Primary osteosarcoma of the short bones: A Surveillance, Epidemiology, and End Results Program (SEER) retrospective study

Introduction: Osteosarcoma (OS) is the most common primary solid malignancy of bone and accounts for 2% of all childhood cancers. OS is most often found in the long bones of the extremities, in particular the femur, tibia, and humerus. However, it is rarely found in the short bones of the upper and lower extremity. This study seeks to address the existing gap in the literature on the incidence, treatment, and outcomes of OS of the short bones of the upper and lower extremity. Methods: Cases of primary short bone OS were identified using the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program database, containing 8,216,169 cancer cases from 2000 to 2020. Demographic, clinical, and treatment characteristics were collected, and univariate and multivariate regression analysis was conducted to determine the relationship between disease-specific survival and tumor spread, tumor size, tumor grade, surgery type, and primary site. Results: Cases of primary short bone OS made up 2.2% of all OS cases in the database. The majority of cases were male, and the most common age group ranged from ages 15 to 39. Within the 201-patient cohort, 58.2% were treated with chemotherapy and 4.5% received radiation therapy. Surgery information was available for 170 patients-50.6% of that group underwent limb-sparing surgery, 31.8% of patients underwent amputation, and 17.6% did not have surgery. Univariate analysis revealed grade and disease spread to be statistically significant predictors of survival; however, upon multivariate analysis, only localized disease was correlated with better disease-specific survival. Interestingly, there was no survival difference between patients treated with amputation versus patients who underwent limb salvage surgery. Conclusions: The results of this study confirm that OS of this location is a rare entity that generally follows the demographic distribution of the more common long bone variant. The results also signal that limb salvage is a reasonable treatment option for this group, given the lack of survival difference between limb salvage surgery and amputation.