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Kirsty Wai Chung Lee
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P3.02 - Biology/Pathology (ID 620)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Biology/Pathology
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.02-031 - Detection of Activating EGFR Mutations and Resistant T790M Mutation from cfDNA in Malignant Pleural Effusion(MPE-DNA) (ID 8389)
09:30 - 09:30 | Presenting Author(s): Kirsty Wai Chung Lee
- Abstract
Background:
Analysis of activating EGFR and resistant T790M mutations from plasma cfDNA is now recognized as one of the standard testing methods in clinical practice.(Mok et al CCR 2015, Oxnard et al JCO 2016) Sensitivity varies from 60 to 80% while specificity is above 90%. Malignant pleural effusion (MPE) is an alternative rich source of cfDNA and efficacy of mutation testing from this sample source remains unclear.
Method:
Objectives of this study is to study the feasibility of testing EGFR mutations using MPE-DNA and to compare the diagnostic utilities with plasma cfDNA in lung cancer patients with known EGFR mutation status established by tumor tissue. 10 ml of blood and 10 ml of pleural fluid were collected after consent. DNA was extracted and tested by digital PCR (Sanomics Inc. Hong Kong, China).
Result:
We enrolled 45 patients between November 2016 and May 2017. Patient demographics are summarized as follows: male (n=21) vs female (n=24); tissue EGFR wild type (n=13) vs mutation (n=24) vs unknown (n=8); treatment naïve (n=26) vs progression of TKI (n=19). Diagnostic utilities are summarized in table below. 9 plasma samples were positive for T790M compared to 14 samples of MPE-DNA being positive. (Detection rate: 0.20 vs 0.31, respectively) Total of 6 negative T790M plasma samples were tested positive in MPE-DNA, and vice versa, 2 samples. Concordance rate of T790M testing between plasma cfDNA and MPE-DNA is 0.82.EGFR mutation Plasma cfDNA vs tumor MPE-DNA vs tumor Sensitivity 0.83 0.92 Specificity 0.92 0.92 Concordance 32/37=0.86 34/37= 0.92 Mean allele frequency of cfDNA only (range) 13.43% (0.10%-58.66%) 31.77% (1.21%-83.40%)
Conclusion:
It is feasible to detect activating EGFR and resistant T790M mutations from MPE-DNA. Sensitivity of testing MPE-DNA is similar if not better than plasma cfDNA. Further investigation is warranted.
