Efficacy of loco-regional ablation therapy of HCC in a population of liver transplanted patients

Trans-arterial chemoembolization as a loco-regional inducer of immunogenic cell death in hepatocellular carcinoma: implications for immunotherapy

BACKGROUND

Modulation of adaptive immunity may underscore the efficacy of trans-arterial chemoembolization (TACE). We evaluated the influence of TACE on T-cell function by phenotypic lymphocyte characterization in samples of patients undergoing surgery with (T+) or without (T-) prior-TACE treatment.

METHODS

We profiled intratumoral (IT), peritumoral (PT) and non-tumoral (NT) background tissue to evaluate regulatory CD4+/FOXP3+ (T-reg) and immune-exhausted CD8+/PD-1+ T-cells across T+ (n=58) and T- (n=61). We performed targeted transcriptomics and T-cell receptor sequencing in a restricted subset of samples (n=24) evaluated in relationship with the expression of actionable drivers of anti-cancer immunity including PD-L1, indoleamine 2,3 dehydrogenase (IDO-1), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), Lag-3, Tim-3 and CD163.

RESULTS

We analyzed 119 patients resected (n=25, 21%) or transplanted (n=94, 79%) for Child-Pugh A (n=65, 55%) and Barcelona Clinic Liver Cancer stage A (n=92, 77%) hepatocellular carcinoma. T+ samples displayed lower IT CD4+/FOXP3+ (p=0.006), CD8+ (p=0.002) and CD8+/PD-1+ and NT CD8+/PD-1+ (p<0.001) compared with T-. Lower IT (p=0.005) and NT CD4+/FOXP3+ (p=0.03) predicted for improved recurrence-free survival. In a subset of samples (n=24), transcriptomic analysis revealed upregulation of a pro-inflammatory response in T+. T+ samples were enriched for IRF2 expression (p=0.01), an interferon-regulated transcription factor implicated in cancer immune-evasion. T-cell clonality and expression of PD-L1, IDO-1, CTLA-4, Lag-3, Tim-3 and CD163 was similar in T+ versus T-.

CONCLUSIONS

TACE is associated with lower IT density of immune-exhausted effector cytotoxic and T-regs, with significant upregulation of pro-inflammatory pathways. This highlights the pleiotropic effects of TACE in modulating the tumor microenvironment and strengthens the rationale for developing immunotherapy alongside TACE.

Gross and microscopic changes of liver neoplasms and background hepatic structures following neoadjuvant therapy

Liver transplantation is a surgical option with curative intent used in the management of some cases of hepatocellular carcinoma and cholangiocarcinoma (hilar, rarely intrahepatic). A number of different therapeutic modalities including ablative techniques, arterially directed therapies, radiation and chemotherapy are used in the neoadjuvant setting prior to liver transplantation with the goals of preventing tumour progression, decreasing post-transplant recurrence and possibly downstaging patients with tumour burden beyond what is acceptable by current transplant criteria. Pathologists evaluating hepatic explants must be aware of these neoadjuvant therapies and the alterations induced by them in both tumourous and non-tumourous tissue. In this review, we discuss common neoadjuvant therapies used in in this setting, as well as the gross and microscopic changes induced by these presurgical treatments within hepatic neoplasms as well as the background hepatic parenchyma and nearby structures. Select secondary tumours involving the liver which are pretreated will also be discussed. Finally, proper reporting of these changes will be mentioned.

Liver transplantation as a management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and has a poor prognosis if untreated. It is ranked the third among the causes of cancer-related death. There are multiple etiologic factors that can lead to HCC. Screening for early HCC is challenging due to the lack of well specific biomarkers. However, early diagnosis through successful screening is very important to provide cure rate. Liver transplantation (LT) did not gain wide acceptance until the mid-1980s, after the effective immunosuppression with cyclosporine became available. Orthotopic LT is the best therapeutic option for early, unresectable HCC. It is limited by both, graft shortage and the need for appropriate patient selection. It provides both, the removal of tumor and the remaining cirrhotic liver. In Milan, a prospective cohort study defined restrictive selection criteria known as Milan criteria (MC) that led to superior survival for transplant patients in comparison with any other previous experience with transplantation or other options for HCC. When transplantation occurs within the established MC, the outcomes are similar to those for nonmalignant liver disease after transplantation. The shortage of organs from deceased donors has led to the problems of long waiting times and dropouts. This has led to the adoption of extended criteria by many centers. Several measures have been taken to solve these problems including prioritization of patients with HCC, use of pretransplant adjuvant treatment, and living donor LT.

