Hepatocellular carcinoma in children and adolescents: results from the Pediatric Oncology Group and the Children's Cancer Group intergroup study

Clinical and immunophenotype correlating with response to immunotherapy in paediatric patients with primary liver carcinoma. A case series

BACKGROUND

Paediatric hepatocellular carcinomas (HCC) traditionally arise in the context of a normal structural and functional liver and carry a dismal prognosis. While chemotherapy is the frontline standard, there is emerging interest in the study of immunotherapies for paediatric patients with relapsed/refractory disease. There is limited data to support whether immunotherapies will be of utility in this patient population.

METHODS

Six paediatric patients (median age:16 years, range: 12-17 at the time of treatment) with advanced hepatocellular neosplams, either conventional hepatocellular or fibrolamellar carcinoma, were treated with immunotherapy. Patients were consented to institutional genomic profiling and biobanking protocols. Baseline samples and serial tissue samples, when available, were evaluated for somatic mutation rate, actionable gene mutations, and pan-immune bulk RNA expression profiling. Results were correlated with clinical course.

FINDINGS

Three patients responded to checkpoint inhibition: one achieved a complete, durable response and the other two, prolonged stable disease. Three additional patients progressed. Diagnostic tissue from the complete responder demonstrated a higher relative mutational burden and robust immune infiltrate. Pre-treatment samples from the three responders demonstrated decreased expression of genes associated with T-cell dysfunction.

INTERPRETATION

A subset of patients with primary paediatric hepatocellular tumours will respond to immunotherapy. Immunotherapies are currently under prospective study for relapsed/refractory liver tumours in paediatric patients. Results from this report support the prospective collection of serial serum and tissue samples which may further identify genomic and immunophenotypic patterns predictive of response.

FUNDING

This work was supported by Philanthropic funds (Pan Mass Challenge, Team Angus and Team Perspective).

Evaluation of surgical strategies and long-term outcomes in pediatric hepatocellular carcinoma

PURPOSE

Hepatocellular carcinoma (HCC), the second most common pediatric malignant liver tumor after hepatoblastoma, represents 1% of all pediatric tumors.

METHODS

A retrospective study was conducted on children with HCC treated at our center from March 2002 to October 2022, excluding those with inadequate follow-up or records. Demographic data, initial complaints, alpha-fetoprotein (AFP) values, underlying disease, size and histopathological features of the masses, chemotherapy, and long-term outcomes were analyzed.

RESULTS

Fifteen patients (8 boys, 7 girls) with a mean age of 11.4 ± 4.1 years (0.8-16.4 years) were analyzed. The majority presented with abdominal pain, with a median AFP of 3.9 ng/mL. Hepatitis B cirrhosis in one patient (6.6%) and metabolic disease (tyrosinemia type 1) in two patients (13.3%) were the underlying diseases. Histopathological diagnoses were fibrolamellar HCC (n:8; 53.3%), HCC (n:6; 40%). Four of the 15 patients underwent liver transplantation, and 9 underwent surgical resection. Due to late diagnosis, two patients were considered inoperable (13.3%). The survival rate for the four patients who underwent liver transplantation was found to be 75%.

CONCLUSION

Surgical treatment of various variants of HCC can be safely performed in experienced centers with a multidisciplinary approach, and outcomes are better than in adults.

The RELIVE consortium for relapsed or refractory pediatric hepatoblastoma and hepatocellular carcinoma: a scoping review of the problem and a proposed solution

Liver tumors account for approximately 2% of all pediatric malignancies. Children with advanced stages of hepatoblastoma (HB) are cured only 50-70% of the time while children with advanced hepatocellular carcinoma (HCC) have a <20% 5-year overall survival. This scoping review was performed to highlight the paucity of rigorous, reliable data guiding the management of relapsed pediatric HB or HCC. When these patients are enrolled on prospective trials, the trials are often histology-agnostic, exclude patients less than a year of age, lack a liquid formulary of the drug under study, exclude recipients of a solid organ transplant, and enroll only 1-2 patients limiting the ability to deduce efficacious regimens for current use or future study. We highlight the creation of a global pediatric consortium intended to source retrospective relapse data from over 100 institutions spanning 4 continents. The data collected from this effort will inform future relapse trials.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part I

Malignant focal liver lesions (FLLs) are commonly reported in adults but rarely seen in the pediatric population. Due to the rarity, the understanding of these diseases is still very limited. In children, most malignant FLLs are congenital. It is very important to choose appropriate imaging examination concerning various factors. This paper will outline common pediatric malignant FLLs, including hepatoblastoma, hepatocellular carcinoma, and cholangiocarcinoma and discuss them against the background of the latest knowledge on comparable/similar tumors in adults. Medical imaging features are of vital importance for the non-invasive diagnosis and follow-up of treatment of FLLs in pediatric patients. The use of CEUS in pediatric patients for characterizing those FLLs that remain indeterminate on conventional B mode ultrasounds may be an effective option in the future and has great potential to be integrated into imaging algorithms without the risk of exposure to ionizing radiation.

Children's Oncology Group's 2023 blueprint for research: Liver tumors

Liver tumors account for approximately 1%-2% of all pediatric malignancies, with the two most common tumors being hepatoblastoma (HB) and hepatocellular carcinoma (HCC). Previous Children's Oncology Group studies have meaningfully contributed to the current understanding of disease pathophysiology and treatment, laying groundwork for the ongoing prospective international study of both HB and HCC. Future work is focused on elucidating the biologic underpinnings of disease to support an evolution in risk categorization, advancements in the multidimensional care required to treat these patients, and the discovery of novel therapies.

Incidence and trends of hepatic cancer among children and adolescents in the United States from 2000 to 2017: Evidence from the Surveillance, Epidemiology, and End Results registry data

OBJECTIVE

Primary liver tumors are rare pediatric malignancies. Knowledge of the epidemiology of pediatric liver tumors is limited. This study aims to present the national incidence trends of pediatric liver tumors over 18 years, according to sociodemographic and histological subtype variation.

METHODS

The Surveillance, Epidemiology, and End Results registry was queried from 2000 to 2017 for 1,099 patients between ages 0 and 19 with liver tumors. Age-standardized incidence rates by age, sex, and race/ethnicity were examined among histological subtypes. Annual percentage change (APC) was calculated via joinpoint regression for various sociodemographic and histotype subgroups.

RESULTS

An increase of age-adjusted incidence rate of pediatric hepatic cancers was observed between 2000 and 2017 (APC, 1.7% [95% confidence interval or CI: 0.6%-2.8%], p-value = 0.006), which may likely attribute to the increasing incidence of hepatoblastoma and mesenchymal tumors (APC, 2.5% [95% CI: 1.1%-3.8%], p-value = 0.001). The incidence trend of hepatocellular carcinoma remained stable in the study period. The non-Hispanic Asian/Pacific Islander children and adolescents had a higher risk of hepatic tumors (incidence rate ratio or IRR, 1.42 [95% CI: 1.16-1.72], p-value = 0.0007) when compared with the non-Hispanic white subgroup, while a non-Hispanic black child was associated with a lower incidence rate (IRR, 0.64 [95% CI: 0.50-0.80], p-value < 0.0001). Significantly lower hepatic tumor incidence occurred in females than males, with an incidence rate ratio of 0.69 (95% CI: 0.61-0.78; p-value < 0.0001). Hepatic tumor incidence was also significantly lower in those aged 1-4 years (IRR, 0.47 [95% CI: 0.40-0.54]; p-value < 0.001) and 5-19 years (IRR, 0.09 [95% CI: 0.08-0.10]; p-value < 0.001) when compared with the youngest age group aged less than 1 year. These significant differences were also detected for the subgroup of hepatoblastoma and mesenchymal liver tumors but less among hepatocellular carcinomas (all p-values less than 0.0001).

