Comparative study between Embosphere® and Marine gel® as embolic agents for chemoembolization of hepatocellular carcinoma.

BACKGROUND: While gelatin sponge particles and calibrated microspheres are commonly used as embolic materials in conventional transarterial chemoembolization (cTACE), direct comparisons between these embolic agents are rare. AIM: To compare the efficacy and safety of superselective cTACE using Embosphere® or Marine gel® in patients with early-stage hepatocellular carcinoma (HCC). METHODS: This retrospective study included 70 patients with small (< 4 cm) HCC who underwent cTACE with Embosphere® (n = 33) or Marine gel® (n = 37) as the embolic agent at a single center between March 2021 and July 2022. The radiologic images and clinical data were retrospectively reviewed, with an emphasis on tumor response, procedure-related complications, and local tumor recurrence. The primary index tumor was assessed on a 1-mo follow-up image, and local progression-free survival was obtained using the Kaplan-Meier method and was compared by the log-rank test. RESULTS: The median tumor size of both groups was 1.5 cm, and 69 patients achieved a complete response one month after cTACE. The cumulative local recurrence rate at 12 mo was 15.5% in the Embosphere® group and 14.4% in the Marine gel® group. The local progression-free survival was not significantly different between the two groups (P = 0.83). In the multivariate analysis, high serum alpha-fetoprotein was the only significant poor prognostic factor for local tumor progression (P = 0.01). Postembolization syndrome occurred in 36.4% of the Embosphere® group and 35.1% of the Marine gel® group, and there were no cases of biloma, biliary duct dilation, or liver abscess in either group. CONCLUSION: Calibrated gelatin sponge particles (Marine gel®) and calibrated microspheres (Embosphere®) have similar outcomes in terms of tumor response for superselective cTACE of small HCC.

Radiation Major Hepatectomy Using Ablative Dose Yttrium-90 Radioembolization in Patients with Hepatocellular Carcinoma 5 cm or Larger.

PURPOSE: To evaluate the safety and effectiveness of ablative radioembolization for large hepatocellular carcinoma (HCC) while preserving a small future liver remnant (FLR). MATERIALS AND METHODS: Twenty-five patients with large HCC of ≥5 cm requiring treatment for >60% of the total liver volume and having well-preserved liver function were treated with ablative glass microsphere radioembolization at a single institution from January 2017 to December 2021. Radioembolization was performed with a mean absorbed dose of >150 Gy, and the FLR per nontumor liver volume (NTLV) was set at >30%. Changes in liver function, adverse events, duration of response (DoR) in a treated area, time-to-progression (TTP), and overall survival (OS) were retrospectively investigated. RESULTS: The largest tumor diameter and planned dose per treated volume were 11.4 cm ± 3.9 and 242.3 Gy ± 63.6 (169.4 Gy ± 45.9 per whole liver volume), respectively. All patients remained at Child-Pugh Class A for 90 days. No patient experienced Grade 3‒4 hyperbilirubinemia or new ascites. One patient (lung dose, 27.8 Gy) developed radiation pneumonitis requiring transient steroid treatment. According to the posttreatment dosimetry, the tumorous and nontumorous liver absorbed doses were 418.8 Gy ± 227.4 and 69.0 Gy ± 32.1, respectively. The median DoR in a treated area and TTP were 22.0 and 17.1 months, respectively. The 5-year OS rate was 83.2%. CONCLUSIONS: Ablative radioembolization of large HCC of ≥5 cm can be performed safely and effectively in patients with preserved liver function when FLR/NTLV exceeds 30%.

Reappraisal of Portal Vein Tumor Thrombosis as a Prognostic Factor for Patients with Hepatocellular Carcinoma.

