93 - Embolization of Neuroendocrine Tumor Metastases to the Liver: A Single Center Experience Before and After Introduction of Pressure Enabled Drug Delivery

Purpose: This study will evaluate differences in treatment type, imaging response, laboratory, and weight data in patients with neuroendocrine tumor (NET) metastases to the liver treated with pressure-enabled drug delivery (PEDD) versus end-hole (EH) microcatheters.

Materials and Methods: A single-institution, retrospective review of patients with NET metastases to the liver treated consecutively before and after switching from EH to PEDD (TriNav, TriSalus Life Sciences, Denver, Colorado, USA) using bland particle embolization was performed. Data from charts and PACS were reviewed. Images were independently reviewed to determine target lesion(s) response using mRECIST. Student T-tests and Chi-Squared analyses were used for statistical evaluation.

Results: A total of 44 patients were evaluated for inclusion in data analysis (22 in PEDD, 22 in EH group), and 6 were excluded due to inpatient treatment or incomplete data

There was no statistically significant difference in baseline parameters between the two groups before treatment.

All patients were treated in a lobar fashion, and all but one were treated to an endpoint of stasis (no flow beyond the right or left hepatic artery).

There was no difference in complication rate or length of inpatient stay between groups.

Treatment response data were available for all patients but one (in the PEDD group) in the first 180 days after treatment. Treatment response in the PEDD versus EH groups was: complete response 22% vs 0%, partial response 61% vs 64%, stable disease 6% vs 7%, progressive disease 0% vs 29% and overall response 83% vs 64%. P-value for all response data was 0.034, and for ORR was 0.044 (Chi Squared analysis).

Overall, there was no difference in laboratory values for all patients after treatment, except for a lower albumin 6 months post procedure in the PEDD group (3.8 vs 4.2 g/dL, p 0.022). This was more pronounced in patients undergoing right lobe treatment at 1-3 months follow-up (3.6 vs 4.3 g/dL, p 0.005) but was no different at 6 months after treatment. For patients with bilirubin > 0.6 g/dL prior to treatment, alkaline phosphatase was elevated at 6 months post-procedure in the PEDD group (394 vs 125 U/L, p 0.034).

To evaluate weight, a 95% confidence interval was used to remove outliers from both groups. Patients in the PEDD group had gained weight at 6 months post-treatment, whereas patients in the EH group lost weight (PEDD: +0.35 lbs, n=12, EH: -3.61 lbs, n=10, p=0.005).

Conclusion: This retrospective review of patients with NET metastases to the liver showed better treatment response and maintained weight in the PEDD group.