(P 92) THE IMPACT OF CHONDROSARCOMA WITH POSITIVE MARGINS AND EXTRAOSSEOUS EXTENSION ON PATIENT OUTCOMES

Objective: Chondrosarcoma accounts for 20% of all bony sarcomas and may present with extraosseous extension (EOE). The presence of an extraosseous component, along with positive surgical margins, have been separately associated with increased risk of local recurrence and decreased survival. This study compared the outcomes between patients with EOE, EOE and positive margins, and a control cohort with neither feature.

Methods: This was a retrospective review of 91 patients over a consecutive thirteen-year period. Data including treatment details and outcomes were included. Thirty-two patients had extraosseous extension of their chondrosarcoma, 7 patients had positive margins and extraosseous extension, and 52 patients had neither characteristic. Tumor characteristics, patient demographics, and overall survival, recurrence rates, and metastatic rates were compared among the three groups.

Results: Patients with positive surgical margins and EOE were noted to have significantly higher resection grade, dedifferentiation on presentation, and use of adjuvant chemotherapy compared to control. Patients with EOE alone were noted to have significantly higher grade and use of adjuvant chemotherapy compared to control. Patients with positive surgical margins and EOE additionally had significantly higher rates of mortality, recurrence, and metastasis on survival analysis compared to control. However, patients with EOE alone did not have significantly different survival rates compared to control.

Conclusion: This study is one of the first to analyze the survival impact of EOE with positive surgical margins in chondrosarcoma. The significance found in mortality, recurrence, and metastatic rates in this unique subgroup may warrant further longitudinal observation and dictate future treatment options.