Denosumab regimens in the treatment of giant cell tumor of bone: A systematic review with meta-analysis.

Background: Giant cell tumor of bone (GCTB) is a rare, locally aggressive neoplasm that should be treated surgically, whenever possible. This treatment approach may be linked with greater morbidity besides functional impairment. Denosumab is a human monoclonal antibody. Its administration inhibits bone resorption and has become part of the therapeutic armamentarium against GCTB, as it allows local control with a view to downstaging for a more conservative surgical procedure. However, there is no consensus in the literature regarding the optimal denosumab regimen for GCTB. Therefore, a wide discussion of denosumab regimen is necessary.

Aim: To assess the effectiveness of various therapy protocols employing denosumab in individuals with GCTB.

Methods: A broad and systematic literature search was carried out using the PRISMA guidelines. We analyzed studies that reported skeletally mature patients with GCTB regardless of sex or ethnicity treated with denosumab. Articles with fewer than five patients and in languages except Spanish, Portuguese and English were excluded. Statistical analysis with proportion meta-analysis was performed due to the dichotomous nature of the data.

Results: 1005 articles were screened, of which 26 articles met the inclusion criteria and were selected, totaling 1742 patients, 51.8% women and 48.2% men, with an average of 35 years of age. Treatment with denosumab was associated with high rates of clinical benefit (CB) and imaging response (IR), without changing local recurrence rates when compared to patients treated without denosumab, regardless of the therapeutic regimen adopted and the number of doses applied. The adverse events (AE) presented were mostly mild, with the exception of a malignant transformation to osteosarcoma.

Conclusion: Treatment of GCTB with denosumab is effective, showing high rates of CB and IR. The AE that occurred were mostly mild. We found no differences between the articles considering the researched outcomes regardless of the therapeutic regimen adopted.