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Effect of EGFR gene mutation in patients with TNBC treated with bevacizumab combined with gemcitabine

Objective: To investigate the effect of Epidermal Growth Factor Receptor (EGFR) gene mutation in patients with Triple Negative Breast Cancer (TNBC) treated with bevacizumab combined with gemcitabine.

Methods: 180 patients with triple-negative breast cancer admitted to our hospital from September 2011 to September 2013 were enrolled in this study. According to their DNA sequencing results, the patients were divided into EGFR mutation group and the non-mutation group, and according to the patient's genetic mutation type, patients in mutation group were divided into exon 19 deletion group, exon 21 mutation group. All patients were treated with bevacizumab and gemcitabine, and the prognosis of each group was compared.

Results: EGFR mutations were found in 51 cases (28.3%). The sex ratio and smoking history of EGFR mutant group were significantly different (P<0.01) compared with non-mutated group. For EGFR mutation group, there were 30 cases (58.8%) of exon 19 deletion, and 21 cases of exon 21 mutation (41.2%). The progression-free survival time and 1-year survival rate were significantly higher in mutant group than in non-mutation group (P<0.05). The total effective rate in EGFR exon 19 deletion group, exon 21 mutation group was 80.0% and 76.2%, higher than 40.3% in the non-mutation group, the disease control rate was also higher than the mutation group, the difference was statistically significant (P<0.05). There was no significant difference in total effective rate and disease control rate between exon 19 deletion mutation group and exon 21 mutation group (P>0.05). Adverse reactions were concentrated in the rash, diarrhea, with mild degree and tolerable. For the incidence of adverse reactions in three groups, the difference was not statistically significant (P>0.05).

Conclusion: EGFR mutations are more sensitive in patients with triple-negative breast cancer treated with bevacizumab and gemcitabine, with better clinical efficacy, and the progression-free survival of tumors is prolonged. EGFR mutation has no significant effect on the safety of treatment.

Author(s): Shihui Ma, Feihai Ling, Shifeng Chen, Anping Gui