Theranostic application of lipiodol for transarterial chemoembolization in a VX2 rabbit liver tumor model.

The goal of this study was to investigate the role of Lipiodol as a tumor-specific imaging biomarker to determine therapeutic efficacy of cTACE and investigate its inter-dependency with tumor perfusion using radiological-pathological correlation in an animal model of liver cancer. METHODS: A total of N=36 rabbits were implanted in the left lobe of the liver with VX2 tumors, treated with cTACE using doxorubicin suspended in Lipiodol, and randomly sacrificed at 24 h, 7 days, or 20 days post-TACE. Unenhanced and contrast-enhanced CT scans including a perfusion protocol were obtained before cTACE and immediately before sacrifice. Tumor vascularity and Lipiodol deposition within tumors and hepatic tissue (non-target deposits) were quantified using 3D quantitative assessment tools and measurements of arterial flow, portal flow, and perfusion index (PI). After sacrifice histologic staining, including hematoxylin and eosin (H&E), CD31, and Oil Red O (ORO) were performed on tumor and liver samples to evaluate necrosis, microvascular density (MVD), and Lipiodol retention over time. Transmission electron microscopy (TEM) was performed to assess Lipiodol deposition and clearance over time. RESULTS: All cTACE procedures were carried out successfully except for one, which was excluded from further analysis. Twenty-four hours post-TACE, tumor PI (p=0.04) was significantly decreased, which was maintained at 7 days (p=0.003), but not at 20 days (p=0.4). A strong correlation (R2 = 0.894) was found between the volume of enhancing tumor tissue at baseline and Lipiodol-positive tumor volume post-TACE. Both ORO and TEM showed deposition of Lipiodol across all imaging time points within the VX2 tumors. However, gradual and ultimately near-complete Lipiodol washout was observed over time in the non-tumoral liver. MVD decreased between 24 h and 7 days post-TACE, and then increased 20 days post-TACE (both p<0.01). CONCLUSIONS: Our data provide radiology-pathology evidence for the function of Lipiodol as a theranostic, tumor-specific drug delivery agent because it is both imageable and tumor-seeking, whereby it is preferentially taken up and retained by tumor cells. Those tumor-specific functions also enable Lipiodol to act as an imaging biomarker for the therapeutic efficacy of cTACE. Together with volumetric quantification of tumor vascularization on CT, Lipiodol could be used as a predictor of a patient's response to cTACE and contribute to the therapeutic management of patients with liver cancer.

Liver and biliary damages following transarterial chemoembolization of hepatocellular carcinoma: comparison between drug-eluting beads and lipiodol emulsion.

OBJECTIVES: To compare transarterial chemoembolization (TACE)-related hepatic toxicities of conventional TACE (cTACE) and drug-eluting beads TACE (DEB-TACE) in patients with intermediate-stage hepatocellular carcinoma. METHODS: In this retrospective study, 151 consecutive patients undergoing cTACE or DEB-TACE and MRI 3-6 weeks before and after therapy were included. Toxicity was assessed on imaging (global hepatic damages (GHD), overall biliary injuries, biliary cast, bile duct dilatation, intrahepatic biloma, portal thrombosis), and clinico-biological follow-ups. Tumour response, time to progression (TTP), and overall survival were assessed. Factors influencing complication rate were identified by generalized equation logistic regression model. RESULTS: Biliary injuries and intrahepatic biloma incidence were significantly higher following DEB-TACE (p < 0.001). DEB-TACE showed a significant increased risk of GHD (OR: 3.13 [1.74-5.63], p < 0.001) and biliary injuries (OR: 4.53 [2.37-8.67], p < 0.001). A significant relationship was found between baseline prothrombin value and GHD, biliary injuries and intrahepatic biloma (all p < 0.01), and between the dose of chemotherapy and intrahepatic biloma (p = 0.001). Only TTP was significantly shorter following DEB-TACE compared to cTACE (p = 0.025). CONCLUSIONS: DEB-TACE was associated with increased hepatic toxicities compared to cTACE. GHD, biliary injuries, and intrahepatic biloma were more frequently observed with high baseline prothrombin value, suggesting that cTACE might be more appropriate than DEB-TACE in patients with less advanced cirrhosis. KEY POINTS: • DEB-TACE demonstrated more therapy-related hepatic locoregional complications compared to cTACE. • TACE-related hepatic locoregional toxicities occurred more frequently with high baseline PT value. • cTACE may be more appropriate in patients with high baseline PT value.

Preclinical Benefit of Hypoxia-Activated Intra-arterial Therapy with Evofosfamide in Liver Cancer.

