Preoperative transarterial chemoembolization for resectable hepatocellular carcinoma in Asia area: a meta-analysis of random controlled trials
Executive Summary
This briefing document synthesizes the findings of a comprehensive meta-analysis evaluating the efficacy and safety of preoperative transarterial chemoembolization (pre-TACE) for patients with resectable hepatocellular carcinoma (HCC) in Asia. Based on an analysis of five randomized controlled trials (RCTs) involving 430 patients, the study concludes that pre-TACE provides no significant benefit to long-term prognosis, specifically regarding overall survival (OS) and disease-free survival (DFS).
Critically, for patients with tumors larger than 5 cm, pre-TACE was found to negatively impact perioperative safety and surgical efficiency. Key findings include:
No Prognostic Benefit: There was no statistical difference in OS or DFS between patients receiving pre-TACE and those undergoing surgery alone.
Increased Surgical Complexity: In the subgroup with mean tumor diameters >5 cm, pre-TACE significantly increased operation times and the need for combined resection of perihepatic organs due to inflammatory adhesions.
Higher Morbidity: Postoperative morbidity rates were significantly higher in the pre-TACE group for patients with larger tumors.
Clinical Recommendation: Pre-TACE is not recommended as a routine therapy for resectable HCC, as it fails to improve survival and may introduce unnecessary surgical risks.
Overview of the Meta-Analysis
The study aimed to resolve ongoing controversies regarding whether pre-TACE can reduce recurrence rates and prolong survival following curative resection. Unlike previous meta-analyses that focused primarily on long-term prognosis, this study also prioritized perioperative safety indicators.
Study Methodology
Data Sources: Databases including PubMed, Embase, Cochrane, Wanfang, CNKI, and VIP were searched through February 25, 2016.
Inclusion Criteria: Only published RCTs involving patients diagnosed with resectable primary HCC comparing TACE plus operation against operation alone were included.
Patient Cohort: A total of five RCTs from China, Japan, and Taiwan were synthesized, comprising 430 patients (212 in the pre-TACE group; 218 in the surgery-alone control group).
Statistical Logic: The analysis utilized Hazard Ratios (HR) for time-to-event outcomes (OS and DFS) and Odds Ratios (OR) or Standardized Mean Difference (SMD) for perioperative data. Subgroup analysis was conducted based on mean tumor diameter (>5 cm vs ≤ 5 cm) to manage heterogeneity.
Long-Term Prognostic Outcomes
The meta-analysis found that pre-TACE did not offer any survival advantages, regardless of tumor size.
Disease-Free Survival (DFS) and Overall Survival (OS)
The pooled data showed no significant intervention effect for pre-TACE:
DFS: HR 0.95 (95% CI: 0.76–1.19, p = 0.68).
OS: HR 1.25 (95% CI: 0.92–1.68, p = 0.15).
Subgroup analysis based on tumor size similarly showed no significant difference for either DFS or OS in patients with tumors above or below the 5 cm threshold.
Comparison of Long-Term Indicators
Perioperative Safety and Surgical Complexity
While long-term outcomes were neutral, the impact of pre-TACE on the surgical process was notably negative, particularly for larger tumors.
Perioperative Mortality and Postoperative Morbidity
Mortality: There was no significant difference in perioperative mortality between the two groups (OR 0.70, p = 0.56).
Morbidity: In the subgroup with tumors >5 cm, pre-TACE was associated with a significantly higher risk of postoperative complications, such as bile leakage, abdominal abscesses, and wound infections (OR 1.90, 95% CI: 1.02–3.53, p = 0.04). This is attributed to drug-induced liver injury from the chemoembolization agents.
Operation Time and Blood Loss
Operation Time: For tumors >5 cm, the pre-TACE group experienced significantly longer operation times (SMD 0.31, 95% CI: 0.06–0.57, p = 0.02). This was largely due to post-TACE inflammatory reactions causing adhesions.
Blood Loss: No significant difference in blood loss was observed across the groups (SMD 0.07, p = 0.51).
Combined Resection of Perihepatic Organs
The analysis revealed a stark increase in the need for combined resection of adjacent organs (diaphragm, stomach, adrenal gland, colon, pancreas, and spleen) in the pre-TACE group for tumors >5 cm:
Combined Resection Rate: OR 5.46 (95% CI: 2.73–11.78, p < 0.0001).
Primary Drivers: This was necessitated by inflammatory peripheral hepatic adhesions caused by TACE and potential tumor invasion of perihepatic organs.
Pathological Observations and Clinical Implications
The study highlights several pathological reasons for the failure of pre-TACE to improve outcomes and its tendency to complicate surgery.
Adhesion Formation
TACE frequently induces varying degrees of adhesion around the liver, hepatic portal area, and diaphragm.
In one cited study (Zhou et al.), 42 of 47 patients in the pre-TACE group had adhesions, compared to only 15 of 56 in the control group.
Another study (Cui et al.) noted gallbladder wall thickening and shrinking in pre-TACE patients, further complicating surgical maneuvers.
Incomplete Necrosis and Tumor Invasiveness
The meta-analysis notes that complete pathological response to TACE is rare for large tumors.
For patients in the >5 cm subgroup, the complete necrosis rate was consistently below 20%.
Clinical Risk: Incomplete necrosis may weaken the adhesive potential within the tumor, potentially facilitating the release of cancer cells into the bloodstream or invasion of adjacent organs. This may explain the higher combined resection rates.
Summary of Intervention Effects for Tumors >5 cm
Conclusion
The evidence from this meta-analysis indicates that preoperative TACE does not achieve its intended goal of improving long-term prognosis for resectable HCC. Conversely, for patients with tumor diameters exceeding 5 cm, pre-TACE introduces significant surgical challenges, including increased operation times, higher complication rates, and a five-fold increase in the necessity for combined organ resection. Consequently, the study advises against the routine use of pre-TACE in patients eligible for one-stage surgical resection.
