Effects of once-yearly zoledronic acid on bone density and incident vertebral fractures in nonmetastatic castration-sensitive prostate cancer patients with osteoporosis

Abstract

Background Androgen deprivation therapy (ADT) is the effective treating prostate cancer but is often accompanied by cancer treatment-induced bone loss (CTIBL), which impairs the patient’s quality of life. In patients with nonmetastatic castration-sensitive prostate cancer (M0CSPC) who already have osteoporosis before starting ADT, appropriate bone-modifying agent intervention must be performed in parallel, as the patient has a high risk of future fracture. However, little is known about therapeutic interventions aimed at preventing the progression of CTIBL and new fractures. The present study explored the effect of once-yearly zoledronic acid 5 mg (ZOL 5 mg) on bone mineral density (BMD) and new vertebral fractures (VFs) in M0CSPC patients with coexisting osteoporosis before starting ADT. Methods We conducted a retrospective, multi-institutional, cohort study involving 42 M0CSPC patients with osteoporosis who had undergone ADT with/without a single intravenous infusion of ZOL 5 mg at the start of ADT (ZOL 5 mg group, n = 26; control group, n = 16). The association of the ZOL 5 mg with changes in the BMD from baseline to 12 months and the incidence of VFs were evaluated. Results Prevalent VFs were found in 47.6% of all patients at baseline. ZOL 5 mg significantly increased the lumbar spine BMD (LS-BMD) (mean rate of change: + 4.02%, p < 0.0001) and significantly decreased the TRACP-5b (mean rate of change: − 52.1%, p < 0.0001) at 12 months after starting ADT. Incident VFs were identified in 19.0% of all patients at 12 months after starting ADT. After adjusting for the age, BMI, and changes in the LS-BMD, ZOL 5 mg was not significantly associated with incident VFs (odds ratio 0.66, 95% confidence interval 0.04–11.3, p = 0.7774). Conclusion ZOL 5 mg significantly increased the LS-BMD 12 months after starting ADT, and our short-term results showed that ZOL 5 mg was not significantly correlated with the suppression of incident vertebral fractures.

The relationship between serum testosterone and bone mineral density in Japanese men and the effects zoledronic acid in prostate cancer patients with low serum testosterone

“…Recently, long-acting zoledronic acid, the blood concentration of which can be controlled by annual administration, has been expected to improve the decrease in BMD [22]. The benefits of long-acting zoledronic acid in patients with prostate cancer undergoing ADT have been reported in several Japanese studies [23,24]. However, these reports have only looked at changes after one year of treatment with a single administration of long-acting zoledronic acid, and there are no reports on changes in BMD when the treatment is continued year by year over multiple years.…”