Background/Aims: : This study aimed to assess whether hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT) could have favorable prognoses with proper treatment under selective conditions. Methods: : This retrospective, single-center study involved 1,168 patients diagnosed with HCC between January 2005 and December 2006, before the introduction of sorafenib. Overall survival (OS) was estimated using the Kaplan-Meier method, and the Cox proportional hazards model was used to identify and adjust the variables associated with OS. Results: : In nodular-type HCC, the OS differed significantly according to the presence of PVTT (log-rank p<0.001), and the level of PVTT, not only its presence, was a major independent factor affecting OS. PVTT at the Vp1-3 branch was associated with significantly longer OS than was PVTT at the Vp4 level (hazard ratio [HR], 1.82; 95% confidence interval [CI], 1.04 to 3.21). In multivariate analysis, the OS was further stratified according to the PVTT level and tumor type, representing that nodular HCC without PVTT exhibited the best OS, whereas nodular HCC with Vp4 PVTT (adjusted HR, 2.59; 95% CI, 1.57 to 4.28) showed a poor prognosis similar to that of infiltrative HCC. The PVTT level was consistently correlated with OS in patients treated with transarterial chemoembolization. Nodular HCC without PVTT showed the best prognosis, while nodular HCC with Vp1-3 PVTT also exhibited a favorable OS, although inferior to that without PVTT (adjusted HR, 1.47, 95% CI, 0.92 to 2.36). Conclusions: : Active treatment such as transarterial chemoembolization can be considered for selected PVTT cases. The level of PVTT and type of HCC were independent prognostic factors.

Transarterial Chemoembolization Using Idarubicin Versus Doxorubicin Chemoemulsion in Patients with Hepatocellular Carcinoma (IDADOX): Protocol for a Randomized, Non-inferiority, Double-Blind Trial.

PURPOSE: This study aims to test the hypothesis that idarubicin-based transarterial chemoembolization (IDA-TACE), using one of the most potent chemotherapeutic agents, could yield oncologic outcomes equivalent to or marginally improved over doxorubicin-based TACE (DOX-TACE). MATERIALS AND METHODS: This single-center, prospective, phase II, randomized controlled, non-inferiority, double-blind trial will enroll 128 treatment-naïve patients with HCC (≤ 5 tumors, 1-5 cm in diameter) for conventional TACE. Participants will be randomly assigned (1:1) to either IDA-TACE or DOX-TACE, with stratification by Child-Pugh class. Superselective conventional TACE will be performed using cone-beam CT and small-bore microcatheters. Patient evaluations, including dynamic imaging and blood tests, will occur at 1, 3, and 6 months post-initial treatment. The primary outcome measure is the objective response rate (ORR) according to mRECIST at 6 months. Secondary outcomes include 3-month and 6-month tumor responses, time-to-progression, the incidence of treatment-related serious adverse events within 30 days, and the incidence and severity of any adverse events. STATISTICS: Non-inferiority will be claimed if the upper limit of a one-sided 97.5% confidence interval for the proportion difference (i.e., "6-month ORR of DOX-TACE" - "6-month ORR of IDA-TACE") falls below 0.15 in both intention-to-treat and per-protocol analyses. The proportion difference and its confidence interval will be calculated by the Cochran-Mantel-Haenszel method to obtain a weighted average of stratum-specific proportion differences. EXPECTED GAIN OF KNOWLEDGE: If IDA-TACE demonstrates outcomes comparable to DOX-TACE, this study could provide compelling evidence that various cytotoxic agents yield similar contributions in TACE, considering the minor role of chemotherapeutic agents in TACE. TRIAL REGISTRATION: ClinicalTrials.gov ( https://clinicaltrials.gov/ ). Identifier: NCT06114082. World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) ( https://trialsearch.who.int/Default.aspx ). Identifier: KCT0008166.

C-Arm Computed Tomographic Image Fusion for Repetitive Transarterial Chemoembolization of Hepatocellular Carcinoma.

