Survival outcomes of liver transplantation versus liver resection among patients with hepatocellular carcinoma: A SEER-based longitudinal study

Insights into the history and tendency of liver transplantation for liver cancer: a bibliometric-based visual analysis

Research on liver transplantation (LT) for liver cancer has gained increasing attention. This paper has comprehensively described the current status, hotspots and trends in this field. A total of 2991 relevant articles from 1 January 1963 to 28 February 2023 were obtained from the Web of Science Core Collection. VOSviewer and CiteSpace software were utilized as bibliometric tools to analyze and visualize knowledge mapping. Between 1963 and 2023, the number of papers in the area of LT for liver cancer increased continuously. A total of 70 countries/regions, 2303 institutions and 14 840 researchers have published research articles, with the United States and China being the two most productive countries. Our bibliometric-based visual analysis revealed the expansion of LT indications for liver cancer and the prevention/treatment of cancer recurrence as ongoing research hotspots over the past decades. Meanwhile, emerging studies also focus on downstaging/bridging treatments before LT and the long-term survival of LT recipient, in particular the precise application of immunosuppressants.

Machine learning methods for accurately predicting survival and guiding treatment in stage I and II hepatocellular carcinoma

Accurately predicting survival in patients with early hepatocellular carcinoma (HCC) is essential for making informed decisions about treatment and prognosis. Herein, we have developed a machine learning (ML) model that can predict patient survival and guide treatment decisions. We obtained patient demographic information, tumor characteristics, and treatment details from the SEER database. To analyze the data, we employed a Cox proportional hazards (CoxPH) model as well as 3 ML algorithms: neural network multitask logistic regression (N-MLTR), DeepSurv, and random survival forest (RSF). Our evaluation relied on the concordance index (C-index) and Integrated Brier Score (IBS). Additionally, we provided personalized treatment recommendations regarding surgery and chemotherapy choices and validated models' efficacy. A total of 1136 patients with early-stage (I, II) hepatocellular carcinoma (HCC) who underwent liver resection or transplantation were randomly divided into training and validation cohorts at a ratio of 3:7. Feature selection was conducted using Cox regression analyses. The ML models (NMLTR: C-index = 0.6793; DeepSurv: C-index = 0.7028; RSF: C-index = 0.6890) showed better discrimination in predicting survival than the standard CoxPH model (C-index = 0.6696). Patients who received recommended treatments had higher survival rates than those who received unrecommended treatments. ML-based surgery treatment recommendations yielded higher hazard ratios (HRs): NMTLR HR = 0.36 (95% CI: 0.25-0.51, P < .001), DeepSurv HR = 0.34 (95% CI: 0.24-0.49, P < .001), and RSF HR = 0.37 (95% CI: 0.26-0.52, P = <.001). Chemotherapy treatment recommendations were associated with significantly improved survival for DeepSurv (HR: 0.57; 95% CI: 0.4-0.82, P = .002) and RSF (HR: 0.66; 95% CI: 0.46-0.94, P = .020). The ML survival model has the potential to benefit prognostic evaluation and treatment of HCC. This novel analytical approach could provide reliable information on individual survival and treatment recommendations.

Transplant Oncology: An Emerging Discipline of Cancer Treatment

Transplant oncology is an emerging concept of cancer treatment with a promising prospective outcome. The applications of oncology, transplant medicine, and surgery are the core of transplant oncology to improve patients' survival and quality of life. The main concept of transplant oncology is to radically cure cancer by removing the diseased organ and replacing it with a healthy one, aiming to improve the survival outcomes and quality of life of cancer patients. Subsequently, it seeks to expand the treatment options and research for hepatobiliary malignancies, which have seen significantly improved survival outcomes after the implementation of liver transplantation (LT). In the case of colorectal cancer (CRC) in the transplant setting, where the liver is the most common site of metastasis of patients who are considered to have unresectable disease, initial studies have shown improved survival for LT treatment compared to palliative therapy interventions. The indications of LT for hepatobiliary malignancies have been slowly expanded over the years beyond Milan criteria in a stepwise manner. However, the outcome improvements and overall patient survival are limited to the specifics of the setting and systematic intervention options. This review aims to illustrate the representative concepts and history of transplant oncology as an emerging discipline for the management of hepatobiliary malignancies, in addition to other emerging concepts, such as the uses of immunotherapy in a peri-transplant setting as well as the use of circulating tumor DNA (ctDNA) for surveillance post-transplantation.

