Comparison of CT findings with resected specimens after chemoembolization with iodized oil for hepatocellular carcinoma

Lipiodol accumulation patterns and their impact on survival outcomes in transarterial chemoembolization for hepatocellular carcinoma: a single institution retrospective analysis

Conventional Transarterial chemoembolization (TACE) using Lipiodol is a pivotal therapeutic modality for hepatocellular carcinoma (HCC). The link between Lipiodol accumulation patterns and patient survival outcomes remains underexplored. This study assesses the impact of these patterns on the prognosis of HCC patients undergoing TACE. We evaluated HCC patients treated with selective TACE between July 2015 and March 2020, classifying post-procedure Lipiodol accumulation observed on CT scans into four distinct patterns: homogeneous, heterogeneous, defective, and deficient. We analyzed cumulative local tumor recurrence (LTR), progression-free survival (PFS), and overall survival (OS) rates across these groups. Univariate and multivariate logistic regression analyses were performed to identify potential prognostic factors influencing PFS and OS. Among 124 HCC nodules, the distribution of Lipiodol patterns was: 65 homogeneous, 24 heterogeneous, 10 defective, and 25 deficient. Median PFS was 33.2, 9.1, 1.1, and 1.0 months, respectively, while median OS spanned 54.8, 44.5, 25.0, and 29.1 months for these groups. A significant difference in survival was found only between the homogeneous and defective patterns (hazard ratio, 2.33; confidence interval 1.25-4.36). Multivariate analyses revealed nonhomogeneous patterns as significant predictors of shorter PFS (HR 6.45, p < 0.001) and OS (HR 1.73, p = 0.033). Nonhomogeneous Lipiodol patterns in HCC following TACE significantly correlate with higher recurrence and decreased survival rates, especially with defective patterns. Early detection of these patterns may guide timely intervention strategies, potentially enhancing survival outcomes for patients with HCC.

Imaging of Neuroendocrine Neoplasms; Principles of Treatment Strategies. What Referring Clinicians Want to Know

ABSTRACT

Neuroendocrine neoplasms (NENs) are a diverse group of tumors that express neuroendocrine markers and primarily affect the lungs and digestive system. The incidence of NENs has increased over time due to advancements in imaging and diagnostic techniques. Effective management of NENs requires a multidisciplinary approach, considering factors such as tumor location, grade, stage, symptoms, and imaging findings. Treatment strategies vary depending on the specific subtype of NEN. In this review, we will focus on treatment strategies and therapies including the information relevant to clinicians in order to undertake optimal management and treatment decisions, the implications of different therapies on imaging, and how to ascertain their possible complications and treatment effects.

Ethiodized oil as an imaging biomarker after conventional transarterial chemoembolization

Conventional transarterial chemoembolization (cTACE) utilizing ethiodized oil as a chemotherapy carrier has become a standard treatment for intermediate-stage hepatocellular carcinoma (HCC) and has been adopted as a bridging and downstaging therapy for liver transplantation. Water-in-oil emulsion made up of ethiodized oil and chemotherapy solution is retained in tumor vasculature resulting in high tissue drug concentration and low systemic chemotherapy doses. The density and distribution pattern of ethiodized oil within the tumor on post-treatment imaging are predictive of the extent of tumor necrosis and duration of response to treatment. This review describes the multiple roles of ethiodized oil, particularly in its role as a biomarker of tumor response to cTACE. CLINICAL RELEVANCE: With the increasing complexity of locoregional therapy options, including the use of combination therapies, treatment response assessment has become challenging; Ethiodized oil deposition patterns can serve as an imaging biomarker for the prediction of treatment response, and perhaps predict post-treatment prognosis. KEY POINTS: • Treatment response assessment after locoregional therapy to hepatocellular carcinoma is fraught with multiple challenges given the varied post-treatment imaging appearance. • Ethiodized oil is unique in that its' radiopacity can serve as an imaging biomarker to help predict treatment response. • The pattern of deposition of ethiodozed oil has served as a mechanism to detect portions of tumor that are undertreated and can serve as an adjunct to enhancement in order to improve management in patients treated with intraarterial embolization with ethiodized oil.

Lipiodol as a Predictive Indicator for Therapy Response to Transarterial Chemoembolization of Hepatocellular Carcinoma

Background: The predictive value of Lipiodol was evaluated for response evaluation of hepatocellular carcinoma (HCC) treated with conventional transarterial chemoembolization (cTACE) by analysis of the enhancement pattern during angiography and in postinterventional computed tomography (CT). Materials and Methods: This retrospective study included 30 patients (mean age 63 years, range: 36 to 82 years, 22 males) with HCC. Patients received three Lipiodol-based cTACE sessions, each followed by an unenhanced CT within 24-h. Contrast-enhanced magnetic resonance imaging (MRI) was acquired before and after the treatment to determine tumor response. Lipiodol enhancement pattern, tumor vascularization, and density were evaluated by angiography and CT. Initial tumor size and response to cTACE were analyzed by MRI according to modified response evaluation criteria in solid tumors (mRECIST) in a 4-week follow-up. Results: Analysis of HCC lesions (68 lesions in 30 patients) during cTACE revealed clear visibility and hypervascularization in angiography as a potential independent parameter able to predict tumor response. A significant correlation was found for response measurements by volume (p = 0.012), diameter (p = 0.006), and according to mRECIST (p = 0.039). The amount of Lipiodol and enhancement pattern in postinterventional CT did not correlate with therapy response. Measurements of Hounsfield unit values after cTACE do not allow sufficient prediction of the tumor response. Conclusion: Hypervascularized HCC lesions with clear visibility after Lipiodol administration in the angiography respond significantly better to cTACE compared to hypo- or nonvascularized lesions.

A Phase 2, Prospective, Multicenter, Single-Arm Trial of Transarterial Chemoembolization Therapy in Combination Strategy with Lenvatinib in Patients with Unresectable Intermediate-Stage Hepatocellular Carcinoma: TACTICS-L Trial

INTRODUCTION

Transarterial chemoembolization (TACE) is the standard treatment for unresectable intermediate-stage hepatocellular carcinoma (HCC), but recurrence after TACE is common. The present phase 2, prospective, multicenter, single-arm trial, the TACTICS-L trial, investigated the efficacy and safety of TACE plus lenvatinib (LEN), a drug that more strongly promotes vascular normalization and has a better objective response rate (ORR) than sorafenib (jRCTs031180074).

METHODS

Participants were patients with HCC who had not previously received systemic therapy, hepatic arterial infusion chemotherapy, or immunotherapy and who were ineligible for resection or percutaneous ablation therapy. LEN was to be administered 14-21 days before the first TACE, stopped 2 days before TACE, and resumed 3 days after TACE. Key inclusion criteria were unresectable HCC, Child-Pugh A liver function, 0-2 prior TACE sessions, tumor size ≤10 cm, number of tumors ≤10, and ECOG performance status 0-1. Key exclusion criteria were vascular invasion and extrahepatic spread. The primary endpoint was progression-free survival (PFS) by RECICL, and secondary endpoints were time to untreatable progression, ORR, overall survival (OS), and safety.

RESULTS

A total of 62 HCC patients were enrolled in this trial. The median age was 72 years, 77.4% of patients were men, and 95.2% had PS 0. The primary endpoint of median PFS was 28.0 months (90% confidence interval [CI] 25.1-31.0) after a minimum 24 months of follow-up. The secondary endpoint of median OS was not reached (90% CI 35.5 months-NR). LEN-TACE achieved a high response rate and high complete response (CR) rate (4 weeks after the first TACE: ORR 79.0%, CR rate 53.2%; best response: ORR 88.7%, CR rate 67.7%) by RECICL. Exploratory subgroup analyses showed that the characteristics of responders/nonresponders (ORR and CR rate) were similar and that LEN-TACE would be effective in all subgroups, including the population in whom TACE alone would be less likely to be curative (e.g., patients with the non-simple nodular type or a high tumor burden). The relative dose intensity of LEN before the first TACE was important for achieving higher CR rate/ORR by LEN-TACE. No new safety concerns were observed.

CONCLUSION

The results of this trial provide encouraging evidence, supporting the efficacy and favorable safety profile of LEN-TACE in patients who are ineligible for locoregional therapy.

Tumor Response on Diagnostic Imaging after Proton Beam Therapy for Hepatocellular Carcinoma

BACKGROUND

Follow-up after treatment for hepatocellular carcinoma (HCC) can be mostly performed using dynamic CT or MRI, but there is no common evaluation method after radiation therapy. The purpose of this study is to examine factors involved in tumor reduction and local recurrence in patients with HCC treated with proton beam therapy (PBT) and to evaluate HCC shrinkage after PBT.

METHODS

Cases with only one irradiated lesion or those with two lesions irradiated simultaneously were included in this study. Pre- and post-treatment lesions were evaluated using Response Evaluation Criteria in Solid Tumors (RECIST) by measuring the largest diameter.

RESULTS

The 6-, 12-, and 24-month CR + PR rates after PBT were 33.1%, 57.5%, and 76.9%, respectively, and the reduction rates were 25.1% in the first 6 months, 23.3% at 6-12 months, and 14.5% at 13-24 months. Cases that reached CR/PR at 6 and 12 months had improved OS compared to non-CR/non-PR cases.

