Preoperative Portal Vein Embolization with N-Butyl Cyanoacrylate Plus Ethiodized Oil: More Rapid and Robust Hypertrophy of the Future Liver Remnant.

Abstract

HomeRadiologyVol. 299, No. 3 PreviousNext Reviews and CommentaryFree AccessEditorialPreoperative Portal Vein Embolization with N-Butyl Cyanoacrylate Plus Ethiodized Oil: More Rapid and Robust Hypertrophy of the Future Liver RemnantRonald S. Arellano Ronald S. Arellano Author AffiliationsFrom the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, GRB 293, Boston, MA 02114.Address correspondence to the author (e-mail: [email protected]).Ronald S. Arellano Published Online:Apr 6 2021https://doi.org/10.1148/radiol.2021210368MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In See also the article by Luz et al in this issue.Dr Arellano is an associate professor of radiology at Harvard Medical School and an attending interventional radiologist at the Massachusetts General Hospital. His research focuses on local-regional therapies to treat hepatic and renal malignancies. He is a fellow of the American College of Radiology, the Society of Interventional Radiology, and the Cardiovascular and Interventional Radiology Society of Europe. He currently serves as chair of the RSNA Annual Meeting Program Planning Committee for Vascular Imaging.Download as PowerPointOpen in Image Viewer Surgical resection offers the only oncologically effective chance of a cure for many patients with primary or secondary liver cancer. Unfortunately, posthepatectomy liver failure is a significant cause of morbidity and mortality and is reported to be as high as 34% (1). This is often the result of insufficient volume and functional reserve of the remnant liver to maintain liver function. Thus, liver regeneration strategies are of critical importance when considering hepatectomy. In 1975, Honjo et al (2) reported the technical feasibility of surgical ligation of a branch of the portal vein to be included in planned resection as a means to induce hypertrophy of the remnant liver, thus limiting the morbidity of posthepatectomy liver failure. Building on this concept, Kinoshita et al (3) described an angiographic approach of portal vein occlusion, without the morbidity of surgical ligation, through particle embolization of the portal vein. Since then, many investigators have reported on various aspects of portal vein embolization (PVE) as an adjunct to hepatic resection, including imaging techniques to assess pre- and postembolization liver volumes, imaging evaluation of functional liver reserves, the impact of chemotherapy on remnant hypertrophy and function, and the use of different embolic materials (4,5). A meta-analysis (6) of 37 publications and more than 1000 patients has demonstrated the overall safety and effectiveness of PVE as a minimally invasive means to induce liver hypertrophy and to limit the incidence of posthepatectomy liver failure. Despite active ongoing investigation into all aspects of PVE, the ideal embolic material has yet to be determined.In this issue of Radiology, Luz et al (7) report their results of a randomized controlled trial comparing the use of a liquid embolic material, N-butyl-cyanoacrylate (NBCA) combined with ethiodized oil (Lipiodol; Guerbet) with standard polyvinyl alcohol (PVA) particles plus coils for preoperative PVE. The authors studied 60 participants with primary or secondary liver cancer in whom the estimated future liver remnant (FLR) was less than 25% in those without cirrhosis or cholestatic liver injury or 40% in those with underlying liver disease. Patients with portal vein thrombosis or tumor invasion were excluded, as were patients previously treated with hepatectomy. To assess change in liver volume, the authors used CT volumetry to calculate the volumetric change of the FLR. Primary end points included absolute hypertrophy, degree of hypertrophy, and overall kinetic growth rate of the FLR at 14 days and 28 days after PVE. Ultimately, PVE was technically successful in 59 participants, and of these, 47 went on to surgical resection. Disease progression was the most common reason for not proceeding to surgery.The findings of this study show the superiority of NBCA plus ethiodized oil over PVA particles plus coils for all primary end points at 14 days and 28 days after PVE. Absolute hypertrophy, FLR volume increases, overall degree of hypertrophy, and kinetic growth rates were significantly better in the NBCA plus ethiodized oil group than in the PVA particles plus coils group.The significance of the findings by Luz et al (7) lies in the accelerated responses to NBCA plus ethiodized oil of the FLR as early as 2 weeks after PVE, potentially allowing for earlier hepatectomy. The timing of resection after PVE remains a controversial topic, as surgeons must weigh the risk of tumor progression with allowing sufficient time for an increase in the FLR. In general, most surgeons operate 3–6 weeks after PVE. With the reported accelerated significant increases in absolute liver volume and degree of hypertrophy and the accelerated kinetic growth rate, the results of the study point toward the potential of earlier surgical intervention and the possibility of allowing surgery as a potential treatment option for more patients.It must be noted that the accelerated changes in the FLR come at a clinical price for the patient. Participants in the NBCA plus ethiodized oil group reported more pain than those in the PVA particles plus coils group. Whereas the risk of posthepatectomy liver failure was lower in the NBCA plus ethiodized oil group than in the PVA particles plus coils group (13% vs 27%), patients with posthepatectomy liver failure had extended intensive care unit and total hospital days, higher-grade Clavien-Dindo complications, and higher 60-day mortality (7). These results attest to the fact that posthepatectomy liver failure remains a clinical challenge for patients undergoing preoperative PVE, regardless of the embolic material used, and for which additional research is necessary.Unfortunately, 10 patients who underwent PVE did not undergo planned hepatectomy because of disease progression. Tumor progression after PVE remains an area of controversy, and additional investigation is warranted. Some reports suggest that PVE may actually accelerate tumor growth within the embolized and nonembolized liver (5). Additionally, 31 of the participants enrolled in the study underwent chemotherapy before PVE. The administration of chemotherapy around PVE is another area of controversy, for which conflicting reports describe no impact of chemotherapy on PVE, whereas others conclude that chemotherapy may inhibit liver regeneration after PVE (5). Furthermore, this study did not evaluate another controversial topic of PVE, that is, right portal vein plus segment IV embolization, which some authors argue leads to an increased rate and absolute increase in FLR of segments II and III (8,9). Nevertheless, the favorable results of NBCA plus ethiodized oil raise the possibility that its use in conjunction with other techniques, such as sequential transarterial embolization and PVE with NBCA plus ethiodized oil, sequential PVE with NBCA plus ethiodized oil and transarterial embolization, sequential or simultaneous PVE with NBCA plus ethiodized oil, and hepatic vein embolization may lead to further advances in optimizing the rate and degree of growth and function of FLRs (10).In summary, preoperative PVE is an important adjunct to curative surgery for patients with primary and secondary liver cancer. The findings reported by Luz et al (7) point favorably to the potential of NBCA plus ethiodized oil in moving the needle forward in identifying an embolic material that induces rapid and robust volumetric growth of the FLR, thus improving hope for curative surgery for patients with primary and secondary liver cancers.Disclosure of Conflicts of Interest: R.S.A. disclosed no relevant relationships.