Clinical characteristics and prognostic factors of malignant fibrous histiocytoma of bone: a SEER population-based study.

BACKGROUND

Malignant fibrous histiocytoma of bone (MFH-B) is an extremely rare type of bone tumor. We aimed to analyze the clinical characteristics of MFH-B and establish nomograms that predict the prognosis of patients with MFH-B based on prognostic factors.

METHODS

A total of 250 patients diagnosed with MFH-B were included from the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier curves and log-rank tests were conducted. Potential prognostic factors were identified using univariate and multivariate Cox regression analysis. Nomograms that predict 3- and 5-year overall survival (OS) and cancer-specific survival (CSS) were further developed and internally validated.

RESULTS

The multivariate analysis suggested that OS of patients was associated with age ≥57 years [hazard ratio (HR), 1.916; 95% confidence interval (CI), 1.329-2.761; P<0.001], pelvic bones (HR, 1.742; 95% CI, 1.024-2.961; P=0.040) and other tumor sites (HR, 2.498; 95% CI, 1.515-4.120; P<0.001), Grade III/IV (HR, 1.750; 95% CI, 1.002-3.056; P=0.049), distant tumor stage (HR, 2.100; 95% CI, 1.351-3.263; P=0.001), tumor size ≥66 mm (HR, 2.629; 95% CI, 1.747-3.959; P<0.001) and no surgery (HR, 2.134; 95% CI, 1.380-3.300; P=0.001). We then developed nomograms based on the prognostic factors. The concordance index (C-index) of nomograms for OS and CSS were 0.74 (95% CI, 0.70-0.77) and 0.74 (95% CI, 0.70-0.78). Calibration plots suggested optimal concordance between the predictive outcomes of nomograms with the actual survival.

CONCLUSIONS

This is the first sizable study that analyzed clinical characteristics and prognostic factors of MFH-B. The nomograms we established for MFH-B were effective tools to predict prognosis of individual patients. These tools can also help doctors identify mortality risk.