A non-small cell lung cancer (NSCLC) patient with leptomeningeal metastasis harboring rare epidermal growth factor receptor (EGFR) mutations G719S and L861Q benefited from doubling dosage of osimertinib: a case report - Shan, Chang-Guo; Wang, Hui; Lin, Tao; Liu, Da; Wen, Lei; Chen, Zhi-Jie; Zhen, Jun-Jie; Lai, Ming-Yao; Zhang, Lu; Zou, Xiao; Hong, Wei-Ping; Cai, Lin-Bo (Annals of Palliative Medicine, 2021)