The Effectiveness of Denosumab in Middle Eastern Patients With Giant Cell Tumor of the Bone: A Single-Center, Retrospective Study

Background: Giant cell tumor of the bone (GCTB) is an aggressive benign tumor, which constitutes 5% of all primary bone tumors. Denosumab, a receptor activator of nuclear factor κB ligand monoclonal antibody, inhibits osteoclast-induced bone destruction and has demonstrated promising results in patients with GCTB. However, the long-term efficacy of the drug has not been extensively studied, especially in the Middle East.

Methodology: In this study, we retrospectively analyzed the five-year progression-free survival (PFS) in patients with GCTB at a single Saudi center. PFS was defined as the time from diagnosis until disease progression, relapse, or death. Events were censored after five years from diagnosis.

Results: Sixty-two patients with GCTB were included in the study. The median age at diagnosis was 31.16 years, and 38 (61.3%) patients were female. Twenty-nine patients (46.8%) received denosumab during the study period. The median duration of denosumab treatment was 5.06 months, and the median number of cycles was 6. The median PFS was not reached, and the five-year PFS rate was 60.3%. Age, gender, body mass index, performance status at presentation, and tumor location had no impact on five-year PFS. Denosumab treatment prolonged PFS; however, this was not statistically significant compared to non-denosumab patients (P = 0.603).

Conclusions: Denosumab does not seem to provide superior long-term outcomes compared to surgery alone. Although our findings are generally consistent with other studies in the literature, larger long-term studies are needed to confirm our findings.