Effectiveness of Transarterial Embolization of Hepatocellular Carcinoma as a Bridge to Transplantation

Examining the Efficacy and Safety of Combined Locoregional Therapy and Immunotherapy in Treating Hepatocellular Carcinoma

More than 800,000 people worldwide are diagnosed with HCC (hepatocellular carcinoma) each year, with approximately 700,000 deaths alone occurring in that same year. Treatment of HCC presents complex therapeutic challenges, particularly in intermediate and advanced stages. LRTs such as transarterial chemoembolization (TACE) and ablations have been the mainstay treatment for early to intermediate-stage HCC, and systemic therapies are used to treat intermediate-late-stage HCC. However, novel literature describing combining LRT with systemic therapies has shown promising results. This review explores recent advances in both liver-directed techniques for hepatocellular carcinoma, including bland transarterial embolization, chemoembolization, radioembolization, and ablative therapies in conjunction as well as with systemic therapies, with a focus on combination therapies, patient selection, procedural technique, periprocedural management, and outcomes. Our findings suggest that LRT combined with systemic therapies is a viable strategy for improving progression-free survival and time to progression for patients with intermediate-to-late-stage HCC. However, further investigation is required to refine treatment protocols and define patient cohorts that would benefit the most.

Transarterial embolization is an acceptable bridging therapy to hepatocellular carcinoma prior to liver transplantation

BACKGROUND

Hepatocellular carcinoma (HCC) is an aggressive malignant neoplasm that requires liver transplantation (LT). Despite patients with HCC being prioritized by most organ allocation systems worldwide, they still have to wait for long periods. Locoregional therapies (LRTs) are employed as bridging therapies in patients with HCC awaiting LT. Although largely used in the past, transarterial embolization (TAE) has been replaced by transarterial chemoembolization (TACE). However, the superiority of TACE over TAE has not been consistently shown in the literature.

AIM

To compare the outcomes of TACE and TAE in patients with HCC awaiting LT.

METHODS

All consecutive patients with HCC awaiting LT between 2011 and 2020 at a single center were included. All patients underwent LRT with either TACE or TAE. Some patients also underwent percutaneous ethanol injection (PEI), concomitantly or in different treatment sessions. The choice of LRT for each HCC nodule was determined by a multidisciplinary consensus. The primary outcome was waitlist dropout due to tumor progression, and the secondary outcome was the occurrence of adverse events. In the subset of patients who underwent LT, complete pathological response and post-transplant recurrence-free survival were also assessed.

RESULTS

Twelve (18.5%) patients in the TACE group (only TACE and TACE + PEI; n = 65) and 3 (7.9%) patients in the TAE group (only TAE and TAE + PEI; n = 38) dropped out of the waitlist due to tumor progression (P log-rank test = 0.29). Adverse events occurred in 8 (12.3%) and 2 (5.3%) patients in the TACE and TAE groups, respectively (P = 0.316). Forty-eight (73.8%) of the 65 patients in the TACE group and 29 (76.3%) of the 38 patients in the TAE group underwent LT (P = 0.818). Among these patients, complete pathological response was detected in 7 (14.6%) and 9 (31%) patients in the TACE and TAE groups, respectively (P = 0.145). Post-LT, HCC recurred in 9 (18.8%) and 4 (13.8%) patients in the TACE and TAE groups, respectively (P = 0.756). Posttransplant recurrence-free survival was similar between the groups (P log-rank test = 0.71).

CONCLUSION

Dropout rates and posttransplant recurrence-free survival of TAE were similar to those of TACE in patients with HCC. Our study reinforces the hypothesis that TACE is not superior to TAE as a bridging therapy to LT in patients with HCC.

Metformin administration is associated with enhanced response to transarterial chemoembolization for hepatocellular carcinoma in type 2 diabetes patients

Transarterial chemoembolization (TACE) is often used as a locoregional therapy for early hepatocellular carcinoma (HCC) when local ablation or resection are not feasible, but incomplete response and recurrence are commonly observed. In this study, we sought to determine the association between metformin administration and TACE outcomes for single nodular HCC in patients with type 2 diabetes mellitus (T2DM). The retrospective cohort analysis included 164 T2DM patients with single nodular HCC who underwent TACE as an initial treatment, and 91 were exposed to metformin before and after TACE. Propensity score (PS) matching was used to balance covariates. Logistic regression analysis was used to determine the predictors of tumor response after TACE, and Cox regression analysis assessed independent predictors of local tumor recurrence (LTR) in patients with complete response after TACE. Metformin use was associated with significantly higher objective response rate (ORR) in the overall and PS-matched cohort (79.1% vs. 60.3 and 78.7% vs. 57.5%; p = 0.008 and p = 0.029, respectively). Logistic regression analysis showed that metformin use was an independent predictor of ORR in all and PS-matched patients (odds ratio = 2.65 and 3.06; p = 0.016 and 0.034, respectively). Cox regression analysis showed metformin administration was an independent predictor for lower LTR in all and PS-matched patients (hazard ratio = 0.28 and 0.27; p = 0.001 and 0.007, respectively). Metformin administration is associated with better initial response and lower local recurrence after TACE for single nodular HCC in T2DM.

