SIR 2024
Interventional Oncology
Tianzhi Tang, MS
Med Student
Georgetown University
Financial relationships: Full list of relationships is listed on the CME information page.
Clark R. Restrepo, MD (he/him/his)
Resident Physician
Medstar Georgetown University Hospital
Financial relationships: Full list of relationships is listed on the CME information page.
Gajan Sivananthan, MD
Assistant Professor of Radiology
MedStar Washington Hospital Center
Disclosure information not submitted.
Emil I. Cohen, MD, FSIR
Associate Professor
Medstar Georgetown University Hospital
Disclosure information not submitted.
For those with high lung shunt fraction (LSF), the total dose given in a TARE session should be adjusted so that the lung receives no more than 30 Gy in a single session or 50 Gy cumulatively{1}. In a previous study, 12 patients with LSF >10% received TARE with dose reduction and none of the patients developed RP within the follow-up period. However, the complete response rate of their tumors was much lower (13%) compared to those who received no reduction (56%){3}.
Balloon occlusion of either the hepatic arteries or veins can also reduce HPS{1,4} A balloon catheter occludes the hepatic vein/artery to induce intravascular pressure changes that allow for flow redistribution and more direct delivery of particles to the tumor. In one study with 3 patients who had LSF >20%, hepatic vein balloon occlusion decreased the LSF to < 5% in one patient and < 2% in the others{5}. Tumor-feeding branches of the hepatic artery can also be occluded in a similar fashion to reduce HPS. In a single case at our institution, balloon occlusion of the tumor-feeding hepatic artery during repeat mapping angiogram reduced the LSF from 28% to 9%.
Lastly, bland arterial embolization (BAE) can reduce LSF. In BAE, inert beads or coils are used to occlude larger arteriovenous shunts and focus arterial flow to allow more Y90 particles to reach the tumor{1}. One study reported 3 patients with high HPS who received BAE using bead particles prior to TARE, resulting in LSF reduction of >60% to below 13% in all patients{6}. In a more recent study, absolute LSF reduction after BAE ranged from -1% to 37%{3}.
Conclusion and/or Teaching Points: With techniques such as dose reduction, hepatic venous or arterial balloon occlusion, and/or BAE, patients with high HPS can now be considered for TARE treatment. All techniques have shown promise in reducing HPS, but more rigorous studies are needed to further establish their reliability.