Secondary pneumothorax as a potential marker of apatinib efficacy in osteosarcoma: a multicenter analysis

Abstract Background Studies have shown that apatinib is effective for treatment of osteosarcoma. However, pneumothorax is a major adverse event associated with treatment of osteosarcoma with apatinib. This study was performed to investigate pneumothorax characteristics and association with clinical outcomes in patients with osteosarcoma treated with apatinib. Methods We retrospectively reviewed the medical records of osteosarcoma patients treated with apatinib between January 2016 and April 2020 at three institutions. We evaluated the prevalence, healing time, recurrence, severity, clinical management, and prognosis of pneumothorax in these patients. Results A total of 54 osteosarcoma patients who received apatinib treatment were enrolled in this study. Among them, 14 patients had pneumothorax. There were significant differences between the patients with and without pneumothorax with regard to the cavitating rate of lung metastases (92.86% vs 32.50%, respectively, p < 0.001), objective response rate (42.86% vs 10.00%, p = 0.013), disease control rate (85.71% vs 42.50%, p = 0.006), 4-month progression-free survival (PFS) rate (57.10% vs 20.00%, p < 0.001), and median PFS (5.65 months vs 2.90 months, p = 0.011). Conclusions Pneumothorax and cavitation in lung metastases may be effective prognostic markers for patients with osteosarcoma treated with apatinib.