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H. He
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P3.01 - Advanced NSCLC (ID 621)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.01-031 - ctDNA Assessment of EGFR Mutation Status in Chinese Patients with Advanced Non–Small-Cell Lung Cancer in Read World Setting (ID 9173)
09:30 - 09:30 | Author(s): H. He
- Abstract
Background:
EGFR mutation in plasma circulating free tumor-derived DNA (ctDNA) by ARMS methods has been widely used in clinical settings in China. However, the prevalence of EGFR mutations in ctDNA was still unknown in the real world. This large-scale study (NCT02623257) aimed to explore the prevalence of EGFR mutations and determine the correlation of EGFR mutation status with clinical characteristics.
Method:
Plasma DNA samples from 721 patients with stage III/IV NSCLC who received ≤1 line chemotherapy were collected from 65 hospitals. EGFR mutations were tested by ARMS method. The EGFR mutation rate was calculated and the associations between EGFR mutant and patients’ demographic data, disease status as well as treatment pattern were explored.
Result:
EGFR mutations were detected in 176 of 721 (24.4%) patients, 165 of 620 (26.6%) in adenocarcinoma and 8 of 85 (9.4%) in squamous carcinoma. 138 (19.1%) harbored sensitizing mutations (66 19del, 62 L858R, 7 G719X, 2 L861Q, and 1 S768I) alone, 20 (2.8%) had resistance mutations (13 T790M, 7 Ins20) alone, 2 (0.3%) had a combination of activating mutations, and 16 (2.2%) had a combination of activating and resistance mutations. Twenty-eight (3.8%) patients were detected de novo T790M mutation either existed alone or combination, but no difference of clinical characteristics was observed. Higher detection rate was observed in 566 chemotherapy-naïve patients than in 155 patients received 1[st] line chemotherapy (27.2% versus 14.2%; p<0.001). Of which, the mutation rate of exon 19 deletion was 11.3% for naïve patients and 8.4% for the patients with 1[st] line chemotherapy; while the mutation rate of L858R decreased most obviously from 11.9%(naïve) to 1.9%(1[st] line). We also noticed 117 patients had ≥ 2 organ metastases and the mutation rate was 35.0% in these patients. Multivariate analysis showed female, chemotherapy native, or patients with ≥2 metastatic organs had higher percentage of EGFR mutation. Additionally, in 194 patients who had the follow-up treatment records, 34 of 49 patients (69.4%) with sensitive EGFR mutations received EGFR-TKI, 96 of 136 (70.6%) patients without sensitive EGFR mutation received chemo±radiation.
Conclusion:
Using plasma samples to detect EGFR mutation is feasible. ctDNA based EGFR mutation test could be a surrogate when tissue biopsy is not available due to limited tissue availability and procedural feasibility.
