Hepatocellular cancer selection systems and liver transplantation: from the tower of babel to an ideal comprehensive score

Immunosuppression in liver transplant oncology: position paper of the Italian Board of Experts in Liver Transplantation (I-BELT)

Liver transplant oncology (TO) represents an area of increasing clinical and scientific interest including a heterogeneous group of clinical-pathological settings. Immunosuppressive management after LT is a key factor relevantly impacting result. However, disease-related guidance is still lacking, and many open questions remain in the field. Based on such a substantial lack of solid evidences, the Italian Board of Experts in Liver Transplantation (I-BELT) (a working group including representatives of all national transplant centers), unprecedently promoted a methodologically sound consensus conference on the topic, based on the GRADE approach. The group final recommendations are herein presented and commented. The 18 PICOs and Statements and their levels of evidence and grades of recommendation are reported and grouped into seven areas: (1) risk stratification by histopathological and bio-molecular parameters and role of mTORi post-LT; (2) steroids and HCC recurrence; (3) management of immunosuppression when HCC recurs after LT; (4) mTORi monotherapy; (5) machine perfusion and HCC recurrence after LT; (6) physiopathology of tumor-infiltrating lymphocytes and immunosuppression, the role of inflammation; (7) immunotherapy in liver transplanted patients. The interest in mammalian targets of rapamycin inhibitors (mTORi), for steroid avoidance and the need for a reduction to CNI exposure emerged from the consensus process. A selected list of unmet needs prompting further investigations have also been developed. The so far heterogeneous and granular approach to immunosuppression in oncologic patients deserves greater efforts for a more standardized therapeutic response to the different clinical scenarios. This consensus process makes a first unprecedented step in this direction, to be developed on a larger scale.

Role of protein induced by vitamin-K absence-II in transplanted patients with HCC not producing alpha-fetoprotein

Elevated Protein Induced by Vitamin-K Absence-II (PIVKA-II) has been shown to be an adverse prognostic factor in HCC patients undergoing liver transplantation (LT). No definitive data are available about the impact of PIVKA-II concerning post-LT recurrence in patients not secreting (≤ 20 ng/mL) alpha-fetoprotein (AFP). An observational retrospective study of the East-West HCC-LT consortium is reported. Between 2000 and 2019, 639 HCC patients were enrolled in 5 collaborative European and Japanese centers. To minimize the initial selection bias, an inverse probability therapy weighting method was adopted to analyze the data. In the post-inverse probability therapy weighting population, PIVKA-II (HR = 2.00; 95% CI: 1.52-2.64; p < 0.001) and AFP (HR=1.82; 95% CI: 1.48-2.24; p < 0.001) were the most relevant independent risk factors for post-LT recurrence. A sub-analysis focusing only on patients who are AFP non-secreting confirmed the negative role of PIVKA-II (HR=2.06, 95% CI: 1.26-3.35; p =0.004). When categorizing the entire population into 4 groups according to the AFP levels (≤ or > 20 ng/mL) and PIVKA (≤ or > 300 mUA/mL) at the time of LT, the lowest recurrence rates were observed in the low AFP-PIVKA-II group (5-year recurrence rate = 8.0%). Conversely, the high AFP-PIVKA-II group had the worst outcome (5-year recurrence rate = 35.1%). PIVKA-II secretion is a relevant risk factor for post-LT HCC recurrence. The role of this marker is independent of the AFP status. Combining both tumor markers, especially in the setting of LT, should be of great relevance for adding information about predicting the post-LT risk of tumor recurrence and selecting these patients for transplantation.

Transplant oncology - Current indications and strategies to advance the field

Liver transplantation (LT) was originally described by Starzl as a promising strategy to treat primary malignancies of the liver. Confronted with high recurrence rates, indications drifted towards non-oncologic liver diseases with LT finally evolving from a high-risk surgery to an almost routine surgical procedure. Continuously improving outcomes following LT and evolving oncological treatment strategies have driven renewed interest in transplant oncology. This is not only reflected by constant refinements to the criteria for LT in patients with HCC, but especially by efforts to expand indications to other primary and secondary liver malignancies. With new patient-centred oncological treatments on the rise and new technologies to expand the donor pool, the field has the chance to come full circle. In this review, we focus on the concept of transplant oncology, current indications, as well as technical and ethical aspects in the context of donor organs as precious resources.

