National Experience on Waitlist Outcomes for Down-Staging of Hepatocellular Carcinoma: High Dropout Rate in All-Comers

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

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

[Liver transplantation for treatment of nonresectable primary and secondary liver malignancies : Hepatocellular and cholangiocellular carcinomas and colorectal liver metastases]

BACKGROUND

With the increasing efficacy of systemic therapy, liver transplantation plays an important role not only for hepatocellular carcinoma (HCC) but also for nonresectable intrahepatic cholangiocellular carcinoma (iCC), perihilar cholangiocellular carcinoma (phCC) and colorectal liver metastases (CRLM).

AIM

To review the current state of knowledge regarding the indications, patient selection and expected outcomes of liver transplantation for HCC, iCC, phCC and CRLM.

RESULTS

When combined with neoadjuvant locoregional therapy (LRT) and/or systemic therapy, patients with nonresectable HCC, iCC, pCC and CRLM confined to the liver can be successfully transplanted with 5‑year survival rates exceeding 65%. The key to success is strict patient selection, which includes oncogenetic (e.g., BRAFV600E mutation status) and clinical criteria indicative of individual tumor biology (tumor markers: alpha-fetoprotein, AFP/carbohydrate antigen 19‑9, CA19-9/carcinoembryonic antigen, CEA, stable response to neoadjuvant therapy) in addition to morphometric criteria.

CONCLUSION

Liver transplantation offers the possibility of curative treatment even for nonresectable hepatic malignancies. A major limitation of this treatment is the lack of donor organs. Crucial for success is patient selection based on individual tumor biology.

Transplant oncology - Current indications and strategies to advance the field

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

Downstaging hepatocellular carcinoma before liver transplantation: A multicenter analysis of the "all-comers" protocol in the Multicenter Evaluation of Reduction in Tumor Size before Liver Transplantation (MERITS-LT) consortium

Patients with hepatocellular carcinoma meeting united network for organ sharing (UNOS)-downstaging (DS) criteria have excellent liver transplantation (LT) outcomes after DS. However, outcomes for "all-comers" (AC) patients with tumors initially exceeding UNOS-DS are poorly understood. Patients meeting AC (n = 82) or UNOS-DS (n = 229) at 7 LT centers in 4 UNOS regions were prospectively followed from 2015-2020. AC patients had a lower probability of successful DS (67% vs 83% within 12 months; P < .001). The 3-year survival was 69% for UNOS-DS vs 58% for AC (P = .05) and reduced to 30% in patients with Child-Pugh B/C cirrhosis or alpha-fetoprotein (AFP) ≥ 500. Five-year LT probability was 42% for AC vs 74% in UNOS-DS (P = .10). Thirty-eight percent were understaged on explant, with the increasing sum of the largest tumor diameter plus the number of lesions before LT (odds ratio 1.3; P = .01) and AFP ≥ 20 (odds ratio 5.9; P = .005) associated with understaging. Post-LT 3-year survival was 91% for AC vs 81% for UNOS-DS (P = .67). In this first prospective multiregional study of AC patients from the multicenter evaluation of reduction in tumor size before liver transplantation (MERITS-LT) consortium, we observed a 65% probability of successful DS. Three-year survival in AC was nearly 60%, though AC with Child-Pugh B/C or AFP ≥ 500 had poor survival. Explant pathology and 3-year post-LT outcomes were similar between cohorts, suggesting that LT is a reasonable goal in selected AC patients.

Cost-Effectiveness Analysis of Interventional Liver-Directed Therapies for a Single, Small Hepatocellular Carcinoma in Liver Transplant Candidates

PURPOSE

To assess the cost effectiveness of 3 main locoregional therapies (LRTs) (transarterial chemoembolization [TACE], transarterial radioembolization [TARE], and percutaneous ablation) as bridging therapy.

MATERIALS AND METHODS

A cost-effectiveness analysis was performed comparing the 3 LRTs for patients with a single hepatocellular carcinoma (HCC) with a diameter of 3 cm or less over a 5-year time horizon from a payer's perspective. The clinical courses, including transplantation, decompensation resulting in delisting, and the need for a second LRT, were based on data from the United Network for Organ Sharing (2016-2019). Costs and effectiveness were measured in U.S. dollars and quality-adjusted life-years, respectively. Probabilistic and deterministic sensitivity analyses were performed.

RESULTS

A total of 2,594, 1,576, and 903 patients underwent TACE, ablation, and TARE, respectively. Ablation was the dominant strategy, with the lowest expected cost and highest effectiveness. The probabilistic sensitivity analysis demonstrated that ablation was the most cost-effective strategy in 93.9% of simulations. A subgroup analysis was performed for different wait times, with ablation remaining the most cost-effective strategy. The sensitivity analysis showed that ablation was most effective if the risk of waitlist dropout was less than 2.00% and the rate of transplantation was more than 15.1% quarterly. TARE was most effective if the risk of dropout was less than 1.19% and the rate of transplantation was more than 24.0%. TACE was most effective if the risk of dropout was less than 1.01% and the rate of transplantation was more than 45.7%. Ablation remained the most cost-effective modality until its procedural cost was more than $34,843.

CONCLUSIONS

Ablation is the most cost-effective bridging strategy for patients with a single, small (≤3 cm) HCC prior to liver transplantation. The conclusion remained robust in multiple sensitivity analyses.

Hepatocellular Carcinoma, Alpha Fetoprotein, and Liver Allocation for Transplantation: Past, Present and Future

Hepatocellular carcinoma (HCC) is one of the leading indications for liver transplantation and has been the treatment of choice due to the oncologic benefit for patients with advanced chronic liver disease (AdvCLD) and small tumors for the last 25 years. For HCC patients undergoing liver transplantation, alpha fetoprotein (AFP) has increasingly been applied as an independent predictor for overall survival, disease free recurrence, and waitlist drop out. In addition to static AFP, newer studies evaluating the AFP dynamic response to downstaging therapy show enhanced prognostication compared to static AFP alone. While AFP has been utilized to select HCC patients for transplant, despite years of allocation policy changes, the US allocation system continues to take a uniform approach to HCC patients, without discriminating between those with favorable or unfavorable tumor biology. We aim to review the history of liver allocation for HCC in the US, the utility of AFP in liver transplantation, the implications of weaving AFP as a biomarker into policy. Based on this review, we encourage the US transplant community to revisit its HCC organ allocation model, to incorporate more precise oncologic principles for patient selection, and to adopt AFP dynamics to better stratify waitlist dropout risk.