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H. Seon
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P3.02b - Poster Session with Presenters Present (ID 494)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Advanced NSCLC
- Presentations: 2
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
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P3.02b-018 - Detection of Epidermal Growth Factor Receptor Mutations in Circulating Cell-Free DNA versus Tumor Biopsy (ID 5550)
14:30 - 14:30 | Author(s): H. Seon
- Abstract
Background:
Epidermal growth factor receptor (EGFR) mutations are predictive marker of EGFR-tyrosine kinase inhibitor (TKI) therapy. We compared the sensitivity of EGFR mutation detection techniques between matched tumor tissue and peripheral blood sample in patients with lung adenocarcinoma.
Methods:
We collected the paired samples from plasma and paraffin-embedded tumor tissue in 202 patients before EGFR-TKIs. DNA extraction was performed using the QIAamp MinElute virus spin kit and EGFR mutation analysis was done by two detection methods. One is the PNAClamp[TM] which is the PNA-based PCR clamping that selectively amplifies only the mutated target DNA sequence as minor portion in mixture with the major wild type DNA sequences. The other is the PANAMutyper[TM] EGFR kit, which use PNA clamping-assisted fluorescence melting curve analysis to perform mutation detection and genotyping. The degree of agreement was evaluated by Cohen's kappa value.
Results:
The EGFR mutation rates by PANAMutyper[TM]R and PNAClamp[TM] were 51.0% vs. 47.0% in tissue, and 22.2% vs. 11.4% in plasma sample, respectively. Overall concordance rates and the degree of agreement between tissue and plasma samples was better in PANAMutyper[TM]R (69.3%, k=0.393, p<0.001) than PNAClamp[TM] (62.3%, k=0.211, p<0.001). Sensitivity of plasma EGFR mutations was higher (41.7% vs. 22.1%, p<0.001) and false negative rate was lower in PANAMutyper[TM]R test (58.3% vs. 77.9%, p<0.001). Response to EGFR-TKI was correlated with plasma EGFR mutation by PANAMutyper[TM]R (p=0.025) unlike PNAClamp[TM ](p=0.829).
Conclusion:
The sensitivity and concordance rate of PANAMutyper[TM]R test were better than standard PNAClamp[TM] test. So this technique can be useful to detect EGFR mutation in circulating cell-free DNA sample.
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P3.02b-112 - Feasibility of Re-Biopsy in Patients with Non-Small Cell Lung Cancer after Failure of Epidermal Growth Factor Receptor Targeted Therapy (ID 5557)
14:30 - 14:30 | Author(s): H. Seon
- Abstract
Background:
After failure of epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), re-biopsy may be helpful to understand resistance mechanism and guide further treatment decision. However, re-biopsy is still challenging due to several hurdles, such as tissue availability, procedural feasibility, and limited new drugs. The aim of this study was to assess the feasibility of re-biopsy in advanced non-small cell lung cancer (NSCLC) in a real-practice.
Methods:
We retrospectively reviewed the clinical and pathologic data of advanced NSCLC patients who had disease progression after previous EGFR-TKI at single institution between January 2015 and February 2016.
Results:
Ninety-one patients had disease progression after using EGFR-TKI. Among them, thirty-three patients (36.3%) underwent re-biopsy. re-biopsy was successfully completed for thirty-two patients (97.0%) and only one patient didn’t get malignant cell. Three patients (9.1%) experienced a pneumothorax, however only one patient required closed thoracostomy. After re-biopsy, 27 patients were performed EGFR mutation test. Among 21 patients who had active mutation, the initial mutation was again found in 9 cases (42.9%) while the T790M mutation was found in 6 cases (28.6%). In 4 cases the initial EGFR mutation was no longer found. The patients who had re-biopsy were younger (61.2±9.7 vs. 66.1±10.8 years, p=0.03) and longer response duration (429±383 vs. 265±284 days, p=0.022) than the patients who didn’t.
Conclusion:
Re-biopsy in advanced NSCLC is feasible in the real practice especially in younger patient and patients with longer response duration of EGFR-TKI.
