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E. Prado
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P1.10 - Poster Session/ Advocacy (ID 228)
- Event: WCLC 2015
- Type: Poster
- Track: Advocacy
- Presentations: 1
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.10-001 - EGFR Mutation Testing Patterns and Results in Brazil and the Need for Greater Public Health Awareness of Molecular Testing (ID 1540)
09:30 - 17:00 | Author(s): E. Prado
- Abstract
Background:
Epidermal growth factor receptor (EGFR) mutation testing allows for optimal selection of therapy with tyrosine kinase inhibitors in patients with non-small-cell lung cancer (NSCLC). Previous studies have shown a variation in EGRF genotype according to ethnic background, with scarce data about EGFR mutation status and testing patterns among Brazilian patients with NSCLC.
Methods:
Between 2011 and 2013, as part of a program sponsored by a pharmaceutical company in Brazil, tumor samples of patients with stage IIIb/IV NSCLC were submitted, at the discretion of the attending physicians, for EGFR mutation testing. All analyses were performed at 02 reference laboratories, as follows: after microdissection, DNA was isolated from serial sections of formalin-fixed, paraffin-embedded tumor tissue to obtain at least 70% tumor cells. Exons 18, 19, 20 and 21 of the EGFR gene were analysed using Sanger sequencing. EGFR mutation rate was calculated and its frequency compared between clinical subgroups using chi-square test. Data about smoking status was incomplete and thus not included in this analysis. Furthermore, a commercial database with 3,296 patients treated in Brazil in 2014 was evaluated for mutation testing patterns.
Results:
3,364 tests out of 3,771 samples analyzed (1,799 male; 1,942 female) yielded informative results. EGFR mutation was present in 25.5% (857/3364) of informative samples. Deletions in exon 19 were the most frequent alteration detected (54%), followed by point mutations in exon 21 (28%) and exon 20 (9.7%). The most important predictors for the presence of EGFR mutations were adenocarcinoma histology (p<0.001), 89% of positive tests occurred in this histology; and female gender (p<0.001), for which 30.2% of the patients tested were positive. No differences in EGFR mutation frequency were found between age groups or regions within the country. In the commercial database of patients with NSCLC treated in the country in 2014, 1,792 patients had adenocarcinomas, 930 had squamous cancer, 71 had large cell cancer and 99 had other histologies. Overall, 34% of patients were tested for mutations (47% in the private sector and 20% in public centers); the corresponding number was 50% for patients with adenocarcinoma (62% of cases in the private and 33% in the public settings, respectively) and 10% for patients with squamous cancer. Of note fewer than 5% of patients overall were tested for ALK alterations.
Conclusion:
To the best of our knowledge, this is the largest study to assess EGFR mutation status in Latin America and in Brazil. Our findings suggest that the frequency of EGFR mutation in this cohort was lower than that found in Asia, but higher than in Caucasian populations, confirming findings seen in other Latin American countries. Despite this high prevalence, a significant number of patients, especially in the public sector, are not currently tested for mutations in the country, and further advocacy efforts are necessary to improve this situation.