OBJECTIVE: The aim of this study was to evaluate the potential implications of fusion imaging with C-arm computed tomography (CACT) scans for repetitive conventional transarterial chemoembolization (cTACE) for hepatocellular carcinoma. MATERIALS AND METHODS: Fifty-six cTACE sessions were performed using fusion CACT images from September 2020 to June 2021 in a tertiary referral center, and the data were retrospectively analyzed. Fusion of unenhanced and enhanced CACT images was considered when previously accumulated iodized oil hampered the identification of local tumor progression or intrahepatic distant metastasis (indication A), when a tumor was supplied by multiple arteries with different origins from the aorta and missing tumor enhancement was suspected (indication B), or when iodized oil distribution on immediate post-cTACE CACT images needed to be precisely compared with the pre-cTACE images (indication C). Fusion image quality, initial tumor response, time to local progression (TTLP) of index tumors, and time to progression (TTP) were evaluated. RESULTS: The fusion quality was satisfactory with a mean misregistration distance of 1.4 mm. For the 40 patients with indication A, the initial tumor responses at 3 months were nonviable, equivocal, and viable in 27 (67.5%), 4 (10.0%), and 9 (22.5%) index tumors, respectively. The median TTLP and TTP were 14.8 months and 4.5 months, respectively. For 10 patients with indication B, the median TTLP and TTP were 8.3 months and 2.6 months, respectively. Among the 6 patients with indication C, 2 patients were additionally treated at the same cTACE session after confirming incomplete iodized oil uptake on fusion imaging. CONCLUSIONS: Fusion CACT images are useful in patients with hepatocellular carcinoma undergoing repetitive cTACE.

Early-Stage HCC Percutaneous Locoregional Management: East versus West Perspectives.

Hepatocellular carcinoma represents an important cause of death worldwide. Early-stage hepatocellular carcinoma patients not suitable for surgery can be treated with a variety of minimally invasive locoregional interventional oncology techniques. Various guidelines in different countries address the treatment of hepatocellular carcinoma, but the actual treatment is usually discussed by a multidisciplinary tumor board in a personalized manner, leading to potential treatment differences based on Western and Eastern perspectives. The aim of this paper is to integrate literature evidence with the eminent experiences collected during a focused session at the Mediterranean Interventional Oncology (MIO) Live Congress 2023.

A Phase I/IIa Trial of Yttrium-90 Radioembolization in Combination with Durvalumab for Locally Advanced Unresectable Hepatocellular Carcinoma.

PURPOSE: Synergistic effect of radiotherapy and immunotherapy for the treatment of hepatocellular carcinoma (HCC) has been reported. This phase I/IIa pilot trial evaluated preliminary efficacy and safety of combination of radioembolization with yttrium-90 microspheres (Y90-radioembolization) and durvalumab in patients with locally advanced unresectable HCC. PATIENTS AND METHODS: Patients with Child-Pugh score ≤ 7 and locally advanced HCC, defined as Barcelona Clinic Liver Cancer (BCLC) stage B HCC or BCLC-C disease without extrahepatic metastases, received Y90-radioembolization followed by intravenous durvalumab 1,500 mg 7 to 14 days after Y90-radioembolization and every 4 weeks thereafter. Primary endpoint was time to progression (TTP) assessed by modified RECIST (mRECIST). Secondary endpoints included overall survival (OS), progression-free survival (PFS), objective response rate (ORR) determined by mRECIST, and safety. RESULTS: All 24 patients enrolled received Y90-radioembolization and 23 received at least one dose of durvalumab. Median follow-up duration was 19.0 months (range, 2.2-24.2). Median TTP was 15.2 months [95% confidence interval (CI), 6.1-not estimated]. Median OS was not reached and 18-month OS rate was 58.3% (95% CI, 36.4-75.0). Median PFS was 6.9 months (95% CI, 5.4-15.2). Seven (29.2%) patients had a complete response and 13 (54.2%) had a partial response; ORR was 83.3% (95% CI, 62.6-95.3). Eleven (47.8%) patients experienced any-grade treatment-related adverse events. Two (8.7%) patients had grade 3 treatment-related adverse events (neutropenia and fever). None experienced any treatment-related serious adverse events. CONCLUSIONS: In patients with locally advanced unresectable HCC, the combination of Y90-radioembolization and durvalumab demonstrated promising efficacy and safety, warranting further evaluation in large-scale controlled trials.

