Purpose: There is a paucity of consistent data concerning genetic mutations in Brazilian patients with lung cancer. The aim of this study was to retrospectively analyze epidermal growth factor receptor (EGFR) mutations detected in a real-world scenario using a large cohort of Brazilian patients with non-small-cell lung cancer (NSCLC).
Materials and methods: This was a cross-sectional, observational, descriptive study on the basis of a database of EGFR molecular analysis from tumor samples of patients with a confirmatory histopathological diagnosis of primary lung cancer. Specimens were collected from 2013 to 2017 and were tested using cobas, next-generation sequencing, and Sanger sequencing platforms.
Results: A total of 7,413 tumor specimens were tested. The patients were predominantly women with a median age of 67.0 years. Patients with at least one mutation represented 24.2% of the total sample. Among the positive patients, the majority had just one mutation, but two or more simultaneous mutations were observed in 1.52% of patients. Exon 19 deletion was the most prevalent alteration in the sample (12.8%), followed by exon 21 L858R (6.9%) and exon 20 insertion (1.6%). All others were considered uncommon mutations and were observed in 18.5% of all mutated patients and 4.0% of the total sample (2.3%-18.7% depending on the sequencing method).
Conclusion: This study examined the prevalence of EGFR mutations in Brazilian patients with NSCLC using different technologies, suggesting that the type of method used, directed or nondirected against specific mutations, influences the analysis, particularly for uncommon mutations, which will be missed by mutation-specific approaches such as cobas testing. Our estimates are the largest in Latin America and are consistent with previous reports from other parts of the world. Besides the variability in methods described here as technology incorporation advances in a nonhomogeneous manner, it is probably like the real-world clinical setting Brazilian oncologists face in their daily practice.