This is a retrospective observational real-world study, which evaluates the efficacy and safety of denosumab and non-denosumab therapies in the treatment of Chinese populations of surgically unsalvageable or severe post-surgery morbidity associated giant cell tumor of bone (GCTB), collectively referred to as unresectable GCTB, during 2013-2021 in three medical centers, serving as the external control for a single arm phase Ib/II trial on JMT103 treatment of GCTB. 301 patients were enrolled and divided into 2 groups according to their actual previous exposures. Group 1 (n=135) was denosumab group. Group 2 (n=166) included two types of exposures other than denosumab: other anti-GCTB drug therapies, or no therapy on GCTB patients. The dosage, route, frequency and other administration methods was collected according to the actual previous treatment records. The primary outcome measure was the tumor response rate [radiographic tumor response (CR/PR evaluated by ICDs or EORTC criteria) within 12 weeks, or at least 90% reduction of osteoclast like giant cells compared with baseline]. The key secondary endpoint was the tumor response rate [radiographic tumor response (CR/PR evaluated by ICDS or EORTC criteria), or at least 90% reduction of osteoclast like giant cells compared with baseline]. Other secondary Outcome Measures include: proportion of patients whose tumors was surgically resectable; median duration of tumor response (DOR), disease control rate (DCR), and time to disease progression (TTP); and types and proportion of key adverse reactions.

Inclusion Criteria:

• 1. Both genders, aged 18 years or above;
• 2. Patients pathologically diagnosed of giant cell tumor of bone (GCTB), and are surgically unsalvageable, or salvageable but surgery was associated with severe morbidity based on physician's judgement;
• 3. For patients received denosumab or other anti-GCTB medications, one of the two is required: imaging data (including X-ray, CT, MRI or PET-CT) prior to and at least once followed to administration, or pathological data on surgically resected GCTB; for patients with no medication, imaging data or pathological data on surgically resected GCTB is required.

Exclusion Criteria:

• 1. No access to definite treatment information;
• 2. Bone metabolic diseases diagnosed before treatment: hypo-/ hyperparathyroidism, hypo-/hyperthyroidism, hypopituitarism, hyperprolactinemia, Cushing syndrome, acromegaly, Paget disease, etc;
• 3. Complication of malignant tumor receiving anti-tumor therapy.

Chinese