Safety of Radioembolization via the Cystic Artery in Patients with Hepatocellular Carcinoma and Parasitized Arterial Supply.

PURPOSE: To evaluate the safety and effectiveness of radioembolization through the cystic artery supplying hepatocellular carcinoma (HCC) adjacent to the gallbladder. MATERIALS AND METHODS: This retrospective, single-center study included 24 patients who underwent radioembolization via the cystic artery between March 2017 and October 2022. The median tumor size was 8.3 cm (range, 3.4-20.4 cm). Twenty-two (92%) patients had Child-Pugh Class A disease, and 2 (8%) patients had Class B cirrhosis. Technical issues, adverse events, and tumor response were analyzed. RESULTS: Infusion of radioactive microspheres was performed from the main cystic artery (n = 6), the deep cystic artery (n = 9), and small feeders from the cystic artery (n = 9). The cystic artery supplied the primary index tumor in 21 patients. The median radiation activity delivered via the cystic artery was 0.19 GBq (range, 0.02-0.43 GBq). The median total radiation activity administered was 4.1 GBq (range, 0.9-10.8 GBq). There was no case of symptomatic cholecystitis requiring invasive intervention. One patient experienced abdominal pain during injection of radioactive microspheres via the cystic artery. Eleven (46%) patients received pain medication during or within 2 days of the procedure. Twelve (50%) patients had gallbladder wall thickening on a 1-month follow-up computed tomography scan. Based on follow-up imaging, 23 (96%) patients showed an objective response (complete or partial response) of the tumor supplied by the cystic artery. CONCLUSION: Radioembolization via the cystic artery may be safe in patients with HCC partially supplied by the cystic artery.

Use of doxorubicin-eluting bead transarterial chemoembolization for unresectable hepatocellular carcinoma with portal vein invasion: a prospective study.

Background/Aim: To evaluate the applicability of transarterial chemoembolization (TACE) treatment with doxorubicin drug-eluting beads (DEBs) in advanced hepatocellular carcinoma (HCC) patients with portal vein invasion (PVI). Methods: This prospective study was approved by the institutional review board and informed consent was obtained from all participants. A total of 30 HCC patients with PVI received DEB-TACE between 2015 and 2018. The following parameters were evaluated: complications during DEB-TACE, abdominal pain, fever, and laboratory outcomes, including liver function change. Overall survival (OS), time to progression (TTP), and adverse events were also analyzed and assessed. Results: DEBs measuring 100-300 µm in diameter were loaded with doxorubicin (150 mg per procedure). There were no complications during DEB-TACE and no significant differences in the levels of prothrombin time, serum albumin, or total bilirubin at follow-up compared to baseline. The median TTP was 102 days (95% confidence interval [CI], 42-207 days) and the median OS was 216 days (95% CI, 160-336 days). Three patients (10%) had severe adverse reactions, including transient acute cholangitis (n=1), cerebellar infarction (n=1), and pulmonary embolism (n=1), but no treatment-related death occurred. Conclusions: DEB-TACE may be a therapeutic option for advanced HCC patients with PVI.

Prognostication and risk factor stratification for survival of patients with hepatocellular carcinoma: a nationwide big data analysis.

