ESMO Asia 2017: Analysis of Mutations in Cerebrospinal Fluid in Lung Cancer With Brain Metastases
In a study presented at the European Society for Medical Oncology (ESMO) Asia 2017 Congress (Abstract 35P_PR), researchers analyzed the presence of mutations in the cerebrospinal fluid of patients with lung cancer and brain metastases.
Tumor tissue from brain metastasis is difficult to obtain, and, therefore, less invasive methods are needed to identify and monitor the presence of known actionable mutations. Brain metastases are a frequent complication of non–small cell lung cancer (NSCLC), especially in patients with lung adenocarcinoma. Patients with epidermal growth factor receptor (EGFR) mutations benefit from EGFR tyrosine kinase inhibitors, but most relapse within 1 to 2 years, many with brain metastases.
“The gold standard for determining EGFR mutation status is DNA sequencing of the tumor, but this is challenging with brain tissue,” said lead author Yang Sen, medical oncologist at The Affiliated Cancer Hospital of Zhengzhou University in Zhengzhou, China. “Tumor-derived DNA from brain metastases may be secreted into cerebrospinal fluid, but not the blood, due to the blood-brain barrier.”
Study Findings
This study compared EGFR mutation status in blood and cerebrospinal fluid and their relationship to neurologic symptoms and leptomeningeal metastases. The study included 41 lung adenocarcinoma patients with EGFR mutations and brain metastases. EGFR mutation status was analyzed in the blood of 37 patients and in the cerebrospinal fluid of all patients. The presence of leptomeningeal metastases was assessed with magnetic resonance imaging (MRI).
In the entire study population, the rate of EGFR mutations in blood (65%) was significantly higher than in cerebrospinal fluid (37%; P = .013). Eleven patients had leptomeningeal metastases detected by MRI. The rate of EGFR mutations in cerebrospinal fluid was significantly higher in patients with leptomeningeal metastases (73%) than in those without leptomeningeal metastases (23%; P = .003).
Neurologic symptoms were present in 27 patients. The rate of EGFR mutations in cerebrospinal fluid was significantly higher in patients with neurologic symptoms (48%) than in those without symptoms (14%; P = .033).
Dr. Sen commented, “Neurologic symptoms and leptomeningeal metastases were closely related with EGFR mutation status in cerebrospinal fluid.”
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