In a large study of individuals with extremity osteosarcomas, investigators found a correlation between the pathologic fractures and inferior overall survival (OS) in adult versus pediatric patients (J Clin Oncol. 2020;38[8]:823-833).

“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,” explained Lisa Marie Kelley, MD, Department of Pediatrics, Kinderklinik München Schwabing, Technical University of Munich School of Medicine, Germany, and colleagues.

Dr Kelley et al conducted a retrospective study of 2847 patients from the Consecutive Cooperative Osteosarcoma Study Group database with primary central high-grade extremity osteosarcomas treated between 1980 and 2010.

Patients in the study had planned pre- and post-operative chemotherapy and surgery. The investigators performed univariable and multivariable survival analyses for all patients before differentiating for adult and pediatric (aged ≤18 years at time of diagnosis) patients.

Ultimately, 11.3% of all patients (including 2193 aged ≤18 years) had pathologic fractures, which correlated significantly with tumor site, histologic subtype, relative tumor size, and primary metastases, but not with body mass index or local surgical remission.

According to univariable analysis, patients with and without pathologic fractures had 5-year OS rates of 63% versus 71%, respectively (P = .007) and 5-year event-free survival (EFS) rates of 51% versus 58%, respectively (P = .026).

Among pediatric patients, OS and EFS did not differ significantly between those with and without pathologic fractures, but for adults, the 5-year OS rates in patients with and without pathologic fractures were 46% versus 69% (P <.001), respectively. In addition, adults had 5-year EFS rates of 36% and 56%, respectively (P <.001).

In the total cohort and amongst pediatric patients in particular, pathologic fractures were not a statistically significant factor for OS or EFS according to multivariable analysis. In adults, however, pathologic fractures were an independent prognostic factor for OS (P = .013; hazard ratio [HR], 1.893) but not for EFS (P = .263; HR, 1.312).

“In this largest study to date with extremity osteosarcomas, we observed the occurrence of PF [pathologic fracture] to correlate with inferior OAS [overall survival] expectancies in adult but not in pediatric patients,” Dr Kelley and co-investigators concluded.—Hina Porcelli