OBJECTIVES: To evaluate the clinical outcomes, especially progression-free survival (PFS), of combining bevacizumab with chemotherapy.

METHODS: DATA SOURCES: The systematic review was carried out by the PRISMA guidelines. The comprehensive searches have been performed on electronic databases such as PubMed, Google Scholar, and Embase by using the following terms as colorectal cancer, adenocarcinoma, bevacizumab, Avastin, chemotherapy, rectal cancer, colon cancer, and monoclonal antibody. STUDY SELECTION: The search was subsequently refined to randomized studies and non-randomized studies that employed the effectiveness of bevacizumab with chemotherapy for metastatic colorectal cancer. DATA EXTRACTION: All studies were screened and coded by two reviewers for each selection step (i.e., screening, data extraction, and quality assessment) based on inclusion and exclusion criteria. A predesigned data collection form was used to collect the data. MAIN OUTCOME: The main outcome of this study was that progression-free survival (PFS) can be defined as the length of time from the start of treatment to the death from any cause or the advancement of the disease, whichever comes first. KEYWORDS: Bevacizumab, CRC, Efficacy, chemotherapy

RESULTS: 24 studies are included in the final analysis. In the final analysis, incorporating bevacizumab with chemotherapy demonstrated favourable outcomes for progression-free survival (PFS) with a hazard ratio (HR= 0.77 95% CI: 0.60-0.96, I²=54%, p<0.01).

CONCLUSIONS: Our results indicate that the combination of bevacizumab with chemotherapy enhances clinical outcomes in untreated metastatic colorectal cancer and represents a significant increase in PFS.