The Effect of Denosumab on Pain and Radiological Improvement in Giant Cell Tumours of the Spine in the Acute Setting.

Study design: Retrospective Cohort Study.

Objectives: The current recommended treatment for Giant Cell Tumour (GCT) of the spine is en bloc excision. Denosumab is a monoclonal antibody reducing osteoclast activity that shows promising results when used as a neo - adjuvant treatment. However, the current literature remains limited. The purpose of this study was to assess the effect of denosumab on tumour characteristics and symptom relief in the acute phase of treatment of spinal GCT.

Methods: We performed a retrospective review of 16 patients treated with denosumab as neo-adjuvant and stand - alone treatment. MRI and PET tumour characteristics were taken before and after treatment and patients were interviewed for subjective pain responses.

Results: Following treatment, all patients showed improvement of pain, of which 68.7% of patients were pain free with 43.75% noting improvement within 48 hours. Mean relative volumetric reduction in tumour volume was 37.3% (P < .001). Eight patients showed high grade of Bilsky classification (Epidural spinal cord compression scale - ESCC) with seven of them showing significant improvement to low grade of ESCC (P = .016). Median baseline PET Standardised Uptake Value (SUV)max was 14.57 and post treatment was 4.8 (P < .001).

Conclusions: This study provides necessary insight to the limited literature on the use of denosumab for spinal GCT in the acute phase. The clinical and radiographic responses observed demonstrate the critical role that neo-adjuvant denosumab has by reducing the tumour burden around critical adjacent neurovascular structures before eventual resection, significant pain improvement even with presence of fractured vertebra.