CONCLUSIONS

It is possible that a lesion that reached SD may subsequently transition to PR; it is reasonable to monitor progress with periodic imaging evaluations even after 1 year of treatment.

Comparison of contrast-enhanced ultrasonography and MRI results obtained by expert and novice radiologists indicating short-term response after transarterial chemoembolisation for hepatocellular carcinoma

AIM

To evaluate inter-reader agreement between novice and expert radiologists in assessing contrast-enhanced ultrasonography (CEUS) and magnetic resonance imaging (MRI) images for detecting viable tumours with different sizes after conventional transarterial chemoembolisation (cTACE).

MATERIALS AND METHODS

This prospective study included patients who had less than five hepatomas and who underwent cTACE. Hepatomas with one or two feeding arteries were selected as target lesions. CEUS and MRI were performed within 1 week after cTACE to evaluate viable tumours.

RESULTS

The expert group had higher kappa values in evaluating all tumour sizes via CEUS compared with MRI. The novice group had similar kappa values. In patients with tumours measuring ≤3 cm, the expert group had higher kappa values in reading CEUS compared with MRI images; however, in the novice group, the kappa value was lower in evaluating CEUS compared with MRI images. In patients with tumours measuring >3 cm, the expert and novice groups had good to excellent kappa values. The confidence level of the two groups in reading MRI images was high; however, the novice group had a lower confidence level.

CONCLUSION

CEUS is a convenient, cost-effective, and easy to apply imaging tool that can help interventionists perform early detection of viable hepatocellular carcinoma post-TACE. It has a higher inter-rater agreement in interpreting CEUS images compared with MRI images among expert radiologists even when they are extremely familiar with post-cTACE MRI images. In novice radiologists, there may be a learning curve to achieve good consistency in CEUS interpretation.

Preoperative Balloon-Occluded Transcatheter Arterial Chemoembolization Followed by Surgical Resection: Pathological Evaluation of Necrosis

This study investigates the clinical and pathological outcomes of preoperative balloon-occluded transcatheter arterial chemoembolization (B-TACE) in patients with single hepatocellular carcinoma (HCC). The data are from 25 consecutive patients who underwent sequential treatment of subsegmental B-TACE and hepatic surgery for single HCC. Radiological and pathological evaluation of oily subsegmentectomy, defined as the iodized oil-laden necrotic area that includes the entire HCC and surrounding liver parenchyma, were performed. Subsegmental B-TACE was technically successful in all patients. The major and minor complication rates were 8% and 24%, respectively. On the first follow-up computed tomography (CT), oily subsegmentectomy was observed in 18 (72%) out of 25 patients. Apart from one patient showing a partial response, the remaining 24 (96%) patients showed a complete response. Pathological complete necrosis of the HCC was observed in 18 (72%) out of 25 patients with complete or extensive necrosis of the peritumoral liver parenchyma. The remaining seven patients without peritumoral parenchymal necrosis had extensive necrosis of the HCCs. In conclusion, preoperative B-TACE can be a safe and effective method for the treatment of single HCC and a good bridge treatment for subsequent surgical resection. In addition, oily subsegmentectomy itself on the CT can be a good predictor of pathological complete necrosis of the HCC. The findings obtained from this study would provide a potential role of B-TACE in the treatment strategy for single HCC.

Local Recurrence following Radiological Complete Response in Patients Treated with Subsegmental Balloon-Occluded Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma

The aim of this study was to determine the local recurrence (LR) rate and identify factors associated with LR in patients who achieve a radiological complete response (CR) after undergoing balloon-occluded transcatheter arterial chemoembolization (B-TACE) for hepatocellular carcinoma (HCC). From November 2017 to September 2021, 60 patients (44 men, 16 women; mean age, 63.5 years; range, 39-82 years) with 72 HCCs (mean diameter, 31 mm; range, 10-50 mm) who underwent subsegmental B-TACE were included in this retrospective study. Radiological and clinical evaluation of oily subsegmentectomy, defined as radiological CR of the HCC and peritumoral parenchymal necrosis, was performed. The CR rate was 97.2% (70 of 72 HCCs) at first follow-up (mean, 41 days; range, 14-110 days). Overall, 13 HCCs (19.7%) demonstrated LR at a mean of 29.8 months (range, 3-63 months) and cumulative LR rates were 1.5% 14.2% 21%, 21%, and 21% at 6, 12, 24, 36, and 48 months, respectively. In 28 (38.9%) of 72 HCCs, oily subsegmentectomy was achieved, tumor markers were normalized, and LR did not occur. The oily subsegmentectomy-positive group had a significantly lower LR rate than the oily subsegmentectomy-negative group (p = 0.001). Age ≥65 years (adjusted hazard ration (HR), 0.124; 95% confidence interval (CI), 0.037-0.412; p < 0.001) and peripheral location (adjusted HR, 0.112; 95% CI, 0.046-0.272; p < 0.001) were independent predictive factors of LR. Subsegmental B-TACE can be an effective method with a high initial CR rate and low LR incidence. Oily subsegmentectomy can be considered as an index of successful treatment because it did not demonstrate any LR.

Appropriate use of morphological imaging for assessing treatment response and disease progression of neuroendocrine tumors

Neuroendocrine tumors (NETs) are relatively rare neoplasms displaying heterogeneous clinical behavior, ranging from indolent to aggressive forms. Patients diagnosed with NETs usually receive a varied array of treatments, including somatostatin analogs, locoregional treatments (ablation, intra-arterial therapy), cytotoxic chemotherapy, peptide receptor radionuclide therapy (PRRT), and targeted therapies. To maximize therapeutic efficacy while limiting toxicity (both physical and economic), there is a need for accurate and reliable tools to monitor disease evolution and progression and to assess the effectiveness of these treatments. Imaging morphological methods, primarily relying on computed tomography (CT) and magnetic resonance imaging (MRI), are indispensable modalities for the initial evaluation and continuous monitoring of patients with NETs, therefore playing a pivotal role in gauging the response to treatment. The primary goal of assessing tumor response is to anticipate and weigh the benefits of treatments, especially in terms of survival gain. The World Health Organization took the pioneering step of introducing assessment criteria based on cross-sectional imaging. This initial proposal standardized the measurement of lesion sizes, laying the groundwork for subsequent criteria. The Response Evaluation Criteria in Solid Tumors (RECIST) subsequently refined and enhanced these standards, swiftly gaining acceptance within the oncology community. New treatments were progressively introduced, targeting specific features of NETs (such as tumor vascularization or expression of specific receptors), and achieving significant qualitative changes within tumors, although associated with minimal or paradoxical effects on tumor size. Several alternative criteria, adapted from those used in other cancer types and focusing on tumor viability, the slow growth of NETs, or refining the existing size-based RECIST criteria, have been proposed in NETs. This review article aims to describe and discuss the optimal utilization of CT and MRI for assessing the response of NETs to treatment; it provides a comprehensive overview of established and emerging criteria for evaluating tumor response, along with comparative analyses. Molecular imaging will not be addressed here and is covered in a dedicated article within this special issue.

Multidisciplinary Taiwan consensus for the use of conventional TACE in hepatocellular carcinoma treatment

Developed in early 1980s, transarterial chemoembolization (TACE) with Lipiodol was adopted globally after large-scale randomized control trials and meta-analyses proving its effectiveness were completed. Also known as "conventional TACE" (cTACE), TACE is currently the first-line treatment for patients with unresectable intermediate stage hepatocellular carcinoma (HCC) and delivers both ischemic and cytotoxic effects to targeted tumors. Although new technology and clinical studies have contributed to a more comprehensive understanding of when and how to apply this widely-adopted therapeutic modality, some of these new findings and techniques have yet to be incorporated into a guideline appropriate for Taiwan. In addition, differences in the underlying liver pathologies and treatment practices for transcatheter embolization between Taiwan and other Asian or Western populations have not been adequately addressed, with significant variations in the cTACE protocols adopted in different parts of the world. These mainly revolve around the amount and type of chemotherapeutic agents used, the type of embolic materials, reliance on Lipiodol, and the degree of selectiveness in catheter positioning. Subsequently, interpreting and comparing results obtained from different centers in a systematic fashion remain difficult, even for experienced practitioners. To address these concerns, we convened a panel of experts specializing in different aspects of HCC treatment to devise modernized recommendations that reflect recent clinical experiences, as well as cTACE protocols which are tailored for use in Taiwan. The conclusions of this expert panel are described herein.

Balloon-occluded transarterial chemoembolization versus conventional transarterial chemoembolization for the treatment of single hepatocellular carcinoma: a propensity score matching analysis

OBJECTIVES

To compare the safety and efficacy of balloon-occluded transarterial chemoembolization (B-TACE) and conventional TACE (C-TACE) in treating single hepatocellular carcinoma (HCC).

METHODS

This single-center retrospective study included 523 patients who underwent C-TACE and 44 who underwent B-TACE as first-line treatment for single HCCs between November 2017 and December 2019. After propensity score matching (PSM), initial tumor response rates, local tumor progression (LTP), and major complication rates were evaluated in the 32 pairs of PSM matched population.

