30 YEARS OF BONE GIANT CELL TUMOR IN THE KNEE: A BRAZILIAN PERSPECTIVE

Objective: To analyze the evolution of patient/tumor characteristics and treatments for GCTB in the knee in Brazil over 30 years and assess changes in local recurrence rates. Methods: Retrospective study of 335 patients (1989-2021) from 16 Brazilian centers. Data on patient/tumor characteristics, recurrence, metastasis, and treatment trends were evaluated. Results: Campanacci grade 3 tumors, pulmonary metastasis, and local recurrence rates were 56.7%, 5.3%, and 15.8%, respectively. Recurrence was 21.4% for curettage and 9% for resection. Curettage with denosumab showed 23.8% recurrence, versus 21% for curettage alone. Overall, local recurrence decreased from 22.9% (1989-2005) to 15.1% (2006-2021), with a significant drop after en bloc resection (23% to 7.8%), while curettage-related recurrence remained stable. Conclusions: Despite an increase in aggressive tumors, local recurrence decreased, especially after en bloc resection. These findings emphasize the challenges of managing rare diseases in emerging economies. Level of evidence: III; Retrospective Cohort Study.