CONCLUSION

Continued increasing incidence of pediatric hepatoblastoma and mesenchymal liver tumors was discovered and warranted further investigation. Additional findings include a lower incidence of hepatic cancer among non-Hispanic black individuals and higher incidence of hepatic cancer in non-Hispanic Asian/Pacific Islander, male, and aged 1-4-year children and adolescents.

State of the art and perspectives in pediatric hepatocellular carcinoma

Hepatoblastoma (HB) and pediatric hepatocellular carcinoma (HCC) are rare primary malignant liver cancers in children and young adults. HB is the most common and accounts for about 70 % cases; it is usually diagnosed during the first 3 years of life. Instead, pediatric HCC is uncommon, and it is associated with a poor prognosis. Overall, the prognosis of pediatric HCC is dismal with 5-year event-free survival of <30 % as compared to >80 % for HB. Surgery approaches, either resection or transplant, remain the best chance for the cure of pediatric HCC. However, chemotherapy can be helpful as an adjuvant or neoadjuvant treatment. International groups have done trials in pediatric HCC with a chemotherapy regimen, based on cisplatin and doxorubicin (PLADO) as for HB, but the efficacy is limited. Sorafenib, a multi-kinase inhibitor, following positive results in adults and in a pilot study in children, is now tested in conjunction with chemotherapy in the PHITT phase III clinical trial. Some studies have been exploring the genetic profiles of patients to find biological hallmarks that determine the aggressiveness of pediatric HCC. Pathways involved in growth and differentiation are dysregulated and as demonstrated in HB and adult HCC, an important role of the Wnt/CTNNB1 pathway in the pathogenesis of pediatric HCC is also emerging. An extended molecular analysis of tumor samples could give information about pathways as possible targets of biological and immunotherapeutic agents bringing new pharmacological options for the treatment of pediatric HCC.

Improved Survival and Higher Rates of Surgical Resection Associated with Hepatocellular Carcinoma in Children as Compared to Young Adults

Hepatocellular adenocarcinoma (HCC) is the second most common primary hepatic malignancy in children with a 5-year overall survival of 30%. Few studies have examined the similarities and differences between pediatric and adult HCC. This paper aims to examine the relationship between tumor characteristics, treatments, and outcomes in pediatric and adult patients with HCC. The 2019 National Cancer Database was queried for patients with HCC. Patients were stratified by age: pediatric <21 years (n = 214) and young adults 21-40 (n = 1102). Descriptive statistics and chi square were performed. The mean age at diagnosis was 15.5 years (SD 5.6) in the pediatric and 33 years (5.3) in the adult group. Children had a comparable rate of metastasis (30% vs 28%, P = 0.47) and increased fibrolamellar histology (32% vs 9%). Surgical resection was more common in children compared with adults (74% vs 62%, P < 0.001), children also had more lymph nodes examined (39% vs 19%, P < 0.001), positive lymph nodes (35% vs 17%, P = 0.02), and surgical resection when metastasis were present at diagnosis (46% vs 18%, P < 0.001). The 1, 3, and 5-year overall survival was higher for pediatric patients than adults (81%, 65%, 55%, vs 70%, 54%, 48%,) Despite higher prevalence of fibrolamellar histology, greater number of positive lymph nodes, and comparable rates of metastasis at diagnosis, children with HCC have improved overall survival compared with adults. Age did not significantly contribute to survivorship, so it is likely that the more aggressive surgical approach contributed to the improved overall survival in pediatric patients. This article is protected by copyright. All rights reserved.

Managing Hepatocellular Carcinoma in Children

Hepatocellular carcinoma (HCC) is a rare pediatric tumor. It differs from its adult counterpart in many ways like etiology, biological behavior, and association with cirrhosis. Treating HCC requires a multidisciplinary team involving pediatric gastroenterology, oncology, hepatobiliary surgery, and interventional radiology. This case series aims to describe presenting features and management plan of three children with HCC treated at a tertiary care liver transplant center in Pakistan.

Second Generation Small Molecule Inhibitors of Gankyrin for the Treatment of Pediatric Liver Cancer

Background: Gankyrin, a member of the 26S proteasome, is an overexpressed oncoprotein in hepatoblastoma (HBL) and hepatocellular carcinoma (HCC). Cjoc42 was the first small molecule inhibitor of Gankyrin developed; however, the IC50 values of >50 μM made them unattractive for clinical use. Second-generation inhibitors demonstrate a stronger affinity toward Gankyrin and increased cytotoxicity. The aim of this study was to characterize the in vitro effects of three cjoc42 derivatives. Methods: Experiments were performed on the HepG2 (HBL) and Hep3B (pediatric HCC) cell lines. We evaluated the expression of TSPs, cell cycle markers, and stem cell markers by Western blotting and/or real-time quantitative reverse transcription PCR. We also performed apoptotic, synergy, and methylation assays. Results: The treatment with cjoc42 derivatives led to an increase in TSPs and a dose-dependent decrease in the stem cell phenotype in both cell lines. An increase in apoptosis was only seen with AFM-1 and -2 in Hep3B cells. Drug synergy was seen with doxorubicin, and antagonism was seen with cisplatin. In the presence of cjoc42 derivatives, the 20S subunit of the 26S proteasome was more available to transport doxorubicin to the nucleus, leading to synergy. Conclusion: Small-molecule inhibitors for Gankyrin are a promising therapeutic strategy, especially in combination with doxorubicin.

Imaging Features of Hepatocellular Carcinoma in Children With and Without Underlying Risk Factors

Background: Pediatric hepatocellular carcinoma (HCC) is an aggressive malignancy for which imaging findings remain poorly described. In comparison with adult HCC, pediatric HCC more commonly occurs without underlying risk factors, and standardized surveillance guidelines for those with predispositions are lacking. Objective: To evaluate imaging findings of non-fibrolamellar pediatric HCC and to identify associations between these imaging findings and presence of predisposing factors. Methods: This retrospective study included children (≤18 years) with histologically confirmed non-fibrolamellar HCC who underwent multiphase CT or MRI at one of four academic children's hospitals between July 2009 and April 2019. Surveillance regimens in children with predispositions were at the discretion of treating physicians. Clinical characteristics were recorded. Scan indications were classified as surveillance versus clinical signs and symptoms. Images from all sites were submitted to a cloud-based server. Two radiologists independently assessed imaging features of HCC, including tumor size, tumor in vein, Pre-Treatment Extent of Tumor (PRETEXT) stage, and LI-RADS major features of adult HCC. Imaging findings were compared between patients with and without predispositions. Results: The study included 39 patients: 17 with predispositions (mean age, 11±5 years; 9 boys, 8 girls) and 22 without predispositions (mean age, 11±5 years; 12 boys, 10 girls). Scan indication was surveillance in 14/17 patients with predispositions versus 0/22 patients without predispositions (P<.001). Patients with, versus without, predispositions had smaller tumor size [reader 1: 6.0 vs 11.9 cm (p=.003); reader 2: 6.0 vs 12.9 cm (p<.001)] and less frequent tumor in vein [reader 1: 0% vs 41% (p=.002); reader 2: 0% vs 36% (p=.006)]. PRETEXT stage of IV was observed in 18% (both readers) of patients with predispositions versus 50-55% of patients without predispositions. No LI-RADS major feature of adult HCC showed a significant difference in frequency between patients with and without predispositions for either reader (all P>.05). Conclusion: Among children with HCC, those with predispositions were diagnosed with smaller and lower-stage tumors having less frequent tumor in vein, likely due to surveillance imaging. Clinical Impact: The study supports the role of routine surveillance imaging in children with HCC predispositions to facilitate earlier detection. Standardization of surveillance guidelines remains needed.

