(P 145) PATHOLOGIC FRACTURE IN CHONDROSARCOMA OF LONG BONES: A RETROSPECTIVE COHORT STUDY

Objective: Chondrosarcoma poses a unique challenge to treat, as this malignancy is characterized by resistance to both radiation and chemotherapy. In the extremities, cases of chondrosarcoma are prone to pathologic fractures, which can further complicate treatment. However, evidence is limited exploring the relationship between pathologic fractures and prognosis in long bone chondrosarcoma patients. This study investigates the impact of pathologic fractures on surgical complications, recurrence rates, and overall outcomes in patients with chondrosarcoma of long bones.

Methods: A retrospective review was performed of 82 cases from 1999 to 2024 with chondrosarcoma of long bones who had undergone surgical resection of their tumor. Long bone chondrosarcoma patients were excluded if they did not receive oncologic surgical intervention or if they were lost to follow-up within one year of surgery for an unknown reason. Univariate and multivariate comparisons were made between patients with and without pathologic fracture regarding surgical and oncologic outcomes.

Results: 15 patients sustained a pathologic fracture (18%). There was no statistical difference noted in patient characteristics between patients who did and did not have a pathologic fracture. Pathologic fracture was associated with higher grade and dedifferentiated histology. There was no difference in margin status at time of definitive resection between patients with and without fracture. Pathologic fracture was associated with a higher risk of any relapse (p < 0.001), local recurrence (p < 0.001) and metastasis (p < 0.001), even when controlling for low grade histology. Disease specific survival was significantly worse for patients with pathologic fracture (5-year survival 20% vs. 75%, p< 0.001). When controlling for potentially confounding variables, histologic grade was independently associated with risk of metastasis while pathologic fracture was independently associated with risk of local recurrence.

Conclusion: Pathologic fractures in chondrosarcoma of the long bones are associated with poorer oncologic outcomes and appear to be an independent predictor of local recurrence.