Local Tumor Recurrence and Escape from Suppression of Bone Resorption With Denosumab Treatment in Two Adolescents With Giant Cell Tumors of Bone.

Giant cell tumors of bone (GCTB) may be difficult to resect because of size or location. We describe two adolescents who were treated with denosumab and followed for tumoral and biochemical responses. Denosumab was effective in achieving sufficient regression to allow surgical resection and in preserving peritumor cortical bone. Reactivation of bone resorption markers was noted while the patients were receiving monthly denosumab. One patient suffered a local tumor recurrence. Denosumab was safe in enabling surgical resection of GCTB. However, the effect was transient, with an escape of resorption markers and tumor recurrence. © 2019 The Authors. published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.