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Vol.63 No.1 contents | Japanese/English |
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- Case Report -
Efficacy of Osimertinib for EGFR Exon 20 Insertion Mutation-positive Non-small Cell Lung Cancer with Brain Metastases in a Very Elderly Man
Yosuke Kakiuchi1, Toshimi Satoh2, Ryoichi Nakai11Department of Respiratory Medicine, 2Department of Pathology, Japan Community Health Care Organization Hitoyoshi Medical Center, Japan
Background. Epidermal growth factor receptor (EGFR) exon 20 insertion mutations represent the third most common EGFR mutation in non-small cell lung cancer (NSCLC). EGFR tyrosine kinase inhibitors (TKIs) are highly effective for EGFR-positive NSCLC but not for EGFR exon 20 insertion mutations, which carry a poor prognosis. Case. A 90-year-old man was referred to our hospital because of an infiltrative shadow and a small nodule in the right lung on chest X-ray. Chest computed tomography revealed a mass in the right lung apex, a small nodule in the right upper lobe, a hypoattenuated area in the left lobe of the liver, bilateral pleural effusion, and enlarged mediastinal lymph nodes. Thoracentesis on the right and transbronchial lung biopsy of the mass were performed. Magnetic resonance imaging of the brain revealed contrast-enhanced nodules. We finally diagnosed the patient with lung adenocarcinoma, cT3N3M1c stage IVB. Genetic testing detected EGFR exon 20 insertion mutations. Considering the patient's age, renal function and performance status (PS), we administered osimertinib, which led to the resolution of the bilateral pleural effusion and a reduction in the size of the primary lesion, as well as the intrapulmonary and brain metastases. The progression-free survival was 5.9 months. Conclusion. In EGFR exon 20 insertion mutation-positive NSCLC, platinum-based chemotherapy has been shown to be more effective than EGFR-TKIs, including osimertinib, and has been the recommended by guidelines. EGFR exon 20 insertion mutations are generally unresponsive to EGFR-TKIs, but some case reports have demonstrated the efficacy of osimertinib. In our case, osimertinib was effective in a very old patient with EGFR exon 20 insertion mutation-positive NSCLC with brain metastases. Osimertinib may be a treatment option in the elderly for whom chemotherapy and late-line treatment options are limited.
key words: EGFR exon 20 insertion mutations, Osimertinib, Non-small cell lung cancer
Received: May 20, 2022
Accepted: September 5, 2022
JJLC 63 (1): 33-39, 2023
