Successful treatment using targeted therapy, radiotherapy, and intrathecal chemotherapy in a patient with leptomeningeal metastasis with an epidermal growth factor receptor exon 20 insertion mutation: a case report.

Abstract

Leptomeningeal metastasis (LM) is a disastrous complication in lung cancer. LM patients with oncogene-addicted non-small cell lung cancer (NSCLC) have a relatively better prognosis than those with the wild-type counterpart; however, overall post-LM survival is short. Additionally, the high heterogenicity of the LM entity creates a treatment challenge, and to date, no standard strategy has been established. This article describes a female lung adenocarcinoma patient with a resistant epidermal growth factor receptor (EGFR) exon20ins mutation who developed LM only 11 months after radical surgery IIIA (pT1bN2). Intrathecal chemotherapy (ITC), whole-brain radiotherapy (WBRT) with a simultaneous integrated boost (SIB) followed by Osimertinib was initiated. The cerebrospinal fluid (CSF) cytology turned negative. The first remission lasted 6 months, then bone metastases occurred, and the LM progressed. An Ommaya reservoir was implanted. ITC with pemetrexed and anlotinib was administered. A CSF next-generation sequencing (NGS) examination revealed EGFR exon20ins (p. A767_V769 dup 1.5%), which was different from that of the primary tumor (p. V769_D770 ins ASV 17.48%). The CSF cytology then turned negative again; however, the patient succumbed to the disease in December 2020. The patient's post-LM overall survival (OS) time was 13.5 months. This case is novel and of great value. Clinicians should pay special attention to populations at high risk of developing LM. Early detection followed by active intervention, including ITC, RT, and systemic treatment, will result in a better prognosis. The NGS of CSF is fundamental to understanding the genetic profiles of LM and providing effective and precise treatment.