Waitlist mortality and post-liver transplant outcomes of pediatric patients with hepatocellular carcinoma and hepatoblastoma in the United States

BACKGROUND

Liver transplantation (LT) is offered in cases of advanced disease for both pediatric patients with hepatoblastoma (HBL) and those with hepatocellular carcinoma (HCC). Current United States organ allocation priorities differ between the two groups.

METHODS

We retrospectively examined the waitlist and posttransplant outcomes of pediatric LT candidates with HBL and HCC using the United Network for Organ Sharing registry (February 2002 to September 2020).

RESULTS

Six hundred sixty-eight children with HBL and 95 children with HCC listed for first LT were identified. Patients with HBL were younger (p < .001), had lower laboratory Model for End-stage Liver Disease (MELD)/Pediatric End-stage Liver Disease (PELD) scores (p < .001), and had lesser proportion with encephalopathy (p = .01). Patients with HCC had an increased risk of waitlist mortality in univariable (unadjusted subdistribution hazard ratio [sHR] = 4.37, 95% confidence interval [CI], 2.01-9.51, p < .001) and multivariable competing risk regression (adjusted sHR = 3.08, 95% CI 1.13-8.37, p = .03) accounting for age and laboratory MELD/PELD score. Five hundred ninety-five children underwent LT for HBL and 76 for HCC. Patients transplanted for HBL had a significantly higher proportion with status 1B exception (71.3% vs. 7.9%, p < .001). No difference was observed in patient (unadjusted log-rank test, p = .52; adjusted hazard ratio [HR] = 0.77, 95% CI, 0.40-1.48, p = .43) or graft survival (unadjusted log-rank test, p = .93; adjusted HR = 0.74, 95% CI 0.42-1.33, p = .32) between HCC and HBL recipients.

CONCLUSION

Waitlist mortality for pediatric LT candidates with HCC is significantly higher than for HBL, while posttransplant patient and graft survival are similar. This highlights an opportunity to improve equitable prioritization for children with HCC who may have reduced access to size-appropriate deceased donor organs and less effective bridge-to-transplant therapies.

Transarterial Radioembolization Treatment as a Bridge to Surgical Resection in Pediatric Hepatocellular Carcinoma

BACKGROUND

Children with unresectable hepatocellular carcinoma (HCC) have a poor prognosis and limited treatment options. Transarterial radioembolization (TARE) using Yttrium-90 (Y90) has emerged as a potential bridge therapy to hepatic resection or transplantation for HCC with very limited studies in children.

OBSERVATIONS

Here we present the clinical course of 2 children successfully treated with TARE Y90 for initially unresectable fibrolamellar HCC (FL-HCC) and bridged to partial hemihepatectomy with >1-year overall survival post-TARE.

CONCLUSION

Although there have been prior published reports of pediatric patients with HCC being treated with TARE Y90 and some being able to undergo subsequent orthotopic liver transplantation, this is the first report of pediatric HCC patients treated with TARE Y90 as a bridge to nontransplant resections and going on to have >1-year overall survival.

Fibrolamellar carcinoma: An entity all its own

Fibrolamellar carcinoma (FLC) is a rare malignant entity arising from the liver and primarily affecting patients in late adolescence and young adulthood. FLC tumors are characterized by their unique histologic features and an only recently discovered genomic alteration: a chimeric fusion protein found in nearly all tumors. The rarity of these tumors coupled with the only recent acknowledgement of this genomic abnormality has likely led to disease under-recognition and de-prioritization of collaborative efforts aimed at establishing an evidence-guided standard of care. Surgical resection undoubtedly remains a mainstay of therapy and a necessity for cure but given the incidence of metastatic disease at diagnosis and high rates of distant relapse, systemic therapies remain a key component of disease control. There are few systemic therapies that have demonstrated proven benefit. Recent efforts have galvanized around single-institute or small consortia-based studies specifically focused on the enrollment of patients with FLC or use of agents with biologic rationale. This review will outline the current state of FLC epidemiology, histology, biology and trialed therapies derived from available published literature.

Hepatocellular carcinoma as a complication of Niemann-Pick disease type C1

Niemann-Pick disease type C (NPC) is a rare and fatal lysosomal storage disorder characterized by neurodegeneration and hepatic involvement. Mutations in either NPC1 or NPC2, two genes encoding lysosomal proteins, lead to an intracellular accumulation of unesterified cholesterol and sphingolipids in late endosomes/lysosomes. Early cholestatic disease is considered a hallmark of patients with early disease onset. This can potentially result in liver failure shortly after birth or subclinical hepatic inflammation. Previous reports suggest an association between NPC and hepatocellular carcinoma, a cancer that is rare during childhood. We present a 12-year-old male with a known diagnosis of NPC1 disease who was found to have a stage III hepatocellular carcinoma, underwent surgical resection with adjuvant chemotherapy, and subsequently died from metastatic disease. This report provides evidence of an increased risk of hepatocellular carcinoma in NPC patients, suggesting a need for screening in this patient population.

Pharmacokinetically guided dosing of oral sorafenib in pediatric hepatocellular carcinoma: A simulation study

Sorafenib improves outcomes in adult hepatocellular carcinoma; however, hand foot skin reaction (HFSR) is a dose limiting toxicity of sorafenib that limits its use. HFSR has been associated with sorafenib systemic exposure. The objective of this study was to use modeling and simulation to determine whether using pharmacokinetically guided dosing to achieve a predefined sorafenib target range could reduce the rate of HFSR. Sorafenib steady‐state exposures (area under the concentration curve from 0 to 12‐h [AUC_0–>12 h]) were simulated using published sorafenib pharmacokinetics at either a fixed dosage (90 mg/m²/dose) or a pharmacokinetically guided dose targeting an AUC_0–>12 h between 20 and 55 h µg/ml. Dosages were either rounded to the nearest quarter of a tablet (50 mg) or capsule (10 mg). A Cox proportional hazard model from a previously published study was used to quantify HFSR toxicity. Simulations showed that in‐target studies increased from 50% using fixed doses with tablets to 74% using pharmacokinetically guided dosing with capsules. The power to observe at least 4 of 6 patients in the target range increased from 33% using fixed dosing with tablets to 80% using pharmacokinetically guided with capsules. The expected HFSR toxicity rate decreased from 22% using fixed doses with tablets to 16% using pharmacokinetically guided dosing with capsules. The power to observe less than 6 of 24 studies with HFSR toxicity increased from 51% using fixed dosing with tablets to 88% using pharmacokinetically guided with capsules. Our simulations provide the rationale to use pharmacokinetically guided sorafenib dosing to maintain effective exposures that potentially improve tolerability in pediatric clinical trials.

C/EBPβ enhances efficacy of sorafenib in hepatoblastoma

Hepatoblastoma (HB) is the predominant hepatic neoplasm in infants and young children. Sorafenib has been used to treat adult and pediatric hepatocellular carcinoma. However, efficacy of monotherapy of sorafenib in HB is not sustained. In this study, we tested a possible combinatory therapy of sorafenib with the CCAAT/enhancer-binding proteins (C/EBP) overexpression in HB cell line. Firstly, we evaluated the expression level of C/EBPβ in the patients with HB by analyzing The Cancer Genome Atlas data. Lower level of C/EBPβ was observed in tumor tissues in comparison with matched normal tissues. Next, we observed that combination of sorafenib and C/EBPβ overexpression led to dramatic growth and migration inhibition of live tumor cells which implied promising probability for clinical trial. Mechanistically, C/EBPβ which can be downregulated by Ras v12, augmented messenger RNA and protein levels of p53. These data suggested that a combination of sorafenib and C/EBPβ overexpression inhibited tumor growth synergistically and provided a promising approach to treat HB.

