Effectiveness and safety of monoclonal antibodies for metastatic colorectal cancer treatment: systematic review and meta-analysis

Background: The effectiveness of chemotherapy (CT) for select cases of metastatic colorectal cancer (MCRC) has been well established in the literature, however, it provides limited benefits and in many cases constitutes a treatment with high toxicity. The use of specific molecular biological treatments with monoclonal antibodies (MA) has been shown to be relevant, particularly for its potential for increasing the response rate of the host to the tumour, as these have molecular targets present in the cancerous cells and their microenvironment thereby blocking their development. The combination of MA and CT can bring a significant increase in the rate of resectability of metastases, the progression-free survival (PFS), and the global survival (GS) in MCRC patients. Objective: To assess the effectiveness and safety of MA in the treatment of MCRC. Methods: A systematic review was carried out with a meta-analysis of randomised clinical trials comparing the use of cetuximab, bevacizumab, and panitumumab in the treatment of MCRC. Results: Sixteen randomised clinical trials were selected. The quality of the evidence on the question was considered moderate and data from eight randomised clinical trials were included in this meta-analysis. The GS and PFS were greater in the groups which received the MA associated with CT, however, the differences were not statistically significant between the groups (mean of 17.7 months versus 17.1 months; mean difference of 1.09 (CI: 0.10-2.07); p = 0.84; and 7.4 versus 6.9 months. mean difference of 0.76 (CI: 0.08-1.44); p = 0.14 respectively). The meta-analysis was not done for any of the secondary outcomes. Conclusion: The addition of MA to CT for patients with metastatic colorectal cancer does not prolong GS and PFS.