Clinical and prognostic implications of RAS mutations in metastatic colorectal cancer.

[PURPOSE] RAS mutations play a critical role in the pathogenesis and progression of colorectal cancer. This study aimed to evaluate the clinical and pathological characteristics associated with RAS mutation status and to investigate its prognostic value in patients with metastatic colorectal cancer.

[METHODS] This retrospective study included 446 adult patients with metastatic colorectal cancer followed at Dokuz Eylul University Medical Oncology Department between 2010 and 2016, all of whom had available RAS mutation data and complete clinical records.

[RESULTS] RAS mutations were identified in 44.8% of patients, predominantly KRAS codon 12 mutations. Early-stage disease and absence of metastasis at diagnosis were more common in the RAS wild-type (WT) group (p < 0.001). Lung metastases occurred more frequently in RAS-mutant cases (p = 0.006). No significant difference in overall survival (OS) was observed between RAS-mutant and WT groups (53.6 vs. 52.5 months; p > 0.05). Anti-VEGF therapy conferred a modest OS benefit in RAS-mutant patients, whereas anti-EGFR therapy showed no effect. Among KRAS-mutant subtypes, codon 61 mutations were associated with the poorest OS.

[CONCLUSION] RAS mutation status may provide insight into metastatic patterns and disease stage in patients with metastatic colorectal cancer. However, its impact on overall survival remains inconclusive. Further prospective studies are needed to clarify its prognostic value.