Impact of tumor size on the outcomes of hepatic resection for hepatocellular carcinoma: a retrospective study

BACKGROUND

To evaluate the impact of tumor size on the perioperative and long-term outcomes of liver resection for hepatocellular carcinoma (HCC).

METHODS

We reviewed the patients' data who underwent liver resection for HCC between November 2009 and 2019. Patients were divided into 3 groups according to the tumor size. Group I: HCC < 5 cm, Group II: HCC between 5 to 10 cm, and Group III: HCC ≥ 10 cm in size.

RESULTS

Three hundred fifteen patients were included in the current study. Lower platelets count was noted Groups I and II. Higher serum alpha-feto protein was noted in Group III. Higher incidence of multiple tumors, macroscopic portal vein invasion, nearby organ invasion and presence of porta-hepatis lymph nodes were found in Group III. More major liver resections were performed in Group III. Longer operation time, more blood loss and more transfusion requirements were found in Group III. Longer hospital stay and more postoperative morbidities were noted in Group III, especially posthepatectomy liver failure, and respiratory complications. The median follow-up duration was 17 months (7-110 months). Mortality occurred in 100 patients (31.7%) and recurrence occurred in 147 patients (46.7%). There were no significant differences between the groups regarding recurrence free survival (Log Rank, p = 0.089) but not for overall survival (Log Rank, p = 0.001).

CONCLUSION

HCC size is not a contraindication for liver resection. With proper selection, safe techniques and standardized care, adequate outcomes could be achieved.

Liver transplantation for HCC in cirrhosis: Are Milan criteria outdated?

In Germany, organ allocation is based on the MELD-system and lab-MELD is usually low in patients with hepatocellular carcinoma (HCC) in cirrhosis. Higher medical urgency can be achieved by standard exception for HCC (SE-HCC), if Milan criteria (MC) are met. Noteworthy, UNOS T2 reflects MC, but excludes singular lesions < 2 cm. Thus, SE-HCC is awarded to patients with one lesion between 2 and 5 cm or 2 to 3 lesions between 1 and 3 cm. These criteria are static and do not reflect biological properties of HCC.We present a retrospective cohort of 111 patients, who underwent liver transplantation at UKSH, Campus Kiel between 2007 and 2017. No difference was found in overall survival for patient cohorts using Milan, UCSF, up-to-seven, and French-AFP criteria. However, there was a significantly reduced survival, if microvascular invasion was detected in the explanted organ and in patients with HCC-recurrence. The exclusive use of static selection criteria including MC appear to limit the access to liver transplantation.

The Role of Donor Gamma-Glutamyl Transferase as a Risk Factor for Early Graft Function after Liver Transplantation

BACKGROUND

Growing interest has been recently reported in the potential detrimental role of donor gamma-glutamyl transferase (GGT) peak at the time of organ procurement regarding the risk of poor outcomes after liver transplantation (LT). However, the literature on this topic is scarce and controversial data exist on the mechanisms justifying such a correlation. This study aims to demonstrate the adverse effect of donor GGT in a large European LT cohort regarding 90-day post-transplant graft loss.

METHODS

This is a retrospective international study investigating 1335 adult patients receiving a first LT from January 2004 to September 2018 in four collaborative European centers.

RESULTS

Two different multivariable logistic regression models were constructed to evaluate the risk factors for 90-day post-transplant graft loss, introducing donor GGT as a continuous or dichotomous variable. In both models, donor GGT showed an independent role as a predictor of graft loss. In detail, the log-transformed continuous donor GGT value showed an odds ratio of 1.46 (95% CI = 1.03-2.07; p = 0.03). When the donor GGT peak value was dichotomized using a cut-off of 160 IU/L, the odds ratio was 1.90 (95% CI = 1.20-3.02; p = 0.006). When the graft-loss rates were investigated, significantly higher rates were reported in LT cases with donor GGT ≥160 IU/L. In detail, 90-day graft-loss rates were 23.2% vs. 13.9% in patients with high vs. low donor GGT, respectively (log-rank p = 0.004). Donor GGT was also added to scores conventionally used to predict outcomes (i.e., MELD, D-MELD, DRI, and BAR scores). In all cases, when the score was combined with the donor GGT, an improvement in the model accuracy was observed.