Pediatric Hepatocellular Carcinoma

PURPOSE

Pediatric hepatocellular carcinoma is rarely seen in childhood. It constitutes approximately 1% of childhood solid organ malignancies. Pediatric hepatocellular carcinoma is the second most common malignant liver tumor after hepatoblastoma in children. In this review, we aimed to review the diagnosis and treatment of pediatric hepatocellular carcinoma in the light of the latest literature.

METHODS

We reviewed the literature in terms of the diagnosis and treatment of pediatric hepatocellular carcinoma.

RESULTS

Hepatocellular carcinoma (HCC) and hepatoblastoma constitute 0.5-1.5% of all childhood malignant tumors. HCC is responsible for 27% of all liver tumors and 4% of all pediatric liver transplantations. While 99.6% of HCC is seen in adults, only 0.4% of it is seen in pediatric patients. Etiological predisposition and biological behavior are different from adults. In a child with cirrhosis or liver disease, HCC should be suspected in the presence of a high level of AFP and an abnormal nodule on ultrasonography. Hepatoblastoma should be considered first in the differential diagnosis.

CONCLUSION

Treatment of pediatric HCC is challenging. Complete surgical resection is essential for the cure. To this end, different neoadjuvant chemotherapy protocols have been designed to convert non-resectable tumors into resectable tumors. For tumors that cannot be resected, liver transplantation for each patient with childhood HCC should be decided individually.

Surgical management of pediatric hepatocellular carcinoma: An analysis of the National Cancer Database

PURPOSE

This study evaluates overall survival (OS) between liver transplantation (LT) and liver resection (LR), while assessing the effect of margin status, in children with hepatocellular carcinoma (HCC).

METHODS

The National Cancer Database was queried (2004-2015) for children (<18 years) with non-metastatic HCC undergoing surgery.

RESULTS

One hundred six children with HCC treated surgically (LT 34, LR 72) were identified. For T1 stage, no difference in OS was observed for LT vs. margin-negative liver resection [LR(-)] (log-rank, p = 0.47). For T2/T3/T4 stage, no difference in OS was observed for LT vs. LR(-) (log-rank, p = 0.08); both subgroups exhibited superior OS vs. margin-positive liver resection [LR(+)] (log-rank, LT vs. LR(+): p = 0.001 and LR(-) vs. LR(+): p = 0.04). On multivariable Cox regression: (i) histology (fibrolamellar vs. not) and T stage (T1 vs. T2/T3/T4) were not associated with OS (both p = 0.06), (ii) chemotherapy and size >5 cm were not associated with OS (both p ≥ 0.42), (iii) when compared to LT, both LR(-) (p = 0.03) and LR(+) (p = 0.001) were associated with increased likelihood of mortality.

CONCLUSION

Although margin-negative resection may be obtained with LT or LR, early LT consultation is warranted for children at high risk of LR(+) regardless of Milan criteria due to the negative impact of LR(+) on OS.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

III.

Liver Tumours in Children: The Hepatologist's View

ABSTRACT

Diagnostic and therapeutic innovations have changed the way we now approach liver tumours in children and adolescents. Novel imaging tools, increasing awareness, and surveillance has led to early diagnosis of benign and malignant liver tumours. Multidisciplinary interventions have favourably altered the natural course in some liver tumours. The role of liver transplantation is expanding and has become fully integrated into today's therapeutic algorithms. Transarterial locoregional and ablation therapies have been successful in adults and are being explored in children to facilitate resectability and improve outcome. For the first time, North American, Japanese, and European experts have designed a global trial to optimize management of malignant liver tumours and aim to find signature molecular profiles that will translate to individualised treatment strategies.This article aims to offer an overview of recent advances in our understanding of liver tumours in children. It focuses on the paediatric hepatologist's view and their role in the multidisciplinary management of benign and malignant liver tumours.

Hepatitis B Virus Seropositivity Is a Poor Prognostic Factor of Pediatric Hepatocellular Carcinoma: a Population-Based Study in Hong Kong and Singapore

Background

Hepatocellular carcinoma (HCC) is a rare hepatic malignancy in children. Hepatitis B virus (HBV) infection is a key predisposing factor in endemic regions but its impact on outcome has not been studied. We aim to evaluate the prognostic implication of HBV seropositivity and role of cancer surveillance in children with HCC from East Asian populations with national HBV vaccination.

Methods

Review of population-based databases for patients (< 18 years old) diagnosed with HCC from 1993 to 2017 in two Southeast Asian regions with universal HBV vaccination (instituted since 1988 and 1987 in Hong Kong and Singapore, respectively).

Results

Thirty-nine patients were identified (Hong Kong, 28; Singapore, 11). Thirty were male; median age at diagnosis was 10.8 years (range, 0.98-16.6). Abdominal pain was the commonest presentation while five patients were diagnosed through surveillance for underlying condition. Alpha-fetoprotein was raised in 36 patients (mean, 500,598 ng/ml). Nineteen had bilobar involvement, among the patients in whom pretreatment extent of disease (PRETEXT) staging could retrospectively be assigned, 3 had stage I, 13 had stage II, 4 had stage III, and 11 had stage IV disease. Seventeen had distant metastasis. HBsAg was positive in 19 of 38 patients. Two patients had fibrolamellar HCC. Upfront management involved tumor resection in 16 (liver transplantation, 2), systemic chemotherapy in 21, interventional procedures in 6 [transarterial chemoembolization (TACE), 5, radiofrequency ablation (RFA), 1], and radiotherapy in 4 (selective internal radiation, 3, external beam radiation, 1). Five-year event-free survival (EFS) and overall survival (OS) were 15.4 ± 6.0 and 26.1 ± 7.2%, respectively. Patient's HBsAg positivity, metastatic disease and inability to undergo definitive resection represent poor prognostic factors in univariate and multivariable analyses. Patients diagnosed by surveillance had significantly better outcome.

Conclusion

Pediatric HCC has poor outcome. HBV status remains relevant in the era of universal HBV vaccination. HBV carrier has inferior outcome and use of surveillance may mitigate disease course.

Clinical heterogeneity of pediatric hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is often a chemoresistant neoplasm with a poor prognosis. Pediatric HCC may reflect unique biological and clinical heterogeneity.

PROCEDURE

An IRB-approved retrospective institutional review of patients with HCC treated between 2004 and 2015 was undertaken. Clinical, radiographic, and histologic data were collected from all patients.

RESULTS

Thirty-two patients with HCC, median age 11.5 years (range 1-20) were identified. Seventeen patients had a genetic or anatomic predisposition. Histology was conventional HCC (25) and fibrolamellar HCC (7). Evans staging was 1 (12); 2 (1); 3 (10); 4 (9). Sixteen patients underwent resection at diagnosis and five patients after neoadjuvant chemotherapy. Surgical procedures included liver transplantation (LT, 11), hemihepatectomy (9), and segmentectomy (1). Eighteen patients had medical therapy (13 neoadjuvant, 5 adjuvant). Most common initial medical therapy included sorafenib alone (7) and cisplatin/doxorubicin-based therapy (8). Overall, 14 (43.8%) patients survived with a median follow-up of 58.8 months (range 26.5-157.6). Cause of death was most often linked to lack of primary tumor surgery (11). Of the survivors, Evans stage was 1 (11), 2 (1), and 3 (2, both treated with LT). Four of 18 patients (22%) who received medical therapy, 8 of 17 patients with a predisposition (47%), and 14 of 21 patients (66%) who underwent surgery remain alive.

