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T.V. Reis
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P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.04-038 - EGFR Mutation Prevalence and Epidemiological Profile of Patients with Metastatic Nonsquamous Non Small Cell Lung Cancer (ID 2498)
09:30 - 09:30 | Author(s): T.V. Reis
- Abstract
Background:
Presence of epidermal growth factor receptor (EGFR) mutation in patients with non small cell lung cancer (NSCLC) is very important for therapeutic choice, since these patients benefit from the use of targeted therapies, such as EGFR tyrosine kinase inhibitors (TKIs). There are different types of EGFR mutation causing deletions in exons 18, 19, 20 and 21. Presence of this mutation is commonly found in female, Asian ethnicity, never smokers and adenocarcinoma histology. Patients with EGFR mutations have benefit of use TKIs because these drugs inhibit tyrosine kinase activity, enabling apoptosis of tumor cells. However, there are cases of TKI resistance due to mutations at EGFR second site, resulting in T790 mutation (T790M), which prevents TKI connection to tyrosine kinase. This study aimed to determine the percentage of patients with metastatic nonsquamous NSCLC which realized molecular analysis for EGFR mutation, especially T790M, and to describe epidemiological profile of these patients.
Methods:
Observational, retrospective, single-institutional study in metastatic nonsquamous NSCLC patients, in attendance during January 2012 and December 2014. Variables analyzed: age, sex, race, smoking, number of metastatic sites, first-line therapy, presence of EGFR mutation and T790M.
Results:
There were 93 eligible patients, 79 (84,94%) of them were tested for EGFR and 23 patients (29.11%) of 79 were mutated. From all patients tested, 15 patients (18.98%) were positive for exon 19, three patients for exon 21 (3.79%), two patients (2.53%) for exon 20 (T790M), two patients (2.53%) for exon 20 (T790M) and exon 21 (L858R) and one patient (1.26%) for exons 20 (R776C) and 21 (L858R). No patients were positive for exon 18. Therefore, percentage of patients with T790M was 5.06% of all patients tested for EGFR mutation. Among patients with positive EGFR, 56.21% was female, 95.65% had adenocarcinoma and 4.34% large cell. About 69.56% was brown, 21.73% white and 8.69% black; 73.91% never smoked, 17.39% former smokers, while 8.69% was current smoker. The mean age was 55.95 and median of 57 years. Approximately 47.82% of patients had one metastatic site, 39.13% 2 metastatic sites and 13.04% 3 metastatic sites. As for first-line therapy, 52.17% of patients used TKIs (Afatinib or Gefitinib or Erlotinib), while 43.47% used platinum-based chemotherapy, 4.34% used only Pemetrexed.
Conclusion:
The percentage of patients who tested EGFR mutation was high and presence of T790M was also quite significant. Other study found that 81% of patients with stage IIIb/IV NSCLC were tested for EGFR before first-line therapy administration. In a multicenter study, about 90.7% of newly diagnosed NSCLC patients were tested for EGFR mutation and mutation rate was 11.6% for exons 19 and 21. Some of our patients have not been tested for EGFR mutation because they were supportive patients or because the sample was insufficient/inadequate. The profile of patients with positive EGFR was similar to that found in literature. Some patients did not use TKI as first-line treatment because the result of mutation delayed to arrive. Molecular study in NSCLC patients is essential for the best treatment choice and TKIs should be started as soon as there is positive result of mutation.