This study was conducted to identify risk factors affecting overall survival (OS) and provide prognostication for patients with hepatocellular carcinoma (HCC) using nationwide big data. Between January 2008 and December 2014, 10,573 adult patients with new HCC were registered in a nationwide database. Among them, 6830 patients without missing data were analyzed to construct a prognostication system. A validation cohort of 4580 patients was obtained from a tertiary hospital. All patients were assumed to have received the best treatment. A conditional inference tree analysis was performed to establish a prognostic system. The C-index and calibration plot for 5-year survival were estimated for validation. As a result, the tumor burden (TB) grade was the most significant factor in determining OS, and the cutoff was TB3 (TB1‒3 versus TB4). The patients were ultimately divided into 13 prognosis groups. The C-indexes were 0.714 and 0.737 (95% confidence interval, 0.733-0.742) in the nationwide (derivation) and hospital (validation) cohorts, respectively. In the calibration plot, the 5-year survival of the validation cohort largely matched the 45-degree line. In conclusion, the proposed prognostication system with a simple tree structure enabled the detailed stratification of patient prognosis and visualized the strata of risk factors affecting OS.

Transarterial radioembolization versus tyrosine kinase inhibitor in hepatocellular carcinoma with portal vein thrombosis.

BACKGROUND/AIMS: Transarterial radioembolization (TARE) has shown promising results in treating advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT). However, whether TARE can provide superior or comparable outcomes to tyrosine kinase inhibitor (TKI) in patients with HCC and PVTT remains unclear. We compared the outcomes of TARE and TKI therapy in treatment-naïve patients with locally advanced HCC and segmental or lobar PVTT. METHODS: This multicenter study included 216 patients initially treated with TARE (n=124) or TKI (sorafenib or lenvatinib; n=92) between 2011 and 2021. Baseline characteristics were balanced using propensity score matching (PSM) or inverse probability of treatment weighting (IPTW). The primary outcome was overall survival (OS). The secondary outcomes included progression-free survival (PFS) and objective response rate (ORR). RESULTS: In the unmatched cohort, the median OS of the TARE and TKI groups were 28.2 and 7.2 months, respectively (p<0.001), and the TARE group experienced significantly and independently longer OS compared to the TKI group (adjusted hazard ratio=0.41, 95% confidence interval=0.28-0.60, p<0.001). Similar results were observed in the study cohorts balanced with IPTW (p=0.003) or PSM (p=0.004). Although PFS was comparable between the two groups, the TARE group showed a trend of prolonged PFS in a subpopulation of patients with Vp1 or Vp2 PVTT (p=0.052). In the matched cohorts, the ORR of the TARE group was 53.0-56.7%, whereas that of the TKI group was 12.3-15.0%. CONCLUSION: For patients with advanced HCC with segmental or lobar PVTT and well-preserved liver function, TARE may provide superior OS compared to sorafenib or lenvatinib.

Transcatheter arterial embolization of cystic artery bleeding.

Purpose: The purpose of this study is to assess the safety and clinical outcomes of transcatheter arterial embolization (TAE) via the cystic artery for treating patients with bleeding from the cystic artery. Materials and Methods: This retrospective study included 20 patients who underwent TAE via the cystic artery between January 2010 and May 2022. Radiological images and clinical data were reviewed to evaluate causes of bleeding, procedure-related complications, and clinical outcomes. Technical success was defined as the disappearance of contrast media extravasation or pseudoaneurysm, as demonstrated on completion angiography. Clinical success was defined as discharge from the hospital without any bleeding-related issues. Results: Hemorrhagic cholecystitis (n = 10) was the most common cause of bleeding, followed by iatrogenic (n = 4), duodenal ulcer (n = 3), tumor (n = 2), and trauma (n = 1). Technical success was achieved in all cases, and clinical success was achieved in 70% (n = 14) of patients. Three patients developed ischemic cholecystitis as a complication. Six patients with clinical failure died within 45 days after embolization. Conclusion: TAE through the cystic artery has a high technical success rate in treating cystic artery bleeding, but clinical failure remains a common occurrence due to concurrent medical conditions and the development of ischemic cholecystitis.

Transarterial chemoembolization as an alternative to radioembolization is associated with earlier tumor recurrence than in radioembolization-eligible patients.

