How safe and effective is denosumab for bone giant cell tumour?

Recent clinical studies have suggested that denosumab is associated with beneficial tumour response, surgical down-staging, and reduced surgical morbidity in patients with giant cell tumour of bone. However, these studies reported results of patients still on denosumab treatment, or patients after denosumab treatment but with a short follow-up. Other studies reported that the new osseous tumour matrix and thickened cortical bone that develop with denosumab treatment does not allow the surgeon to delineate the true extent of the tumour, and probably increases the risk for local recurrence. A study showed that cell proliferation is only diminished by denosumab; the cells continue to proliferate in vitro, albeit at a slower rate. More importantly, nine cases of malignant transformation of GCT during denosumab therapy without previous radiation exposure have been reported; inhibition of RANKL may increase the risk of new malignancies due to immunosuppression. With these concerns in mind, this article is an attempt to put essential information in one place, creating a comprehensive review that the curious reader would find interesting and informative.