RESULTS

In the 32 pairs of PSM cohort, B-TACE showed distinct superiority over C-TACE in treating single HCCs, with significantly higher initial complete response (CR) rates (93.8% vs. 62.5%, p = 0.005). During a median follow-up of 37 months (range, 12.7-46.5 months), 13 patients (40.6%) who underwent B-TACE and 16 (50%) who underwent C-TACE showed LTP of treated lesions. Size-based sub-group analysis showed that the median times to LTP in patients with medium- to large-sized tumors (> 3 cm) were significantly longer in the B-TACE (27 months; 95% confidence interval [CI], 19.7-34.3 months) than in the C-TACE (13 months; 95% CI, 3.9-22.1 months) group (p = 0.019). The major complication rate was similar between the two groups.

CONCLUSIONS

B-TACE had a higher initial CR rate than C-TACE in treating single HCCs. Moreover, size-based subgroup analysis showed that time to LTP was significantly longer in patients with medium- to large-sized HCCs (> 3 cm) who underwent B-TACE rather than C-TACE.

KEY POINTS

• B-TACE was superior to C-TACE in treating single HCC, with a significantly higher initial complete response rate after one session of treatment. • In size-based subgroup analysis, time to LTP was significantly longer in patients with medium- to large-sized HCCs (>3 cm) who underwent B-TACE rather than C-TACE. • B-TACE should be considered an alternative treatment option for medium- to large-sized single HCCs (>3 cm) in patients with a nonresectable condition and those who prefer nonsurgical treatment.

Transcriptome analysis creates a new era of precision medicine for managing recurrent hepatocellular carcinoma

The high incidence of hepatocellular carcinoma (HCC) recurrence negatively impacts outcomes of patients treated with curative intent despite advances in surgical techniques and other locoregional liver-targeting therapies. Over the past few decades, the emergence of transcriptome analysis tools, including real-time quantitative reverse transcription PCR, microarrays, and RNA sequencing, has not only largely contributed to our knowledge about the pathogenesis of recurrent HCC but also led to the development of outcome prediction models based on differentially expressed gene signatures. In recent years, the single-cell RNA sequencing technique has revolutionized our ability to study the complicated crosstalk between cancer cells and the immune environment, which may benefit further investigations on the role of different immune cells in HCC recurrence and the identification of potential therapeutic targets. In the present article, we summarized the major findings yielded with these transcriptome methods within the framework of a causal model consisting of three domains: primary cancer cells; carcinogenic stimuli; and tumor microenvironment. We provided a comprehensive review of the insights that transcriptome analyses have provided into diagnostics, surveillance, and treatment of HCC recurrence.

The radiological prognostic factors of transcatheter arterial chemoembolization to hepatocellular carcinoma

Transcatheter arterial chemoembolization (TACE) is the recommended treatment modality for intermediate stage hepatocellular carcinoma (HCC). The aim of this study was to determine the HCC radiological characteristics associated with prognosis of patients with intermediate stage HCC receiving TACE. Patients with HCC BCLC stage B from January 2005 to December 2009 were collected. According to mRECIST criteria, patients with complete response and partial response were assigned to the objective response (OR) group, while those with stable disease and progressive disease were assigned to the nonobjective response (non-OR) group. Among a total of 128 enrolled patients, there were 66 (51.6%) and 62 (48.4%) patients in the OR group and non-OR group, respectively. The clinical parameters in the two groups were similar, although HCC size was smaller in the OR group. Logistic analysis found combined radiological characteristics including complete lipiodol retention, tumor feeding artery blockage, and no residual tumor blush were significant correlated with achievement of OR (odds ratio 2.46, 95% CI 1.08-5.61, P = .032). However, no radiological characteristics had significant strength to predict overall survival. Patients with OR after TACE had significantly longer survival time than those with non-OR. Combined characteristics of complete lipiodol retention, tumor feeding artery blockage, and no residual tumor blush had a positive impact on OR in TACE. In patients receiving TACE, those who achieved OR had a better overall survival.

Initiative on Superselective Conventional Transarterial Chemoembolization Results (INSPIRE)

Several publications show that superselective conventional TransArterial ChemoEmbolization (cTACE), meaning cTACE performed selectively with a microcatheter positioned as close as possible to the tumor, improves outcomes, maximizing the anti-tumoral effect and minimizing the collateral damages of the surrounding liver parenchyma. Recent recommendations coming from the European Association for the Study of the Liver (EASL) and European Society of Medical Oncology (ESMO) highlighted that TACE must be used in Hepatocellular Carcinoma (HCC) “selectively targetable” and “accessible to supraselective catheterization.” The goal of the manuscript is to better define such population and to standardize superselective cTACE (ss-cTACE) technique. An expert panel with extensive clinical-procedural experience in TACE, have come together in a virtual meeting to generate recommendations and express their consensus. Experts recommend that anytime cTACE is proposed, it should be ss-cTACE, preferably with a 1.5–2.0 Fr microcatheter. Ideally, ss-cTACE should be proposed to patients with less than five lesions and a maximum number of two segments involved, with largest tumor smaller than 5 cm. Angio Cone-Beam Computed Tomography (CBCT) should be used to detect enhancing tumors, tumor feeders and guide tumor targeting. Whole tumor volume should be covered to obtain the best response. Adding peritumoral margins is encouraged but not mandatory. The treatment should involve a water-in-oil emulsion, whose quality is assessable with the “drop test.” Additional particulate embolization should be systematically performed, as per definition of cTACE procedure. Non-contrast CBCT or Multi-Detector Computed Tomography (MDCT) combined with angiography has been considered the gold standard for imaging during TACE, and should be used to assess tumor coverage during the procedure. Experts convene that superselectivity decreases incidence of adverse effects and improves tolerance. Experts recommend contrast-enhanced Computed Tomography (CT) as initial imaging on first follow-up after ss-cTACE, and Magnetic Resonance Imaging (MRI) if remaining tumor viability cannot be confidently assessed on CT. If no response is obtained after two ss-cTACE sessions within six months, patient must be considered unsuitable for TACE and proposed for alternative therapy. Patients are best served by multidisciplinary decision-making, and Interventional Radiologists should take an active role in patient selection, treatment allocation, and post-procedural care.

Role of gadoxetic acid-enhanced liver magnetic resonance imaging in the evaluation of hepatocellular carcinoma after locoregional treatment

Locoregional treatments, as alternatives to surgery, play a key role in the management of hepatocellular carcinoma (HCC). Liver magnetic resonance imaging (MRI) enables a multiparametric assessment, going beyond the traditional dynamic computed tomography approach. Moreover, the use of hepatobiliary agents can improve diagnostic accuracy and are becoming important in the diagnosis and follow-up of HCC. However, the main challenge is to quickly identify classical responses to loco-regional treatments in order to determine the most suitable management strategy for each patient. The aim of this review is to provide a summary of the most common and uncommon liver MRI findings in patients who underwent loco-regional treatments for HCC, with a special focus on ablative therapies (radiofrequency, microwaves and cryoablation), trans-arterial chemoembolization, trans-arterial radio-embolization and stereotactic ablative radiotherapy techniques, considering the usefulness of gadoxetate disodium (Gd-EOB-DTPA) contrast agent.

Can Posttransarterial Chemoembolization Volumetric Oil Deposition on Computed Tomography Predict Treatment Response on Magnetic Resonance Imaging in Leiomyosarcoma Metastases to the Liver?

OBJECTIVE

To predict early tumor response to transarterial chemoembolization (TACE) based on volumetric oil deposition on posttreatment computed tomography (CT) in patients with leiomyosarcoma liver metastases.

METHODS

This retrospective lesion-by-lesion based study included 32 lesions. The volumetric percent enhancing tumor on pre-TACE and 1-month post-TACE venous phase magnetic resonance imaging (MRI), and the percent oil deposition on CT 1 day after TACE were calculated. The predicted post-TACE enhanced percentage was computed by subtracting percent oil deposition from baseline percent enhanced.

RESULTS

Mean percentage of viable tumor on pre-TACE MRI was 90.6% ± 9.3%. Mean oil deposition was calculated as 51.4% ± 26.2%. Mean percentage of measured residual tumor enhancement 1 month after TACE was 58.3% ± 27%, which correlates with predicted enhancement percentage of 43.9% ± 25.1% (r = 0.72, P < 0.001). A threshold of 35.5% for enhancement reduction was determined to predict tumor response with an accuracy of 78.1%.

CONCLUSION

Volumetric oil deposition on CT can predict residual enhancement on post-TACE MRI.

Response Evaluation Criteria in Cancer of the liver version 6 (Response Evaluation Criteria in Cancer of the Liver 2021 revised version)

Response Evaluation Criteria in Solid Tumors (RECIST) is inappropriate to assess the direct effects of treatment on hepatocellular carcinoma (HCC) by locoregional therapies, such as radiofrequency ablation or transarterial chemoembolization. Therefore, establishment of response evaluation criteria solely devoted to HCC is needed in clinical practice, as well as in clinical trials of HCC treatment, such as systemic therapies, which cause necrosis of the tumor. Response Evaluation Criteria in Cancer of the Liver (RECICL) was revised in 2021 by the Liver Cancer Study Group of Japan based on the 2019 version of RECICL, which was commonly used in Japan. The major revised points of the RECICL 2021 is inclusion of RECIST version 1.1 and modified RECIST as response evaluation criteria in systemic therapy for HCC. We hope this new treatment response criteria, RECICL, proposed by the Liver Cancer Study Group of Japan will benefit the HCC treatment response evaluation in the setting of daily clinical practice and clinical trials as well, not only in Japan, but also internationally.

