Identification of an Upper Limit of Tumor Burden for Downstaging in Candidates with Hepatocellular Cancer Waiting for Liver Transplantation: A West-East Collaborative Effort

Immunotherapy for hepatocellular carcinoma: The next evolution in expanding access to liver transplantation

Immunotherapy has revolutionised the treatment of advanced hepatocellular carcinoma (HCC). In addition, several phase III trials of immunotherapy in combination with surgical or locoregional therapies for early-to intermediate-stage HCC have recently reported positive results, and other phase III trials in the same patient population are currently in progress. As the application of immunotherapy is shifting to include patients with earlier stages of HCC, one looming question now emerges: What is the role of immunotherapy in the pre-liver transplant population? Liver transplantation is a potentially curative therapy for HCC and confers the additional advantage of restoring a normal, healthy liver. In pre-transplant patients, immunotherapy may improve downstaging success and tumour control at the cost of some immunologic risks. These include immune-related toxicities, which are particularly relevant in a uniquely vulnerable population with chronic liver disease, and the possibility of acute rejection after transplantation. Ultimately, the goal of immunotherapy in this population will be to effectively expand access to liver transplantation while preserving pre- and post-transplant outcomes. In this review, we discuss the mechanisms supporting combination immunotherapy, summarise key recent clinical data from major immunotherapy trials, and explore how immunotherapy can be applied in the neoadjuvant setting prior to liver transplantation in selected high-risk patients.

Combined transarterial chemoembolization and thermal ablation in candidates to liver transplantation with hepatocellular carcinoma: pathological findings and post-transplant outcome

OBJECTIVES

Evaluating the pathological response and the survival outcomes of combined thermal ablation (TA) and transarterial chemoembolization (TACE) as a bridge or downstaging for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) > 3 cm.

MATERIALS AND METHODS

A retrospective review encompassed 36 consecutive patients who underwent combined TA-TACE as bridging or downstaging before LT. Primary objectives included necrosis of the target lesion at explant pathology, post-LT overall survival (OS) and post-LT recurrence-free survival (RFS). For OS and RFS, a comparison with 170 patients subjected to TA alone for nodules <3 cm in size was also made.

RESULTS

Out of the 36 patients, 63.9% underwent TA-TACE as bridging, while 36.1% required downstaging. The average node size was 4.25 cm. All cases were discussed in a multidisciplinary tumor board to assess the best treatment for each patient. Half received radiofrequency (RF), and the other half underwent microwave (MW). All nodes underwent drug-eluting beads (DEB) TACE with epirubicin. The mean necrosis percentage was 65.9% in the RF+TACE group and 83.3% in the MW+TACE group (p-value = 0.099). OS was 100% at 1 year, 100% at 3 years and 94.7% at 5 years. RFS was 97.2% at 1 year, 94.4% at 3 years and 90% at 5 years. Despite the different sizes of the lesions, OS and RFS did not show significant differences with the cohort of patients subjected to TA alone.

CONCLUSIONS

The study highlights the effectiveness of combined TA-TACE for HCC>3 cm, particularly for bridging and downstaging to LT, achieving OS and RFS rates significantly exceeding 80% at 1, 3 and 5 years.

From evidence to clinical practice: Bridging the gap of new liver cancer therapies in Latin America

The most common primary liver tumors are hepatocellular carcinoma and cholangiocarcinoma. They constitute the sixth most common neoplasia and the third cause of cancer-related deaths worldwide. Although both tumors may share etiologic factors, diagnosis, prognostic factors, and treatments, they differ substantially in determining distinctive clinical management. In recent years, significant advances have been made in the management of these neoplasms, particularly in advanced stages. In this review, we focus on the most relevant diagnostic, prognostic, and treatment aspects of both, hepatocellular carcinoma and cholangiocarcinoma, underlying their applicability in Latin America.

