Characterization of patients with lung adenocarcinoma treated at a reference oncology center in northeastern Brazil and submitted to EGFR gene mutation research.

Abstract

e20548 Background: Lung cancer has the highest incidence and mortality worldwide. In Brazil, it is the second most common, and individualized therapy, although more efficient than traditional chemotherapy, is still a challenge for health services, especially in developing countries, as socioeconomic disparities make access to genetic testing difficult or treatment. Thus, it is understood that greater knowledge about the genetic profile and therapeutic response of different populations can contribute to policy changes that guarantee expanded access to individualized therapy. Methods: the EGFR gene mutation status was correlated with clinical-epidemiological, socioeconomic, treatment, and survival parameters of patients with lung adenocarcinoma treated from 2014 to 2021 at an oncology referral center in northeastern Brazil. Data were obtained retrospectively from the patient's charts at the Hospital Haroldo Juaçaba/Instituto do Câncer do Ceará. The X²/Fisher and Log-Rank Mantel-Cox tests were used to associate clinical variables and overall survival curves. The Research Ethics Committee approved the research under protocol number 3.544.754. Results: 586 patients tested, 157 (26.8%) had an EGFR mutation, with exon 19 deletion (n = 83, 52.9%). the most frequent followed by L858R (n = 54, 34.4%) and others (n = 30, 12.8%). The EGFR mutation was inversely associated with smoking history (p < 0.001) and previous use of carboplatin plus paclitaxel (p < 0.001). The median overall survival was 33 (95%CI = 25-41) months, and the presence of a mutation was not associated with a worse outcome (p = 0.146). Interestingly, patients with sensitivity mutation who used gefitinib (64.1%) did not show a significant difference in overall survival (p = 0.218). However, when stratifying analyzes according to mutation type, it was observed that patients with exon 19 deletion treated with gefitinib had greater median overall survival (32, 95%CI = 27-37 months) than patients with this mutation not treated with gefitinib (median = 15, 95%CI = 2-25 months) (p < 0.001). Patients with the L858R type sensitivity mutation (p = 0.523) or other mutations (p = 0.439) did not experience significant benefits from gefitinib use. Conclusions: In the population studied, the exon 19 deletion was the most frequent and the only one associated with a substantial benefit from using gefitinib.