Objective: To analyze the EGFR mutation index on the cancer blocs of the patients with non - small cell lung cancer (NSCLC) at the Department of Pathology - Hue Central Hospital. Subjects and methods: A prospective, cross-sectional descriptive study of 227 patients with advanced, metastatic non - small cell lung cancer who were mutated in the EGFR gene. The study were carried out on the cancer parrafin blocs stored in Pathology Department, Hue Central Hospital. Results: Mean age 58.29 ± 9.36 years old, male/female ratio 1.58. Histopathology is mainly adenocarcinoma: 96%, squamous epithelium: 0.9%, large cell: 3.1%. EGFR mutation rate positive 38.3%, negative: 61.7%. The rate of positive EGFR mutations in women: (53.4%) is higher than in men: (28.8%). The rate of positive EGFR mutations in the smoking group: (24.4%), insignificant smoking: (32.8%), the non - smoking group (56.6%). The cases of patients carrying mutations in EGFR gene have 50.6% of LREA deletion mutations in exon 19
40.23% are L858R substitution mutations in exon 21
3.45% are G719X mutations and 2.3% are G719S mutations in exon 18
1.14% are Q787 mutations in exon 20
1.14% are double mutations S768I + V769L in exon 20 and T790M + L858R in exons 20 and 21. Conclusion: The rate of EGFR gene mutation in NSCLC patients was 38.3%, higher in women than in men and especially high in non - smokers or non - smokers, the difference was statistically significant with p. <
0.05. The most common TKI - sensitive mutations include deletion mutations in exon 19 and substitution mutations in exon 21 (accounting for more than 90%), a percentage less than 5% are mutations.