Multidisciplinary Treatment of Hepatocellular Carcinoma in 2023: Italian practice Treatment Guidelines of the Italian Association for the Study of the Liver (AISF), Italian Association of Medical Oncology (AIOM), Italian Association of Hepato-Bilio-Pancreatic Surgery (AICEP), Italian Association of Hospital Gastroenterologists (AIGO), Italian Association of Radiology and Clinical Oncology (AIRO), Italian Society of Pathological Anatomy and Diagnostic Cytology (SIAPeC-IAP), Italian Society of Surgery (SIC), Italian Society of Gastroenterology (SIGE), Italian Society of Medical and Interventional Radiology (SIRM), Italian Organ Transplant Society (SITO), and Association of Patients with Hepatitis and Liver Disease (EpaC) - Part I - Surgical treatments

Worldwide, hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death. The remarkable improvements in treating HCC achieved in the last years have increased the complexity of HCC management. Following the need to have updated guidelines on the multidisciplinary treatment management of HCC, the Italian Scientific Societies involved in the management of this cancer have promoted the drafting of a new dedicated document. This document was drawn up according to the GRADE methodology needed to produce guidelines based on evidence. Here is presented the first part of guidelines, focused on the multidisciplinary tumor board of experts and surgical treatments of HCC.

AFP score and metroticket 2.0 perform similarly and could be used in a "within-ALL" clinical decision tool

BACKGROUND & AIMS

Two recently developed composite models, the alpha-fetoprotein (AFP) score and Metroticket 2.0, could be used to select patients with hepatocellular carcinoma (HCC) who are candidates for liver transplantation (LT). The aim of this study was to compare the predictive performance of both models and to evaluate the net risk reclassification of post-LT recurrence between them using each model's original thresholds.

METHODS

This multicenter cohort study included 2,444 adult patients who underwent LT for HCC in 47 centers from Europe and Latin America. A competing risk regression analysis estimating sub-distribution hazard ratios (SHRs) and 95% CIs for recurrence was used (Fine and Gray method). Harrell's adapted c-statistics were estimated. The net reclassification index for recurrence was compared based on each model's original thresholds.

RESULTS

During a median follow-up of 3.8 years, there were 310 recurrences and 496 competing events (20.3%). Both models predicted recurrence, HCC survival and survival better than Milan criteria (p <0.0001). At last tumor reassessment before LT, c-statistics did not significantly differ between the two composite models, either as original or threshold versions, for recurrence (0.72 vs. 0.68; p = 0.06), HCC survival, and overall survival after LT. We observed predictive gaps and overlaps between the model's thresholds, and no significant gain on reclassification. Patients meeting both models ("within-ALL") at last tumor reassessment presented the lowest 5-year cumulative incidence of HCC recurrence (7.7%; 95% CI 5.1-11.5) and higher 5-year post-LT survival (70.0%; 95% CI 64.9-74.6).

CONCLUSIONS

In this multicenter cohort, Metroticket 2.0 and the AFP score demonstrated a similar ability to predict HCC recurrence post-LT. The combination of these composite models might be a promising clinical approach.

IMPACT AND IMPLICATIONS

Composite models were recently proposed for the selection of liver transplant (LT) candidates among individuals with hepatocellular carcinoma (HCC). We found that both the AFP score and Metroticket 2.0 predicted post-LT HCC recurrence and survival better than Milan criteria; the Metroticket 2.0 did not result in better reclassification for transplant selection compared to the AFP score, with predictive gaps and overlaps between the two models; patients who met low-risk thresholds for both models had the lowest 5-year recurrence rate. We propose prospectively testing the combination of both models, to further optimize the LT selection process for candidates with HCC.

The Role of Radiomics and AI Technologies in the Segmentation, Detection, and Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary hepatic neoplasm. Thanks to recent advances in computed tomography (CT) and magnetic resonance imaging (MRI), there is potential to improve detection, segmentation, discrimination from HCC mimics, and monitoring of therapeutic response. Radiomics, artificial intelligence (AI), and derived tools have already been applied in other areas of diagnostic imaging with promising results. In this review, we briefly discuss the current clinical applications of radiomics and AI in the detection, segmentation, and management of HCC. Moreover, we investigate their potential to reach a more accurate diagnosis of HCC and to guide proper treatment planning.

