Intra-Arterial Therapy for Unresectable Colorectal Liver Metastases: A Meta-Analysis

Purpose: To evaluate the efficacy of hepatic arterial infusion (HAI), conventional transarterial chemoembolization, drug-eluting embolic transarterial chemoembolization (DEE-TACE), transarterial radioembolization, and their combinations with systemic chemotherapy (SCT) for unresectable colorectal liver metastases. Methods: A search was conducted on Embase, Scopus, PubMed, and Web of Science for prospective nonrandomized studies and randomized controlled trials (RCTs) from inception to June 20, 2020. Survival data of patients were recovered from original Kaplan-Meier curves by exploiting a graphical reconstructive algorithm. One-stage meta-analyses were conducted for the median overall survival (OS), survival rates (SRs), and restricted mean survival time (RMST), whereas two-stage meta-analyses of proportions were conducted to determine response rates (RRs) and conversion to resection rates (CRRs). Results: A total of 71 prospective nonrandomized studies and 21 RCTs were identified, comprising 6,695 patients. Among patients treated beyond the first-line, DEE-TACE + SCT (n = 152) had the best survival outcomes of median OS of 26.5 (95% confidence interval [CI], 22.5-29.1) months and a 3-year RMST of 23.6 (95% CI, 21.8-25.5) months. Upon further stratification by publication year, DEE-TACE + SCT appeared to consistently have the highest pooled SRs at 1 year (81.9%) and 2 years (66.1%) in recent publications (2015-2020). DEE-TACE + SCT and HAI + SCT had the highest pooled RRs of 56.7% (I-2 = 0.90) and 62.6% (I-2 = 0.87) and pooled CRRs of 35.5% (I-2 = 0.00) and 30.3% (I-2 = 0.80), respectively. Conclusions: Albeit significant heterogeneity, the paucity of high-quality evidence, and the noncomparative nature of all analyses, the overall evidence suggests that patients treated with DEE-TACE + SCT have the best oncological outcomes and greatest potential to be converted for resection.