Posters— Surgical Treatment of Sarcomas

PATHOLOGIC FRACTURE IN OSTEOSARCOMA: PROGNOSTIC SIGNIFICANCE AND TREATMENT IMPLICATIONS:

Ghert MA, Zurakowski D, Gebhardt MC, Thompson RC, Scully SP (Duke University Medical Center, Durham, NC 27710)

INTRODUCTION: The presence of a pathologic fracture in an osteosarcoma has been considered a poor prognostic factor and an indication for immediate amputation in many tumor centers. The purpose of this study was to determine, in the current era of neoadjuvant chemotherapy, if the presence of a pathologic fracture in an osteosarcoma has prognostic significance, and if limb salvage can be safely performed in these patients without compromising clinical outcome.

METHODS: In a cooperative effort of the Musculoskeletal Tumor Society (MSTS), members from eight institutions provided retrospective data on 58 patients treated for a pathologic fracture in an osteosarcoma, and 55 patients treated for an osteosarcoma without pathologic fracture. The two groups were matched for tumor location and grade. The following variables were analyzed: age, gender, stage of disease, anatomic location, tumor size, pathological fracture, fracture union, fracture displacement, tumor management (limb salvage vs. amputation), chemotherapy, surgical margin, vascular invasion and percent necrosis. Survival analysis was performed with the Kaplan-Meier product-limit method with variables having a P value < 0.10 based on the log-rank test entering into the multivariate Cox proportional-hazards regression model. Outcomes examined were survival, disease-free survival, local recurrence and distant metastasis. Multiple stepwise logistic regression analysis was used to compare the outcome of limb salvage vs. amputation with respect to local recurrence.

RESULTS: The median age of the 113 patients was 17.4 years (range 2-69 years). Mean follow-up was 4.0 years (range 6 months-12.7 years). Ninety-five percent of the patients presented with MSTS stage IIB disease. All but 8 patients underwent induction chemotherapy. Of the 58 patients with a pathologic fracture, 32 were managed with immobilization, 6 with internal fixation, and 16 with amputation. Overall mortality was 35% with 14 patients (12%) suffering a local recurrence. All patients who experienced a local recurrence died of the disease process. The presence of a pathologic fracture was a significant univariate factor associated with decreased overall survival (P=0.03), disease-free survival (P=0.03), increased local recurrence (P=0.005) and distant metastasis (P=0.03). Multivariate analysis revealed that the presence of a pathologic fracture was a significant risk factor for local recurrence (P=0.003). In the group with a pathologic fracture, 10/41 (24%) treated with limb salvage and 1/17 (6%) treated with an amputation suffered a local recurrence. Stepwise multiple logistic regression revealed that limb salvage was a multivariate risk factor for local recurrence in the pathologic fracture group, with those patients undergoing limb salvage estimated to be 9 times more likely to develop local recurrence than those undergoing amputation (odds ratio=9.0, 95% confidence interval 5.0-35.5, P=0.01).

DISCUSSION AND CONCLUSION: The presence of a pathologic fracture in an osteosarcoma is an independent predictor of local recurrence with limb salvage significantly increasing the risk. Given the fact that recurrence in an osteosarcoma has a uniformly fatal outcome, our data indicate that the presence of a pathologic fracture may be a contraindication to limb salvage in these patients.