Practical Update for the Use of Bone-Targeted Agents in Patients with Bone Metastases from Metastatic Breast Cancer or Castration-Resistant Prostate Cancer

Bone metastases are a significant source of morbidity and mortality for patients with breast and prostate cancer. In this review, we discuss key practical themes regarding the use of bone-targeted agents (btas) such as bisphosphonates and denosumab for managing bony metastatic disease. The btas both delay the onset and reduce the incidence of skeletal-related events (sres), defined as any or all of a need for radiation therapy or surgery to bone, pathologic fracture, spinal cord compression, or hypercalcemia of malignancy. They have more modest benefits for pain and other quality-of-life measures. Regardless of the benefits of btas, it should always be remembered that the palliative management of metastatic bone disease is multimodal and multidisciplinary. The collaboration of all disciplines is essential for optimal patient care. Special consideration is given to these key questions: (1) What are btas, and what is their efficacy? (2) What are their common toxicities? (3) When should they be initiated? (4) How do we choose the appropriate bta? (5) What is the appropriate dose, schedule, and duration of btas?