[Prevention of gastrointestinal cancer]

Throughout the past decades, considerable progress has been made in the (early) diagnosis and treatment of gastrointestinal cancers. However, the prognosis for advanced stages of gastrointestinal tumors remains limited for many patients and approximately one third of all tumor patients die as a result of gastrointestinal tumors. The prevention and early detection of gastrointestinal tumors is therefore of great importance.For this reason, we summarize the current state of knowledge and recommendations for the primary, secondary and tertiary prevention of esophageal, stomach, pancreas, liver and colorectal cancer in the following.

Identification and Characterization of Alcohol-related Hepatocellular Carcinoma Prognostic Subtypes based on an Integrative N6-methyladenosine methylation Model

Background: Alcohol consumption increases the risk of hepatocellular carcinoma (HCC), and associated with a high mortality rate and poor prognosis. N6-methyladenosine (m6A) methylations play key roles in tumorigenesis and progression. However, our current knowledge about m6A in alcohol-related HCC (A-HCC) remains elucidated. Herein, the authors construct an integrative m6A model based on A-HCC subtyping and mechanism exploration workflow. Methods: Based on the m6A expressions of A-HCC and in vivo experiment, different prognosis risk A-HCC subtypes are identified. Meanwhile, multiple interdependent indicators of prognosis including patient survival rate, clinical pathological prognosis and immunotherapy sensitivity. Results: The m6A model includes LRPPRC, YTHDF2, KIAA14219, and RBM15B, classified A-HCC patients into high/low-risk subtypes. The high-risk subtype compared to the low-risk subtype showed phenotypic malignancy, poor prognosis, immunosuppression, and activation of tumorigenesis and proliferation-related pathways, including the E2F target, DNA repair, and mTORC1 signalling pathways. The expression of Immunosuppressive cytokines DNMT1/EZH2 was up-regulated in A-HCC patients, and teniposide may be a potential therapeutic drug for A-HCC. Conclusion: Our model redefined A-HCC prognosis risk, identified potential m6As linking tumour progress and immune regulations and selected possible therapy target, thus promoting understanding and clinical applications about A-HCC.

The Treatment Effect of Liver Transplantation versus Liver Resection for HCC: A Review and Future Perspectives

For patients presenting with hepatocellular carcinoma within the Milan criteria, either liver resection or liver transplantation can be performed. However, to what extent either of these treatment options is superior in terms of long-term survival is unknown. Obviously, the comparison of these treatments is complicated by several selection processes. In this article, we comprehensively review the current literature with a focus on factors accounting for selection bias. Thus far, studies that did not perform an intention-to-treat analysis conclude that liver transplantation is superior to liver resection for early-stage hepatocellular carcinoma. In contrast, studies performing an intention-to-treat analysis state that survival is comparable between both modalities. Furthermore, all studies demonstrate that disease-free survival is longer after liver transplantation compared to liver resection. With respect to the latter, implications of recurrences for survival are rarely discussed. Heterogeneous treatment effects and logical inconsistencies indicate that studies with a higher level of evidence are needed to determine if liver transplantation offers a survival benefit over liver resection. However, randomised controlled trials, as the golden standard, are believed to be infeasible. Therefore, we suggest an alternative research design from the causal inference literature. The rationale for a regression discontinuity design that exploits the natural experiment created by the widely adopted Milan criteria will be discussed. In this type of study, the analysis is focused on liver transplantation patients just within the Milan criteria and liver resection patients just outside, hereby ensuring equal distribution of confounders.

