Comparison between fluoropyrimidine-hepatic arterial infusion and systemic chemotherapy for unresectable liver metastases: A protocol for systematic review and meta-analysis based on 16 observational studies

BACKGROUND: The benefit of loco-regional treatments such as hepatic arterial infusion (HAI) in terms of survival and response rate is unclear. The aim of this work is to quantitatively summarize the results of both randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSIs) comparing fluoropyrimidine-HAI (F-HAI) to systemic chemotherapy (SCT) for the treatment of colorectal liver metastases (CRLMs). METHODS: We searched the Cochrane Library, PubMed, EMBASE, and Web of Science up to July 1, 2021. The outcome measures were tumor response rate and overall survival (OS). Both RCTs and NRSIs comparing HAI to SCT for patients with unresectable CRLMs were included. The outcome measures were tumor response rate and OS. Two reviewers assessed trial quality and extracted data independently. All statistical analyses were performed using standard statistical procedures provided in Review Manager 5.2. RESULTS: A total of 16 studies including 11 RCTs and 5 NRSIs were identified for the present meta-analysis. Nine RCTs compared F-HAI to SCT for patients with unresectable CRLMs and the pooled result indicated that patients who received F-HAI experienced more than twofold response rate than SCT, with a pooled risk ratio of 2.10 (95%CI 1.59–2.79; P < .00001). In addition, the pooled result based on RCTs showed that F-HAI had a significant benefit regarding OS, with a pooled HR of 0.83 (95% CI 0.70–0.99; P = .04). Similarly, the benefit of F-HAI in terms of OS was also observed in the results of NRSIs. CONCLUSIONS: Our results indicated that the F-HAI regimen had a greater tumor response rate and survival advantage than SCT for patients with unresectable CRLMs. Future propensity score-matched analyses with a large sample size should be conducted to support the evidence of our results based on RCTs and NRSIs.