Surgical resection provides the best opportunity for cure for metastatic colorectal cancer. Whether addition of a biologic agent to chemotherapy improves the rate of conversion from unresectable to resectable disease remains uncertain. We carried out a systematic review of the literature and meta-analysis to define the impact of biologic agents on resection and survival. We searched Medline, Embase, CENTRAL and PubMed for randomized controlled trials published up until April 2017 comparing chemotherapy and biologics (intervention) vs. chemotherapy alone (control) in treatment-naïve patients with unresectable metastatic colorectal cancer. Study selection, data abstraction, risk of bias and quality of evidence assessment were performed in duplicate. Random-effects meta-analysis was used to estimate the pooled odds ratio (OR) for resection rate and corresponding confidence interval (CI). Similarly, pooled hazard ratios were estimated for overall survival and progression free survival. 17 studies, including a total of 8233 patients were analyzed. The intervention was associated with higher resection rate (OR 1.47, 95% CI 1.07-2.02; resection rate 8.4% vs. 6.1%) and increased progression-free survival (HR 0.80, 95% CI 0.72-0.89). There was no difference between groups for overall survival, (HR 0.93, 95% CI 0.86-1.01), however, overall survival was increased with the use of antiangiogenic monoclonal antibodies (HR 0.84, 95% CI 0.71-0.99) and anti-epidermal growth factor receptor monoclonal antibodies (HR 0.87, 95% CI 0.79-0.97). The addition of biologic agents to systemic chemotherapy in patients with unresectable metastatic colorectal cancer improved resection rate and progression free survival. The use of monoclonal antibodies improved overall survival.

Does the Addition of Biologic Agents to Chemotherapy in Patients with Unresectable Colorectal Cancer Metastases Result in a Higher Proportion of Patients Undergoing Resection? A Systematic Review and Meta-analysis.