Adjuvant denosumab treatment in patients with resectable high-risk giant cell tumor of bone

Aims: Giant cell tumor of bone (GCTB) is an uncommon, benign, but aggressive osteolytic skeletal neoplasm of young adults. Although denosumab is frequently used in neoadjuvant treatment and metastatic unresectable disease in these patients, its role in adjuvant therapy is unclear. In this study, we evaluated the efficacy and safety of denosumab as an adjuvant therapy in patients with resectable high-risk GCTB. Methods: Patients with resectable high-risk GCTB over the age of 16 who received postoperative denosumab between January 2013 and September 2022 were included. Demographic and clinical characteristics of the patients, tumor localization, prior treatments, response to denosumab treatment, and adverse effects of the drug were analyzed retrospectively. Results: A total of 18 patients (10 women) with a median age of 23 (16-45) years were recruited. The median follow-up time was 7.1 (4.2-8.7) years and the median denosumab treatment duration was 12 (12-90) months. One (6%) patient experienced a partial response, and 17 (94%) patients had stable disease. Grade 1 or 2 hypophosphatemia was the most frequent adverse effect (16.7%, n=3). No patients stopped therapy due to side effects, and no grade 3 or 4 incident were observed. Conclusion: Postoperative denosumab may also be useful in the adjuvant treatment of patients with high-risk resectable GCTB.