Clinical and pathological results of denosumab treatment for giant cell tumors of bone: Prospective study of 14 cases

Objective: Giant cell tumor of bone (GCT) is a primary, osteolytic, benign tumor of the bone. Surgery isthe commonly used treatment; however, recurrence remains a problem. Receptor activator of nuclearfactor kappa B (RANKL) is responsible for the formation of osteoclastic cells. Discovery of RANKL and itshuman monoclonal antibody, denosumab, led to use of denosumab for treatment of GCT. The aim of thisstudy was to evaluate clinical and pathological results of treatment of GCT with denosumab and to assessadverse effect proŞle and recurrence rate.Methods: Thirteen patients with 14 lesions were enrolled in the study. Mean age was 38.3 years. Patientswere given subcutaneous injections of denosumab (120 mg) every 4 weeks (with additional doses ondays 0, 8 and 15 in cycle 1 only) and were radiologically evaluated for tumor response. Pain and functional status were measured using Visual Analog Score (VAS) and Musculoskeletal Tumor Society Score(MSTS). Adverse effects were analyzed after each cycle.Results: Participants were 5 men and 8 women. Mean follow-up was 17 months. One lesion was Campanacci grade I, 8 were grade II, and 5 were grade III. Eight lesions were recurrent, and remaining wereprimary lesions. After average of 9 cycles (range: 4e17 cycles), all tumors underwent radiologicalregression. Ten lesions were removed surgically. More than 90% of giant cells were found to haveregressed in all pathological specimens. On last follow-up, average VAS was 1 and MSTS was 87%. Fatigueand joint and muscle pain after injections was reported by 46% of patients, and mild hypocalcaemia wasseen in 1 patient.Conclusion: Denosumab has been shown to be a successful drug in treatment of GCT. Denosumab can beused as neoadjuvant for all recurrent lesions, grade II lesions with high surgical risk, grade III lesions, andmetastatic cases of GCT.Level of evidence: Level IV, Therapeutic study© 2016 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Objective: Giant cell tumor of bone (GCT) is a primary, osteolytic, benign tumor of the bone. Surgery isthe commonly used treatment; however, recurrence remains a problem. Receptor activator of nuclearfactor kappa B (RANKL) is responsible for the formation of osteoclastic cells. Discovery of RANKL and itshuman monoclonal antibody, denosumab, led to use of denosumab for treatment of GCT. The aim of thisstudy was to evaluate clinical and pathological results of treatment of GCT with denosumab and to assessadverse effect proŞle and recurrence rate.Methods: Thirteen patients with 14 lesions were enrolled in the study. Mean age was 38.3 years. Patientswere given subcutaneous injections of denosumab (120 mg) every 4 weeks (with additional doses ondays 0, 8 and 15 in cycle 1 only) and were radiologically evaluated for tumor response. Pain and functional status were measured using Visual Analog Score (VAS) and Musculoskeletal Tumor Society Score(MSTS). Adverse effects were analyzed after each cycle.Results: Participants were 5 men and 8 women. Mean follow-up was 17 months. One lesion was Campanacci grade I, 8 were grade II, and 5 were grade III. Eight lesions were recurrent, and remaining wereprimary lesions. After average of 9 cycles (range: 4e17 cycles), all tumors underwent radiologicalregression. Ten lesions were removed surgically. More than 90% of giant cells were found to haveregressed in all pathological specimens. On last follow-up, average VAS was 1 and MSTS was 87%. Fatigueand joint and muscle pain after injections was reported by 46% of patients, and mild hypocalcaemia wasseen in 1 patient.Conclusion: Denosumab has been shown to be a successful drug in treatment of GCT. Denosumab can beused as neoadjuvant for all recurrent lesions, grade II lesions with high surgical risk, grade III lesions, andmetastatic cases of GCT.Level of evidence: Level IV, Therapeutic study© 2016 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/