Locoregional Therapy Approaches for Hepatocellular Carcinoma: Recent Advances and Management Strategies

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and third leading cause of cancer-related mortality worldwide. While surgical resection and transplantation are the standard first-line treatments for early-stage HCC, most patients do not fulfill criteria for surgery. Fortunately, catheter-directed and percutaneous locoregional approaches have evolved as major treatment modalities for unresectable HCC. Improved outcomes have been achieved with novel techniques which can be employed for diverse applications ranging from curative-intent for small localized tumors, to downstaging or bridging to resection and transplantation for early and intermediate disease, and locoregional control and palliation for advanced disease. This review explores recent advances in liver-directed techniques for HCC including bland transarterial embolization, chemoembolization, radioembolization, and ablative therapies, with a focus on patient selection, procedural technique, periprocedural management, and outcomes.

Embolotherapy for Hepatic Oncology: Current Perspectives and Future Directions

Primary and secondary liver cancers are a major cause of mortality worldwide. Transarterial liver-directed therapy, or embolotherapy, represents an important locoregional treatment strategy for primary and secondary liver tumors. Embolotherapeutic modalities include bland embolization (transarterial embolization), chemoembolization (transarterial chemoembolization), and radioembolization or selective internal radiotherapy. A brief technical overview of embolotherapeutic modalities as well as supportive evidence for the treatment of most common primary and secondary liver tumors will be discussed in this review. Several potential future applications, including synergy with systemic therapy, interventional theranostics, and artificial intelligence will also be reviewed briefly.

Embolotherapeutic Strategies for Hepatocellular Carcinoma: 2020 Update

Hepatocellular carcinoma (HCC) represents a significant contributor to cancer-related morbidity and mortality with increasing incidence in both developing and developed countries. Embolotherapy as a locoregional therapeutic strategy consists of trans-arterial or “bland” embolization (TAE), trans-arterial chemoembolization (TACE), and selective internal radiotherapy (SIRT). Trans-catheter arterial therapies can be applied along all stages of HCC, either as an alternative or neoadjuvant to surgical resection/transplantation in very early and early stage HCC or as a palliative option for local disease control in unresectable and advanced stage HCC. In advanced stage HCC, SIRT did not demonstrate superiority in comparison to systemic treatment options in several recent large prospective trials, though for carefully selected patients, may confer improved tolerability with similar disease control rates. The latest embolotherapeutic techniques and literature as they pertain to the management of HCC, as well as future directions, are reviewed in this article.

LI-RADS Treatment Response Algorithm: Performance and Diagnostic Accuracy

Background In 2017, the Liver Imaging Reporting and Data System (LI-RADS) included an algorithm for the assessment of hepatocellular carcinoma (HCC) treated with local-regional therapy. The aim of the algorithm was to enable standardized evaluation of treatment response to guide subsequent therapy. However, the performance of the algorithm has not yet been validated in the literature. Purpose To evaluate the performance of the LI-RADS 2017 Treatment Response algorithm for assessing the histopathologic viability of HCC treated with bland arterial embolization. Materials and Methods This retrospective study included patients who underwent bland arterial embolization for HCC between 2006 and 2016 and subsequent liver transplantation. Three radiologists independently assessed all treated lesions by using the CT/MRI LI-RADS 2017 Treatment Response algorithm. Radiology and posttransplant histopathology reports were then compared. Lesions were categorized on the basis of explant pathologic findings as either completely (100%) or incompletely (<100%) necrotic, and performance characteristics and predictive values for the LI-RADS Treatment Response (LR-TR) Viable and Nonviable categories were calculated for each reader. Interreader association was calculated by using the Fleiss κ. Results A total of 45 adults (mean age, 57.1 years ± 8.2; 13 women) with 63 total lesions were included. For predicting incomplete histopathologic tumor necrosis, the accuracy of the LR-TR Viable category for the three readers was 60%-65%, and the positive predictive value was 86%-96%. For predicting complete histopathologic tumor necrosis, the accuracy of the LR-TR Nonviable category was 67%-71%, and the negative predictive value was 81%-87%. By consensus, 17 (27%) of 63 lesions were categorized as LR-TR Equivocal, and 12 of these lesions were incompletely necrotic. Interreader association for the LR-TR category was moderate (κ = 0.55; 95% confidence interval: 0.47, 0.67). Conclusion The Liver Imaging Reporting and Data System 2017 Treatment Response algorithm had high predictive value and moderate interreader association for the histopathologic viability of hepatocellular carcinoma treated with bland arterial embolization when lesions were assessed as Viable or Nonviable. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Gervais in this issue.