PURPOSE: To evaluate safety and characterize anticancer efficacy of hepatic hypoxia-activated intra-arterial therapy (HAIAT) with evofosfamide in a rabbit model. EXPERIMENTAL DESIGN: VX2-tumor-bearing rabbits were assigned to 4 intra-arterial therapy (IAT) groups (n = 7/group): (i) saline (control); (ii) evofosfamide (Evo); (iii) doxorubicin-lipiodol emulsion followed by embolization with 100-300 µm beads (conventional, cTACE); or (iv) cTACE and evofosfamide (cTACE + Evo). Blood samples were collected pre-IAT and 1, 2, 7, and 14 days post-IAT. A semiquantitative scoring system assessed hepatocellular damage. Tumor volumes were segmented on multidetector CT (baseline, 7/14 days post-IAT). Pathologic tumor necrosis was quantified using manual segmentation on whole-slide images. Hypoxic fraction (HF) and compartment (HC) were determined by pimonidazole staining. Tumor DNA damage, apoptosis, cell proliferation, endogenous hypoxia, and metabolism were quantified (γ-H2AX, Annexin V, caspase-3, Ki-67, HIF1α, VEGF, GAPDH, MCT4, and LDH). RESULTS: cTACE + Evo showed a similar profile of liver enzymes elevation and pathologic scores compared with cTACE. Neither hematologic nor renal toxicity were observed. Animals treated with cTACE + Evo demonstrated smaller tumor volumes, lower tumor growth rates, and higher necrotic fractions compared with cTACE. cTACE + Evo resulted in a marked reduction in the HF and HC. Correlation was observed between decreases in HF or HC and tumor necrosis. cTACE + Evo promoted antitumor effects as evidenced by increased expression of γ-H2AX, apoptotic biomarkers, and decreased cell proliferation. Increased HIF1α/VEGF expression and tumor glycolysis supported HAIAT. CONCLUSIONS: HAIAT achieved a promising step towards the locoregional targeting of tumor hypoxia. The favorable toxicity profile and enhanced anticancer effects of evofosfamide in combination with cTACE pave the way towards clinical trials in patients with liver cancer. Clin Cancer Res; 23(2); 536-48. ©2016 AACR.

Early sorafenib-related adverse events predict therapy response of TACE plus sorafenib: A multicenter clinical study of 606 HCC patients.

The purpose of our study was to test the hypothesis that sorafenib-related dermatologic adverse events (AEs) as an early biomarker can predict the long-term outcomes following the combination therapy of transarterial chemoembolization (TACE) plus sorafenib (TACE-S). The intermediate-stage hepatocellular carcinoma patients who received either TACE-S or TACE-alone treatment were consecutively included into analysis. In the TACE-S group, patients with ≥ grade 2 dermatologic AEs within the first month of sorafenib initiation were defined as responders; whereas those with < grade 2 were defined as nonresponders. In the TACE-S group, the median overall survival (OS) of the responders was significantly longer than that of nonresponders (28.9 months vs. 16.8 months, respectively; p = 0.004). Multivariate analysis demonstrated that nonresponders were significantly associated with an increased risk of death compared with responders (HR = 1.9; 95% confidence Interval-CI: 1.3-2.7; p = 0.001). The survival analysis showed that the median OS was 27.9 months (95% CI: 25.0-30.8) among responders treated with TACE-S vs.18.3 months (95% CI: 14.5-22.1) among those who received TACE-alone (p = 0.046). The median time to progression was 13.1 months (95% CI: 4.4-21.8) in the TACE-S group, a duration that was significantly longer than that in the TACE-alone group [5 months (95% CI: 6.4-13.3), p = 0.014]. This study demonstrated that sorafenib-related dermatologic AEs are clinical biomarkers to identify responders from all of the patients for TACE-S therapy. Sorafenib-related dermatologic AEs, clinical biomarkers, can predict the efficacy of TACE-S in future randomized controlled trials.

A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study.