Introduction: Although transarterial radioembolization (TARE) using yttrium-90 (90Y) is a treatment option for large hepatocellular carcinoma (HCC), a fraction of patients are ineligible for TARE due to high lung shunt fraction (LSF). Methods: We evaluated if treatment with transarterial chemoembolization (TACE), owing to TARE ineligibility was associated with early HCC progression. Consecutive patients with HCC who were initially TARE candidates were included. Patients with vascular invasion or metastasis were excluded. Primary endpoints were time-to-progression (TTP) and overall survival (OS). The secondary endpoint was objective response rate. Results: In total, 175 patients were included: 144 underwent TARE (TARE-eligible group) and 31 underwent TACE due to high LSF (TARE-ineligible group). This latter group had larger tumors (13.8 cm vs. 7.8 cm, P<0.001) and higher MoRAL scores (1,385.8 vs. 413.3, P=0.002) than the TARE-eligible group. After balancing baseline characteristics with an inverse probability of treatment weighting (IPTW), the TARE-ineligible group showed shorter TTP [adjusted hazard ratio (aHR)=2.16, 95% confidence interval (CI)=1.14-4.07, P=0.02] and OS (aHR=1.80, 95% CI=0.85-3.80, P=0.12), although the latter was not statistically significant. The TARE-ineligible group had a significantly lower objective response rate than the TARE-eligible group (9.7% vs. 56.9%, P<0.001). Conclusion: TARE-ineligible patients had larger tumors and higher MoRAL scores than TARE-eligible patients. Treatment with TACE, owing to high LSF, was associated with a shorter TTP even after balancing tumor size and MoRAL scores.

Radiation pneumonitis following Yttrium-90 radioembolization: A Korean multicenter study.

Objective: To report the incidence of radiation pneumonitis after radioembolization. Methods: In this retrospective study, from May 2009 to July 2021, 782 consecutive patients underwent radioembolization in two institutes. Medical internal radiation dose dosimetry and partition dosimetry were used for glass and resin Yttrium-90-labeled microspheres (90Y-microspheres), respectively. Medical records and radiological findings were retrospectively evaluated with emphasis on the symptomatic radiation pneumonitis. Results: Of the 732 patients with lung shunt study and follow-up, 13 (1.8%) had symptomatic radiation pneumonitis and six patients died due to radiation pneumonitis. Of the 721 patients whose lung doses were calculated, 10 patients who were treated with glass (n = 5) and resin (n = 5) 90Y-microspheres had radiation pneumonitis. No significant statistical difference between glass and resin 90Y-microspheres (p = 0.304) was noted in terms of radiation pneumonitis incidence. Among the patients with radiation pneumonitis, all five patients treated with glass 90Y-microspheres had estimated lung doses > 29 Gy, whereas five patients treated with resin 90Y-microspheres had relatively wide range of lung dose reaching much lower value (13.21Gy). Conclusion: The present study suggests that radiation pneumonitis after radioembolization may occur even though the manufacturer's instructions are followed.

Clinical Outcomes of Transarterial Embolization for Chronic Achilles Tendinopathy Refractory to Conservative Treatment: A Pilot Study.

PURPOSE: To evaluate the effectiveness and safety of transarterial embolization (TAE) for chronic Achilles tendinopathy (AT) refractory to conservative treatment. MATERIALS AND METHODS: This retrospective study included 20 patients (12 men and 8 women; mean age, 30.3 years) who received TAE using imipenem/cilastatin sodium for refractory chronic AT from May 2019 to April 2021. Nine patients had bilateral involvement. A total of 29 procedures were performed (8 for nonathletes and 21 for athletes). If feasible, embolization was performed superselectively of the arterial branch demonstrating hypervascularity, early venous drainage, and/or supplying the pain site noted using a radiopaque marker. The visual analog scale (VAS, 0-10) score was used to assess pain symptoms at baseline and during the follow-up period (1 day; 1 week; 1, 3, and 6 months; and open period). Clinical success was defined as a decrease of >50% in the VAS score at 6 months when compared with baseline. RESULTS: In 25 (86.2%) of 29 procedures, clinical success was achieved. Significant decreases in the VAS scores were noted at 1 day, 1 week, 1 month, 3 months, and 6 months (6.86 at the baseline vs 3.48, 3.41, 3.10, 2.55, and 1.62, respectively; all P < .01). For patients available for the 12- and 24-month follow-ups (n = 19 and 6, respectively), the mean VAS scores significantly decreased (6.84 vs 2.00 and 7.33 vs 1.17, respectively; all P < .01). No serious adverse events were observed during follow-up. CONCLUSIONS: TAE may alleviate pain for patients with chronic AT refractory to the conservative treatment with a low risk of adverse events.

