Background Prostate cancer most commonly metastasises to the bones, and preventing related complications is important. Denosumab and Zoledronic Acid are recommended to prevent skeletal-related events and malignant hypercalcaemia.
Purpose The aim of this study was to analyse the efficacy and safety of Denosumab and Zoledronic Acid for the treatment of metastatic prostate cancer.
Material and methods A retrospective observational study including patients with metastatic prostate cancer in treatment with Denosumab or Zoledronic Acid (ZA), from 1 January 2015 until 30 August 2018 was conducted. An electronic prescription oncology program and medical records were consulted. The variables recorded were age, administered drug, duration of treatment, calcium levels (baseline and final) and adverse events. Efficacy was assessed as absence of malignant hypercalcaemia defined as serum calcium of grade ≥2 by the Common Terminology Criteria of Adverse Events version 3.0 (serum calcium >11.5 mg/dl). Safety criteria were considered: treatment interruptions, grade-3 hypocalcaemia in final test (serum calcium <7–6 mg/dl), osteonecrosis of the jaw and/or incidence of secondary cancers.
Results We included 52 patients with an average age of 73 (52–96) years: 43 treated with Denosumab 120 mg every 4 weeks, and nine treated with ZA every 3–4 weeks in a specific dosage according to renal function. Average duration of treatment with Denosumab and ZA was of 11 (0–40) and 11 (1–26) months respectively. Average blood baseline and final calcium levels in patients on Denosumab or ZA were respectively: 9 (8.5–11) mg/dl and 8.9 (6.7–10.4) mg/dl versus 8.3 (8.8–9.6) mg/dl and 8 (7.8–10) mg/dl. No patients presented with malignant hypercalcaemia. Twenty-two per cent of patients (n=2 patients) with ZA suspended treatment due to compromised renal function, and 2% of the patients (n=1 patient) with Denosumab suspended treatment due to jaw discomfort. A case of grade-3 hypocalcaemia and another one of jaw osteonecrosis were identified, both inside the group of patients on Denosumab. No secondary cancers were diagnosed.
Conclusion Most participants were treated with Denosumab. Both drugs were effective for the prevention of malignant hypercalcaemia. Most of the treatment interruptions were due to compromised renal function in patients who received ZA.
References and/or acknowledgements No conflict of interest.