Survival and prognosis in malignant giant cell tumor of bone: A population-based analysis from 1984 to 2013

BACKGROUND: Malignant giant cell tumor of bone (MGCTB) is extremely rare. Currently, population-based prognosis studies are lacking. This study aimed to determine the impact of demographics, tumor characteristics, and treatment on prognosis among patients with MGCTB. METHODS: The Surveillance, Epidemiology, and End Results database was used to identify patients with MGCTB from 1984 to 2013. Kaplan-Meier analyses were performed to determine the overall survival (OS). Univariable and multivariable Cox analyses were conducted to identify prognostic factors. RESULTS: There were 250 patients with MGCTB included in our study. The multivariate Cox analysis revealed that age at diagnosis (hazard ratio [HR]: 1.09; 95% confidence interval [CI]: 1.07–1.11; P < 0.001), tumor size (HR: 7.04; 95% CI: 2.38–20.77; P < 0.001), tumor extension (regional vs. localized, HR: 2.64; 95% CI: 1.10–6.34; P = 0.030; distant vs. localized, HR: 6.12; 95% CI: 2.27–16.49; P < 0.001), and radiotherapy (HR: 0.41; 95% CI: 0.18–0.89; P = 0.025) were independent risk factors of OS in patients with MGCTB. Notably, tumor site (HR: 1.98; 95% CI: 0.99–4.00; P = 0.055) exhibited borderline significance. Additionally, we found that patients with tumors measuring >70 mm (P = 0.015), located in the axial skeleton (P < 0.001) and presented with distant metastasis (P < 0.001) tended to receive radiotherapy. Moreover, a nomogram model integrating independent predictors was established to estimate the OS of patients with MGCTB. CONCLUSION: This study provides a population-based assessment of the largest number of patients with MGCTB. We found that older age, larger tumor size, regional or distant metastasis, and lack of radiotherapy was associated with poor OS. Surgical methods were not significantly associated with OS. Furthermore, we built a high-quality nomogram to predict 1-, 3-, and 5-year OS for patients with MGCTB. These findings may assist in the clinical diagnosis and treatment of MGCTB.