Quantitative Automated Segmentation of Lipiodol Deposits on Cone Beam CT Imaging acquired during Transarterial Chemoembolization for Liver Tumors: A Deep Learning Approach

PURPOSE

The purpose of this study was to show that a deep learning-based, automated model for Lipiodol segmentation on CBCT after cTACE performs closer to the "ground truth segmentation" than a conventional thresholding-based model.

MATERIALS & METHODS

This post-hoc analysis included 36 patients with a diagnosis of HCC or other solid liver tumor who underwent cTACE with an intra-procedural CBCT. Semi-automatic segmentation of Lipiodol were obtained. Then, a convolutional U-net model was used to output a binary mask that predicts Lipiodol deposition. A threshold value of signal intensity on CBCT was used to obtain a Lipiodol mask for comparison. Dice similarity coefficient (DSC), Mean-squared error (MSE), and Center of Mass (CM), and fractional volume ratios for both masks were obtained by comparing them to the ground truth (radiologist segmented Lipiodol deposits) to obtain accuracy metrics for the two masks. These results were used to compare the model vs. the threshold technique.

RESULTS

For all metrics, the U-net outperformed the threshold technique: DSC (0.65±0.17 vs. 0.45±0.22,p<0.001) and MSE (125.53±107.36 vs. 185.98±93.82,p=0.005). Difference between the CM predicted, and the actual CM was (15.31±14.63mm vs. 31.34±30.24mm,p<0.001), with lesser distance indicating higher accuracy. The fraction of volume present ([predicted Lipiodol volume]/[ground truth Lipiodol volume]) was 1.22±0.84vs.2.58±3.52,p=0.048 for our model's prediction and threshold technique, respectively.

CONCLUSION

This study showed that a deep learning framework could detect Lipiodol in CBCT imaging and was capable of outperforming the conventionally used thresholding technique over several metrics. Further optimization will allow for more accurate, quantitative predictions of Lipiodol depositions intra-procedurally.

Limitations and Possibilities of Transarterial Chemotherapeutic Treatment of Hepatocellular Carcinoma

Because diagnostic tools for discriminating between hepatocellular carcinoma (HCC) and advanced cirrhosis are poor, HCC is often detected in a stage where transarterial chemoembolization (TACE) is the best treatment option, even though it provides a poor survival gain. Despite having been used worldwide for several decades, TACE still has many limitations. First, there is a vast heterogeneity in the cellular composition and metabolism of HCCs as well as in the patient population, which renders it difficult to identify patients who would benefit from TACE. Often the delivered drug does not penetrate sufficiently selectively and deeply into the tumour and the drug delivery system is not releasing the drug at an optimal clinical rate. In addition, therapeutic effectiveness is limited by the crosstalk between the tumour cells and components of the cirrhotic tumour microenvironment. To improve this widely used treatment of one of our most common and deadly cancers, we need to better understand the complex interactions between drug delivery, local pharmacology, tumour targeting mechanisms, liver pathophysiology, patient and tumour heterogeneity, and resistance mechanisms. This review provides a novel and important overview of clinical data and discusses the role of the tumour microenvironment and lymphatic system in the cirrhotic liver, its potential response to TACE, and current and possible novel DDSs for locoregional treatment.

Predicting early necrosis of colorectal liver metastases using volumetric enhancement on baseline MRI and oil deposition on post-cTACE unenhanced CT

PURPOSE

To predict tumor necrosis after conventional TACE (cTACE) in patients with colorectal liver metastasis (CRLM) based on volumetric oil deposition on CT one day after treatment.

METHODS

Thirty-four lesions in 20 men and 6 women were included in this IRB-approved HIPAA-compliant, retrospective lesion-by-lesion-based study. Semiautomatic volumetric segmentation of target lesions was performed on baseline MRI and post-treatment CT. Predicted percentage of tumor necrosis was defined as 100%-(%baseline MRI enhancement-%CT oil deposition). Necrosis on post-TACE MRI was measured after volumetric segmentation to assess the accuracy of predicting tumor necrosis. The relationship between predicted necrosis percent and post-cTACE measured necrosis percent on MRI was compared using Pearson correlation analysis. Inter-reader agreement was calculated by intraclass correlation coefficient (ICC) after using the same method.

RESULTS

Patients in this cohort had a mean age of 64 ± 14 years. Mean percentage of the viable tumor on pre-cTACE venous phase MRI was 58.5% ± 23.9%. Mean oil deposition was 19.8% ± 14.6%. Mean percentage of calculated necrosis one month after cTACE was 59.2% ± 22.7% on venous phase MRI, which had a significant correlation with predicted necrotic percentage of 61.3% ± 19.3% (r = 0.89, p < 0.0001). ICC for enhancement percentage on pre-cTACE and post-cTACE venous phase MRIs were 0.93 (95% CI 0.83, 0.97) and 0.86 (95% CI 0.66, 0.94), respectively. ICC for oil deposition was 0.92 (95% CI 0.81, 0.96).

CONCLUSION

Measuring oil deposition of the whole tumor on CT one day after cTACE can assist to predict post-cTACE tumor necrosis.

Applying arterial enhancement fraction (AEF) texture features to predict the tumor response in hepatocellular carcinoma (HCC) treated with Transarterial chemoembolization (TACE)

Background

To evaluate the application of Arterial Enhancement Fraction (AEF) texture features in predicting the tumor response in Hepatocellular Carcinoma (HCC) treated with Transarterial Chemoembolization (TACE) by means of texture analysis.

Methods

HCC patients treated with TACE in Shengjing Hospital of China Medical University from June 2018 to December 2019 were retrospectively enrolled in this study. Pre-TACE Contrast Enhanced Computed Tomography (CECT) and imaging follow-up within 6 months were both acquired. The tumor responses were categorized according to the modified RECIST (mRECIST) criteria. Based on the CECT images, Region of Interest (ROI) of HCC lesion was drawn, the AEF calculation and texture analysis upon AEF values in the ROI were performed using CT-Kinetics (C.K., GE Healthcare, China). A total of 32 AEF texture features were extracted and compared between different tumor response groups. Multi-variate logistic regression was performed using certain AEF features to build the differential models to predict the tumor response. The Receiver Operator Characteristic (ROC) analysis was implemented to assess the discriminative performance of these models.

Results

Forty-five patients were finally enrolled in the study. Eight AEF texture features showed significant distinction between Improved and Un-improved patients (p < 0.05). In multi-variate logistic regression, 9 AEF texture features were applied into modeling to predict “Improved” outcome, and 4 AEF texture features were applied into modeling to predict “Un-worsened” outcome. The Area Under Curve (AUC), diagnostic accuracy, sensitivity, and specificity of the two models were 0.941, 0.911, 1.000, 0.826, and 0.824, 0.711, 0.581, 1.000, respectively.

Conclusions

Certain AEF heterogeneous features of HCC could possibly be utilized to predict the tumor response to TACE treatment.

Correlation of tumor response on CT with pathologically proven necrosis in hepatocellular carcinoma treated by conventional transcatheter arterial chemoembolization: threshold value of intratumoral Lipiodol accumulation predicting tumor necrosis

PURPOSE

To evaluate associations between pathology and CT assessments made according to the mRECIST in HCC treated by conventional TACE (cTACE), and to identify predictors of complete tumor necrosis.

METHODS

From March 2016 to July 2018, 83 patients with a total of 100 masses were retrospectively included. Patients underwent sequential cTACE and portal vein embolization, and later hepatic surgery. Evaluation of treatment response and measurement of baseline lipiodol accumulation as mean HU was performed on CT at the time point closest to the time of operation (mean, 54.5 days after cTACE). Significant predictors associated with complete necrosis were identified by multivariate analysis. The optimal cut-off HU value of lipiodol accumulation for prediction of complete necrosis was determined using a ROC analysis.

RESULTS

According to mRECIST, complete response (CR, n = 70) and partial response (n = 30) were classified. 34.3% (24/70) masses classified as CR according to mRECIST were found to have viable lesions on pathology. On multivariate analysis, mean HU of lipiodol accumulation was the only significant predictor of complete necrosis (p = .003, odds ratio 1.746, 95% CI 1.201-2.539). On ROC analysis, 460 HU as a cut-off value was significantly associated with complete necrosis (67.4% sensitivity, 75.0% specificity).

CONCLUSIONS

A threshold value for lipiodol accumulation > 460 HU was highly sensitive and specific for complete necrosis, even in complete response according to mRECIST. Therefore, if lipiodol accumulation is insufficient in post-TACE CT, recurrence should be monitored more sensitively.

