Bone modifying agents: incidence and risk factors of adverse reactions in bone metastasis

Background: Bone-targeted agents such as Zoledronic Acid (ZA) and Denosumab (DE) are essential in preventing skeletal-related events in cancer patients with bone metastasis. Both drugs carry risks of adverse events (AEs), including electrolyte disorder, nephrotoxicity, and osteonecrosis of the jaw. Aim: To compare the safety profiles of ZA and DE and identify risk factors associated with AEs in cancer patients with bone metastasis. Methodology: A retrospective cohort study was conducted from August 1, 2021, to August 1, 2023, at the Cancer Care and Research Centre. Adult patients with solid tumors and confirmed bone metastasis who received either ZA or DE were included. Patients taking these agents for other indications were excluded. Data from electronic health records, lab results, and medication charts were analyzed. Univariate analysis was used to assess AE risk factors. Results: A total of 250 patients were included (ZA=125, DE=125). The incidence of AEs was higher in the ZA group. Calcium disorder occurred in both groups. Comorbidities were significantly associated with increased AE risk (p<0.001). DE showed a better safety profile. Conclusion: Denosumab was linked to fewer AEs than Zoledronic Acid. Comorbidities increased AE risk, highlighting the need for preventive strategies.