Survival and analysis of prognostic factors for fibroblastic osteosarcoma patients: a population-based study.

Background: Osteosarcoma is the most common mesenchymal cell malignancy, 10% of which is fibroblastic osteosarcoma (FOS). Due to the low incidence of osteosarcoma, the impact of many pathological factors on survival is still unclear, especially FOS. The goal of this study was to assess the latest survival rates for FOS and the risk factors affecting survival using the Surveillance, Epidemiology, and End Results (SEER) database.

Methods: Age, sex, race, SEER stage, surgery, radiation, chemotherapy, site of FOS, and survival time were collected from the SEER database for survival and prognostic factor analysis. The patients were randomly assigned to either the training cohort or the testing cohort. The overall survival (OS) curves were obtained by Kaplan-Meier according to different factors. A multivariate Cox regression model and a predictive nomogram have also been constructed.

Results: The study enrolled a total of 120 patients. OS at 1, 3, and 5 years for all patients was 90.83%, 79.17%, and 70.83%, respectively. In the 5-year survival analysis, in distant of SEER stage (P<0.01), radiation (P=0.03), and no surgery (P<0.01) were associated with a worse prognosis in patients with FOS. Multivariate analysis showed that age, and in distant of SEER stage were independent indicators of unfavorable prognosis. A nomogram was used to predict the prognosis of FOS and a calibration curve was used to validate the nomogram prediction against the actual observed survival outcomes.

Conclusions: In summary, older age, and worse SEER stage were associated with poorer OS. The nomogram effectively predicted the probabilities of 1-, 3-, and 5-year OS, demonstrating strong concordance with the actual observed outcomes.