Meta-analysis of oncologic effect of primary tumor resection in patients with unresectable stage IV colorectal cancer in the era of modern systemic chemotherapy

Purpose: The management of primary tumors in patients with stage IV colorectal cancer remains unclear. This meta-analysis evaluated the survival benefits of primary tumor resection (PTR) in patients with unresectable stage IV colorectal cancer in the era of modern chemotherapy. Methods: Multiple comprehensive databases were searched for studies comparing survival outcomes in patients with metastatic colorectal cancer who did and did not undergo PTR. Outcome data were pooled, and overall effect size was calculated using random effect models. Results: Seventeen nonrandomized studies involving 18,863 patients met the inclusion criteria. Meta-analysis showed that PTR significantly improved overall survival (hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.56–0.71; P < 0.001) and progression free survival (HR, 0.76; 95% CI, 0.67–0.87; P < 0.001). Subgroup analyses and sensitivity analyses, performed by predefined methods, also indicated that PTR improved overall patient survival. Conclusion: Palliative resection of the primary tumor may have survival benefits in patients with unresectable stage IV colorectal cancer. Randomized controlled trials are needed to determine the optimal treatment for these patients.