Proximal location in extremity long bones is a poor prognostic factor for osteosarcoma: A retrospective cohort study of 153 patients

Abstract

Background: Osteosarcomas arising in the proximal femur, humerus, and tibia appear to have poorer outcomes than those arising in distal long bones. However, the strength of this association is uncertain, particularly in light of other prognostic factors. Therefore, this retrospective cohort study was performed to compare patient outcomes between proximal and distal tumor location within extremity long bones. Material and methods: A total of 153 patients with conventional high-grade osteosarcoma of the extremity long bones, pelvis, or axial skeleton who had undergone neoadjuvant chemotherapy and surgical resection between 1985 and 2010 were identified in the Surgical Pathology files at Vanderbilt Medical Center. Effect of anatomic location within a proximal long bone was assessed using multivariable Cox proportional hazard regression. Results: Proximal tumor location was a strong predictor of poor prognosis in univariate survival analysis. Multivariate regression analysis showed that after controlling for American Joint Committee on Cancer (AJCC) stage, histologic response to chemotherapy, surgical resection margin status, and histologic type, location in the proximal femur, tibia, and humerus were independent risk factors for death due to osteosarcoma, but not event-free survival. Conclusion: Osteosarcomas of the proximal extremity long bones are associated with decreased disease-specific survival compared to tumors of the distal long bones, even after accounting for other key prognostic covariates.