CONCLUSIONS

Genetic and anatomic predisposing conditions were seen in over half of this cohort. Evans stage 1 or 2 disease was linked to improved survival. LT trended toward improved survival. Use of known chemotherapy agents may benefit a smaller group of pediatric HCC and warrants formal prospective study through cooperative group trials.

Population-Based Analysis of Hepatocellular Carcinoma in Children: Identifying Optimal Surgical Treatment

BACKGROUND

Hepatocellular carcinoma (HCC) constitutes 0.5% of childhood malignancies and exhibits poor prognosis. Complete tumor extirpation either by partial liver resection (LR) or liver transplantation (LT) is the only curative treatment. Due to the poor initial outcomes of LT, LR has remained the mainstay of treatment for all but select children fulfilling the Milan criteria (originally designed for adults).

METHODS

We conducted a retrospective cohort study of pediatric HCC patients (younger than 18 years of age) registered in the Surveillance, Epidemiology, and End Results database between 2004 and 2015. Survival analysis was performed by means of Kaplan-Meier methods, 2-sided stratified log-rank tests, and Cox regression models.

RESULTS

Of 127 children with HCC, 46 did not undergo operation (36.2%), 32 underwent LT (25.2%), and 49 underwent LR (38.6%). Using the Kaplan-Meier method, the 5-year cancer-specific survival (CSS) rates for LT and LR were 87% and 63%, respectively. LT exhibited superior CSS vs LR (log-rank, p = 0.007). For T1 stage, LT showed equivalent CSS compared with LR (log-rank, p = 0.23), and for T2 and T3 stage, LT exhibited superior CSS (log-rank, p = 0.047 and p = 0.01, respectively). On multivariable Cox regression analysis, T3/T4 stage (adjusted hazard ratio 13.63; 95% CI, 2.9 to 64.07; p = 0.001), and LR (adjusted hazard ratio 7.51; 95% CI, 2.07 to 27.29; p = 0.002) were found to be independently associated with cancer-specific mortality. Fibrolamellar histology and lymph node status were not found to be associated with mortality.

CONCLUSIONS

Our findings suggest that children diagnosed with nonmetastatic advanced-stage HCC have a favorable prognosis after LT compared with LR. Early inclusion of an LT consultation after the initial diagnosis is warranted, especially in children with unresectable HCC or when complete tumor extirpation with LR is not feasible.

Liver Transplantation for Pediatric Liver Cancer

Unresectable hepatocellular carcinoma (HCC) was first removed successfully with total hepatectomy and liver transplantation (LT) in a child over five decades ago. Since then, children with unresectable liver cancer have benefitted greatly from LT and a confluence of several equally important endeavors. Regional and trans-continental collaborations have accelerated the development and standardization of chemotherapy regimens, which provide disease control to enable LT, and also serve as a test of unresectability. In the process, tumor histology, imaging protocols, and tumor staging have also matured to better assess response and LT candidacy. Significant trends include a steady increase in the incidence of and use of LT for hepatoblastoma, and a significant improvement in survival after LT for HCC with each decade. Although LT is curative for most unresectable primary liver sarcomas, such as embryonal sarcoma, the malignant rhabdoid tumor appears relapse-prone despite chemotherapy and LT. Pediatric liver tumors remain rare, and diagnostic uncertainty in some settings can potentially delay treatment or lead to the selection of less effective chemotherapy. We review the current knowledge relevant to diagnosis, LT candidacy, and post-transplant outcomes for these tumors, emphasizing recent observations made from large registries or larger series.

Novel patient-derived preclinical models of liver cancer

Preclinical models of cancer based on the use of human cancer cell lines and mouse models have enabled discoveries that have been successfully translated into patients. And yet the majority of clinical trials fail, emphasising the urgent need to improve preclinical research to better interrogate the potential efficacy of each therapy and the patient population most likely to benefit. This is particularly important for liver malignancies, which lack highly efficient treatments and account for hundreds of thousands of deaths around the globe. Given the intricate network of genetic and environmental factors that contribute to liver cancer development and progression, the identification of new druggable targets will mainly depend on establishing preclinical models that mirror the complexity of features observed in patients. The development of new 3D cell culture systems, originating from cells/tissues isolated from patients, might create new opportunities for the generation of more specific and personalised therapies. However, these systems are unable to recapitulate the tumour microenvironment and interactions with the immune system, both proven to be critical influences on therapeutic outcomes. Patient-derived xenografts, in particular with humanised mouse models, more faithfully mimic the physiology of human liver cancer but are costly and time-consuming, which can be prohibitive for personalising therapies in the setting of an aggressive malignancy. In this review, we discuss the latest advances in the development of more accurate preclinical models to better understand liver cancer biology and identify paradigm-changing therapies, stressing the importance of a bi-directional communicative flow between clinicians and researchers to establish reliable model systems and determine how best to apply them to expanding our current knowledge.

DNAJB1-PRKACA-positive metastatic fibrolamellar carcinoma with unknown primary in a pediatric patient

Fibrolamellar carcinoma (FLC) is a rare variant of hepatocellular carcinoma, occurring in children and young adults without underlying liver disease. The diagnosis is based on morphological characteristics of the tumor, supplemented by immunohistochemistry and/or genetic testing. Recently, the presence of a characteristic DNAJB1-PRKACA fusion gene has been associated with FLC. Herein, we report a case of FLC presenting as peritoneal carcinomatosis in a 14-year-old female. Interestingly, no liver tumor was seen on imaging, and an alternative possibility is that the tumor arose outside the liver as a hepatoid carcinoma with fibrolamellar features.

The risk of liver cancer in autoimmune liver diseases

Hepatocellular carcinoma (HCC), the dominant primary malignancy of the liver, has almost invariably a fatal outcome that can be averted only by early diagnosis and treatment. While the close association of HCC with chronic viral hepatitis and alcohol abuse has impacted favourably on screening and treatment of this deadly tumour, at the same time it has long obscured the etiologic role of autoimmune liver diseases. Recently, a systematic analysis of 25 published cohorts disclosed a 3.1 × 1000 patients/year incidence of HCC in autoimmune hepatitis patients that tripled in those with cirrhosis. HCC is also a sequela of primary biliary cholangitis, where the incidence is more relevant in males, those with advanced liver disease and nonresponders to ursodeoxycholic acid therapy. Cholangiocarcinoma (CCA), the second ranking primary cancer of the liver, is also on the rise with its intrahepatic pattern, in part reflecting an association with chronic liver diseases of diverse aetiology. In the USA and northern Europe, perihilar CCA is a frequent complication of primary sclerosing cholangitis, a cholestatic disorder thought to be immune mediated. International Guidelines clearly recommend HCC screening with abdominal ultrasonography every 6 months in autoimmune cirrhotic patients. While surveillance of patients with autoimmune liver disorders who are at risk of HCC affects both early diagnosis and radical therapy of this tumour, this is not the case for CCA, where early diagnosis is challenged by the lack of sensitive and accurate tests for screening.

