Mobile Spine Osseous Sarcoma: Descriptive Epidemiological Analysis Based on a National Population-Based Study.

Background: Primary osseous sarcomas of the mobile spine are rare bony tumors. Ewing sarcoma, chondrosarcoma, chordoma and osteosarcoma constitute the majority of primary bone sarcomas of the spine; however, other rare sarcoma tumors may also affect the spine. In order to perform an epidemiological study of theses tumors, national registries may help to evaluate data for populations with similar characteristics. Methods: A population-based study was designed based on data from the Iran National Cancer Registry (INCR). All morphology codes (M-Code) of primary osseous sarcomas of the mobile spine (C-code 41.2) were derived and analyzed. Results: Among 186 patients with primary osseous sarcomas of the mobile spine, 67.2% were men and 32.8% were women. The median (IQR) age was 37.0 (20.0-59.0) years and the age-standardized incidence rate (ASIR) was 0.37 per million. The majority of cases of Ewing sarcoma (29.5%) were observed in the age group 20-25 years. Among male patients with chondrosarcoma, the median age was 39.0 (30.0-50.0), while females showed a median age of 56.0 (50.0-59.0). The median age of patients with chordoma was 54.0 (47.0-63.0) years. The crude incidence rate of mobile spine osteosarcoma was 0.04 per million. Conclusion: Ewing sarcoma was the most frequent primary osseous sarcoma of the mobile spine. A male predilection was observed among all major sarcomas of the mobile spine. Ewing sarcoma in Iran affects the mobile spine in slightly older ages compared to other studies. Myxoid chondrosarcoma is the most frequent subtype of the mobile spine chondrosarcoma. Chordoma affects male in older ages compared to females. In contrast with other studies which showed a bimodal distribution of osteosarcoma of the spine including young adult and older age groups, 86% of cases in Iran were in the age group of 10-40 years. [ABSTRACT FROM AUTHOR]