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

A brief report on the mutational landscape in non-small cell lung cancer of South Asian patients: Comparison at a US and an Indian Institution

Background

Various molecular underpinnings of lung cancer have been noted in Asian populations, especially with targetable oncogenic drivers such as EGFR mutations and ALK rearrangements, although they have been lesser described in South Asian/Indian patients.

Methods

Tumour molecular testing results from non-small cell lung cancer (NSCLC) patients with a name of South Asian origin and diagnosed from 2005 to 2019 at the Stanford Cancer Center in the United States were retrospectively reviewed and compared to the results of molecular testing from PGIMER in Chandigarh, India, from the patients diagnosed from 2011 to 2019.

Results

We identified 72 patients of South Asian (largely Indian) origin, of whom 64 patients (51% female) had mutational testing at Stanford. Of the tested patients, 33% of cases harboured either an EGFR exon 19 deletion or exon 21 L858R mutation, and 12.5% had ALK rearrangements. At PGIMER, a larger sample of 1,264 patients was identified (33% female), with 22.5% of patients having two main EGFR activating mutations, and 9.5% harbouring an ALK rearrangement.

Conclusions

South Asian, largely Indian, patients with NSCLC appear to have a higher chance of harbouring EGFR mutations and ALK translocation as compared to Caucasians. The percentage of South Asian patients with these molecular abnormalities was largely similar in two different geographical locations. These findings corroborate prior single-institution findings and emphasise the importance of molecular testing.

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.