Improved contemporary outcomes of liver transplantation for pediatric hepatoblastoma and hepatocellular carcinoma

PURPOSE

Improvement in outcomes of LT for pediatric HB and HCC has been reported in small series. We analyzed national outcomes and changes in donor, recipient, and perioperative factors over time that may contribute to survival differences.

METHODS

The UNOS database was queried for patients age <21 years that underwent LT for a primary diagnosis of HB or HCC (1987-2017). Subjects were divided into historic (transplant before 2010) and contemporary (transplant after 2010) cohorts. Baseline characteristics were compiled and examined. Survival was estimated using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

In total, 599 children with HB received LT (320 historic vs 279 contemporary). Concurrently, 141 children with HCC received LT (92 historic vs 49 contemporary). For both tumors, waitlist time decreased (HB 56.2 days historic vs 33.2 days contemporary, P = 0.017; HCC 189.3 days historic vs 71.7 days contemporary, P = 0.012). In the historic cohorts, patients with HB had a 1-year and 5-year OS of 84.6% and 75.1%, respectively. Survival for HCC was 84.4% and 59.9%, respectively. Outcomes improved in the contemporary era to 89.1% and 82.6% for HB, and 94.7% and 80.8% for HCC, respectively (both log-rank test P < 0.0001).

CONCLUSION

Outcomes of LT have improved significantly, with contemporary survival now equivalent between these tumors and exceeding 80% 5-year OS. Future studies are needed to explore whether offering LT in patients that are resectable is justifiable.

Surgical management of children and adolescents with upfront completely resected hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is an aggressive malignant neoplasm that is often chemoresistant. Complete surgical resection remains the mainstay of therapy. The role of liver transplantation (LT) in pediatric HCC is in evolution, as is the role of adjuvant chemotherapy for stage I disease.

METHODS

A retrospective review of patients < 18 years of age with completely resected HCC treated with surgical intervention alone at our institution from 2004 to 2015 was conducted.

RESULTS

Twelve patients with a median age of 12 years (range = 1-17; number of females = 7) with upfront resected HCC (Evans stage I) were identified. Four patients had HCC without identifiable risk factors (fibrolamellar-HCC = 2; early HCC arising in focal nodular hyperplasia = 1, well-differentiated [wd] HCC = 1). Four patients had early or wd-HCC in the context of portosystemic shunts (Abernethy = 2; mesocaval shunt and portal vein thrombosis = 2). Four patients had moderate to wd-HCC in the context of pre-existing liver disease with cirrhosis (progressive familial intrahepatic cholestasis type-2 = 2, alpha-1 antitrypsin deficiency = 1, Alagille syndrome = 1). Seven patients underwent LT (multifocal = 5; solitary = 2); five exceeded Milan criteria (MC) by imaging. Five patients underwent complete resection (segmentectomy = 2; hemihepatectomy = 3). Ten patients received no adjuvant chemotherapy. All patients are alive without evidence of disease with a median follow-up of 54.1 months (range = 28.1-157.7 months).

CONCLUSIONS

Pediatric and adolescent patients with upfront, completely resected HCC can be effectively treated without chemotherapy. LT should be considered for nonmetastatic HCC, especially in the context of pre-existing chronic liver disease, even when the tumor exceeds MC. Distinct pediatric selection criteria are needed to identify patients most suitable for LT.

Pediatric Liver Tumors

Although liver tumors are rare in the pediatric population, they are common in the setting of children with specific risk factors requiring increased awareness and, in some instances, screening. The evaluation of a liver mass in children is largely driven by the age at diagnosis, the presence of any medical comorbidities, and initial testing with alpha fetoprotein and imaging. Specific guidelines for the management of different tumors have been implemented in recent years such that a multidisciplinary approach is ideal and care should be provided by centers with experience in their management.

Pediatric hepatocellular carcinoma

Pediatric hepatocellular carcinoma (HCC) is the second common malignant liver tumor in children after hepatoblastoma. It differs from the adult HCC in the etiological predisposition, biological behavior and lower frequency of cirrhosis. Perinatally acquired hepatitis-B virus, hepatorenal tyrosinemia, progressive familial intrahepatic cholestasis, glycogen storage disease, Alagille’s syndrome and congenital portosystemic shunts are important predisposing factors. Majority of children (87%) are older than 5 years of age. Following mass immunization against hepatitis-B, there has been a drastic fall in the incidence of new cases of pediatric HCC in the Asia-Pacific region. Management is targeted on complete surgical removal either by resection or liver transplantation. There is a trend towards improving survival of children transplanted for HCC beyond Milan criteria. Chemotherapeutic regimens do not offer good results but may be helpful for down-staging of advanced HCC. Surveillance of children with chronic liver diseases with ultrasound and alpha-fetoprotein may be helpful in timely detection, intervention and overall improvement in outcome of HCC.

Hepatocellular carcinoma in children: hepatic resection and liver transplantation

Hepatocellular carcinoma (HCC) is a rare malignancy in children and at the time of diagnosis up to 80% of pediatric HCC are unresectable due to large and multiple lesions. The majority of pediatric HCC occurs on a background of normal liver, and consequently the absence of concomitant chronic liver disease generally allows tolerating pre- and post-operative chemotherapy. Based on the large experiences of adult HCC and pediatric hepatoblastoma, in the last years a multidisciplinary aggressive treatment composed of surgical resection and chemotherapy (based on cisplatin and doxorubicin) has been proposed, improving patient outcomes and recurrence rate in children with HCC. However, the overall survival rate in children with HCC is not satisfactory yet; while the 5-year survival rate may achieve up to 70-80% in non-metastatic resectable HCC, it remains <20% in children with unresectable HCC. The mainstay of the pediatric HCC therapeutic strategy is the radical tumor resection, weather by hepatic resection or liver transplantation, nevertheless the best surgical approaches as well as the optimal neoadjuvant and adjuvant treatment are still under debate. Different strategies have been explored to convert unresectable HCC into resectable tumors by extending criteria for surgical treatment and/or associating multi-modal treatments, such as systemic and local-regional therapy, but universal recommendation needs to be defined yet. The purpose of this review is to outline the role of different surgical approaches, including hepatic resection and liver transplantation, in pediatric HCC with or without underlying chronic liver disease.

Transarterial chemoembolization in children to treat unresectable hepatocellular carcinoma

Children with unresectable HCC have a dismal prognosis and few approved treatment options. TACE is an effective treatment option for adults with HCC, but experience in children is very limited. Retrospective analysis was performed of 8 patients aged 4-17 years (4 male, mean 12.5 years) who underwent TACE for unresectable HCC. Response to TACE was evaluated by change in AFP, RECIST and tumor volume, PRETEXT, and transplantation eligibility by UCSF and Milan criteria. Post-procedure mean follow-up was 8.2 years. Mean overall change in tumor volume for the 8 patients was 51%. Percent change in AFP ranged from a decrease of 100% to an increase of 89.3%, with a mean change of -49.6%. Two patients did not undergo resection or transplantation and died of progressive disease. Six patients underwent orthotopic liver transplantation with mean first TACE-to-transplant interval of 141 days (range 11-514). Following transplantation, 5 patients were alive at the end of the follow-up period and one died of recurrent disease. Based on our initial experience, TACE for children with unresectable HCC appears to be a safe and effective method for managing hepatic tumor burden and for downstaging and bridging to liver transplantation.

