Multiple rebound-associated vertebral fractures after denosumab discontinuation: is prompt antiresorptive therapy always recommended, even when the risk of fracture seems low? A case report.

Background Non-osteoporotic patients with endocrine-sensitive breast cancer are often treated with denosumab only during the anti-aromatase treatment, and when the anti-aromatase therapy is discontinued, no antiresorptive drug is prescribed. This case report clearly shows how even a patient with a low risk of fractures could have multiple rebound vertebral fractures after denosumab discontinuation. Case presentation We report the case of a 60-year-old woman who suffered from multiple vertebral fractures only seven months after discontinuation of denosumab that had been administered to prevent bone loss related to three years of aromatase inhibitors as adjuvant therapy for breast cancer. No antiresorptive therapy was prescribed at the time of denosumab discontinuation, assuming that the patient had a low absolute risk of fracture after the withdrawal of the aromatase inhibitor. Conclusion This case underlines the relative irrelevance of bone mineral density and clinical algorithms in predicting the risk of rebound-associated vertebral fractures after denosumab discontinuation and the strong recommendation to always switch to another antiresorptive therapy (such as zoledronic acid) immediately at the time of denosumab discontinuation.