Pathological Fracture and Prognosis of High-Grade Osteosarcoma of the Extremities: An Analysis of 2,847 Consecutive Cooperative Osteosarcoma Study Group (COSS) Patients

PURPOSE The objective of this study was to investigate potential correlations between pathologic fractures (PFs) and prognosis of patients with primary central high-grade osteosarcoma of the extremities. METHODS We retrospectively analyzed 2,847 patients registered in the Consecutive Cooperative Osteosarcoma Study Group database with primary central high-grade osteosarcoma of the extremities, treated between 1980 and 2010. Intended treatment included pre- and postoperative chemotherapy and surgery. Univariable and multivariable survival analyses were performed for all patients and then differentiated for adult and pediatric (≤ 18 years at time of diagnosis) patients. RESULTS A total of 2,193 patients were ≤ 18 years of age; 11.3% of all patients had PFs. In the overall cohort, presence of PF correlated significantly with tumor site, histologic subtype, relative tumor size, and primary metastases, but not with body mass index or local surgical remission. In univariable analysis, 5-year overall survival (OAS) of patients with and without PF was 63% versus 71%, respectively ( P = .007), and 5-year event-free survival (EFS) was 51% versus 58% ( P = .026). In pediatric patients, OAS and EFS did not differ significantly between patients with and without PF. In adults, 5-year OAS in patients with and without PF was 46% versus 69% ( P < .001), and 5-year EFS was 36% versus 56% ( P < .001). In multivariable analysis, PF was not a statistically significant factor for OAS or EFS in the total cohort or in pediatric patients. In adult patients, PF remained an independent prognostic factor for OAS ( P = .013; hazard ratio [HR], 1.893). It was not a significant prognostic factor for EFS ( P = .263; HR, 1.312). CONCLUSION In this largest study to date with extremity osteosarcomas, we observed the occurrence of PF to correlate with inferior OAS expectancies in adult but not in pediatric patients.