Role of interventional radiology in managing pediatric liver tumors : Part 1: Endovascular interventions

Primary liver malignancies are rare in children. Hepatoblastoma and hepatocellular carcinoma (HCC) together represent the overwhelming majority of cases. Overall survival of hepatoblastoma approaches 80% with multimodal treatment approaches that include chemotherapy, surgery and transplantation. However, there remains a subset of children with hepatoblastoma in whom resection or transplantation is not possible. The 5-year survival for children diagnosed with HCC is less than 30% and remains a significant therapeutic challenge. The poor outcomes for children with primary liver tumors motivate investigation of new therapeutic alternatives. Interventional oncology offers a broad scope of percutaneous and transcatheter endovascular cancer therapies that might provide clinical benefits. Minimally invasive approaches are distinct from medical, surgical and radiation oncologic treatments, and in adults these approaches have been established as the fourth pillar of cancer care. Transarterial chemoembolization is a minimally invasive locoregional treatment option performed by interventional radiologists with level-I evidence as standard of care in adults with advanced liver malignancy; transarterial chemoembolization in adults has served to prolong disease-free progression, downstage and bridge patients for surgical and transplant interventions, and improve overall survival. However, while several groups have reported that transarterial chemoembolization is feasible in children, the published experience is limited primarily to small retrospective case series. The lack of prospective trial evidence has in part limited the utilization of transarterial chemoembolization in the pediatric patient population. The purpose of this article is to provide an overview of the role of interventional radiology in the diagnosis and endovascular management of hepatic malignancies in children.

Pediatric liver transplantation for hepatocellular cancer and rare liver malignancies: US multicenter and single-center experience (1981-2015)

A tenth of all pediatric liver transplantations (LTs) are performed for unresectable liver malignancies, especially the more common hepatoblastoma (HBL). Less understood are outcomes after LT for the rare hepatocellular carcinoma, nonhepatoblastoma embryonal tumors (EMBs), and slow growing metastatic neuroendocrine tumors of childhood. Pediatric LT is increasingly performed for rare unresectable liver malignancies other than HBL. We performed a retrospective review of outcomes after LT for malignancy in the multicenter US Scientific Registry of Transplant Recipients (SRTR; n = 677; 1987-2015). We then reviewed the Children's Hospital of Pittsburgh (CHP; n = 74; 1981-2014) experience focusing on LT for unresectable hepatocellular cancer (HCC), EMBs, and metastatic liver tumors (METS). HBL was included to provide reference statistics. In the SRTR database, LT for HCC and HBL increased over time (P < 0.001). Compared with other malignancies, the 149 HCC cases received fewer segmental grafts (P < 0.001) and also experienced 10-year patient survival similar to 15,710 adult HCC LT recipients (51.6% versus 49.6%; P = 0.848, not significant [NS], log-rank test). For 22 of 149 cases with incidental HCC, 10-year patient survival was higher than 127 primary HCC cases (85% [95% confidence interval (CI), 70.6%-100%] versus 48.3% [95% CI, 38%-61%]; P = 0.168, NS) and similar to 3392 biliary atresia cases (89.9%; 95% CI, 88.7%-91%). Actuarial 10-year patient survival for 17 EMBs, 10 METS, and 6 leiomyosarcoma patients exceeded 60%. These survival outcomes were similar to those seen for HBL. At CHP, posttransplant recurrence-free and overall survival among 25 HCC, 17 (68%) of whom had preexisting liver disease, was 16/25 or 64%, and 9/25 or 36%, respectively. All 10 patients with incidental HCC and tumor-node-metastasis stage I and II HCC survived recurrence-free. Only vascular invasion predicted poor survival in multivariate analysis (P < 0.0001). A total of 4 of 5 EMB patients (80%) and all patients with METS (neuroendocrine-2, pseudopapillary pancreatic-1) also survived recurrence-free. Among children, LT can be curative for unresectable HCC confined to the liver and without vascular invasion, incidental HCC, embryonal tumors, and metastatic neuroendocrine tumors. Liver Transplantation 23 1577-1588 2017 AASLD.

Liver transplantation for primary hepatic malignancies of childhood: The UNOS experience

BACKGROUND/PURPOSE

The purpose of this study was to determine factors associated with patient and graft survival following orthotopic liver transplantation (OLT) in children and adolescents with primary hepatic malignancies.

METHODS

The United Network for Organ Sharing (UNOS) database was queried for all patients <18years old who received an OLT with a primary malignant liver tumor between 1987 and 2012 (n=544). Five-year patient and graft survival were determined using Kaplan-Meier methodology, and independent predictors of survival were determined using multivariate Cox proportional hazards model.

RESULTS

The majority of patients were diagnosed with hepatoblastoma (HB) (n=376, 70%) with 84 (15%) hepatocellular carcinoma (HCC) and 84 (15%) other. HCC patients were older, more often hospitalized at the time of transplant, and more likely to receive a cadaveric organ compared to HB patients. Five-year patient and graft survival for the entire cohort was 73% and 74%, respectively, with the majority of deaths owing to malignancy. On multivariate analysis, independent predictors of 5-year patient and graft survival included diagnosis, transplant era, and medical condition at transplant.

CONCLUSIONS

In recent years, there has been significant improvement in posttransplant patient and graft survival for children and adolescents with primary hepatic malignancies. However, patients with HCC continue to have worse outcomes than those with other cancer types.

TYPE OF STUDY

Case series with no comparison group.

LEVEL OF EVIDENCE

IV.

Hepatocellular malignant neoplasm, NOS: a clinicopathological study of 11 cases from a single institution

AIMS

The primary aim of this study is to characterize hepatocellular malignant neoplasm, NOS (HEMNOS), a new provisional entity describing a subset of paediatric hepatocellular tumours, which have histological features of neither typical hepatoblastoma (HB) nor hepatocellular carcinoma (HCC).

METHODS AND RESULTS

The clinicopathological features of 11 patients with HEMNOS were analysed retrospectively. The median age and serum alpha-fetoprotein level at diagnosis was 7 years and 182 000 ng/ml, respectively. Ten patients presented with pretreatment extent of disease (PRETEXT) stages III/IV multifocal tumours, eight with major vascular involvement, three with lung metastases and three with extrahepatic extension. The original pathology diagnoses were: HB in seven patients, HCC in two and HEMNOS in two. Our pathology review of pre-chemotherapy specimens showed that six tumours had equivocal/overlapping histological features of HB and HCC, four had predominant HB histology along with focal HCC-like histology and one had HB histology. Seven of nine post-chemotherapy resection specimens showed predominant HCC-like histology. Beta-catenin, glypican 3 and spalt-like transcription factor 4 immunostaining showed that all the tumours had a mixed HB/HCC immunophenotype. Telomerase reverse transcriptase immunostaining showed nuclear staining in nine of the 11 tumours. All patients received chemotherapy and achieved gross total primary tumour resection. Nine of the 11 patients were treated with established HB chemotherapy regimens. After a median follow-up of 6.1 years (range: 1.2-11.8 years), all patients were in remission.

CONCLUSIONS

HEMNOS is a subtype of HB with focal HCC-like histology, a high-risk clinical profile but favourable outcome following chemotherapy and complete tumour resection.