Loco-regional hepatocellular carcinoma treatment services as a bridge to liver transplantation

BACKGROUND

Liver transplantation remains the main curative treatment option for hepatocellular carcinoma (HCC) patients. In the Eurotransplant area Milan criteria are used to assign priority extra points (exceptional MELD, exMELD) for patients on the waiting list. To prevent patients from tumor progression, loco-regional (neoadjuvant) treatment (LRT) is used. For patients unlikely to timely receive an organ via primary allocation, "extended critera donor (ECD) organs" are used. The present study aimed to investigate the survival after LT with a strategy of minimizing waiting list dropouts by using LRT for bridging and transplanting ECD organs if possible and necessary.

METHODS

Between October 2010 and May 2015, 50 liver transplants for HCC were included in this retrospective study. Of those, 42 (84%) met the Milan criteria according to the preoperative radiological examination. Forty-one patients (82%) received LRT. The waiting time was analyzed according to LRT. Kaplan-Meier curves with log-rank statistics were used for survival analyses.

RESULTS

One- and five-year overall survival within Milan criteria was 94.3% and 83.7% compared with 91.7% and 67.9% beyond Milan criteria, though statistical significance was not reached (P = 0.487). LRT had no impact on overall survival (P = 0.629). Median waiting time was shorter if no LRT was performed (4.6 months vs. 1.5 months, P = 0.006) and there were no cases of waiting list dropouts. Using ECD organs had no impact on overall survival (P = 0.663).

CONCLUSIONS

Patients with an expected waiting time to transplantation of >6 months could be successfully treated with LRT as a bridge to transplant. Overall and disease-free survival for patients within and beyond Milan criteria was comparable and the use of ECD organs in this cohort of HCC patients proved to be a safe option.

Clinical Case Panel: Treatment Alternatives for Inoperable Hepatocellular Carcinoma

Surgical resection or liver transplantation offers the best chance of cure for patients with hepatocellular carcinoma (HCC). Unfortunately, most patients are not good candidates for liver resection due to locally advanced disease or compromised liver function. Moreover, liver transplantation waiting lists are long. For those cases not amenable for resection, a variety of local treatment modalities are available, such as image-guided ablative procedures, transarterial chemoembolization, and radioembolization, as well as external beam radiation. HCC presentation can vary considerably in size, number, and location of lesions. The management of inoperable HCC is, therefore, quite complex, and there is a lack of consensus on the best local treatment modality for each type tumor presentation. Here, we present 4 clinical case scenarios representative of commonly seen cases in the clinical setting, with different therapeutic perspectives from institutions with high expertise in the management of HCC.

Skin ischemia and ulceration as a complication of inferior phrenic artery embolization for hepatocellular carcinoma

Nontarget embolization from transarterial liver-directed therapy for hepatocellular carcinoma is a rare complication. We present a case of flank skin ulceration after embolization of the inferior phrenic artery supplying tumor. This complication of inferior phrenic artery embolization underscores caution when using small particles to embolize extrahepatic supply to hepatocellular carcinoma.

Therapies for patients with hepatocellular carcinoma awaiting liver transplantation: A systematic review and meta-analysis

