Hepatocellular Carcinoma Recurrence in Living and Deceased Donor Liver Transplantation

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Hepatocellular Carcinoma Recurrence in Living and Deceased Donor Liver Transplantation: A Systematic Review and Meta-Analysis

Liver transplantation has emerged as a cornerstone in treating hepatocellular carcinoma (HCC), particularly for early-stage tumors. While deceased donor liver transplantation (DDLT) has been widely adopted, the persistent shortage of deceased donor organs has driven the expansion of living donor liver transplantation (LDLT), especially in regions like East Asia. Despite resolving technical and donor safety challenges associated with LDLT, concerns about increased HCC recurrence rates in LDLT compared to DDLT persist. This meta-analysis evaluates the risk of HCC recurrence between LDLT and DDLT, focusing on underlying factors such as surgical techniques, graft size, and organ allocation policies.

Background and Rationale

HCC recurrence after liver transplantation remains a critical concern, as it significantly impacts patient survival. Initial clinical studies suggested higher recurrence rates in LDLT, potentially linked to biological and surgical differences between the two procedures. LDLT preserves major vascular and biliary structures in the recipient, which may inadvertently leave residual HCC cells near critical anatomical sites. Additionally, partial grafts used in LDLT undergo rapid regeneration, a process hypothesized to accelerate residual HCC growth through cytokine and growth factor activation. Animal studies support this theory, demonstrating enhanced tumor growth in partial hepatectomy and reduced graft size models.

Organ allocation policies further complicate comparisons between LDLT and DDLT. In many regions, deceased donor organs are prioritized for patients with early-stage HCC and higher Model for End-Stage Liver Disease (MELD) scores, creating inherent selection biases. LDLT candidates, however, often include patients with advanced HCC who face prolonged waiting times for DDLT. These disparities necessitate rigorous adjustments for tumor staging and patient selection in comparative studies.

Methodology

Literature Search and Selection

A systematic search of PubMed, Embase, and the Cochrane Library identified studies comparing HCC recurrence in LDLT and DDLT. Keywords included “Liver Transplantation,” “Hepatocellular Carcinoma,” and “Living Donor.” After removing duplicates, 641 articles were screened, and 22 underwent full-text review. Studies with overlapping data, non-HCC tumors, or insufficient adjustment for HCC staging were excluded. Seven studies met the eligibility criteria, encompassing 527 LDLT and 781 DDLT cases.

Quality Assessment and Bias Control

The Newcastle-Ottawa Scale (NOS) evaluated study quality, emphasizing comparability between LDLT and DDLT groups. Key exclusion criteria included unadjusted differences in HCC staging, post-transplant therapies, or selection biases. Studies were excluded if they lacked multivariate adjustments for tumor size, vascular invasion, or MELD scores. For example, reports prioritizing DDLT for tumors near major vessels were excluded due to uncontrolled confounding.

Statistical Analysis

Hazard ratios (HRs) for HCC recurrence were pooled using random-effects models in Review Manager 5.3. Adjusted HRs from multivariate analyses were prioritized, while unadjusted HRs were derived from recurrence rates and survival data. Sensitivity analyses assessed the impact of large studies and regional differences.

Key Findings

Overall Recurrence Risk

The meta-analysis revealed a significantly higher HCC recurrence risk in LDLT (HR = 1.61, 95% CI: 1.12–2.30, P = 0.01). Heterogeneity among studies was moderate (I² = 48%*). Subgroup analyses highlighted critical nuances:

  • Multivariate-adjusted studies: Consistently demonstrated elevated recurrence risk in LDLT (HR = 2.63, 95% CI: 1.68–4.12, I² = 0%).
  • Regional differences: Studies from mainland China showed no significant risk increase (HR = 0.94, 95% CI: 0.73–1.21), contrasting with non-Chinese studies (HR = 2.59, 95% CI: 1.71–3.94, P < 0.0001*).

Impact of Organ Allocation Policies

Recurrence risk was most pronounced in regions allocating deceased donor organs to non-HCC patients. For instance, studies from the U.S. and Europe, where DDLT prioritizes early-stage HCC, reported higher LDLT recurrence rates. Conversely, mainland China’s shorter DDLT waiting times and less stringent HCC criteria diminished baseline differences between LDLT and DDLT cohorts.

Surgical and Graft-Related Factors

Preservation of recipient vasculature in LDLT may leave residual tumor cells, while partial grafts’ regenerative environment could promote HCC growth. One study noted a trend toward higher recurrence in LDLT recipients with graft-to-recipient weight ratios (GRWR) <0.8 (P = 0.17), particularly for tumors beyond Milan criteria (P = 0.047).

Discussion

Biological and Technical Factors

The elevated recurrence risk in LDLT may stem from multiple mechanisms:

  1. Incomplete tumor clearance: Preserving hepatic veins and portal structures during LDLT increases residual tumor risk.
  2. Graft regeneration: Partial grafts’ regeneration upregulates growth factors like VEGF and HGF, potentially accelerating micrometastases.
  3. Shorter preoperative observation: LDLT’s expedited timeline may insufficiently screen for aggressive HCC biology.

Regional Disparities and Selection Bias

Mainland China’s unique organ allocation context—shorter DDLT wait times and broader HCC criteria—likely attenuated LDLT-associated risks. In contrast, regions with prolonged DDLT waiting periods (e.g., Hong Kong and Korea) faced higher LDLT recurrence due to negative selection (advanced HCC cases opting for LDLT).

Clinical Implications

The findings advocate for cautious LDLT use in HCC patients, emphasizing stringent selection criteria and optimized surgical techniques. For high-risk cases (e.g., vascular proximity), DDLT remains preferable. Future studies should standardize HCC staging adjustments and evaluate adjuvant therapies to mitigate recurrence.

Conclusion

This meta-analysis confirms a heightened HCC recurrence risk in LDLT compared to DDLT, driven by biological and procedural factors rather than staging differences alone. Regional variations in organ allocation policies and preoperative observation periods critically influence outcomes. Refining LDLT protocols, including extended observation windows and graft size optimization, could reduce recurrence risks. Clinicians must weigh LDLT’s benefits against its oncological limitations, ensuring personalized treatment strategies for HCC patients.

doi.org/10.1097/CM9.0000000000000287

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