The impact of biological features for a better prediction of posttransplant hepatocellular cancer recurrence

PURPOSE OF REVIEW

Morphological criteria (i.e., Milan Criteria) have been considered for a long time to be the best tool for selecting patients with hepatocellular cancer (HCC) waiting for liver transplantation (LT). In the last ten years, a refinement of the selection criteria has been observed, with the introduction of biological tumor characteristics enabling to enlarge the number of potential transplant candidates and to select LT candidates with a lower risk of posttransplant recurrence.

RECENT FINDINGS

Several biological tumor aspects have been explored and validated in international cohorts to expand the ability to predict patients at high risk for recurrence. Alpha-fetoprotein, radiological response to locoregional treatments, and other more recently proposed markers have been principally explored. Moreover, more complex statistical approaches (i.e., deep learning) have been advocated to explore the nonlinear intercorrelations between the investigated features.

SUMMARY

The addition of biological aspects to morphology has improved the ability to discriminate among high- and low-risk patients for recurrence. New prognostic algorithms based on the more sophisticated artificial intelligence approach are further improving the capability to select LT candidates with HCC.

Patient Selection for Downstaging of Hepatocellular Carcinoma Prior to Liver Transplantation—Adjusting the Odds?

Background and Aims: Morphometric features such as the Milan criteria serve as standard criteria for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC). Since it has been recognized that these criteria are too restrictive and do not adequately display the tumor biology, additional selection parameters are emerging.

Methods: Concise review of the current literature on patient selection for downstaging and LT for HCC outside the Milan criteria.

Results: The major task in patients outside the Milan criteria is the need for higher granularity with patient selection, since the benefit through LT is not uniform. The recent literature clearly shows that beneath tumor size and number, additional selection parameters are useful in the process of patient selection for and during downstaging. For initial patient selection, the alpha fetoprotein (AFP) level adds additional information to the size and number of HCC nodules concerning the chance of successful downstaging and LT. This effect is quantifiable using newer selection tools like the WE (West-Eastern) downstaging criteria or the Metroticket 2.0 criteria. Also an initial PET-scan and/or tumor biopsy can be helpful, especially in the high risk group of patients outside the University of California San Francisco (UCSF) criteria. After this entry selection, the clinical course during downstaging procedures concerning the tumor and the AFP response is of paramount importance and serves as an additional final selection tool.

Conclusion: Selection criteria for liver transplantation in HCC patients are becoming more and more sophisticated, but are still imperfect. The implementation of molecular knowledge will hopefully support a more specific risk prediction for HCC patients in the future, but do not provide a profound basis for clinical decision-making at present.

Prognostic role of selection criteria for liver transplantation in patients with hepatocellular carcinoma: a network meta-analysis

BACKGROUND

Patients with hepatocellular carcinoma (HCC) are selected for transplantation if they have a low tumour burden and low risk of recurrence. The morphometric Milan criteria have been the cornerstone for patient selection, but dynamic morphological and biological tumour characteristics surfaced as an encouraging tool to refine the selection of patients with HCC and to support the expansion of the Milan criteria. The outcomes of the most prevalent models that select patients with HCC for liver transplantation were analysed in this study, which aimed to identify the selection model that offered the best recurrence-free and overall survival after transplantation.

METHODS

Studies that compared Milan, University of California San Francisco (UCSF), up-to-seven (UPTS), alpha-fetoprotein (AFP), and MetroTicket 2.0 (MT2) models were included. One-year, 3-year, and 5-year recurrence-free and overall survival rates of patients selected for transplantation using different models were analysed.

RESULTS

A total of 60 850 adult patients with HCC selected for liver transplantation using Milan, UCSF, UPTS, AFP, or MT2 criteria were included. Patients selected for transplantation using the MT2 model had the highest 1-, 3-, and 5-year recurrence-free survival. In addition, patients selected for transplantation using MT2 criteria had the best 1- and 3-year overall survival, whereas patients selected for transplantation using the Milan criteria had the best 5-year overall survival rates.

