P37.20 Diagnostic EGFR Mutations in Non Small Cell Lung Cancer With Specimens of Body Cavity Fluids

Abstract

Based on the nature of the body fluid samples, there are the presence of suspended DNA fragments that help to make an EGFR mutation diagnosis. From this principle, we conduct research with the following objectives: 1. Investigate the positive rate of EGFR mutations in body fluid samples. 2. Comparison with the same patient result diagnosed with EGFR mutation in paraffine block histological specimens. 3. Partially surveying the diagnostic value of EGFR mutations in body fluid samples. Retrospective, descriptive statistics cross-section: a. Cases of NSCLC are diagnosed with EGFR mutations by paraffine block histological specimens with Cobas Test EGFR Version 1. b. And body fluid samples (pleural fluid, pericardial fluid, peritoneal fluid, cerebrospinal fluid) with Cobas Test EGFR Version 2. a. There are 117 cases in the research: Results of EGFR mutation diagnosis on paraffine block histology: (+) 49 cases # 41.88%, equivalent to statistics in the Vietnam and the World (Asia). The majority are still two types of drug-sensitive mutants TKIs: Exon 19 Deletion and Exon 21 L858R (53% and 23%). b. Results of diagnosis of EGFR mutation in samples of body cavity fluids: Most samples of body cavity performing diagnosis of EGFR mutation were pleural fluid (91 cases # 77.77%). The highest rate of detection of mutations in pleural and cerebrospinal fluid samples (29.67% & 83.33%). Comparing the rate of detection of EGFR mutation in body fluid samples (35/117 cases # 29.91%) with the statistically lower rate of detection in histological samples (29.91% ↔ 41, 88% with P = 0.0125). Compared with other studies in the world, the majority of studies have higher results than those at Pham Ngoc Thach Hospital. Investigation of EGFR mutations in body cavity fluids, a positive result of 29.91% shows that this is a new application step to help diagnose EGFR mutations in cases where histological specimens are difficult to obtain. Especially in cases of NSCLC progresses. The ability to detect EGFR mutations was highest in pleural fluid (29.67%) and cerebrospinal fluid (83.33%). It is necessary to improve the technique of performing EGFR mutant diagnosis in body cavity samples with the more sensitive methods: Droplet Digital PCR, Next Generation Sequencing ect.