Effect of the First-Line Therapy with Osimertinib for a Metastatic Choroidal Tumor in Advanced-Stage Lung Cancer: A Case Report

Although the advent of molecular-targeted drugs has improved the prognosis of various cancers, the long-term prognosis and side effects as the first-line therapy for metastatic choroidal tumors remain unclear. We describe a case in which the first-line therapy of osimertinib has shown long-term successful and minimum side effect responses for metastatic choroidal tumors in a patient with advanced-stage lung cancer. The patient was a 62-year-old man who complained of foggy vision and visual field defects in his left eye for 1 month. When he visited his local doctor, a serous retinal detachment was noted in the left eye, and he was referred to our hospital for further examination. The patient had no history of systemic disease. A fundus examination of his left eye showed a slightly elevated choroidal lesion along with the superior retinal vascular arcade. Optical coherence tomography showed a serous retinal detachment around the lesion. Fluorescein angiography showed that the site of the lesion had spotty and mottled hyperfluorescence in the early phase and ring hypofluorescence in the late phase. We suspected a metastatic choroidal tumor and performed a whole-body computed tomography scan, which indicated lung cancer and metastasis to the left iliac bone. The patient was referred to the department of respiratory medicine of our hospital, and after a thorough examination, a diagnosis of lung adenocarcinoma (stage IV-B, epidermal growth factor receptor [EGFR] gene mutation positive) was made. Treatment with osimertinib was initiated, and shrinkage of the primary tumor was observed. The elevated choroidal lesion and serous retinal detachment resolved after 2 months of treatment, and no recurrence was observed during the 20 months of treatment. The use of osimertinib as primary treatment for EGFR mutation-positive lung cancer was found to significantly reduce the size of metastatic choroidal tumors and to have a relatively long-lasting antitumor effect without serious ocular complications.