MOLECULAR PROFILING IN PATIENTS WITH NON-SMALL-CELL LUNG CANCER: POPULATION ANALYSIS OF A BRAZILIAN CANCER CENTER

Introduction: Molecular profiling of advanced non-small cell lung cancers (NSCLC) is essential in the selection of the candidate population to targeted therapy (TT). TT has greater efficacy, with better response rates, survival and tolerance in comparison to standard therapies such as chemotherapy. Objectives: To determine the mutational profile in NSCLC of a population in a Brazilian Cancer Center and to compare results with international cohorts in order to determine differences in mutation frequency. Methods: A retrospective single-institution cohort of 1133 patients (pts) diagnosed NSCLC, from May 2015 to May 2019, screened for EGFR, KRAS and BRAF mutations and also ALK and ROS-1 rearrangements. Additionally to genomic findings, PD-L1 expression was also determined. Not all pts underwent identical molecular profiling. Results: Median age was 65.3 years. Adenocarcinoma was the most common histology (89.3%) followed by squamous cell carcinoma (6%). KRAS was the most common mutation (144/514 pts - 28%) with G12C and G12D the 2 most frequent mutations (74.8% and 18%, respectively). EGFR mutations were reported in 22.3% of cases (141/632 pts); of the EGFR mutated pts, 86.5% had sensitivity mutations, with del19 (45.3%) and L858R (36.8%) the most common mutations. Complex EGFR mutations were observed in 4 pts. ALK and ROS-1 rearrangements frequency was 7.3% (67/915 pts) and 2.2% (4/181 pts), respectively. BRAF was found altered in 3.5% (18/508 pts); V600E was the most common BRAF mutation (66%). Regarding PD-L1, expression was lower than expected. Mean expression was 15.8% and median and mode were 0%. Only 47.44% of patients (130/274) had a positive (≥ 1%) PD-L1, with only 16% pts with a PD-L1 ≥ 50%. Conclusion: This cohort shows incidence of EGFR and ROS-1 alterations similar to international studies. ALK was more common than in international series. PD-L1 expression was much lower in the Brazilian population than shown in previously reported trials. The difference between mutational profile in Brazil and elsewhere remains to be properly clarified, what is specially important with the advancement of target therapy.

 

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No conflict of interest has been declared by the author(s).

Publication History

Article published online:
23 October 2019