The correlation with tumor radiological characteristics and prognosis of patients with early-stage hepatocellular carcinoma receiving transcatheter arterial chemoembolization

Transcatheter arterial chemoembolization (TACE) is a standard treatment modality for intermediate stage hepatocellular carcinoma (HCC). The aim of this study was to determine the tumor radiological characteristics associated with prognosis of patients with early-staged HCC receiving TACE.Patients with BCLC stage A HCC were enrolled at Taichung Veterans General Hospital from January 2005 to December 2009. According to mRECIST criteria, patients with or without complete response (CR) were assigned to either the CR group or the non-CR group. Clinical and radiological characteristics were compared between the two groups.In 40 enrolled patients, 24 (60%) were in the CR group, and 16 (40%) in the non-CR group. Clinical parameters were similar between the 2 groups. Radiological characteristics including complete lipidol retention and the absence of residual tumor blush were significantly correlated with achievement of CR in the patients with small-sized HCC. Patients with CR after TACE had a significantly longer overall survival than those without (31.29 vs 22.63 months, P = .021).Complete lipidol retention and the absence of residual tumor blush were correlated with the radiological complete tumor response of these patients with small-sized early-stage HCC receiving TACE.

Current Strategies to Identify Patients That Will Benefit from TACE Treatment and Future Directions a Practical Step-by-Step Guide

Treatment of hepatocellular carcinoma (HCC) depends on the stage of disease. In the Western Hemisphere, the Barcelona Clinic Liver Cancer classification (BCLC) is the preferred staging system. Approximately one-third of patients initially present with intermediate-stage disease. For these patients, transarterial chemoembolization (TACE) is the treatment of choice. However, the intermediate-stage comprises a heterogeneous subgroup of patients with considerable differences in tumor burden and liver function. In addition, differences in individual factors that are not captured by the BCLC framework, such as the tumor growth pattern, degree of hypervascularity, and vascular supply, complicate further evaluation of these patients. Due to these differences, not all patients benefit equally from TACE. Several tools and scoring systems have been devised to provide decision-making support. All of these have shown promising initial results but failed external evaluation and have not been translated to the clinic. Nevertheless, criteria for objectifying treatment decisions in daily clinical practice are needed in all stages of disease. Therefore, this review provides a concise practical step-by-step guide on current strategies for patient selection and decision-making, with a focus on TACE, to critically evaluate the existing decision-support tools and provide a summary of the latest updates in the field.

Duration of response after DEB-TACE compared to lipiodol-TACE in HCC-naïve patients: a propensity score matching analysis

Objectives

To retrospectively compare long-term outcomes of first-line drug-eluting particle (DEB)- transarterial chemoembolization (TACE) and lipiodol-TACE, in patients with unresectable hepatocellular (HCC).

Methods

We retrospectively reviewed our database to identify adult patients with treatment-naïve unresectable HCC, who underwent TACE from 2006 to 2013. Patients were excluded in the absence of complete medical records relative to first TACE, 1-month follow-up, and/or sufficient follow-up data. Periprocedural complications, duration of hospitalization, 1-month tumor response by mRECIST, time to tumor progression (TTP) and target tumor progression (TTTP), and overall survival (OS) were evaluated.

Results

Out of an initial series of 656 patients, 329 patients were excluded for unavailability of sufficient baseline and/or follow-up data. The remaining 327 patients underwent either lipiodol-TACE (n = 160) or DEB-TACE (n = 167). Patients treated with lipiodol-TACE had a significantly higher tumor burden. By propensity score, patients were matched according to baseline differences (BCLC stage, uninodular or multinodular HCC, and unilobar or bilobar HCC), resulting in 101 patients in each treatment group. Lipiodol-TACE was associated with a significantly higher incidence of adverse events (p = 0.03), and longer hospitalization (mean, 2.5 days vs 1.9 days; p = 0.03), while tumor response, TTP, and OS were comparable. In patients achieving 1-month complete response (CR) of target tumor, TTTP was significantly (p = 0.009) longer after DEB-TACE compared to lipiodol-TACE (median, 835 vs 353 days), resulting in a lower number of re-treatments during the entire follow-up (0.75 vs 1.6, p = 0.01).

Conclusion

Compared to lipiodol-TACE, DEB-TACE offers higher tolerability, reduced hospitalization, and more durable target tumor response after CR.

Key Points

• Compared to lipiodol-TACE, DEB-TACE is better tolerated and has reduced side effects, which translates into shorter hospitalization.

• When complete radiological response according to the mRECIST is obtained 1 month after the procedure, DEB-TACE offers a more durable local tumor control compared to lipiodol-TACE.

• In these patients, the longer duration of response after DEB-TACE translates into a lower number of re-interventions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-07905-x.

Early prediction of 1-year tumor response of hepatocellular carcinoma with lipiodol deposition pattern through post-embolization cone-beam computed tomography during conventional transarterial chemoembolization

OBJECTIVE

To evaluate whether parenchyma-to-lipiodol ratio (PLR) and lesion-to-lipiodol ratio (LLR) on C-arm cone-beam computed tomography (CBCT) can predict 1-year tumor response in patients with hepatocellular carcinoma (HCC) treated with conventional transcatheter arterial chemoembolization (cTACE).

METHODS

This retrospective analysis included 221 HCC target lesions within up-to-seven criteria in 80 patients who underwent cTACE with arterial-phase CBCT and unenhanced CBCT after cTACE from 2015 to 2018. PLR and LLR of every tumor slice were obtained through mean density division of liver parenchyma and tumor enhancement with intratumoral lipiodol deposition. The cutoff values (COVs) of maximal PLR and LLR of every tumor were analyzed using Youden's index. The reliability of COV, correlations between the related parameters, and 1-year progression were assessed through interobserver agreement and multivariate analysis. COV validity was verified using the chi-square test and Cramer's V coefficient (V) in the validation cohort.

RESULTS

Standard COVs of PLR and LLR were 0.149 and 1.4872, respectively. Interobserver agreement of COV for PLR and LLR was near perfect (kappa > 0.9). Multivariate analysis suggested that COV of PLR is an independent predictor (odds ratio = 1.23532×10¹⁴, p = 4.37×10^-7). COV of PLR showed strong consistency, correlation with 1-year progression in prediction model (V = 0.829-0.776; p < 0.0001), and presented as an effective predictor in the validation cohort (V = 0.766; p < 0.0001).

CONCLUSION

The COV of PLR (0.149) assessed through immediate post-embolization CBCT is an objective, effective, and approachable predictor of 1-year HCC progression after cTACE.

KEY POINTS

• The maximal PLR value indicates the least lipiodol-distributed region in an HCC tumor. The maximal LLR value indicates the least lipiodol-deposited region in the tumor due to incomplete lipiodol delivery. PLR and LLR are concepts like signal-to-noise ratio to characterize the lipiodol retention pattern objectively to predict 1-year tumor progression immediately without any quantification software for 3D image analysis immediately after cTACE treatment. • COV of PLR can facilitate the early prediction of tumor progression/recurrence and indicate the section of embolized HCC, providing the operator's good targets for sequential cTACE or combined ablation. • The validation cohort in our study verified standard COVs of PLR and LLR. The validation process was more convincing and delicate than that of previous retrospective studies.

Usefulness of Cone-Beam CT-Based Liver Perfusion Mapping for Evaluating the Response of Hepatocellular Carcinoma to Conventional Transarterial Chemoembolization

We investigated the cone beam computed tomography (CBCT)-based-liver-perfusion-mapping usefulness during transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) to access treatment response and predict outcomes. From October 2016 to September 2018, 42 patients with HCCs scheduled for conventional TACE were prospectively enrolled. Three reviewers evaluated the unenhanced and contrast-enhanced CBCT and CBCT-based-liver-perfusion-mapping of each tumor. Parenchymal blood volume (PBV) was measured. The operator’s judgment on the technical results was recorded. Response outcome was determined on follow-up CT or magnetic resonance imaging, according to the modified Response Evaluation Criteria in Solid Tumors. Diagnostic performance for detection of a viable tumor was evaluated using multiple logistic regression with C-statistics. CBCT-based-liver-perfusion-mapping and the maximum PBV of the tumor were significant in multiple logistic regression analysis of response (p < 0.0001, p = 0.0448, respectively), with C-statistics of 0.9540 and 0.7484, respectively. Diagnostic accuracy of operator’s judgment was 79.66% (95%CI 69.39%–89.93%). Diagnostic performance of CBCT-based-liver-perfusion-mapping showed a high concordance in three reviewers. The mean PBV of tumor, maximum PBV of tumor, and mean PBV of liver significantly decreased after TACE (each p < 0.001). In ROC curve analysis, the AUC for prediction of residual tumor by the maximum PBV of tumor after TACE was 0.7523, with 80.8% sensitivity and 60.6% specificity.

