21%) were severe requiring hospitalization. Following RSE, 8 patients (42.1%) had partial response, 1 patient (5.3%) had stable disease, and 9 patients (47.4%) progressed. Median hepatic progression-free survival was 5.1 months. 6 patients had died during the follow-up period with median overall survival of 26.7 months following embolization.

Conclusion: Rapid sequence bland embolization is a therapeutic option for patients with large-volume hepatic metastases from neuroendocrine tumors with uncertain hepatic reserve. Further study is needed to better define the role of RSE in the treatment of neuroendocrine tumor hepatic metastases.