Hepatocellular Carcinoma Supplied by the Inferior Phrenic Artery or Cystic Artery: Anatomic and Technical Considerations.

Intra-arterial treatment has been identified as one of the mainstays in the management of unresectable hepatocellular carcinoma. A thorough knowledge of tumor arterial supply enables selective therapy, which improves both safety and efficacy. The inferior phrenic artery (IPA) is the most common extrahepatic collateral artery that feeds hepatocellular carcinoma. The bilateral IPAs are known to have a specific vascular anatomy. A systemic-to-pulmonary shunt and a gastric branch from the IPAs may be present and should not be confused with tumor blush. The supraceliac aorta and celiac trunk are the common origin sites of the IPAs, and their orifice may be compressed by the diaphragm. Various techniques and catheters are used for catheterization of the IPAs, depending on their origin sites. Because the IPA is normally connected with the intercostal, internal mammary, retroperitoneal, and hepatic arteries, its hemodynamics may be altered when its orifice is occluded. In general, superselective chemoembolization via the target branch of the IPA is safe and effective. When a systemic-to-pulmonary shunt from the IPA is adequately embolized with coils or particles, radioembolization through the IPA can be performed safely in most cases. The cystic artery branches into deep and superficial cystic arteries; deep cystic arteries often supply tumors near the gallbladder. Chemoembolization through the cystic artery is relatively safe, with transient embolic materials. Radioembolization through the cystic artery has been recently tried, with acceptable efficacy and toxicity results, but it requires further investigation. ©RSNA, 2022.

Ideal Size Range for Embolic Agents in Interventional Oncology Experiments Involving Rat Models of Hepatocellular Carcinoma.

PURPOSE: To optimize future translational research, this study aimed to determine the ideal range of sizes for embolic agents in interventional oncology experiments utilizing rat models of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-five male Sprague-Dawley rats were divided into 2 groups to evaluate the distribution of microparticles and tumor response rates. After implanting hepatoma cells into the rodent liver, fluorescent microparticles of sizes ranging from 5 to 35 µm were administered via the hepatic artery. In the first group, the distribution of microparticles was evaluated in hepatoma-free rats, and the tumor necrosis rates following administration of a predetermined aliquot of microparticles (0.4 mL) were measured in tumor-bearing rats. Thereafter, the 3 microparticle sizes associated with the best tumor response rates were chosen for analysis of the tumor necrosis rates following hepatic artery embolization until angiographic stasis is achieved in the second group. RESULTS: The tendency for microparticles to distribute in nontarget organs increased as the microparticle size decreased below 15 µm. Tumor necrosis rates tended to be higher in rats treated with 15-19-µm microparticles than in those treated with 19-24-µm or 19-24-µm microparticles. The in-group deviation of the tumor necrosis rates was highest for microparticle sizes of 19-24 and 25-35 µm, which implies the proximal embolization of the hepatic artery for larger microparticle sizes. However, there was no statistical significance among the 3 groups (P = .095). CONCLUSIONS: The 15-19-µm embolic agents were the most favorable for causing tumor necrosis without nontarget toxicity in the transarterial treatments of rat HCC models.