Use of bone-modifying agents for bone metastases from neuroendocrine neoplasms: a single-centre audit

Bone metastases in neuroendocrine neoplasms are uncommon but cause significant morbidity. A recent Italian survey of 320 patients with neuroendocrine neoplasms and bone metastases reported skeletal-related events in 23% and bone-targeted agent use in 31%, highlighting limited evidence for bone-modifying agents. We identified adults with confirmed or clinically suspected neuroendocrine bone involvement who received a bone-modifying agent at a UK tertiary centre (January 2019-September 2024), using institutional prescribing records. Demographic, tumour, treatment, and toxicity data were extracted from records. Twenty-two patients received treatment (denosumab 17 (77%); zoledronic acid 5 (23%)). Most (91%) had grade 1-2 tumours; 64% had gastroenteropancreatic primaries. Bone metastases were synchronous in 45% and widespread (more than three lesions) in 73%. At diagnosis, 23% were symptomatic; during follow-up, 77% developed pain, high blood calcium, or a skeletal-related event. Skeletal-related events, a composite of pathological fracture, spinal cord compression, radiotherapy to bone, or orthopaedic surgery, occurred in 41% (radiotherapy alone in 36%); pain-relieving medication was used universally. Treatment was mainly given every 12 weeks (median six doses). Low blood calcium occurred in 9% and osteonecrosis of the jaw in 5%; dental assessment before therapy was recorded in only 9%. Treatment use was heterogeneous, reflecting a lack of disease-specific guidelines, and recorded toxicity was infrequent and generally manageable, although exposure varied s. Our findings highlight the need for prospective studies and structured registries to clarify treatment use, dosing, and impact on quality of life and prognosis.