PURPOSE: Embolotherapy using microshperes is currently performed with soluble contrast to aid in visualization. However, administered payload visibility dimishes soon after delivery due to soluble contrast washout, leaving the radiolucent bead's location unknown. The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model. MATERIALS AND METHODS: RO Beads, which are based on LC Bead® platform, were compared to LC Bead. Bead size (light microscopy), equilibrium water content (EWC), density, X-ray attenuation and iodine distribution (micro-CT), suspension (settling times), deliverability and in vitro penetration were investigated. Fifteen rabbits were embolized with either LC Bead or RO Beads + soluble contrast (iodixanol-320), or RO Beads+dextrose. Appearance was evaluated with fluoroscopy, X-ray single shot, cone-beam CT (CBCT). RESULTS: Both bead types had a similar size distribution. RO Beads had lower EWC (60-72%) and higher density (1.21-1.36 g/cc) with a homogeneous iodine distribution within the bead's interior. RO Beads suspension time was shorter than LC Bead, with durable suspension (>5 min) in 100% iodixanol. RO Beads ≤300 µm were deliverable through a 2.3-Fr microcatheter. Both bead types showed similar penetration. Soluble contrast could identify target and non-target embolization on fluoroscopy during administration. However, the imaging appearance vanished quickly for LC Bead as contrast washed-out. RO Beads+contrast significantly increased visibility on X-ray single shot compared to LC Bead+contrast in target and non-target arteries (P=0.0043). Similarly, RO beads demonstrated better visibility on CBCT in target arteries (P=0.0238) with a trend in non-target arteries (P=0.0519). RO Beads+dextrose were not sufficiently visible to monitor embolization using fluoroscopy. CONCLUSION: RO Beads provide better conspicuity to determine target and non-target embolization compared to LC Bead which may improve intra-procedural monitoring and post-procedural evaluation of transarterial embolization.

Multimodality Imaging of Ethiodized Oil-loaded Radiopaque Microspheres during Transarterial Embolization of Rabbits with VX2 Liver Tumors.

Purpose To assess the visibility of radiopaque microspheres during transarterial embolization (TAE) in the VX2 rabbit liver tumor model by using multimodality imaging, including single-snapshot radiography, cone-beam computed tomography (CT), multidetector CT, and micro-CT. Materials and Methods The study was approved by the institutional animal care and use committee. Fifteen VX2-tumor-bearing rabbits were assigned to three groups depending on the type of embolic agent injected: 70-150-µm radiopaque microspheres in saline (radiopaque microsphere group), 70-150-µm radiopaque microspheres in contrast material (radiopaque microsphere plus contrast material group), and 70-150-µm radiolucent microspheres in contrast material (nonradiopaque microsphere plus contrast material group). Rabbits were imaged with single-snapshot radiography, cone-beam CT, and multidetector CT. Three to 5 weeks after sacrifice, excised livers were imaged with micro-CT and histologic analysis was performed. The visibility of the embolic agent was assessed with all modalities before and after embolization by using a qualitative three-point scale score reading study and a quantitative assessment of the signal-to-noise ratio (SNR) change in various regions of interest, including the tumor and its feeding arteries. The Kruskal-Wallis test was used to compare the rabbit characteristics across groups, and the Wilcoxon signed rank test was used to compare SNR measurements before and after embolization. Results Radiopaque microspheres were qualitatively visualized within tumor feeding arteries and targeted tissue with all imaging modalities (P < .05), and their presence was confirmed with histologic examination. SNRs of radiopaque microsphere deposition increased after TAE on multidetector CT, cone-beam CT, and micro-CT images (P < .05). Similar results were obtained when contrast material was added to radiopaque microspheres, except for additional image attenuation due to tumor enhancement. For the group with nonradiopaque microspheres and contrast material, retained tumoral contrast remained qualitatively visible with all modalities except for micro-CT, which demonstrated soluble contrast material washout over time. Conclusion Radiopaque microspheres were visible with all imaging modalities and helped increase conspicuity of the tumor as well as its feeding arteries after TAE in a rabbit VX2 liver tumor model. (©) RSNA, 2015.

Intraprocedural 3D Quantification of Lipiodol Deposition on Cone-Beam CT Predicts Tumor Response After Transarterial Chemoembolization in Patients with Hepatocellular Carcinoma.