Hepatic Resection for Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of 7226 Patients

Objective

To systematically review and compare the overall (OS) and disease-free (DFS) survival after hepatic resections for hepatocellular carcinoma (HCC) of patients with nonalcoholic fatty liver disease (NAFLD) versus other risk factors.

Background

Different clinical and tumor characteristics are associated with HCC in the setting of NAFLD in comparison to other risk factors. It is still unclear whether these differences impact patient survival after radical hepatectomies.

Methods

Randomized controlled trials and observational studies published in the English literature between July 1980 and June 2020 were searched using multiple databases. Patients' baseline characteristics and the hazard ratios (HRs) of the OS and DFS were extracted and meta-analyses were performed.

Results

Fifteen retrospective cohort studies with a total of 7226 patients were included. Among them, 1412 patients (19.5%) had NAFLD and 5814 (80.4%) had other risk factors (eg, viral hepatitis B or C, alcoholic cirrhosis, or cryptogenic cirrhosis). Summary statistics showed that patients with NAFLD had better DFS (HR = 0.81; 95% CI: 0.70-0.94; P = 0.006) and OS (HR = 0.78; 95% CI: 0.67-0.90; P = 0.001) than the control group. Subgroups analyses also indicated that the OS favored NAFLD patients versus patients with viral hepatitis B or C (HR = 0.80; 95% CI: 0.67-0.96; P = 0.017) or alcoholic and cryptogenic cirrhosis (HR = 0.68; 95% CI: 0.47-1.0; P = 0.05).

Conclusion

After hepatic resections for HCC, NAFLD patients have better DFS and OS than patients with other risk factors. Subgroup analysis and meta-regression suggested that the survival advantage of NAFLD patients was more pronounced in studies published after 2015 and from Asian centers.

Modest Impact of Liver Transplantation on Hepatocellular Carcinoma Mortality in the United States, Findings from The Transplant Cancer Match (TCM) Study

Liver transplantation is considered the most curative treatment for patients with localized hepatocellular carcinoma (HCC). Recent organ allocation policies have reduced the priority of patients with HCC for liver transplantation, which might affect overall liver transplantation usage and HCC-specific mortality among patients with HCC. Therefore, studies on the impact of liver transplantation on population-level HCC-specific mortality rates are necessary and essential. Mahale and colleagues used comprehensive, linked population databases on both HCC cancer cases and liver transplantation recipients and applied incidence-based mortality (IBM) analysis to evaluate the overall impact of liver transplantation on HCC mortality in the United States. Although liver transplantation rates continue to rise in the United States, the authors showed that liver transplantation has had modest impact over time on HCC-specific mortality at the population level (liver transplantation was associated with a 0.5% reduction in the annual rate of increase in the IBM rate vs. nontransplant). Considering these findings, HCC screening and surveillance for early detection should be a priority, meanwhile, increased availability of liver transplantation for patients with HCC and other HCC curative-intent treatment modalities are also necessary to improve HCC survival. Moreover, HCC risk factors, viral hepatitis and nonalcoholic fatty liver disease prevention and treatment should also be incorporated in future HCC mortality research.See related article by Mahale et al., p. 513.

Long-term outcomes after resection of alcohol-related versus hepatitis-related hepatocellular carcinoma: A SEER-Medicare database analysis

BACKGROUND

The objective of this study was to define the relative impact of alcohol and/or hepatitis-related HCC etiology on the outcomes of patients who underwent resection or transplantation for HCC.

METHODS

The SEER-Medicare database was used to identify patients with HCC between 2004 and 2015. Patients with history of alcohol abuse or hepatitis were identified. Overall survival (OS) and cancer-specific survival (CSS) were calculated using the Kaplan-Meier method and multivariable Cox regression analysis.

