Abstract
Stereotactic ablative radiotherapy (SABR) is an effective and attractive treatment option for patients who are poor surgical candidates. This case report describes a rare but serious complication of intractable pleural effusion after SABR for early-stage lung cancer. The patient was an 89-year-old woman with a medical history of early-stage breast cancer who was treated with partial resection and postoperative radiotherapy of 50 gray (Gy) in 25 fractions. SABR using 55 Gy in four fractions was conducted for lung lesions. The patient developed a pleural effusion that was refractory to conservative management and required multiple interventions, including repeated thoracentesis. This case report emphasizes the importance of monitoring and managing pleural effusion in patients with lung cancer receiving radiotherapy.