Effective treatment in lung adenocarcinoma patient with brain metastases harboring novel CLHC1/RNT4 intergenic region- ALK fusion A case report

Rationale: Anaplastic lymphoma kinase (ALK) fusion, an important oncogenic mutation, occurs in 3% to 7% of non-small cell lung cancer (NSCLC) cases, and EML4 is the most common partner gene. With the widespread application of next-generation sequencing (NGS), more gene breakpoint fusions have been discovered and functional fusion transcripts can provide targeted clinical benefits. Patient concerns and diagnosis: A 40-year-old woman was diagnosed with lung adenocarcinoma with brain metastases. A novel CLHC1/RNT4 intergenic region, ALK (Exon20-29) (abundance 39.97%), was identified using lung puncture tissue by NGS analysis (Simceredx), and results of immunohistochemistry and fluorescence in situ hybridization confirmed ALK fusion. Interventions and outcomes: The patient was administered oral crizotinib (250 mg bid) combined with endostar (30 mg d1-7) for 12 cycles from June 18, 2020. The patient's condition was controlled, and the curative effect was evaluated as stable disease (SD). Unfortunately, brain magnetic resonance images showed multiple nodules in the left cerebellar hemisphere, and chest computed tomography showed no significant changes in the progression of the disease. Subsequently, alectinib (600 mg bid) was administered on April 1, 2021. Brain lesions were significantly reduced and partial remission (PR) was achieved. No significant changes were observed in the lung lesions. Lessons: ALK fusion is a risk factor for brain metastasis (BM) in patients with advanced non-small NSCLC patients. In our case, a novel CLHC1/RNT4 intergenic region, ALK fusion, was identified for the first time in a lung adenocarcinoma patient with BM, who benefited from crizotinib and endostar sequential alectinib. Our case highlights the advantages of NGS for fusion detection and provides promising treatment options for NSCLC patients with BM harboring ALK fusions.