ESMO Asia 2017: Mutations in Blood and CSF of Lung Cancer Patients With Brain Metastases
“The gold standard for determining EGFR mutation status is DNA sequencing of the tumor, but this is challenging with brain tissue,” stated Yang Sen, MD, of the Affiliated Cancer Hospital of Zhengzhou University, China, in a European Society for Medical Oncology (ESMO) press release. However, a study by Dr. Sen, presented at ESMO Asia 2017 Congress in Singapore (Abstract 35P_PR), suggested the use of a less invasive modality—genotyping of cell-free DNA using droplet digital polymerase chain reaction (ddPCR) in cerebrospinal fluid (CSF)—may prove to be an alternative, although clinical trials are needed to clarify how best to use liquid biopsies in clinical practice to make informed decisions on targeted treatment.
The study included 41 patients with lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutation and central nervous system metastases. EGFR mutation status was analyzed in the blood of 37 patients and in the CSF of all 41 patients with ddPCR.
In the entire study population, the rate of EGFR mutations in the blood was higher than in the CSF (65% vs. 37%). In addition, the rate of these mutations in the CSF was higher in those with leptomeningeal metastases than in those without (73% vs. 23%). As for neurologic symptoms, the rate of EGFR mutations in the CSF was significantly higher in those with neurologic symptoms than in those without such symptoms (48% vs. 14%).