EFFECTIVENESS OF BISPHOSPHONATES AND DENOSUMAB ON RISK OF VERTEBRAL FRACTURES IN PROSTATE CANCER PATIENTS UNDER ANDROGEN-DEPRIVATION THERAPIES: A REAL-WORLD PROSPECTIVE STUDY.

Objectives: This prospective study investigated the real-world effectiveness of bisphosphonates and denosumab in reducing vertebral fractures (VFs) risk induced by androgen-deprivation therapies (ADTs).

Methods: 226 consecutive men (mean age 74.8±6.9 years) undergoing ADT were evaluated for morphometric VFs at baseline and after 26.1±10.7 months of follow-up (range 18-64). Following enrolment, 153 patients commenced bisphosphonates (98 cases) or denosumab (55 cases), while 73 patients (32.3%) received only vitamin D and calcium supplementation. As additional control group, we enrolled 62 consecutive men (mean age 74.9±7.2 years) under chronic ADTs who had never been either evaluated or treated for skeletal fragility before study entry.

Results: Incident VFs were found in 16/226 (7.1%) patients enrolled in the prospective study and in 18/62 (29.0%) control subjects (p<0.001). The risk of VFs was significantly lower in patients treated with bone active drugs as compared to those treated with vitamin D (hazard ratio 0.26, 95% confidence interval 0.09-0.73; p=0.01), without significant difference between denosumab and bisphosphonates treatment (p=0.423), although denosumab treated patients had lower BMD, higher C-terminal telopeptide of type I collagen (CTX), and more prevalent VFs. Noteworthy, incident VFs were significantly lower in patients receiving vitamin D with calcium as compared to those subjects under chronic ADT who had not been ever evaluated and treated for skeletal fragility prior to the study (12.3% vs. 29.0%; p=0.016).

Conclusions: In real-world clinical practice, bisphosphonates or denosumab might be effective in reducing risk of VFs related to ADTs.