Promising Effects of Afatinib on Leptomeningeal Carcinomatosis Derived from Erlotinib-resistant Lung Adenocarcinoma.

We herein report a case of a 67-year-old woman previously treated with erlotinib for adenocarcinoma with an epidermal growth factor receptor (EGFR) mutation in exon 19, which rapidly developed to progressive symptomatic leptomeningeal carcinomatosis. The primary tumor and lung metastases also worsened and the performance status (PS) score declined to 3. With a re-biopsy from the pulmonary metastases, the T790M mutation was detected by the cobas EGFR mutation test, but not the cycleave test, although an exon 19 deletion was detected by both of the tests. A week after afatinib initiation, the neurological symptoms disappeared and the PS improved to 1 with a radiological response in all disease sites. Chest physicians should consider the use of afatinib for patients with leptomeningeal carcinomatosis from 1st-generation EGFR-TKI resistant adenocarcinoma, regardless of the PS score and the presence of the T790M mutation in the extracranial lesion.