PURPOSE: To evaluate whether intraprocedural 3D quantification of Lipiodol deposition on cone-beam computed tomography (CBCT) can predict tumor response on follow-up contrast-enhanced magnetic resonance imaging (CE-MRI) in patients with hepatocellular carcinoma (HCC) treated with conventional transarterial chemoembolization (cTACE). MATERIALS AND METHODS: This IRB approved, retrospective analysis included 36 patients with 51 HCC target lesions, who underwent cTACE with CBCT. CE-MRI was acquired at baseline and 1 month after cTACE. Overall tumor volumes as well as intratumoral Lipiodol volumes on CBCT were measured and compared with the overall and necrotic (non-enhancing) tumor volumes on CE-MRI using the paired student's t test. Tumor response on CE-MRI was assessed using modified response evaluation criteria in solid tumors (mRECIST). A linear regression model was used to correlate tumor volumes, Lipiodol volumes, and the percentage of Lipiodol deposition on CBCT with the corresponding parameters on CE-MRI. Nonparametric spearman rank-order correlation and trend test were used to correlate the percentage of Lipiodol deposition in the tumor with tumor response. RESULT: A strong correlation between overall tumor volumes on CBCT and CE-MRI was observed (R(2) = 0.986). In addition, a strong correlation was obtained between the volume of Lipiodol deposition on CBCT and tumor necrosis (in cm(3)) on CE-MRI (R(2) = 0.960), and between the percentage of Lipiodol deposition and tumor necrosis (R(2) = 0.979). Importantly, the extent of Lipiodol deposition (in percentage of total tumor volume) correlated strongly with tumor response on CE-MRI (Spearman rho = 0.84, p < 0.001). CONCLUSIONS: Intraprocedural 3D quantification of Lipiodol deposition on CBCT can be used to predict tumor response on follow-up CE-MRI.

Combination of intra-arterial therapies and sorafenib: is there a clinical benefit?

Intra-arterial therapies (IATs) play a major role in the treatment of patients with unresectable hepatocellular carcinoma. Over the last three decades, multiple loco-regional approaches such as transarterial chemoembolization or radioembolization were shown to effectively achieve local tumor control, offering significant survival benefits for selected patients with intermediate to advanced-stage disease (Barcelona Clinic Liver Cancer stage B and C). These therapies provide a dual benefit of safely delivering a highly cytotoxic payload directly to the tumor while reducing systemic toxicity. This capability maintained the advantage of IATs over conventional systemic chemotherapy. The introduction of sorafenib as a systemically applicable drug, the first of its kind to provide survival benefits by means of oral monotherapy, contributed to a paradigm change. The idea of combining this novel agent with IATs seemed intriguing, and a variety of national and international clinical trials were initiated to explore the potential benefits of this exciting new option. A plethora of preliminary data has been made available throughout the last 5 years, and the interpretation of the inhomogeneously designed protocols proved difficult. In this review, we will provide a brief state-of-the-art update on the most frequently used intra-arterial modalities and discuss the molecular mechanism, potential biomarkers as well as the safety profile of sorafenib. Furthermore, we will discuss the role of the sequence of administration in combined therapies. Finally, this review will examine the evidence for clinical outcomes for the combination of different IATs with sorafenib.

Three-dimensional evaluation of lipiodol retention in HCC after chemoembolization: a quantitative comparison between CBCT and MDCT.

RATIONALE AND OBJECTIVES: To evaluate the capability of cone-beam computed tomography (CBCT) acquired immediately after transcatheter arterial chemoembolization (TACE) in determining lipiodol retention quantitatively and volumetrically when compared to 1-day postprocedure unenhanced multidetector computed tomography (MDCT). MATERIALS AND METHODS: From June to December 2012, 15 patients met the inclusion criteria of unresectable hepatocellular carcinoma (HCC) that was treated with conventional TACE (cTACE) and had intraprocedural CBCT and 1-day post-TACE MDCT. Four patients were excluded because the lipiodol was diffuse throughout the entire liver or lipiodol deposition was not clear on both CBCT and MDCT. Eleven patients with a total of 31 target lesions were included in the analysis. A quantitative three-dimensional software was used to assess complete, localized, and diffuse lipiodol deposition. Tumor volume, lipiodol volume in the tumor, percent lipiodol retention, and lipiodol enhancement in Hounsfield units (HU) were calculated and compared between CBCT and MDCT using two-tailed Student's t test and Bland-Altman plots. RESULTS: The mean value of tumor volume, lipiodol-deposited regions, calculated average percent lipiodol retention, and HU value of CBCT were not significantly different from those of MDCT (tumor volume: 9.37 ± 11.35 cm(3) vs 9.34 ± 11.44 cm(3), P = .991; lipiodol volume: 7.84 ± 9.34 cm(3) vs 7.84 ± 9.60 cm(3), P = .998; lipiodol retention: 89.3% ± 14.7% vs. 90.2% ± 14.9%, P = .811; HU value: 307.7 ± 160.1 HU vs. 257.2 ± 120.0 HU, P = .139). Bland-Altman plots showed only minimal difference and high agreement when comparing CBCT to MDCT. CONCLUSIONS: CBCT has a similar capability, intraprocedurally, to assess lipiodol deposition in three dimensions for patients with HCC treated with cTACE when compared to MDCT.