GIANT CELL TUMORS OF BONE: A BRAZILIAN EPIDEMIOLOGICAL PROFILE EVALUATION

Introduction: Giant cell tumor of bone (GCTB) is a rare locally aggressive osteolytic skeletal neoplasm of young adults. It is generally characterized by a unique lesion in the metaepiphyses of the long bones and infrequently metastasize to the lungs. Objective: To evaluate the epidemiological and clinical profile of patients (pts) with GCTB in a cohort of a Brazilian Cancer Center. Methods: All consecutive patients diagnosed with GCTB and treated at our center were retrospectively evaluated. Data were retrieved from medical records and summarized using descriptive statistics. Quantitative variables were described by means and qualitative ones by frequencies and percentages. Time-to-event variables were described by Kaplan-Meier curves. Results: Between 1975 to 2018, 55 pts were recruited. The median follow-up was 8 (5.3-10.7) years (y). The majority were female (52.7%) and treated in the private health system (63.6%). The median age at diagnosis was 33y (190). The presence of a single lesion (90.1%), and extremities involvement (65.5%) were predominant. The most affected sites: femur (20.0%), tibia/fibula (18.2%), fingers (14.5%) and pelvis/sacral bone (14.5%). 56.4% had symptoms at diagnosis: pain (40.0%), extremity deformity (36.4%), motor alteration (14.5%), sensitivity alteration (9.1%), and secondary hyperparathyroidism (1.8%). Only 5% required opioids intake. A quarter had soft tissue involvement. Surgery was the main treatment for 47 pts (85.5%). 7.3% were submitted to curettage, without complete tumor excision; 9.1% to radiotherapy, and 7.3% underwent tumor ablation/embolization. Eight (14.0%) local and four (7.3%) distant recurrences were observed. All metastatic pts had lung involvement. Palliative treatment with Denosumab and zoledronic acid were used by 3 pts. Two pts received chemotherapy with anthracyclines, platinum, and alkylating agents. The median disease-free (DFS) and overall survival were not reached. The 13-y DFS and metastasis-free survivals were 69.4% and 86.2%, respectively. Conclusion: In this cohort, young females were the most affected. The most common presentation was unique lesions in extremities, causing symptoms at diagnosis, especially pain. Surgery was the gold standard treatment, and local and distant recurrences were rare. Considering the rarity of the giant cell tumor of bone, case series are valuable for the comprehension of its behavior and better management.