CONCLUSION

The MT2 model offered the best post-transplant outcomes in patients with HCC, highlighting the importance of considering tumour morphology and biology when selecting patients with HCC for liver transplantation.

International study on the outcome of locoregional therapy for liver transplant in hepatocellular carcinoma beyond Milan criteria

BACKGROUND & AIMS

Good outcomes after liver transplantation (LT) have been reported after successfully downstaging to Milan criteria in more advanced hepatocellular carcinoma (HCC). We aimed to compare post-LT outcomes in patients receiving locoregional therapies (LRT) before LT according to Milan criteria and University of California San Francisco downstaging (UCSF-DS) protocol and 'all-comers'.

METHODS

This multicentre cohort study included patients who received any LRT before LT from Europe and Latin America (2000-2018). We excluded patients with alpha-foetoprotein (AFP) above 1,000 ng/ml. Competing risk regression analysis for HCC recurrence was conducted, estimating subdistribution hazard ratios (SHRs) and corresponding 95% CIs.

RESULTS

From 2,441 LT patients, 70.1% received LRT before LT (n = 1,711). Of these, 80.6% were within Milan, 12.0% within UCSF-DS, and 7.4% all-comers. Successful downstaging was achieved in 45.2% (CI 34.8-55.8) and 38.2% (CI 25.4-52.3) of the UCSF-DS group and all-comers, respectively. The risk of recurrence was higher for all-comers (SHR 6.01 [p <0.0001]) and not significantly higher for the UCSF-DS group (SHR 1.60 [p = 0.32]), compared with patients remaining within Milan. The all-comers presented more frequent features of aggressive HCC and higher tumour burden at explant. Among the UCSF-DS group, an AFP value of ≤20 ng/ml at listing was associated with lower recurrence (SHR 2.01 [p = 0.006]) and better survival. However, recurrence was still significantly high irrespective of AFP ≤20 ng/ml in all-comers.

CONCLUSIONS

Patients within the UCSF-DS protocol at listing have similar post-transplant outcomes compared with those within Milan when successfully downstaged. Meanwhile, all-comers have a higher recurrence and inferior survival irrespective of response to LRT. Additionally, in the UCSF-DS group, an ALP of ≤20 ng/ml might be a novel tool to optimise selection of candidates for LT.

CLINICAL TRIAL NUMBER

This study was registered as part of an open public registry (NCT03775863).

LAY SUMMARY

Patients with more extended HCC (within the UCSF-DS protocol) successfully downstaged to the conventional Milan criteria do not have a higher recurrence rate after LT compared with the group remaining in the Milan criteria from listing to transplantation. Moreover, in the UCSF-DS patient group, an ALP value equal to or below 20 ng/ml at listing might be a novel tool to further optimise selection of candidates for LT.

Sustained Complete Response after Biological Downstaging in Patients with Hepatocellular Carcinoma: XXL-Like Prioritization for Liver Transplantation or "Wait and See" Strategy?

The XXL trial represents the first prospective validation of "biological downstaging" in liver transplantation (LT) for hepatocellular carcinoma. The aim of this study was to compare the Padua downstaging protocol to the XXL protocol in terms of downstaging failure rates and patient outcome. A total of 191 patients undergoing aggressive surgical downstaging and potentially eligible for LT from 2012 to 2018 at our center were retrospectively selected according to XXL trial criteria. Unlike the XXL trial, patients with a complete response to downstaging did not receive any prioritization for LT. Downstaging failure was defined as stable progressive disease or post-treatment mortality. The statistical method of "matching-adjusted indirect comparison" was used to match the study group to the XXL population. Downstaging failure rate was considerably lower in the study group than in the XXL trial (12% vs. 32%, d value = |0.683|). The survival curves of our LT group (n = 68) overlapped with those of the LT-XXL group (p = 0.846). Survival curves of non-LT candidates with a sustained complete response (n = 64) were similar to those of transplanted patients (p = 0.281). Our study represents a validation of the current Padua and Italian policies of denying rapid prioritization to patients with complete response to downstaging. Such a policy seems to spare organs without worsening patient outcome.

