Effect of primary tumor resection on survival in patients with asymptomatic unresectable metastatic colorectal cancer: a systematic review and meta-analysis

It remains controversial whether primary tumor resection (PTR) improves survival in patients with asymptomatic, unresectable metastatic colorectal cancer (mCRC). Therefore, we conducted a meta-analysis to assess the latest evidence on clinical outcomes. We systematically searched PubMed, Web of Science, Cochrane Library, and Embase databases for eligible studies published between database inception and May 2022. RevMan 5.4 and Stata 16.0 were used for the meta-analysis. A total of nine studies were included, including four randomized controlled trials (RCTs) and five retrospective cohort studies. Meta-analysis showed that overall survival (OS) [HR = 0.89, 95%CI (0.74, 1.06), P = 0.19] and progression-free survival (PFS) [HR = 0.87, 95%CI (0.71, 1.06), P = 0.17] were not significantly different between the PTR and non-PTR groups. In the subgroup analysis, all subgroups showed no significant difference in OS between the two groups. PTR may not provide additional survival benefits over chemotherapy in asymptomatic, unresectable mCRC patients. However, in view of the limitations of this study, more well-designed RCTs are needed to validate our conclusions.