Review article: liver transplantation for hepatocellular carcinoma - a critical appraisal of the current worldwide listing criteria

BACKGROUND

Liver transplantation (LT) plays an important role in the management of patients with hepatocellular carcinoma (HCC). Although early results following LT for HCC were poor, since the introduction of the Milan criteria in 1996 morphological criteria have since been well established. Thereafter, various expansions of the Milan criteria were introduced worldwide. Listing criteria for LT for HCC in the United Kingdom (UK) initially conformed to the Milan criteria but were re-defined in 2009 by expansion of the Milan criteria.

AIMS

To look at the evidence in literature on listing criteria and management of HCC worldwide in comparison with the UK. Secondly, we aim to review worldwide vs. UK literature on prioritisation models, loco-regional therapy protocols and role of alpha-fetoprotein (AFP) in LT for HCC.

METHODS

An electronic literature search with Medline was carried out to identify articles related to LT for HCC.

RESULTS

Although various expansions of the Milan criteria have been described, they remain the gold standard against which other criteria are measured. The UK criteria are an expansion of the Milan criteria that go beyond Milan and University of California, San Francisco (UCSF) criteria. The current UK listing criteria for LT for HCC when compared to the worldwide criteria have a worse survival benefit (projected 5-year survival between 35-50%) when plotted on the metroticket calculator.

CONCLUSIONS

In keeping with most transplant centres worldwide, the UK have adopted expansions to Milan to allow more patients to benefit from LT. However, currently, as it stands the UK criteria when plotted in the modification of the Metroticket model project worse survival that would seem unjustified.

Mixed phenotype hepatocellular carcinoma after transarterial chemoembolization and liver transplantation

We investigated the phenotype of hepatocellular carcinoma (HCC) in livers removed during transplantation after local ablation therapy by transarterial chemoembolization (TACE). This study involved 80 HCC nodules (40 treated with TACE and 40 not treated with local ablation before transplantation) observed in 64 explanted livers and included clinicopathological evaluations as well as single and double immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR) for cytokeratin 19 (CK19), epithelial cell adhesion molecule (EpCAM), neural cell adhesion molecule (NCAM), and CD133. HCCs with complete necrosis post-TACE without viable tumors were excluded from the analysis. Cholangiolar, glandular, or spindle cell areas suggestive of a mixed hepatocholangiocellular phenotype were seen in 14 post-TACE HCCs and in none of the non-TACE HCCs (P < 0.001). According to single-epitope immunohistochemistry of post-TACE HCCs, CD133, CK19, EpCAM, and NCAM were expressed in 14 (35%), 8 (20%), 12 (30%), and 8 (20%), respectively. Only EpCAM was detected in 4 non-TACE HCC cases (10%). RT-PCR experiments using tissues obtained by laser microdissection showed that 4 of 5 investigated post-TACE HCCs expressed at least 1 of the markers, which were coexpressed in 3 of 5 tumors, whereas CD133 and EpCAM were individually expressed in 2 non-TACE HCCs. Double immunostaining showed that CD133(+) cells frequently coexpressed CK19, EpCAM, or NCAM. Interestingly, the recurrence rate for patients with CD133(+) post-TACE HCC was significantly higher than the rate for patients with CD133(-) post-TACE HCC (P = 0.025). In conclusion, HCC with the combined hepatocholangiocellular phenotype appears to be more frequent in post-TACE HCC versus untreated HCC. Further studies are needed to investigate the potential relationships between TACE and HCC subpopulations with a chemoembolization-resistant phenotype and their clinical significance.

Liver transplantation for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the commonest primary malignancy of the liver. It usually occurs in the setting of chronic liver disease and has a poor prognosis if untreated. Orthotopic liver transplantation (OLT) is a suitable therapeutic option for early, unresectable HCC particularly in the setting of chronic liver disease. Following on from disappointing initial results, the seminal study by Mazzaferro et al in 1996 established OLT as a viable treatment for HCC. In this study, the “Milan criteria” were applied achieving a 4-year survival rate similar to OLT for benign disease. Since then various groups have attempted to expand these criteria whilst maintaining long term survival rates. The technique of living donor liver transplantation has evolved over the past decade, particularly in Asia, and published outcome data is comparable to that of OLT. This article will review the evidence, indications, and the future direction of liver transplantation for liver cancer.