Atypical Femoral Fracture During Long-Term Treatment With Denosumab in Patients With Metastatic Bone Tumors

Bone-modifying agents (BMAs) are used to treat metastatic bone tumors and are also administered to reduce bone loss caused by bone metastases. Adverse events, such as osteonecrosis of the jaw and hypocalcemia, have been associated with long-term use of bisphosphonates; however, atypical femoral fracture (AFF) is rare. We encountered a patient who received long-term treatment with denosumab (DEN) and had a history of zoledronic acid hydrate administration. Severe complications may have been prevented if the patient had consulted with an orthopedic surgeon when she developed pain in the left thigh one month before AFF. The provision of relevant information on AFF to patients starting treatment with DEN may lead to its early detection. Since it is important to disseminate rare adverse events to the public, we report the present results based on a literature review.