Patients with hepatocellular carcinoma (HCC) who are listed for liver transplantation (LT) are often treated while on the waiting list with locoregional therapy (LRT), which is aimed at either preventing progression of HCC or reducing the measurable disease burden of HCC in order to receive increased allocation priority. We aimed to synthesize evidence regarding the effectiveness of LRT in the management of patients with HCC who were on the LT waitlist. We conducted a comprehensive search of multiple databases from 1996 to April 25, 2016, for studies that enrolled adults with cirrhosis awaiting LT and treated with bridging or down-staging therapies before LT. Therapies included transcatheter arterial chemoembolization, transarterial radioembolization, ablation, and radiotherapy. We included both comparative and noncomparative studies. There were no randomized controlled trials identified. For adults with T1 HCC and waiting for LT, there were only two nonrandomized comparative studies, both with a high risk of bias, which reported the outcome of interest. In one series, the rate of dropout from all causes at 6 months in T1 HCC patients who underwent LRT was 5.3%, while in the other series of T1 HCC patients who did not receive LRT, the dropout rate at median follow-up of 2.4 years and the progression rate to T2 HCC were 30% and 88%, respectively. For adults with T2 HCC awaiting LT, transplant with any bridging therapy showed a nonsignificant reduction in the risk of waitlist dropout due to progression (relative risk [RR], 0.32; 95% confidence interval [CI], 0.06-1.85; I² = 0%) and of waitlist dropout from all causes (RR, 0.38; 95% CI, 0.060-2.370; I² = 85.7%) compared to no therapy based on three comparative studies. The quality of evidence is very low due to high risk of bias, imprecision, and inconsistency. There were five comparative studies which reported on posttransplant survival rates and 10 comparative studies which reported on posttransplant recurrence, and there was no significant difference seen in either of these endpoints. For adults initially with stage T3 HCC who received LRT, there were three studies reporting on transplant with any down-staging therapy versus no downstaging, and this showed a significant increase in 1-year (two studies, RR, 1.11; 95% CI, 1.01-1.23) and 5-year (1 study, RR, 1.17; 95% CI, 1.03-1.32) post-LT survival rates for patients who received LRT. The quality of evidence is very low due to serious risk of bias and imprecision.

CONCLUSION

In patients with HCC listed for LT, the use of LRT is associated with a nonsignificant trend toward improved waitlist and posttransplant outcomes, though there is a high risk of selection bias in the available evidence. (Hepatology 2018;67:381-400).

Close observation versus upfront treatment in hepatocellular carcinoma: are the exception points worth the risk?

INTRODUCTION

To assess the outcomes of immediate LDT versus observation strategies for T1 hepatocellular carcinoma (HCC) with respect to progression beyond Milan and survival.

METHOD

T1 HCCs were retrospectively reviewed from a multidisciplinary tumour board database between September 2007 and May 2015. In the observation group, T1 lesions were observed until the tumour grew to meet T2 criteria (=2 cm). The treatment group consisted of T1 lesions treated at diagnosis with liver directed therapy (LDT). Kaplan-Meier plots were constructed for tumour progression beyond Milan and overall survival.

RESULTS

87 patients (observation n=56; LDT n=31) were included in the study. A total of 22% (n=19) of patients progressed beyond Milan with no difference in progression between treatment and observation groups (19% vs 23%, p=0.49). Median time to progression beyond Milan was 16 months. Overall transplantation rate was 22% (observation group n=16; treatment group n=3, p=0.04). Median survival was 55 months with LDT versus 36 months in the observation group (p=0.22). In patients who progressed to T2 (n=60), longer time to T2 progression was a predictor of improved survival (HR=0.94, 95% CI 0.88 to 0.99, p=0.03).

CONCLUSIONS

Immediate LDT of T1 lesions was not associated with increased risk of progression beyond Milan criteria when compared with an observation approach. Longer time to T2 progression was associated with increased survival and may be a surrogate for favourable tumour biology.

Update on Embolization Therapies for Hepatocellular Carcinoma

PURPOSE OF REVIEW

The purpose of the review is to summarize the latest applications for embolotherapy in the management of patients with HCC according to BCLC stage.

RECENT FINDINGS

While traditionally reserved for patients with unresectable HCC and stage B disease, there is an important role for embolization therapies in earlier stage patients as an adjunct to ablation, bridging, or downstaging therapy, as a means to improve safety of resection, and potentially as an arterial ablative option in the case of radioembolization. Newer applications of radioembolization such as radiation segmentectomy have the potential to provide cure in localized unifocal disease, and transarterial chemoembolization-portal vein embolization and radiation lobectomy may provide a combination of treatment and future liver remnant hypertrophy for planned hepatic resection. There is also an increasing role for embolization in the treatment of stage C disease, and recent data suggest it can be used in combination with sorafenib with the potential for survival benefit over sorafenib alone, even in the case of portal vein tumor thrombus. Embolization therapies play an increasingly important role in patients with BCLC stage A-C hepatocellular carcinoma. While different therapies may be offered on a patient-specific basis, there are limited prospective RCT data to support superiority of one technique over another.