Automated feature quantification of Lipiodol as imaging biomarker to predict therapeutic efficacy of conventional transarterial chemoembolization of liver cancer

Conventional transarterial chemoembolization (cTACE) is a guideline-approved image-guided therapy option for liver cancer using the radiopaque drug-carrier and micro-embolic agent Lipiodol, which has been previously established as an imaging biomarker for tumor response. To establish automated quantitative and pattern-based image analysis techniques of Lipiodol deposition on 24 h post-cTACE CT as biomarker for treatment response. The density of Lipiodol deposits in 65 liver lesions was automatically quantified using Hounsfield Unit thresholds. Lipiodol deposition within the tumor was automatically assessed for patterns including homogeneity, sparsity, rim, and peripheral deposition. Lipiodol deposition was correlated with enhancing tumor volume (ETV) on baseline and follow-up MRI. ETV on baseline MRI strongly correlated with Lipiodol deposition on 24 h CT (p < 0.0001), with 8.22% ± 14.59 more Lipiodol in viable than necrotic tumor areas. On follow-up, tumor regions with Lipiodol showed higher rates of ETV reduction than areas without Lipiodol (p = 0.0475) and increasing densities of Lipiodol enhanced this effect. Also, homogeneous (p = 0.0006), non-sparse (p < 0.0001), rim deposition within sparse tumors (p = 0.045), and peripheral deposition (p < 0.0001) of Lipiodol showed improved response. This technical innovation study showed that an automated threshold-based volumetric feature characterization of Lipiodol deposits is feasible and enables practical use of Lipiodol as imaging biomarker for therapeutic efficacy after cTACE.

Randomised, multicentre prospective trial of transarterial chemoembolisation (TACE) plus sorafenib as compared with TACE alone in patients with hepatocellular carcinoma: TACTICS trial

OBJECTIVE

This trial compared the efficacy and safety of transarterial chemoembolisation (TACE) plus sorafenib with TACE alone using a newly established TACE-specific endpoint and pre-treatment of sorafenib before initial TACE.

DESIGN

Patients with unresectable hepatocellular carcinoma (HCC) were randomised to TACE plus sorafenib (n=80) or TACE alone (n=76). Patients in the combination group received sorafenib 400 mg once daily for 2-3 weeks before TACE, followed by 800 mg once daily during on-demand conventional TACE sessions until time to untreatable (unTACEable) progression (TTUP), defined as untreatable tumour progression, transient deterioration to Child-Pugh C or appearance of vascular invasion/extrahepatic spread. Co-primary endpoints were progression-free survival (PFS), which is not a conventional one but defined as TTUP, or time to any cause of death plus overall survival (OS). Multiplicity was adjusted by gatekeeping hierarchical testing.

RESULTS

Median PFS was significantly longer in the TACE plus sorafenib than in the TACE alone group (25.2 vs 13.5 months; p=0.006). OS was not analysed because only 73.6% of OS events were reached. Median TTUP (26.7 vs 20.6 months; p=0.02) was also significantly longer in the TACE plus sorafenib group. OS at 1 year and 2 years in TACE plus sorafenib group and TACE alone group were 96.2% and 82.7% and 77.2% and 64.6%, respectively. There were no unexpected toxicities.

CONCLUSION

TACE plus sorafenib significantly improved PFS over TACE alone in patients with unresectable HCC. Adverse events were consistent with those of previous TACE combination trials.

TRIAL REGISTRATION NUMBER

NCT01217034.

Follow-up after radiological intervention in oncology: ECIO-ESOI evidence and consensus-based recommendations for clinical practice

Interventional radiology plays an important and increasing role in cancer treatment. Follow-up is important to be able to assess treatment success and detect locoregional and distant recurrence and recommendations for follow-up are needed. At ECIO 2018, a joint ECIO-ESOI session was organized to establish follow-up recommendations for oncologic intervention in liver, renal, and lung cancer. Treatments included thermal ablation, TACE, and TARE. In total five topics were evaluated: ablation in colorectal liver metastases (CRLM), TARE in CRLM, TACE and TARE in HCC, ablation in renal cancer, and ablation in lung cancer. Evaluated modalities were FDG-PET-CT, CT, MRI, and (contrast-enhanced) ultrasound. Prior to the session, five experts were selected and performed a systematic review and presented statements, which were voted on in a telephone conference prior to the meeting by all panelists. These statements were presented and discussed at the ECIO-ESOI session at ECIO 2018. This paper presents the recommendations that followed from these initiatives. Based on expert opinions and the available evidence, follow-up schedules were proposed for liver cancer, renal cancer, and lung cancer. FDG-PET-CT, CT, and MRI are the recommended modalities, but one should beware of false-positive signs of residual tumor or recurrence due to inflammation early after the intervention. There is a need for prospective preferably multicenter studies to validate new techniques and new response criteria. This paper presents recommendations that can be used in clinical practice to perform the follow-up of patients with liver, lung, and renal cancer who were treated with interventional locoregional therapies.

Response Assessment Following Image-Guided Therapy of Hepatocellular Carcinoma

Image-guided locoregional therapies have an important role in the management of patients with hepatocellular carcinoma (HCC). Recent advances in the ablative as well as endovascular therapies have expanded the role of interventional radiologists in the treatment of HCC. Following image-guided therapy, an accurate response assessment is vital. Knowledge regarding normal postprocedure changes and subtle signs of residual or recurrent disease is important. In this review, we discuss various response evaluation criteria currently employed for HCC. We also discuss the postprocedure imaging features suggestive of residual disease or recurrence and imaging biomarkers for response assessment.

A differential risk assessment and decision model for Transarterial chemoembolization in hepatocellular carcinoma based on hepatic function

BACKGROUND

The decision of transarterial chemoembolization (TACE) initiation and/or repetition remains challenging in patients with unresectable hepatocellular carcinoma (HCC). The aim was to develop a prognostic scoring system to guide TACE initiation/repetition.

METHODS

A total of 597 consecutive patients who underwent TACE as their initial treatment for unresectable HCC were included. We derived a prediction model using independent risk factors for overall survival (OS), which was externally validated in an independent cohort (n = 739).

RESULTS

Independent risk factors of OS included Albumin-bilirubin (ALBI) grade, maximal tumor size, alpha-fetoprotein, and tumor response to initial TACE, which were used to develop a scoring system ("ASAR"). C-index values for OS were 0.733 (95% confidence interval [CI] = 0.570-0.871) in the derivation, 0.700 (95% CI = 0.445-0.905) in the internal validation, and 0.680 (95% CI = 0.652-0.707) in the external validation, respectively. Patients with ASAR< 4 showed significantly longer OS than patients with ASAR≥4 in all three datasets (all P < 0.001). Among Child-Pugh class B patients, a modified model without TACE response, i.e., "ASA(R)", discriminated OS with a c-index of 0.788 (95% CI, 0.703-0.876) in the derivation, and 0.745 (95% CI, 0.646-0.862) in the internal validation, and 0.670 (95% CI, 0.605-0.725) in the external validation, respectively. Child-Pugh B patients with ASA(R) < 4 showed significantly longer OS than patients with ASA(R) ≥ 4 in all three datasets (all P < 0.001).

CONCLUSIONS

ASAR provides refined prognostication for repetition of TACE in patients with unresectable HCC. For Child-Pugh class B patients, a modified model with baseline factors might guide TACE initiation.

Evaluation of liver tumour response by imaging

The goal of assessing tumour response on imaging is to identify patients who are likely to benefit - or not - from anticancer treatment, especially in relation to survival. The World Health Organization was the first to develop assessment criteria. This early score, which assessed tumour burden by standardising lesion size measurements, laid the groundwork for many of the criteria that followed. This was then improved by the Response Evaluation Criteria in Solid Tumours (RECIST) which was quickly adopted by the oncology community. At the same time, many interventional oncology treatments were developed to target specific features of liver tumours that result in significant changes in tumours but have little effect on tumour size. New criteria focusing on the viable part of tumours were therefore designed to provide more appropriate feedback to guide patient management. Targeted therapy has resulted in a breakthrough that challenges conventional response criteria due to the non-linear relationship between response and tumour size, requiring the development of methods that emphasize the appearance of tumours. More recently, research into functional and quantitative imaging has created new opportunities in liver imaging. These results have suggested that certain parameters could serve as early predictors of response or could predict later tumour response at baseline. These approaches have now been extended by machine learning and deep learning. This clinical review focuses on the progress made in the evaluation of liver tumours on imaging, discussing the rationale for this approach, addressing challenges and controversies in the field, and suggesting possible future developments.

Combined conventional transarterial chemoembolization with Mitomycin and percutaneous ablation for unresectable hepatocellular carcinoma

Background

Conventional transarterial chemoembolization (cTACE) has been the standard treatment for intermediate stage hepatocellular carcinoma (HCC). For early stage HCC, percutaneous ablation is a curative option. There is growing evidence to support combined therapy to improve tumor response and overall survival (OS) in patients with unresectable HCC. The goal of this study is to retrospectively review a single institution patient population who underwent the combined approach to determine its efficacy and safety, and possible predictive factors for OS and tumor response.

Methods

Retrospective analysis identified all patients that underwent c-TACE with Mitomycin followed by percutaneous ablation from 2011 to 2016 at our institution. Efficacy was assessed by OS, time to progression (TTP), and tumor response according to mRECIST criteria. Initial imaging was obtained 1 month after each treatment and after complete response was achieved, every 3 months for 2 years. Percentage of Lipiodol uptake was determined at 30-day follow-up with contrasted abdominal CT. Safety was assessed using Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Multiple linear regressions were conducted to predict OS and number of progression-free survival days based on potential predictive factors.

Results

A total of 50 patients were identified. At 1-month follow-up, objective response (CR + PR) was achieved in 44 patients (88%). The median OS was 26.6 months and median TTP was 9.7 months (n=50). There was no statistically significant difference in median OS between patients with different lesion size (P=0.95), BCLC stage (P=0.84) or Lipiodol uptake (P=0.36). Higher albumin/bilirubin ratio was significantly correlated with improved OS (P=0.024).

