Lipiodol Deposition in NET Liver Metastases during TACE using Pressure-Enabled versus Endhole Catheters: Pilot Data from a Randomized, Internally-Controlled Trial

Intratumoral lipiodol deposition in transarterial chemoembolization (TACE) is an imaging biomarker for response and survival in hepatocellular carcinoma.  In neuroendocrine tumors (NETs) improved delivery of liquid therapeutics may improve TACE outcomes. Pressure-enabled delivery catheters (PED) overcome the tumor microvasculature resistance and interstitial pressure compared to endhole catheters (EH). PED have been shown to increase deposition of solid particles in tumors. We investigated if PED would enhance delivery of emulsified lipiodol in TACE.

Materials and Methods:

Single-center, randomized, internally controlled comparison of EH (Renegade HI-FLO, Boston Scientific) versus PED catheter (TriNav, TriSalus) for TACE of NET liver metastases. Patients with bilobar metastases undergoing staged TACE were eligible beginning February 2024. First TACE catheter was randomized, with the other catheter used for second TACE. Pre-embolization CTA was performed during TACE to delineate viable tumor. Post-TACE dual energy CT scan was performed (100/Sn150 kVp). Blinded analysis of iodine density and percent volume tumor coverage was calculated from iodine maps. Student’s t-tests were used to compare mean iodine density and Mann-Whitney for % volume. 1-month response MRIs are pending.

Results:

Five patients are enrolled, and 4 patients (8 total TACEs) have been analyzed. Thirteen PED- and 13 EH-treated lesions were analyzed. There were 3 small bowel NET and 1 rectal primary with Ki-67 5.5%, 6%, 10.6%, and 26%. Mean tumor diameter did not differ: average diameter 3.5 cm vs 3.2 cm in PED vs EH (p=0.64). For PED- versus EH-treatments, mean iodine density per tumor was 7.6 vs 8.9 (mg /cm3) (p=0.46), and % volume coverage was 93% versus 95% (p=0.65), respectively. Comparing PED to EH within individual patients, 2 patients showed increased and 2 showed decreased density and coverage with PED. One decreased PED deposition was in a patient with hypovascular metastases. Lipiodol deposition in nontumor liver was the same between catheters (p=0.59). There was no difference in adverse events.

Conclusion:

Pilot data show no difference in lipiodol tumor deposition by mean density or % volume coverage from TACE in NET liver metastases when treated with PED or EH catheter on a per-tumor basis. Limited intrapatient data suggests augmented PED deposition may depend on underlying hypervascularity of tumors.