(P 63) EVALUATION OF LOCAL RECURRENCE AND DIAGNOSTIC DISCORDANCE IN CHONDROSARCOMA PATIENTS UNDERGOING PREOPERATIVE BIOPSY

Objective: Preoperative biopsy of chondroid lesions has demonstrated discordance between biopsy grade and surgical resection grade. Furthermore, there is evidence to suggest risk of tumor contamination during biopsy. We evaluated our large chondrosarcoma institutional cohort to compare the rates of local recurrence based on undergoing pre-surgical biopsy, as well as other tumor characteristics and disease related outcomes.

Methods: This was a retrospective review of 75 patients who underwent surgical resection for chondrosarcoma at our institution between 2005 and 2020. Outcomes included rates of local recurrence, metastasis, and overall survival.

Results: There were no significant differences in local recurrence and recurrence free survival in the cases that had undergone pre-operative biopsy. Thirteen (28.2%) patients had discordance between histologic grade on biopsy and resection. Seven of 11 patients with dedifferentiation present on final resection were not identified on biopsy. The only independent predictor of recurrence free survival and metastasis free survival was the presence of dedifferentiation on resection.

Conclusion: To our knowledge, this is the first study evaluating risk of local recurrence in the setting of pre-surgical biopsy in chondrosarcoma patients. Although pre-operative biopsy may contaminate biopsy tracts, appropriate surgical planning and final resection results in no difference in local recurrence rates in this cohort. However, discordance rates between preoperative biopsy and resected specimen must be considered while determining clinical treatment.