EGFR mutations and ROS1 and ALK rearrangements in a large series of non-small cell lung cancer in South India.

Background: Driver mutations are seen in 80% of lung adenocarcinomas, and they influence prognosis and choice of therapy.

Aim: Aim of this study was to analyse the frequency of epidermal growth factor receptor (EGFR) mutations, ALK and ROS1 rearrangements and their association with age and gender in non-small cell lung cancer reported from a tertiary care center in South India.

Methods: Tumors from patients with non-small cell carcinoma of lung were evaluated for EGFR mutations, ALK and ROS1 rearrangements and their association with age and gender were studied.

Results: Two thirds of non-small cell carcinomas had driver mutations or rearrangements. EGFR mutation was common and seen in 34.1%, whereas ALK rearrangement was seen in 11.1% and ROS1 rearrangement in 2% patients. Among EGFR mutations, most common were Exon 19 deletion and L858R seen in 21.3% and 11% of patients, respectively. Adenocarcinoma was the histologic diagnosis in 81% to 85% of patients with exon 19 deletion and L858R mutation, respectively. EGFR mutation frequency in patients less than 36 years was 13.6%, whereas in older patients, it varied from 34% to 36%. Exon 19 deletion was seen in 29.8% females and 17.2% of males.

Conclusion: EGFR mutations are more common than ALK and ROS1 rearrangements. They are more common in females. Patients less than 36 years have reduced frequency of EGFR mutations. Exon 19 deletion and L858R are most common and are more prevalent in lung adenocarcinomas. Rare EGFR mutations are seen in patients aged more than 50 years.