RESULTS

Among 1140 patients, 11.9% (n = 136) of patients had alcohol-related HCC, 30.0% (n = 342) hepatitis-related HCC, and 58.1% (n = 662) had other cause-related HCC. On multivariable analysis, patients with alcohol-related HCC (HR:1.06, 95%CI:0.82-1.35) or hepatitis-related HCC (HR:1.05, 95%CI:0.88-1.26) had similar hazards of death compared with patients who had non-alcohol/non-hepatitis-related HCC. Patients who had tumor size ≤5 cm had lower hazards of death (HR:0.81, 95%CI:0.68-0.97), while individuals who underwent liver resection (vs. transplantation) had almost a two-fold higher hazards of death (HR:1.99, 95%CI:1.47-2.69).

CONCLUSION

Tumor specific factors (i.e. tumor size and stage) and operative approach (i.e. resection vs. transplantation) -rather than HCC etiology- dictated both OS and CSS.

A 2020 update on liver transplant for hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma is the most frequent liver tumor and is associated with chronic liver disease in 90% of cases. In selected cases, liver transplantation represents an effective therapy with excellent overall survival.

AREA COVERED

Since the introduction of Milan criteria in 1996, numerous alternative selection systems to LT for HCC patients have been proposed. Debate remains about how best to select HCC patients for transplant and how to prioritize them on the waiting list.

EXPERT OPINION

The selection of the best scoring system to propose in the context of LT for HCC is far to be identified. In this review, we analyze and categorize the various selection systems, assessing their roles in the different decisional phases.

MRI contrast enhancement of liver pre-neoplasia using iron-tannic nanoparticles

The most challenging part of liver cancer detection is finding it in the very early stages. It has been argued that liver preneoplasia is found at the very earliest stages of liver cancer. The presence of a lesion is closely related to the development of HCC. We report herein a new class of iron-based T₁ MRI contrast agents which are nanoparticles of iron–tannic complexes (so-called Fe–TA NPs) that can be used for detecting liver preneoplasia. Preliminary assessment of their toxicity in healthy rats provides suitable imaging dose ranges with acceptable toxicity. In diethylnitrosamine (DEN) induced rats, it is shown that Fe–TA NPs are capable of enhancing MRI signals in rat livers having pre-neoplastic lesions within 60 minutes post-injection. The enhancement efficacy is strongly dependent on the characteristics of pre-neoplastic foci (GST-P+ foci). The highest enhancement was in good correlation with the size of GST-P+ foci and amount of Fe–TA NPs accumulated in the liver, and might be caused by the dysfunction of liver sinusoids along with cellular uptake capability of pre-neoplastic hepatocytes. Our results show that Fe–TA NPs are of great interest to develop as an efficient MRI imaging agent for risk assessment of liver cancer.

Imaging liver preneoplasia could be considered beneficial in first-line assessment of early stage liver cancer.

Options for the treatment of intrahepatic recurrent hepatocellular carcinoma: Salvage liver transplantation or rehepatectomy?

OBJECTIVE

To explore prognostic factors by comparing the efficacy of salvage liver transplantation (sLT) and rehepatectomy (RH) for the treatment of recurrent hepatocellular carcinoma after hepatectomy.

METHODS

Clinical data were collected for 124 patients treated at our center from January 2012 to August 2018. The median follow-up time for the patients was 39 months. By analyzing the clinical data between the sLT group (46 cases) and RH group (78 cases), the factors affecting the prognosis of patients were compared.

RESULTS

The proportion of alpha-fetoprotein (AFP) ≥ 100 µg/L in the recurrence group was significantly higher than that in the recurrence-free group (70.0% vs 22.2%, P = .014). The postoperative overall survival (OS) and recurrence-free survival (RFS) were better in the sLT group than in the RH group (81.2% vs 36.9%, P < .01; 77.1% vs 55.6%, P = .019). In the sLT group, the OS and RFS in the AFP < 100 µg/L group were superior to those in the AFP ≥ 100 µg/L group (P = .046 and P = .002).

CONCLUSION

The sLT group had achieved better efficacy than RH group, but when AFP ≥ 100 µg/L, sLT did not achieve better efficacy than RH.