Impact of neoadjuvant chemotherapy on post-hepatectomy regeneration for patients with colorectal cancer liver metastasis – Systematic review and meta-analysis

Background Today, there is still debate on the impact of neoadjuvant chemotherapy (NeoChem) on liver regeneration (LivReg). The objectives of this study were to assess the impact of NeoChem and its characteristics (addition of bevacizumab, number of cycles and time from end of NeoChem) on post-hepatectomy LivReg. Material & methods Studies reporting LivReg in patients submitted to liver resection were included. Pubmed, Scopus, Web of Science, Embase, and Cochrane databases were searched. Only studies comparing NeoChem vs no chemotherapy or comparing chemotherapy characteristics from 1990 to present were included. Two researchers individually screened the identified records registered in a predesigned database. Primary outcome was future liver remnant regeneration rate (FLR3). Bias of the studies was evaluated with the ROBINS-I tool, and quality of evidence with the GRADE system. Data was presented as mean difference or standard mean difference. Results Eight studies with a total of 681 patients were selected. Seven were retrospective and one prospective comparative cohort studies. In patients submitted to major hepatectomy, NeoChem did not have an impact on LivReg (MD 3.12, 95% CI -2,12–8.36, p 0,24). Adding bevacizumab to standard NeoChem was associated with better FLR3 (SMD 0.45, 95% CI 0.19–0.71, p 0.0006). Discussion The main drawback of this review is the retrospective nature of the available studies. NeoChem does not have a negative impact on postoperative LivReg in patients submitted to liver resection. Regimens with bevacizumab seem to be associated with better postoperative LivReg rates when compared to standard NeoChem.