106PD - EGFR mutation detection in plasma of lung tumor patients in the absence of contributive tissue is a relevant alternative for prescription of tyrosin...

Date 16 April 2015
Event ELCC 2015
Session Advanced NSCLC
Topics Non-Small-Cell Lung Cancer, Metastatic
Translational Research
Presenter Marc Denis
Citation Annals of Oncology (2015) 26 (suppl_1): 29-44. 10.1093/annonc/mdv050
Authors M.G. Denis1, A. Vallée1, P. Masson2, T. Pigeanne3, H. Lacroix4
  • 1Dept Of Biochemistry, CHU de Nantes, 44093 - Nantes/FR
  • 2Pneumology, CH Cholet, Cholet/FR
  • 3Medical Oncology, CH Cote de Lumière, Les Sables d'Olonnes/FR
  • 4Medical Oncology, CHU de Nantes, Nantes/FR

Abstract

Aim/Background

EGFR alterations can be detected in the plasma of lung cancer patients mutated in their tumor. Recently, the European Medicines Agency has allowed the use of gefitinib in patients tested positive in blood if a tumor sample is not evaluable. But there has been no prospective report evaluating the efficacy of tyrosine kinase inhibitors (TKI) in patients only tested on circulating DNA (ctDNA). We report here the results obtained for 3 patients in a clinical setting.

Methods

Blood was collected in EDTA-containing tubes. Cell-free DNA was extracted from plasma using the PureLink Virus Kit on an iPrep Purification Instrument (Life Technologies). Detection of EGFR alterations was performed using the approved Therascreen EGFR RGQ kit (Qiagen). This simple process allowed us to detect EGFR mutation in ctDNA of 80-90% of patients presenting an EGFR alteration in their tumor before treatment (Lung Cancer 2013).

Results

We routinely analyze ctDNA for lung tumor patients before treatment initiation. During the past year, 3 patients that could not be evaluated on tissue were found to be EGFR mutated in ctDNA. Patient 1 (women, 74) was diagnosed with lung tumor and brain metastases in May 2014. A biopsy was performed, but the turnaround time for tissue analysis was not compatible with the rapid neurological degradation. Blood was tested, and a p.L858R mutation was detected. Patient 2 (man, 85), had surgery for lung cancer in 2007. He relapsed in September 2014. Analysis of the surgical sample was not contributive (poor quality DNA). A p.L858R mutation was detected in plasma. Patient 3 (man, 64) was diagnosed with lung tumor and bone metastases in September 2014. The lung biopsy contained too few tumor cells, and could not be tested. An exon 19 deletion was detected in plasma. These patients were immediately treated with an EGFR TKI. They all presented a significant partial response, with disappearance of most of brain metastases in pt 1, and of bone metastases in pt 3.

Conclusions

We show for the first time that in routine clinical practice, when tumor sample is not available for molecular testing, detection of an EGFR alteration in plasma is a relevant alternative for TKI prescription.

Disclosure

All authors have declared no conflicts of interest.