Detection of epidermal growth factor receptor mutation in the peripheral blood of patients with esophageal carcinoma to guide epidermal growth factor receptor-tyrosine kinase inhibitor treatment.

Objective: This study aimed to explore the epidermal growth factor receptor (EGFR) mutation in the peripheral blood of patients with esophageal carcinoma and analyze the relationship between EGFR-tyrosine kinase inhibitor (EGFR-TKI) therapeutic effect and EGFR mutation in peripheral blood.

Methods: A retrospective analysis was performed on 66 patients with esophageal carcinoma treated with EGFR-TKI (Gefitinib) from February 2014 to March 2017 in our hospital. Real-time polymerase chain reaction was applied to detect the mutation of the EGFR gene in peripheral blood specimens before patients were treated with EGFR-TKI. The relationship between EGFR mutation in the peripheral blood and clinical features of patients were analyzed. The correlation between EGFR mutation in peripheral blood and EGFR-TKI treatment response was also demonstrated.

Results: Among the 66 patients, 18 cases were determined as EGFR mutation in peripheral blood. The mutation rate was 27.3%. Among these patients, it observed 1 case of exon 18 2155G>A mutation, 3 cases of exon 19 2235-2249Del mutation, 5 cases of 2236-2250Del mutation, 1 case of 2254-2277Del mutation, 1 case of L747-A750Del mutation, 3 cases of exon 21 2576T>G mutation, 3 cases of 2497T>G mutation, and 1 case of 2504A>T mutation. EGFR mutation in the peripheral blood of patients with esophageal carcinoma was unrelated to the gender, age, and the location of the tumor (P < 0.05). By contrast, EGFR mutation was related to the pathological types of the patients (P < 0.05). The mutation rate of the EGFR of squamous cell carcinoma patients was significantly higher than that of adenocarcinoma patients (P < 0.05). Among EGFR wild-type patients, 8 cases were stable disease (SD), and 40 cases were progressive disease (PD), after EGFR-TIK treatment. No complete response (CR) and partial response (PR) patients were reported. The overall response rate (ORR) was 0.0%. Among the EGFR mutation group, 5 were SD cases, 5 were PD cases, and 8 were PR cases. No CR case was reported. The ORR was 44.4%. The ORR of the EGFR group was significantly higher than that of the wild-type group (P < 0.05).

Conclusion: The detection of EGFR mutation in peripheral blood can be applied as an effective index for EGFR-TKI (Gefitinib) treatment in patients with esophageal carcinoma.