Epidemiology of benign giant cell tumor of bone in the Chinese population.

Background: Quantifying the incidence of giant cell tumor (GCT) of bone is challenging because it is a rare, histologically benign bone tumor for which population-level statistics are unavailable in most countries. We estimated the 2017 incidence of GCT in China using a direct (registry-based) approach with available population-based data.

Materials and Methods: The most recent age- and sex-specific incidence rates of GCT recorded in the Bone Tumor Registry in Japan (2015) were applied to 2017 age- and sex-matched populations projected by the United Nations for China in order to estimate 2017 incidence. An adjustment factor calculated using registry data suggesting that GCT may represent a greater proportion of bone tumors in China than in Japan (Guo, 1999) was applied to provide secondary estimates.

Results: Annual GCT incidence was estimated to be 1.49 per million population or 2094 new cases in China for 2017. A comparison of this estimated incidence with Japan (1.25 per million) and the United States (1.38 per million) indicates that the incidence is somewhat higher in China using identical methods. Secondary estimates suggest that GCT incidence in China may be as high as 2.57 per million or 3625 new cases in 2017. The corresponding 3-year limited-duration prevalence of GCT in China using a registry-based approach and general age-specific mortality is 6276 (secondary estimate: 10,876).

Conclusions: Leveraging unique population-based registry data, we estimated that GCT is a rare disease in the Chinese population with an incidence ranging between 1.49 and 2.57 cases per million persons per year. Possible differences in diagnostic classification of GCT, urban-rural demographics, and the younger demographic distribution of the Chinese population may underlie observations that GCT, a condition that primarily affects young individuals (20-40 years of age), accounts for a higher proportion of skeletal tumors in China than in other regions.