Association of ctDNA RAS mutational status and clinical benefits in first-line metastatic colorectal cancer therapy with chemotherapy plus anti-EGFR (overall response rate and progression-free survival): a brief report of systematic review and meta-analysis.

Monitoring RAS mutations in circulating tumor DNA (ctDNA) is increasingly relevant in metastatic colorectal cancer (mCRC). In patients with tissue RAS wild-type (WT) tumors treated with first-line chemotherapy plus anti-epidermal growth factor receptor therapy (1LChT + anti-EGFR), some studies suggest that RAS WT ctDNA is associated with better outcomes, whereas others reported no differences according to ctDNA RAS mutational status. These inconsistencies may be related to small sample sizes, methodological heterogeneity, differences in assay sensitivity and tumor heterogeneity. We performed a systematic review in patients with tissue RAS WT treated with 1LChT + anti-EGFR. PubMed, Web of Science, and Scopus were searched up to April 2026. Risk of bias was assessed using the QUIPS tool, and random-effect models were applied. Fourteen studies met the inclusion criteria (ten non-interventional studies and four clinical trials). Compared with ctDNA RAS mutated tumors, ctDNA RAS WT tumors showed significantly higher overall response rates [ORR: pooled odds ratio (OR) 2.1, 95% confidence interval (CI): 1.3-3.4; P=0.002] and longer progression-free survival [PFS: pooled hazard ratio (HR) 1.6, 95% CI: 1.3-1.9; P<0.001] [non-interventional studies (NIS) + clinical trials (CT) data]. The pooled prevalence of ctDNA RAS mutations was 10.5% (95% CI: 6.2-14.8%). These findings support ctDNA RAS status as a potential biomarker of benefit from anti-EGFR-based therapy in mCRC, although methodological standardization and prospective validation remain necessary.