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Berta Hernandez
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FP12 - Tumor Biology and Systems Biology - Basic and Translational Science (ID 188)
- Event: WCLC 2020
- Type: Posters (Featured)
- Track: Tumor Biology and Systems Biology - Basic and Translational Science
- Presentations: 1
- Moderators:
- Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall
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FP12.01 - Circulating Tumor DNA to the Identification of EGFR Positive NSCLC Long-Term Survivors (ID 3013)
00:00 - 00:00 | Author(s): Berta Hernandez
- Abstract
Introduction
Survival data supports the use of first-line osimertinib as standard of care for EGFR positive non-small lung cancer (NSCLC). However, it remains unclear whether upfront osimertinib is superior to sequential first- or second-generation tyrosine kinase inhibitor (TKI) followed by osimertinib for all patients. The impossibility of predicting which patients are at high risk of progression constitutes a major limitation of the sequential TKI approach.
Methods
Seven hundred and forty-five plasma samples from 192 stage IV, EGFR positive NSCLC patients who were treated with first-line TKI were analysed by digital PCR.
Results
Patients with EGFR sensitizing mutations in plasma with mutant allele frequency (MAF) <7% before treatment initiation had median OS 37.9 months (25.3-NR), compared 17.5 (95%CI: 11.3-25.5) months for patients with MAF≥7% (adjusted HR=0.43; 95%CI: 0.25-0.76, respectively). OS was achieved with 53.1% of the patients treated with a 2nd line treatment other than osimertinib. In the multivariable analysis, undetectable levels of circulating tumour DNA (ctDNA) after 3 and 6 months of treatment were associated with improved PFS and OS (P<0.001 in all cases). Patients who became ctDNA negative after 3 or 6 months of treatment with MAF<7% at diagnosis had more than two-thirds lower risk of progression and death compare to the rest of patients (adjusted HR=0.28; 95%CI: 0.17-0.46 and HR=0.24; 95%CI: 0.12-0.48 for PFS and OS, respectively).
Conclusion
Pre-treatment ctDNA levels identify patients at low risk of progression and death who could benefit from sequential TKI treatment. Information regarding EGFR sensitizing mutation clearance could improve patient selection.