Conclusions

Combined c-TACE and PTA is a safe and effective approach for patients with unresectable HCC. Elevated albumin/bilirubin ratio was a predictor for improved OS.

Lipiodol retention pattern after TACE for HCC is a predictor for local progression in lesions with complete response

Background

To evaluate the predictive value of the lipiodol retention pattern for local progression of HCC with a complete response (CR) on CT according to mRECIST criteria after a first session of conventional chemoembolization (cTACE).

Methods

From January 2014 to May 2016 all consecutive patients undergoing a first cTACE session for HCC were identified. Inclusion criteria were the presence of ≤3 HCCs and available pre- and post-cTACE CT. Tumor response was classified according to mRECIST criteria. The analysis focused on tumors with a CR. The lipiodol retention pattern in these tumors was classified as complete (C-Lip, covering the entire tumor volume), or incomplete (I-Lip). Local progression was defined as the reappearance of areas of enhancement on arterial-phase images with washout on portal/delayed phase images within 2 cm from treated tumors on follow-up CT.

Results

The final population included 50 patients with 82 HCCs. A total of 46 (56%) HCCs were classified with a CR, including 16 (35%) with I-Lip, and 30 (65%) with C-Lip. After a median follow-up of 14 months (3.2–35.9 months), 15/16 (94%) and 10/30 (30%) of I-Lip and C-Lip HCCs showed local progression on CT, respectively (p < 0.001), with no significant difference in the time to progression (mean 11.1 ± 2 vs. 13.4 ± 3 months for I-Lip and C-Lip, respectively p = 0.51).

Conclusions

HCCs with incomplete lipiodol retention after a first cTACE session have a high risk of local progression even when there is a CR according to mRECIST, and should be considered to be incompletely treated.

Radiological appearance of hepatocellular carcinoma predicts the response to trans-arterial chemoembolization in patients undergoing liver transplantation

Background

The ultimate goal of locoregional therapy (LRT) to the liver is to induce total tumor necrosis. Trans-arterial chemoembolization (TACE) is the mainstay bridging therapy for patients with hepatocellular carcinoma (HCC) waiting for liver transplantation (LT). However, tumor response rate is variable. The purpose of this study was to correlate HCC radiological appearance with level of tumor necrosis during explant analysis from patients undergoing LT who received pre-LT TACE.

Methods

From January 2000 to December 2018, a total of 66 patients with HCC who had been treated prior to LT by means of TACE were analyzed. Diagnosis of HCC was made based on AASLD guidelines and confirmed via histopathology explant analysis. Radiologic tumor response after TACE was based on modified Response Evaluation Criteria in Solid Tumors (mRECIST). Degree of tumor necrosis was determined by histopathology analysis of liver explants. HCC radiological appearances on CT before TACE were assessed and correlated with histological findings after LT.

Results

Eighty nine TACE procedures (1.35 ± 0.67; 1–4) were performed, of which 18 were repeated TACE (27.3%) procedures. In 56.1% of the patients, ≥90% (near-complete) tumor necrosis was achieved. Concordance between mRECIST criteria and pathology was observed in 63% of the patients, with an underestimation of tumor response in 18 (27%) patients and an overestimation in 6 (9.1%). Near-complete tumor necrosis upon pathological analysis was associated with tumor hyper-enhancement in the arterial phase (P = 0.002), “typical tumor enhancement” (P = 0.010) and smooth tumor margins (p = 0.011). The multivariate analysis showed that well circumscribed HCCs with smooth margins and arterial hyper-enhancement independently correlated with post-TACE near-complete histological tumor necrosis.

Conclusions

The well circumscribed HCC lesions with arterial hyper-enhancement are more susceptible to TACE than lesions with arterial phase iso or hypo-enhancement and lesions with infiltrative appearance. Pre-TACE CT imaging may ease the selection of an optimal treatment strategy for bridging patients with HCC to liver transplantation.

Response Evaluation Criteria in Cancer of the Liver version 5 (RECICL 2019 revised version)

Response Evaluation Criteria in Solid Tumors (RECIST) is inappropriate to assess the direct effects of treatment on hepatocellular carcinoma (HCC) by locoregional therapies, such as radiofrequency ablation and transarterial chemoembolization. Therefore, establishment of response evaluation criteria solely devoted to HCC is needed in clinical practice, as well as in clinical trials of HCC treatment, such as systemic therapies, which cause necrosis of the tumor. Response Evaluation Criteria in Cancer of the Liver (RECICL) was revised in 2019 by the Liver Cancer Study Group of Japan based on the 2015 version of RECICL, which was commonly used in Japan. The major revised points of the RECICL 2019 are as follows: (i) CEA and CA19-9 have been newly added as tumor markers that should be recorded for use as criteria in the response evaluation for intrahepatic cholangiocarcinoma; (ii) the criteria now state that the details of molecular targeted therapy should be specified; and (iii) specific methods for overall evaluation are now described. Also, as an assessment of overall TE4 requires that TE4 is achieved in all nodules (even non-target lesions), the same calculation methods described above are used. We hope this new treatment response criteria, RECICL, proposed by the Liver Cancer Study Group of Japan will benefit the HCC treatment response evaluation in the setting of daily clinical practice and clinical trials as well, not only in Japan, but also internationally.

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.

Long-term follow-up after conventional transarterial chemoembolization (c-TACE) with mitomycin for hepatocellular carcinoma (HCC)

Background

Conventional transarterial chemoembolization (c-TACE) is a common treatment for unresectable hepatocellular carcinoma (HCC). It is associated with increased overall survival (OS) when compared to conservative management. The purpose of this study is to analyze all c-TACE with mitomycin in patients with HCC at a single institution to determine safety, efficacy, and prognostic factors in a long-term follow-up.

Methods

Retrospective analysis of patients with HCC treated only with c-TACE with Mitomycin between 2007 and 2012. Efficacy was determined by OS at 1, 3, and 5 years, censored by date of death or last known follow-up. Treatment response was assessed according to mRECIST criteria and the degree of lipiodol uptake by the lesions was assessed by CT at 1-month follow-up. Prognostic factors were analyzed by multiple linear regression analysis, significance levels set at 0.05.

Results

A total of 60 patients were identified. OS rate at 1, 3 and 5 years was 72.1%, 47.8% and 39.3%, respectively. Median OS was 15 months. Tumor response by mRECIST criteria was complete; objective response, defined as combination of complete response (CR) and partial response (PR) patients, was 76%. When stratified by tumor response, risk of death in patients with progressive disease in 5 years was significantly higher compared to patients with objective response [hazard ratio (HR): 2.531, 95% confidence interval (CI): 1.110-5.778, P=0.0273]. Lipiodol uptake analysis was available in 51 patients; there was no statistically significant difference in OS in patients with higher lipiodol uptake compared to less uptake (<50% versus >50% uptake; HR: 0.713, 95% CI: 0.316-1.611, P=0.4161].

Conclusions

c-TACE with mitomycin was effective and safe in this long-term follow-up study. Risk of death was significantly higher in patients without objective tumor response.

Combined Therapy with Transarterial Chemoembolization and Radiofrequency Ablation for Hepatocellular Carcinoma: Does the Degree of Ethiodized Oil Accumulation within the Tumor Affect the Therapeutic Efficacy?

PURPOSE

To evaluate the effects of the degree of ethiodized oil accumulation achieved by transarterial chemoembolization followed by radiofrequency (RF) ablation on the treatment efficacy for a single intermediate-sized hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 153 consecutive patients who underwent chemoembolization and RF ablation for a single intermediate-sized HCC (2-5 cm) were included. On the basis of the degree of ethiodized oil accumulation in HCC on cone-beam CT images, patients who underwent chemoembolization and RF ablation were classified into 2 groups: compact accumulation (≥ 75%) and noncompact accumulation (< 75%). The rates of cumulative local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) were compared between groups.

RESULTS

Of the 153 patients, 89 were classified into the compact ethiodized oil accumulation group and 64 in the noncompact ethiodized oil accumulation group. There were no significant differences in patient demographic or HCC characteristics between groups except for the incidence of liver cirrhosis (P = .038) and the tumor margin morphology (P = .008). The cumulative LTP rate was significantly lower in the compact accumulation group than in the noncompact accumulation group (P = .013). There were no significant differences in the incidences of complications, DFS rates (P = .055), or OS rates (P = .184).

CONCLUSIONS

The degree of ethiodized oil accumulation does not play a role in decreasing the OS or DFS rate after chemoembolization and RF ablation for intermediate-sized HCC; however, it may contribute to reducing the rate of LTP.