Expanding the Limits of Liver Transplantation for Hepatocellular Carcinoma: Is There a Limit?

Liver transplantation is a treatment option for hepatocellular carcinoma within Milan criteria. With careful selection practices, patients with larger tumors can do well with successful downstaging followed by liver transplantation and should not be excluded based on tumor size or number alone. When considering expanded criteria for hepatocellular carcinoma, however, survival outcomes after liver transplantation should be comparable with patients without hepatocellular carcinoma. Surrogate measures of tumor biology, such as α-fetoprotein, other biomarkers, and dynamic tumor behavior including response to locoregional therapy can aid in risk stratification of patients before liver transplantation.

Incorporating Tumor Biology to Predict Hepatocellular Carcinoma Recurrence in Patients Undergoing Living Donor Liver Transplantation Using Expanded Selection Criteria

Conventional selection criteria for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) are based on tumour size/number only, and do not consider vital surrogates of tumor biology such as alpha-fetoprotein (AFP) and tumor [¹⁸ F]fluorodeoxyglucose positron emission tomography ([¹⁸ F]FDG PET) avidity. We analyzed survival outcomes, and predictors of HCC recurrence in 405 patients with cirrhosis and HCC (HCC-cirr) who underwent living donor LT (LDLT) using our expanded selection criteria: no extrahepatic disease or major vascular invasion, irrespective of tumor size/number. Fifty-one percent patients had tumours beyond Milan, and 43% beyond the University of California San Francisco [UCSF] criteria. The 5-year overall survival (OS) and recurrence-free survival (RFS) were 64% and 70%, respectively. Three preoperatively available factors predicted recurrence: pre-LT AFP ≥100 ng/mL (P = 0.005; hazard ratio [HR], 2.190), tumor burden beyond the UCSF criteria (P = 0.001; HR, 2.640), and [¹⁸ F]FDG PET avidity (P = 0.004; HR, 2.442). A prognostic model based on the number and combination of the aforementioned preoperative risk factors was developed using a competing-risk RFS model. Three risk groups were identified: low (none or a single risk factor present, 9.3% recurrence), moderate (AFP ≥100 ng/mL and [¹⁸ F]FDG PET avidity, or beyond UCSF tumor and [¹⁸ F]FDG PET avidity, 25% recurrence), and high (AFP ≥100 ng/mL and beyond UCSF, or presence of all 3 risk factors, 46% recurrence). Acceptable long-term outcomes were achieved using our expanded selection criteria. Our prognostic model to predict recurrence based on preoperative biological and morphological factors could guide pretransplant management (downstaging versus upfront LDLT) with the aim of reducing post-LDLT recurrence.

Liver transplantation for hepatocellular carcinoma: impact of expansion criteria in a multicenter cohort study from a high waitlist mortality region

This study aimed to compare liver transplantation (LT) outcomes and evaluate the potential rise in numbers of LT candidates with hepatocellular carcinoma (HCC) of different allocation policies in a high waitlist mortality region. Three policies were applied in two Latin American cohorts (1085 HCC transplanted patients and 917 listed patients for HCC): (i) Milan criteria with expansion according to UCSF downstaging (UCSF-DS), (ii) the AFP score, and (iii) restrictive policy or Double Eligibility Criteria (DEC; within Milan + AFP score ≤2). Increase in HCC patient numbers was evaluated in an Argentinian prospective validation set (INCUCAI; NCT03775863). Expansion criteria in policy A showed that UCSF-DS [28.4% (CI 12.8-56.2)] or "all-comers" [32.9% (CI 11.9-71.3)] had higher 5-year recurrence rates compared to Milan, with 10.9% increase in HCC patients for LT. The policy B showed lower recurrence rates for AFP scores ≤2 points, even expanding beyond Milan criteria, with a 3.3% increase. Patients within DEC had lower 5-year recurrence rates compared with those beyond DEC [13.3% (CI 10.1-17.3) vs 24.2% (CI 17.4-33.1; P = 0.0006], without significant HCC expansion. In conclusion, although the application of a stricter policy may optimize the selection process, this restrictive policy may lead to ethical concerns in organ allocation (NCT03775863).

