Rebound Vertebral Fractures in a Patient With Lung Cancer After Oncology-Dose Denosumab Discontinuation: A Cautionary Tale

We describe a 55-year-old woman with lung cancer complicated by bone metastases. Treatment with denosumab (120 mg monthly) was interrupted after 9 doses because of concern for potential osteonecrosis of the jaw during upcoming dental work. Fifteen months after receiving the last dose of denosumab, the patient presented with 7 atraumatic spinal compression fractures requiring kyphoplasty for symptom relief. No malignancy was found in pathology specimens. Evaluation for secondary causes of osteoporosis was negative. This phenomenon of rebound fractures after discontinuing the use of denosumab, an inhibitor of RANK ligand, has been well described in patients with osteoporosis, who receive much lower doses than do patients with cancer. However, this has not been previously reported in oncology patients, likely because most succumb to their disease before denosumab therapy is stopped.