CONCLUSIONS

Donor GGT could represent a valuable marker for evaluating graft quality at transplantation. Donor GGT should be implemented in scores aimed at predicting post-transplant clinical outcomes. The exact mechanisms correlating GGT and poor LT outcomes should be better clarified and need prospective studies focused on this topic.

Are patients with hepatocellular carcinoma and portal vein tumour thrombosis candidates for liver transplantation?

In this debate, the authors consider whether patients with hepatocellular carcinoma (HCC) and portal vein tumour thrombosis are candidates for liver transplantation (LT). The argument for LT in this context is based on the premise that, following successful downstaging treatment, LT confers a much greater clinical benefit in terms of survival outcomes than the available alternative (palliative systemic therapy). A major argument against relates to limitations in the quality of evidence for LT in this setting - in relation to study design, as well as heterogeneity in patient characteristics and downstaging protocols. While acknowledging the superior outcomes offered by LT for patients with portal vein tumour thrombosis, the counterargument is that expected survival in such patients is still below accepted thresholds for LT and, indeed, the levels achieved for other patients who receive transplants beyond the Milan criteria. Based on the available evidence, it seems too early for consensus guidelines to recommend such an approach, however, it is hoped that with higher quality evidence and standardised downstaging protocols, LT may soon be more widely indicated, including for this population with high unmet clinical need.

New Insights in the Setting of Transplant Oncology

Background and Objectives: Liver transplantation (LT) is the best strategy for curing several primary and secondary hepatic malignancies. In recent years, growing interest has been observed in the enlargement of the transplant oncology indications. This paper aims to review the most recent developments in the setting of LT oncology, with particular attention to LT for unresectable colorectal liver metastases (CRLM) and cholangiocellular carcinoma (CCA). Materials and Methods: A review of the recently published literature was conducted. Results: Growing evidence exists on the efficacy of LT in curing CRLM and peri-hilar and intrahepatic CCA in well-selected patients when integrating this strategy with (neo)-adjuvant chemotherapy, radiotherapy, or locoregional treatments. Conclusion: For unresectable CCA and CRLM management, several prospective protocols are forthcoming to elucidate LT’s impact relative to alternative therapies. Advances in diagnosis, treatment protocols, and donor-to-recipient matching are needed to better define the oncological indications for transplantation. Prospective, multicenter trials studying these advances and their impact on outcomes are still required.

Liver transplantation and portal vein tumour thrombus: futile enterprise?

PURPOSE OF REVIEW

To summarize recent evidence in literature regarding liver transplantation in patients with hepatocellular carcinoma (HCC) and portal vein tumour thrombosis (PVTT) with no extrahepatic disease. In addition, in this review, we have tried to highlight the advances in downstaging with ablative therapies that have made liver transplantation a possibility, and also the key points to focus on when considering liver transplantation in these patients with locally advanced HCC.

RECENT FINDINGS

Advances in the understanding of technicalities and effectiveness of ablative therapies, including transarterial chemoembolization, stereotactic body radiotherapy and transarterial radioembolization on PVTT have helped successfully downstage patients with HCC and PVTT to within transplant criteria. This provides the opportunity to offer a curative liver transplantation in these patients who are generally managed with systemic or palliative therapy alone with dismal prognosis. Meticulous patient selection based on tumour biology, documented downstaging based on imaging and decrease in tumour marker levels, an adequate waiting period to demonstrate stable disease, liver transplantation with some technical modifications, and a modified immunosuppression protocol may offer long-term survival in a select group of patients treated with initial downstaging therapies in an intention to treat strategy.

