ABSTRACT
Background: There are no standardized treatments for giant cell tumors of the bone (GCTB) in rare locations such as the spine and pelvis or for those that are inoperable and recurrent, let alone for multicentric GCTB. This study reports a novel case of multicentric GCTB treated with a promising antiangiogenic drug, apatinib, a small-molecule tyrosine kinase inhibitor. The efficacy of apatinib in the treatment of GCTB has not been reported previously. Patients and Methods: A 27-year-old female presented with two giant cell tumors of the spine and sacrum–ilium diagnosed on December 15, 2016. Surgery and selective arterial embolization (SAE) were not reasonable options for this patient, and denosumab was unavailable; therefore, the antiangiogenic drug apatinib and the osteoclast inhibitor zoledronic acid were administered. Apatinib was initially administered at a dose of 850 mg daily, which was decreased to 425 mg daily after 7 months, and then increased again to 635 mg after 11 months. The patient was prescribed a maintenance dose of 500 mg daily after 16 months. The patient reported side effects of Grades I–III nausea, vomiting, and Grades II–III hand–foot syndrome. The patient underwent SAE at 26 months, and at that time, she was switched to denosumab instead of zoledronic acid. Results: The patient showed noticeable symptomatic improvement and visibly reduced tumor size after the first month of treatment. Computed tomography in the 4th month identified a partial response based on the RECIST criteria. The patient has achieved an objective reduction in tumor size at 32 months. Conclusions: Comprehensive treatment including apatinib represents a potential new treatment strategy for inoperable GCTB, with tolerable side effects. However, further clinical trials are now necessary to confirm an effective dose and determine the efficacy and safety of apatinib in the treatment of GCTB