Advantages and Disadvantages of Bone Protective Agents in Metastatic Prostate Cancer: Lessons Learned

Nine out of ten metastatic prostate cancer (PCa) patients will develop osseous metastases. Of these, every second will suffer from skeletal-related events (SRE). SRE are associated with an increased risk for death, which is markedly increased in the presence of pathological fracture. Moreover, health insurance costs nearly double in the presence of SRE. Zoledronic acid and denosumab are both approved drugs for the prevention or delay of SRE in castration-resistant prostate cancer (CRPC) patients with osseous metastases. However, long-term treatment with one of these two drugs is associated with the development of medication-related osteonecrosis of the jaw (MRONJ). Routine inspections of the oral cavity before and during treatment are mandatory in these patients. Regarding imaging techniques, bone scintigraphy seems to be a promising tool to detect early stage MRONJ. Zoledronic acid does not reduce the incidence of SRE in hormone-sensitive PCa. First data shows 3-monthly application of zoledronic acid to be equi-effective to monthly application.