SUMMARY

In patients with HCC, presence of PVTT is generally considered the end of the road by many. A multidisciplinary approach combining ablation and a curative liver transplantation may offer the best hope of long-term survival in a select group of patients with favourable tumour biology. Although promising, current evidence is limited, and future studies with larger number of patients, and longer follow-up may pave the way for an elaborate selection algorithm to choose the ideal candidates for such a curative strategy in patients with locally advanced HCC with PVTT.

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.

Prognostic Factors for 10-Year Survival in Patients With Hepatocellular Cancer Receiving Liver Transplantation

Background

Long-term survival after liver transplantation (LT) for hepatocellular cancer (HCC) continues to increase along with the modification of inclusion criteria. This study aimed at identifying risk factors for 5- and 10-year overall and HCC-specific death after LT.

Methods

A total of 1,854 HCC transplant recipients from 10 European centers during the period 1987-2015 were analyzed. The population was divided in three eras, defined by landmark changes in HCC transplantability indications. Multivariable logistic regression analyses were used to evaluate the significance of independent risk factors for survival.

Results

Five- and 10-year overall survival (OS) rates were 68.1% and 54.4%, respectively. Two-hundred forty-two patients (13.1%) had HCC recurrence. Five- and 10-year recurrence rates were 16.2% and 20.3%. HCC-related deaths peaked at 2 years after LT (51.1% of all HCC-related deaths) and decreased to a high 30.8% in the interval of 6 to 10 years after LT. The risk factors for 10-year OS were macrovascular invasion (OR = 2.71; P = 0.001), poor grading (OR = 1.56; P = 0.001), HCV status (OR = 1.39; P = 0.001), diameter of the target lesion (OR = 1.09; P = 0.001), AFP slope (OR = 1.63; P = 0.006), and patient age (OR = 0.99; P = 0.01). The risk factor for 10-year HCC-related death were AFP slope (OR = 4.95; P < 0.0001), microvascular (OR = 2.13; P < 0.0001) and macrovascular invasion (OR = 2.32; P = 0.01), poor tumor grading (OR = 1.95; P = 0.001), total number of neo-adjuvant therapies (OR = 1.11; P = 0.001), diameter of the target lesion (OR = 1.11; P = 0.002), and patient age (OR = 0.97; P = 0.001). When analyzing survival rates in function of LT era, a progressive improvement of the results was observed, with patients transplanted during the period 2007-2015 showing 5- and 10-year death rates of 26.8% and 38.9% (vs. 1987-1996, P < 0.0001; vs. 1997-2006, P = 0.005).

Conclusions

LT generates long-term overall and disease-free survival rates superior to all other oncologic treatments of HCC. The role of LT in the modern treatment of HCC becomes even more valued when the follow-up period reaches at least 10 years. The results of LT continue to improve even when prudently widening the inclusion criteria for transplantation. Despite the incidence of HCC recurrence is highest during the first 5 years post-transplant, one-third of them occur later, indicating the importance of a life-long follow-up of these patients.

THE MANAGEMENT OF POST-TRANSPLANTATION RECURRENCE OF HEPATOCELLULAR CARCINOMA

The annual incidence of hepatocellular carcinoma (HCC) continues to rise. Over the last two decades, liver transplantation (LT) has become the preferable treatment of HCC, when feasible and strict selection criteria are met. With the rise in HCC-related LT, compounded by downstaging techniques and expansion of transplant selection criteria, a parallel increase in number of post-transplantation HCC recurrence is expected. Additionally, in the context of an immunosuppressed transplant host, recurrences may behave aggressively and more challenging to manage, resulting in poor prognosis. Despite this, no consensus or best practice guidelines for post-transplantation cancer surveillance and recurrence management for HCC currently exist. Studies with adequate population sizes and high-level evidence are lacking, and the role of systemic and locoregional therapies for graft and extrahepatic recurrences remains under debate. This review seeks to summarize the existing literature on post-transplant HCC surveillance and recurrence management. It highlights the value of early tumour detection, re-evaluating the immunosuppression regimen, and staging to differentiate disseminated recurrence from intrahepatic or extrahepatic oligo-recurrence. This ultimately guides decision-making and maximizes treatment effect. Treatment recommendations specific to recurrence type are provided based on currently available locoregional and systemic therapies.