Outcome of Treatment of Giant-Cell Tumor of Bone: a Single-Institutional Retrospective Study

Background: Giant-cell tumor of bone (GCTB) is a locally aggressive tumor which metastasizes infrequently to the lungs. The standard treatment of GCTB was surgery until the approval of denosumab. Aim: To describe the outcome of treatment of this rare tumor and to determine factors that influence survival.  Methods: Retrospective review of the medical records of GCTB patients treated at our institution. Collected data includes: clinicopathological data, treatment modalities and possible prognostic factors. Results: Forty-two patients were identified between May 2008 and November 2017. Their median age was 31 years, and the majority (62%) were females. The commonest primary sites were the upper and lower limbs (50% and 43%, respectively). Eight (19%) patients initially presented with lung metastases. Thirteen (31%) patients received denosumab as first line treatment before surgery and 12 of them underwent surgery post-denosumab. Denosumab was given after recurrence in 12 (29%) patients [8 (19%) with lung metastasis and 4 (10%) with localized disease]. The objective response rate to denosumab after recurrence was 50%. Four (10%) patients achieved complete response and 2 (5%) partial response. After a median follow up of 4.7 years, 6 (14%) patients had local recurrence and 8 (19%) had lung metastasis with no recorded deaths. The 5-year progression-free survival rate was 61%. Conclusion: Denosumab is effective and tolerable in the management of GCTB preoperatively in localized disease to facilitate surgery and in the management of metastatic disease. Multi-institutional prospective studies are needed for further assessment.