The Efficacy Of Anti-EGFR Therapy In Patients With (K)RAS Wild-type Metastatic Colorectal Cancer

Objective: The present study was designed to investigate the efficacy of anti-EGFR treatment in(K)RAS wild-type metastatic colorectal cancer;to explore potential predictive clinicopathological characteristics and biomarkers;to investigate whether maintenance treatment with anti-EGFR antibody after induction therapy can further improve the efficacy.Methods: The present study was a retrospective study.From May 2009 to March 2017,patients with(K)RAS wild-type metastatic colorectal who were treated with anti-EGFR antibody in the First Hospital of China Medical University were enrolled.The clinicopathological data were collected,and the short-term efficacy and long-term survival were recorded.Results: A total of 80 patients were included in the studies,Sixty-five patients were included in short-term efficacy analysis.The overall response rate was 36.93%,and the disease control rate was 93.85%.Fifty-six patients were included in progression free survival analysis.The median progression free survival was 11.2 months(95% CI,7.71 to 14.69).Eighty patients were included in overall survival analysis.The median overall survival was 27.6 months(95% CI,22.99 to 32.28).To further explore the relationship between clinicopathological characteristics and therapeutic effect,univariate and multivariate analysis were performed.Our data showed that only liver-limited disease correlated with objective response rate(P=0.019).In terms of survival analysis,only the line of anti-EGFR therapy correlated with progression free survival(P=0.016).Pathological type,synchronous metastases,the level of CEA and CA199 before treatment correlated with overall survival(P <0.050).Multivariate analysis showed that the line of anti-EGFR therapy was independent predictive factor for progression free survival(P=0.047),and pathological type and synchronous metastases were independent predictive factors for overall survival(P=0.009 and P=0.018,respectively).Further exploratory analysis showed that BRAF gene type and baseline CA199 level did affect overall survival(P<0.001 and P=0.047,respectively).Furthermore,after induction treatment,maintenance therapy with anti-EGFR antibody had longer survival compared with chemotherapy maintenance and no maintenance group(P=0.010).Conclusion: Anti-EGFR therapy resulted in significant survival benefits in(K)RAS wild-type metastatic colorectal cancer.In patients treated with anti-EGFR antibody,the line of anti-EGFR therapy was the independent predictive factors for progression free survival,and pathological type and synchronous metastases were independent predictive factors for overall survival.Patients with wild-type BRAF,normal baseline level of CEA and CA199,maintenance therapy with anti-EGFR antibody after induction treatmentcan benefit more from anti-EGFR therapy.