Risk factors for pulmonary metastases from giant cell tumor of bone.

Background: Giant cell tumor (GCT) of bone is a rare, benign, aggressive bone tumor with an unusual capacity to metastasize to the lung. It was the goal of this study to identify patient and treatment-specific variables associated with the development of pulmonary metastases of GCT of bone.

Methods: From 1980 to 2009, 291 patients with benign GCT of bone were treated at our institution, and 167 were followed for at least two years. Eleven (6.6%) of these 167 patients developed biopsy-confirmed pulmonary metastasis. All patients were evaluated relative to nine patient, disease, and treatment-specific variables.

Results: We identified four properties of benign GCT of bone associated with an increased risk of metastasis on univariate analysis: age at diagnosis, axial location of the primary GCT, primary Enneking stage-3 disease, and local recurrence. Multivariate analysis showed local recurrence to be an independent risk factor for pulmonary metastasis (adjusted odds ratio, 7.42).

Conclusions: There is an increased risk of pulmonary metastasis of GCT of bone in patients who are younger, present with Enneking stage-3 disease, develop local recurrence, and/or present with axial disease. The mode of treatment was not found to be associated with the development of pulmonary metastasis.