Successful treatment of refractory lung adenocarcinoma harboring a germline BRCA2 mutation with olaparib: A case report

BACKGROUND In recent years, targeted therapy and immunotherapy have become important treatment strategies for patients with non-small cell lung cancer (NSCLC). However, the clinical evidence for successful off-label use of targeted drugs for patients with NSCLC following progression on multiple lines of treatment is still lacking. CASE SUMMARY We describe a 62-year-old male patient with a right lung adenocarcinoma who harbored an EGFR exon 19 deletion mutation. He received gefitinib combined with six cycles of vinorelbine, cisplatin, and recombinant human endostatin as the first-line therapy. Then gefitinib was administered in combination with recombinant human endostatin as maintenance therapy, resulting in a progression-free survival (PFS) of 14 mo. Chemoradiotherapy was added following progression (enlarged brain metastases) on maintenance treatment. Unfortunately, the brain lesions were highly refractory and progressed again after 15 mo, at which time next-generation sequencing (NGS) of 1021 cancer-related genes was performed using peripheral blood to identify potential actionable mutations. NGS revealed that the patient harbored a BRCA2 germline mutation, the EGFR exon 19 deletion mutation disappeared, and no additional targetable genetic variant was detected. Therefore, the patient received olaparib combined with gefitinib and recombinant human endostatin, with a rapid and long-lasting clinical response (PFS = 13.5 mo). CONCLUSION This is a rare case of lung adenocarcinoma in a patient with a BRCA2 germline mutation who had long- term benefit from olaparib combination treatment, suggesting that NGS-based genetic testing may render the possibility of long-term survival in NSCLC patients after disease progression.