Updated use of TACE for hepatocellular carcinoma treatment: How and when to use it based on clinical evidence

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, representing the sixth leading cause of cancer and the third leading cause of cancer-related mortality. Patient stratification and treatment allocation are based on tumor stage, liver function, and performance status. According to the Barcelona Clinic Liver Cancer (BCLC) staging system, transarterial chemoembolization (TACE) is the first-line treatment for patients with intermediate stage HCC, including those with large or multinodular HCC, well-preserved liver function, and no cancer-related symptoms or evidence of vascular invasion or extrahepatic spread. Two TACE techniques have been used since 2004, conventional TACE (cTACE) and TACE with drug-eluting beads (DEB-TACE). cTACE was evidenced first to treat intermediate stage HCC patients. It combines the transcatheter delivery of chemotherapy using Lipiodol-based emulsion plus an embolizing agent to achieve strong cytotoxic and ischemic effects. Drug-eluting beads (DEBs) were developed in order to slowly release chemotherapeutic agents, and to increase ischemia intensity and duration. Recent advances allow TACE treatment of both early stage patients (i.e. those with a solitary nodule or up to 3 nodules under 3 cm) and some advanced stage patients. Here we review recent clinical evidence related to TACE treatment of patients with early, intermediate, and advanced stage HCC. Based on the 2014 TACE algorithm of Raoul et al., this international expert panel proposes an updated TACE algorithm and provides insights into TACE use for patients at any HCC stage.

Radiation exposure during TACE procedures using additional cone-beam CT (CBCT) for guidance: safety and precautions

Background During transarterial chemoembolization (TACE), cone-beam computed tomography (CBCT) can be used for tumor and feeding vessel detection as well as postembolization CT imaging. However, there will be additional radiation exposure from CBCT. Purpose To evaluate the additional dose raised through CBCT-assisted guidance in comparison to TACE procedures guided with pulsed digital subtraction angiography (DSA) alone. Material and Methods In 70 of 140 consecutive patients undergoing TACE for liver cancer, CBCT was used to facilitate the TACE. Cumulative dose area product (DAP), cumulative kerma(air), DAP values of DSA, total and cine specific fluoroscopy times (FT) of 1375 DSA runs, and DAP of 91 CBCTs were recorded and analyzed using Spearman's correlation, Mann-Whitney U-test, and Kruskal-Wallis test. P values < 0.05 were considered significant. Results Additional CBCT increased DAP by 2% ( P = 0.737), kerma(air) by 24.6% ( P = 0.206), and FT by 0.02% ( P = 0.453). Subgroup analysis revealed that postembolization CBCT for detection of ethiodized oil deposits added more DAP to the procedure. Performing CBCT-assisted TACE, DSA until first CBCT contributed about 38% to the total DAP. Guidance CBCT acquisitions conduced to 6% of the procedure's DAP. Additional DSA for guidance after CBCT acquisition required approximately 46% of the mean DAP. The last DSA run for documentation purposes contributed about 10% of the DAP. Conclusion CBCT adds radiation exposure in TACE. However, the capability of CBCT to detect vessels and overlay in real-time during fluoroscopy facilitates TACE with resultant reduction of DAPs up to 46%.

Computed tomography and histopathological findings after embolization with inherently radiopaque 40μm-microspheres, standard 40μm-microspheres and iodized oil in a porcine liver model

Purpose

The present study compared standard computed tomography (CT) and histopathological findings after endovascular embolization using a prototype of inherently radiopaque 40μm-microspheres with both standard 40μm-microspheres and iodized oil in a porcine liver model.

Materials and methods

Twelve pigs were divided into six study groups, of two pigs each. Four pigs were embolized with iodized oil alone and four with radiopaque microspheres; two animals in each group were sacrificed at 2 hours and two at 7 days. Two pigs were embolized with radiopaque microspheres and heparin and sacrificed at 7 days. Two pigs were embolized with standard microspheres and sacrificed at 2 hours. CT was performed before and after segmental embolization and before sacrifice at 7 days. The distribution of embolic agent, inflammatory response and tissue necrosis were assessed histopathologically.

Results

Radiopaque microspheres and iodized oil were visible on standard CT 2 hours and 7 days after embolization, showing qualitatively comparable arterial and parenchymal enhancement. Quantitatively, the enhancement was more intense for iodized oil. Standard microspheres, delivered without contrast, were not visible by imaging. Radiopaque and standard microspheres similarly occluded subsegmental and interlobular arteries and, to a lesser extent, sinusoids. Iodized oil resulted in the deepest penetration into sinusoids. Necrosis was always observed after embolization with microspheres, but never after embolization with iodized oil. The inflammatory response was mild to moderate for microspheres and moderate to severe for iodized oil.

Conclusion

Radiopaque 40μm-microspheres are visible on standard CT with qualitatively similar but quantitatively less intense enhancement compared to iodized oil, and with a tendency towards less of an inflammatory reaction than iodized oil. These microspheres also result in tissue necrosis, which was not observed after embolization with iodized oil. Both radiopaque and standard 40μm-microspheres are found within subsegmental and interlobar arteries, as well as in hepatic sinusoids.

Post Locoregional Therapy Treatment Imaging in Hepatocellular Carcinoma Patients: A Literature-based Review

Imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC) as well as in determining treatment efficacy, or complications, following therapy. Unlike other cancers, HCC is most commonly treated by locoregional therapies (LRTs) such as thermal ablation, transarterial chemoembolization, and transarterial radioembolization. These treatments can lead to changes on imaging that make determination of residual/recurrent disease difficult. This literature-based review discusses the expected postimaging findings following LRT.

Pickering-Emulsion for Liver Trans-Arterial Chemo-Embolization with Oxaliplatin

PURPOSE

Biodegradable polylactic-co-glycolic acid (PLGA) nanoparticles can adsorb at the water/oil interface to stabilize the emulsion (forming Pickering-emulsion). The purpose of this study was to compare the release profiles of oxaliplatin from Pickering-emulsion and Lipiodol-emulsion.

MATERIALS/METHODS

Pickering-emulsions and Lipiodol-emulsions were both formulated with oxaliplatin (5 mg/mL) and Lipiodol (water/oil ratio: 1/3). For Pickering-emulsion only, PLGA nanoparticles (15 mg/mL) were dissolved into oxaliplatin before formulation. In vitro release of oxaliplatin from both emulsions was evaluated. Then, oxaliplatin was selectively injected into left hepatic arteries of 18 rabbits bearing VX2 liver tumors using either 0.5 mL Pickering-emulsion (n = 10) or 0.5 mL Lipiodol-emulsion (n = 8). In each group, half of the rabbits were killed at 1 h and half at 24 h. Mass spectrometry was used to quantify drug pharmacokinetics in blood and resulting tissue (tumors, right, and left livers) oxaliplatin concentrations.

RESULTS

Pickering-emulsion demonstrated a slow oxaliplatin release compared to Lipiodol-emulsion (1.5 ± 0.2 vs. 12.0 ± 6% at 1 h and 15.8 ± 3.0 vs. 85.3 ± 3.3% at 24 h) during in vitro comparison studies. For animal model studies, the plasmatic peak (C_max) and the area under the curve (AUC) were significantly lower with Pickering-emulsion compared to Lipiodol-emulsion (C_max = 0.49 ± 0.14 vs. 1.08 ± 0.41 ng/mL, p = 0.01 and AUC = 19.8 ± 5.9 vs. 31.8 ± 14.9, p = 0.03). This resulted in significantly lower oxaliplatin concentrations in tissues at 1 h with Pickering-emulsion but higher ratio between tumor and left liver at 24 h (43.4 vs. 14.5, p = 0.04).

CONCLUSION

Slow release of oxaliplatin from Pickering-emulsion results in a significant decrease in systemic drug exposure and higher ratio between tumor and left liver oxaliplatin concentration at 24 h.

Prediction of post-TACE necrosis of hepatocellular carcinoma usingvolumetric enhancement on MRI and volumetric oil deposition on CT, with pathological correlation

OBJECTIVE

To investigate whether volumetric enhancement on baseline MRI and volumetric oil deposition on unenhanced CT would predict HCC necrosis and response post-TACE.

METHOD

Of 115 retrospective HCC patients (173 lesions) who underwent cTACE, a subset of 53 HCC patients underwent liver transplant (LT). Semiautomatic volumetric segmentation of target lesions was performed on dual imaging to assess the accuracy of predicting tumour necrosis after TACE in the whole cohort and at pathology in the LT group. Predicted percentage tumour necrosis is defined as 100 % - (%baseline MRI enhancement - %CT oil deposition).

RESULTS

Mean predicted tumour necrosis by dual imaging modalities was 61.5 % ± 31.6%; mean percentage tumour necrosis on follow-up MRI was 63.8 % ± 31.5 %. In the LT group, mean predicted tumour necrosis by dual imaging modalities was 77.6 % ± 27.2 %; mean percentage necrosis at pathology was 78.7 % ± 31.5 %. There was a strong significant correlation between predicted tumour necrosis and volumetric necrosis on MRI follow-up (r = 0.889, p<0.001) and between predicted tumour necrosis and pathological necrosis (r = 0.871, p<0.001).

CONCLUSION

Volumetric pre-TACE enhancement on MRI and post-TACE oil deposition in CT may accurately predict necrosis in treated HCC lesions.

KEY POINTS

• Imaging-based tumour response can assist in therapeutic decisions. • Lipiodol retention as carrier agent in cTACE is a tumour necrosis biomarker. • Predicting tumour necrosis with dual imaging potentially obviates immediate post-treatment MRI. • Predicting tumour necrosis would facilitate further therapeutic decisions in HCC post-cTACE. • Pre-TACE MRI and post-TACE CT predict necrosis in treated HCC.