The role of neoadjuvant chemotherapy for resectable colorectal liver metastases: a systematic review and meta-analysis

Neoadjuvant chemotherapy is being increasingly accepted as an effective treatment of resectable colorectal liver metastases (CRLM), but it may also damage the hepatic parenchyma. We performed a meta-analysis to compare the outcomes of patients who received neoadjuvant chemotherapy (NEO) prior to hepatic resection with hepatic resection without neoadjuvant chemotherapy (SG). Eligible trials were identified from Embase, PubMed, the Web of Science and the Cochrane library. Hazard ratios (HRs) with a 95% confidence intervals (CIs) were used to measure the pooled effect using a random-effects model. Statistical heterogeneity was detected by I(2) test. Sensitivity analyses and publication bias were also assessed. The study outcomes included 3-year, 5-year disease-free and overall survival rate, respectively. Eighteen studies involving 6,254 patients were included. The pooled HRs for 5-year DFS and 5-year OS for NEO in the included studies calculated using the random-effects model were 1.38 (95 % CI; 1.26-1.51, p=0.00; I(2)=9.6%, p=0.36) and 1.19 (95% CI: 1.02-1.38; p=0.03; I(2)=49.2%, p=0.03), respectively. For CRLM patients with factors indicating a high risk of recurrence, the pooled HR for 5-year OS of NEO in the included studies calculated using the random-effects model was 0.69 (95% CI: 0.55-0.87; p=0.00; I(2)=0.0%, p=0.48). These results suggest neoadjuvant chemotherapy improved survival of patients with initially resectable CRLM and a high risk of disease recurrence.