Similar outcomes with first-line observation versus metastasectomy for bone giant cell tumor lung metastases

Background: The outcome of lung metastases in patients with giant cell tumor of bone (GCTB) varies from spontaneous regression to uncontrolled growth. To investigate whether observation is an appropriate first-line management for patients with lung metastases from GCTB, we compared the outcomes of patients initially treated with observation with those treated with metastasectomy.Methods: We retrospectively reviewed the data of 29 patients with lung metastases from histologically confirmed GCTB. The median follow-up period was 114 months. We evaluated progression-free survival, which was defined as the time from the date of occurrence of lung metastases to the date of disease progression in the observation or incomplete metastasectomy group, disease recurrence in the complete metastasectomy group, or the last follow-up.Results: Disease progression or recurrence occurred in 14 patients (48.3%). Progression-free survival did not vary significantly between the observation and metastasectomy groups (p=0.373). The total number of metastasectomies was significantly higher in the initial metastasectomy group than in the observation group (p=0.017).Conclusions: The number of patients included in this study is small, however the data suggests that observation can be used safely as first-line management for patients with lung metastases from GCTB with an outcome similar to that of metastasectomy. It is necessary to confirm our result in multi-institutional study with sufficient number of patients.