Using Hepatocellular Carcinoma Tumor Burden Score to Stratify Prognosis after Liver Transplantation

Liver transplantation (LT) remains a mainstay of treatment for hepatocellular carcinoma (HCC). Tumor factors such as size and number of tumors define eligibility for LT using the Milan criteria. The tumor burden score (TBS) incorporates both tumor number and size into a single continuous variable and has been used to differentiate prognosis among patients undergoing resection for HCC. The objective of the present study was to evaluate the ability of the TBS to predict overall and recurrence-free survival in patients undergoing LT for HCC. The Scientific Registry of Transplant Recipients (SRTR) was used to analyze all liver transplants for HCC, with initial tumor size data from 2004 to 2018. There were 12,486 patients in the study period. In the unadjusted analyses, patients with a high TBS had worse overall (p < 0.0001) and recurrence-free (p < 0.0001) survival. In the adjusted analyses, a high TBS was associated with a greater hazard ratio (HR) of death (HR = 1.21; 95%CI, [1.13-1.30]; p < 0.001) and recurrence (HR = 1.49; 95%CI [1.3-1.7]; p < 0.001). When we superimposed the TBS on the Milan criteria, we saw that a higher TBS was associated with a higher hazard of recurrence at values that were either all within (HR = 1.20; 95%CI, [1.04-1.37]; p = 0.011) or variably within (HR = 1.53; 95%CI, [1.16-2.01]; p = 0.002) the Milan criteria. In conclusion, the TBS is a promising tool in predicting outcomes in patients with HCC after LT.

Prognostic role of artificial intelligence among patients with hepatocellular cancer: A systematic review

BACKGROUND

Prediction of survival after the treatment of hepatocellular carcinoma (HCC) has been widely investigated, yet remains inadequate. The application of artificial intelligence (AI) is emerging as a valid adjunct to traditional statistics due to the ability to process vast amounts of data and find hidden interconnections between variables. AI and deep learning are increasingly employed in several topics of liver cancer research, including diagnosis, pathology, and prognosis.

AIM

To assess the role of AI in the prediction of survival following HCC treatment.

METHODS

A web-based literature search was performed according to the Preferred Reporting Items for Systemic Reviews and Meta-Analysis guidelines using the keywords "artificial intelligence", "deep learning" and "hepatocellular carcinoma" (and synonyms). The specific research question was formulated following the patient (patients with HCC), intervention (evaluation of HCC treatment using AI), comparison (evaluation without using AI), and outcome (patient death and/or tumor recurrence) structure. English language articles were retrieved, screened, and reviewed by the authors. The quality of the papers was assessed using the Risk of Bias In Non-randomized Studies of Interventions tool. Data were extracted and collected in a database.

RESULTS

Among the 598 articles screened, nine papers met the inclusion criteria, six of which had low-risk rates of bias. Eight articles were published in the last decade; all came from eastern countries. Patient sample size was extremely heterogenous (n = 11-22926). AI methodologies employed included artificial neural networks (ANN) in six studies, as well as support vector machine, artificial plant optimization, and peritumoral radiomics in the remaining three studies. All the studies testing the role of ANN compared the performance of ANN with traditional statistics. Training cohorts were used to train the neural networks that were then applied to validation cohorts. In all cases, the AI models demonstrated superior predictive performance compared with traditional statistics with significantly improved areas under the curve.

CONCLUSION

AI applied to survival prediction after HCC treatment provided enhanced accuracy compared with conventional linear systems of analysis. Improved transferability and reproducibility will facilitate the widespread use of AI methodologies.