Histomorphological Changes in Campanacci Grade III Giant Cell Tumors After Use of Denosumab in a Neoadjuvant Setting

Objectives: To determine the histomorphological changes induced in Campanacci grade III giant cell tumors (GCTs) of bones by a short course of denosumab in a neoadjuvant setting.
Methods: This is a retrospective study of all adult patients with biopsy-proven GCTs of bones, Campanacci grade III, treated by denosumab at a single tertiary care hospital in Pakistan from January 2014 till December 2020. Data items were extracted from the case records of patients and histopathological reports. Optimal histological response was defined as ≥50% decrease in giant cells with fibrosis and ossification. Data analysis was done by SPSS version 22.0.
Results: The mean age of 28 patients was 31.8±12.4 years with 15 (53.6%) males and 13 (46.4%) females. Tibia, femur, radius, pelvic girdle, humerus and ulna were involved in 9 (32.1%), 8 (28.6%], 6 (21.4%), 2 (7.1%), 2 (7.1%) and 1 (3.5%) patients, respectively. The optimal histological response was obtained in 25 (89.3%) cases. Denosumab-induced changes were noted in all except one (3.6%) case. In 11 (39.3%) patients, complete necrosis was found. In rest, variable amount of viable tumor (range: 2 to 100%) and denosumab-induced changes were observed.
Conclusion: Denosumab in neoadjuvant setting induces significant histomorphological changes in high-grade GCTs.