Leptomeningeal metastases (LM) incidence is far more common in patients with non-small cell lung cancer harboring epidermal growth factor receptor (EGFR) mutations and is best treated with targeted tyrosine kinase inhibitors, according to research published in the Journal of Thoracic Oncology.
The leptomeninges are membranes that surround the brain, including the arachnoid mater and pia mater, when cancer cells metastasize to intracranial structures and the cerebrospinal fluid. The condition is typically a predictor of poor survival in patients with lung cancer due in part to the lack of standard treatment practices.
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To help determine those most at risk for LM and identify optimal treatment strategies to manage the condition, a group of Chinese researchers led by Yang-Si Li, Guangdong General Hospital (Guangzhou, China), retrospectively screened 5387 patients with non-small cell lung cancer at Guangdong General Hospital from January 2011 to June 2015 to examine the prevalence of EGFR mutations in this patient population and how outcomes changed based on therapeutic choice.
Of the 5387 patients included in the study, 3775 were tested for EGFR gene status and 1258 had confirmed mutations. The remaining 2517 had wild-type EGFR or no identified mutations. The incidence of LM in the entire cohort was 3.4% (n=184); however, it was significantly more common among those harboring EGFR mutations (118 patients [9.4%]) than in patients with a wild-type EGFR status (42 patients [1.7%]). Of those harboring EGFR mutations, 53 patients had exon 19 deletions (del 19) and 56 had Leu858Arg mutations (L858R), the most common EGFR subtypes.
Among these 109 patients, 88 were treated with tyrosine kinase inhibitors and demonstrated longer overall survival than those who did not (10 months vs 3.3 months, respectively). However, 42 patients who underwent whole brain radiotherapy did not experience longer overall survival compared with patients who did not receive radiotherapy. Additionally, a combination of tyrosine kinase inhibitors and whole brain radiotherapy did not add any survival benefit beyond what was observed in patients who received tyrosine kinase inhibitors alone.
Thus, researchers concluded that LM were much more common in patients with non-small cell lung cancer harboring EGFR mutations. Tyrosine kinase inhibitors targeting these specific mutations were the most effective treatment for prolonging overall survival while treatment with whole brain radiotherapy with or without tyrosine kinase inhibitors did not improve outcomes.
