Epidermal growth factor receptor mutation in lung adenocarcinoma in India: A single center study

BACKGROUND: Adenocarcinoma, a subgroup of non-small cell lung cancer, is the most frequent form occurring in the non-smokers. Mutation in tyrosine kinase domain of epidermal growth factor receptor (EGFR) has been a common feature observed in lung adenocarcinoma. The study was carried out to detect the prevalence of EGFR mutation in lung adenocarcinoma. MATERIALS AND METHODS: EGFR mutation status in 166 lung adenocarcinoma patients was obtained retrospectively. Mutation tests were performed on paraffin embedded tissue blocks as a routine diagnostic procedure by polymerase chain reaction followed by direct nucleotide sequencing. Patient’s demographics and other clinical details were obtained from the medical records. RESULTS: EGFR mutation was detected in 43/166 (25.9%) patients. Gender wise mutation was observed as 18/55 (32.7%) in females and 25/111 (22.5%) in males. Overall, EGFR mutation was correlated with never smokers and distant metastasis (P < 0.05), but not associated with the gender, disease stage and pleural effusion. Exon 19 deletions were significantly correlated with females, never smokers, pleural effusion and distant metastasis (P < 0.05). However, point mutation on exon 21 did not show any statistical association with the above variables. Median overall survival was 22 months (95% confidence interval, 15.4-28.6). Female sex, EGFR mutation and absence of metastasis are associated with good prognosis. CONCLUSION: EGFR mutation in lung adenocarcinoma was higher in never smokers, females and patients with distant metastasis. However, it was not linked with tobacco smoking. The prevalence of EGFR mutation observed is in range with the previously published reports from the Asian countries.