THE RESULTS OF TREATMENT OF GIANT CELL TUMOR OF LONG BONES WITH DENOSUMAB

Abstract

Surgical intervention remains a gold standard for the treatment of giant cell tumors (GCT) of long bones. The significant risk of recurrence after the curettage and a high complication rate after radical resections is still an unsolved problem. Targeted therapy with denosumab could solve this problem in favor of curettage, but recent studies have shown negative results with denosumab in such situation. Objective. To analyze the results of the denosumab application in patients with long bone GCP with indications for joint salvage surgery. Methods. We compared the treatment results in two groupsof patients: 1st retrospective (control) group — 57 patients, who underwent curettage with surgical treatment and the 2nd prospective (main) group — 42 patients with combination of surgery with neoadjuvant and adjuvant denosumab tretment. In the 2nd group of patients received 5 neoadjuvant and 5 adjuvant cycles of denosumab. The median follow-up period was 189 months in the control group, and 45 months in the main group. Results. Disease progression which identified as a local recurrence was revealed in the control group in 15 patients (25.4 %) and in 7 patients (16.7 %) in the maingroup (p = 0.19). In the main group, the median time to relapse was 19.8 months (8–34 months) from the date of surgery, in the control group — 15.1 months (9–28 months), respectively. The statistically significant difference in relapse-free survival (RFS) between patients in the main group and in the control group (p = 0.18) was not revealed. But the 5-year RFS in the main group was higher and reached to 85 % (95 % CI 74–96 %) versus 75 % (95 % CI 64–86 %) in control group, respectively. There was no evidence of malignant transformation in the main group and one case in retrospective group. Conclusions. The application of denosumab in the regimen before and after curettage is associated with lees number of relapses — 16.7 % vs. 25.4 % without denosumab, respectively. The lack of statistically significant difference between groups does not provide the sufficient reasons for denosumab prescription in neoadjuvant regimen. But adjuvant administration of denosumab can be considered as preventing factor of recurrence after primary tumor curettage, which may be perspective for further study and optimization of indications for its application in patients with GCT.