1782P - Assessing the role of denosumab in managing aneurysmal bone cysts: A scoping review

Background

Aneurysmal bone cysts (ABCs) are expansile osteolytic lesions containing blood-filled spaces separated by fibrous septa. Denosumab, a monoclonal antibody, targets RANKL, halting osteoclast activity and bone resorption. While approved for giant cell tumours, its effectiveness in managing ABC remains uncertain. This scoping review examines its use in ABCs, focusing on its role, outcomes, and adverse effects.

Methods

A scoping review was conducted following the PRISMA Extension for Scoping Reviews guidelines. The search encompassed five databases from inception to December 31, 2023.

Results

Initially, 390 studies were identified. After screening, 29 studies involving 67 patients were selected for inclusion. The spine (n=42) and pelvis (n=7) were the more frequent locations for ABC. Denosumab was used as primary treatment in 25 patients (37.3%), neoadjuvant therapy in 11 (16.4%), second-line therapy following inadequate initial treatments in 24 (35.8%) cases, and as adjunct therapy in seven cases. All patients exhibited favourable clinical and radiological responses following denosumab treatment. Tumour recurrence occurred in 10 patients (15%): six after discontinuation of denosumab (3-17 months post-cessation), three following surgeries after neoadjuvant denosumab, and one during ongoing treatment. Reported adverse effects included hypocalcaemia (n=10), hypercalcemia (n=14), and sclerotic metaphyseal bands (n=2); all observed in the paediatric age group. Hypocalcaemia typically occurred early during denosumab therapy, while hypercalcemia manifested 2.5-6 months post-discontinuation, often managed with bisphosphonates. Less than 50% of studies had follow-up periods exceeding two years.

Conclusions

Denosumab appears to be a promising therapy for ABC, particularly for high-risk cases such as spinal and pelvic tumours. It may also serve as a second-line option for recurrence or failed initial interventions, as well as neoadjuvant therapy. However, concerns persist regarding tumour recurrence and rebound hypercalcemia, necessitating vigilant monitoring, extended follow-up, and prophylactic measures. Prospective clinical trials are warranted to gain deeper insights into its efficacy and safety profile.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.