Pediatric hepatocellular carcinoma: challenges and solutions

Hepatocellular carcinoma (HCC) is a very rare entity in children, making it nearly impossible to orchestrate Phase II/III studies even as multinational cooperative trials. In contrast to adults, nearly 50% of the children have a response (α-fetoprotein decline and/or tumor shrinkage) to chemotherapeutic agents such as cisplatin and doxorubicin (PLADO), demonstrating that HCC in childhood can be chemotherapy sensitive. As a result, the main treatment options in pediatric HCC focus on systemic drug therapies and resection as the central therapy. In nonmetastatic patients with complete resection upfront, the 5-year event-free survival and overall survival has reached 80%–90%. In almost all reported studies, children received adjuvant chemotherapy (mostly PLADO), but it has never been proven that postoperative chemotherapy is superior to observation. No data are available for the effects of sorafenib. The 3-year survival is <20% in children with unresectable HCC independent of the chemotherapy given preoperatively. Currently, PLADO in combination with sorafenib is recommended with the goal of achieving operability status. Alternatively, data are promising for the combination of sorafenib with gemcitabine and oxaliplatin. For children with nonresectable and nonmetastastic liver tumors, it has been shown that the Milan criteria regarding liver transplantation are not applicable – individual decisions have to be made. Transarterial chemoembolization could be offered to patients with chemotherapy-resistant liver tumors for palliative care or potentially to achieve surgical resectability, and therefore cure. Information about the feasibility or effects of new agents or approaches as discussed in adult HCC patients is not available for childhood HCC. Research has to be done for characterizing the molecular and genomic mechanisms of pediatric HCC to support the development of novel therapeutic approaches and the implementation of personalized medicine.

Hepatocellular Carcinoma in Children and Adolescents: Clinical Characteristics and Treatment

BACKGROUND

Hepatocellular carcinoma (HCC) occurs rarely in children and adolescents (C&A), and its clinical characteristics, prognostic factors, and treatment were rarely explored.

METHODS

This retrospective study focused on 65 HCC patients aged ≤20 years from August 1994 to August 2012. Cox regression models and Kaplan-Meier curves were used to investigate prognostic factors and compare overall survival (OS), respectively.

RESULTS

We found 61.5% of patients to have multiple tumors, 30.8% to have portal vein tumor thrombus, and 16.9% to have distant metastasis. Diameter of tumors was 10.2 ± 4.1 cm. OS at 5 years was 15.8%. Multivariate analyses showed initial treatment (P < 0.001) to be a predictor for OS. For moderate-stage HCC, the median OS of patients who underwent resection was longer than that of patients who underwent transarterial chemoembolization (TACE) or supportive treatment (ST) (P < 0.001). For advanced-stage HCC, the median OS of patients who underwent TACE was longer than that of patients who underwent ST (P = 0.045).

CONCLUSIONS

HCC in C&A tends to be more advanced than that in adults, and resection remains the mainstay of treatment for those patients. Moreover, compared with ST, TACE may benefit C&A with moderate- and advanced-stage HCC, which needs further study.

Malignant tumors of the liver in children

This article aims to give an overview of pediatric liver tumors; in particular of the two most frequently occurring groups of hepatoblastomas and hepatocellular carcinomas. Focus lays on achievements gained through worldwide collaboration. We present recent advances in insight, treatment results, and future questions to be asked. Increasing international collaboration between the four major Pediatric Liver Tumor Study Groups (SIOPEL/GPOH, COG, and JPLT) may serve as a paradigm to approach rare tumors. This international effort has been catalyzed by the Children's Hepatic tumor International Collaboration (CHIC) formation of a large collaborative database. Interrogation of this database has led to a new universal risk stratification system for hepatoblastoma using PRETEXT/POSTTEXT staging as a backbone. Pathologists in this international collaboration have established a new histopathological consensus classification for pediatric liver tumors. Concomitantly there have been advances in chemotherapy options, an increased role of liver transplantation for unresectable tumors, and a web portal system developed at www.siopel.org for international education, consultation, and collaboration. These achievements will be further tested and validated in the upcoming Paediatric Hepatic International Tumour Trial (PHITT).

Patient-derived mouse xenografts from pediatric liver cancer predict tumor recurrence and advise clinical management

Identification of new treatments for relapsing pediatric cancer is an unmet clinical need and a societal challenge. Liver cancer occurrence in infancy, 1.5 for million children per year, falls far below the threshold of interest for dedicated drug development programs, and this disease is so rare that it is very difficult to gather enough children into a phase II clinical trial. Here, we present the establishment of an unprecedented preclinical platform of 24 pediatric liver cancer patient-derived xenografts (PLC-PDXs) from 20 hepatoblastomas (HBs), 1 transitional liver cell tumor (TCLT), 1 hepatocellular carcinoma, and 2 malignant rhabdoid tumors. Cytogenetic array and mutational analysis of the parental tumors and the corresponding PLC-PDXs show high conservation of the molecular features of the parental tumors. The histology of PLC-PDXs is strikingly similar to that observed in primary tumors and recapitulates the heterogeneity of recurrent disease observed in the clinic. Tumor growth in the mouse is strongly associated with elevated circulating alpha-fetoprotein (AFP), low rate of necrosis/fibrosis after treatment, and gain of chromosome 20, all indicators of resistance to chemotherapy and poor outcome. Accordingly, the ability of a tumor to generate PLC-PDX is predictive of poor prognosis. Exposure of PLC-PDXs to standards of care or therapeutic options already in use for other pediatric malignancies revealed unique response profiles in these models. Among these, the irinotecan/temozolomide combination induced strong tumor regression in the TCLT and in a model derived from an AFP-negative relapsing HB.

CONCLUSION

These results provide evidence that PLC-PDX preclinical platform can strongly contribute to accelerate the identification and diversification of anticancer treatment for aggressive subtypes of pediatric liver cancer. (Hepatology 2016;64:1121-1135).

YAP Subcellular Localization and Hippo Pathway Transcriptome Analysis in Pediatric Hepatocellular Carcinoma

Pediatric hepatocellular carcinoma (HCC) is a rare tumor which is associated with an extremely high mortality rate due to lack of effective chemotherapy. Recently, the Hippo pathway and its transcriptional co-activator Yes-associated protein (YAP) have been shown to play a role in hepatocyte proliferation and development of HCC in animal models. Therefore, we sought to examine the activity of YAP and the expression of Hippo pathway components in tumor and non-neoplastic liver tissue from 7 pediatric patients with moderately differentiated HCC. None of the patients had underlying cirrhosis or viral hepatitis, which is commonly seen in adults with HCC. This highlights a major difference in the pathogenesis of HCC between children and adults. We found a statistically significant increase in YAP nuclear localization in 100% of tumors. YAP target gene (CCNE1, CTGF, Cyr61) mRNA expression was also increased in the tumors that had the most significant increase in YAP nuclear localization. Based on Ki67 co-localization studies YAP nuclear localization was not simply a marker of proliferation. Our results demonstrate a clear increase in YAP activity in moderately differentiated pediatric HCC, providing evidence that it may play an important role in tumor survival and propagation.

Translational Pharmacokinetic-Pharmacodynamic Modeling and Simulation: Optimizing 5-Fluorouracil Dosing in Children With Pediatric Ependymoma

We previously investigated novel therapies for pediatric ependymoma and found 5‐fluorouracil (5‐FU) i.v. bolus increased survival in a representative mouse model. However, without a quantitative framework to derive clinical dosing recommendations, we devised a translational pharmacokinetic‐pharmacodynamic (PK‐PD) modeling and simulation approach. Results from our preclinical PK‐PD model suggested tumor concentrations exceeded the 1‐hour target exposure (in vitro IC₉₀), leading to tumor growth delay and increased survival. Using an adult population PK model, we scaled our preclinical PK‐PD model to children. To select a 5‐FU dosage for our clinical trial in children with ependymoma, we simulated various 5‐FU dosages for tumor exposures and tumor growth inhibition, as well as considering tolerability to bolus 5‐FU administration. We developed a pediatric population PK model of bolus 5‐FU and simulated tumor exposures for our patients. Simulations for tumor concentrations indicated that all patients would be above the 1‐hour target exposure for antitumor effect.