The study achieved n=17 participants (56.6% of the initial proposition) with a mean = 18 months follow-up. All patients completed 12 months follow-up or deceased. We chose to terminate and publish the data available.

This study will evaluate the clinical response and safety of cone beam computed-tomography guided percutaneous cryoablation in bone metastases from thyroid, adrenal and neuroendocrine tumors in 30 patients.

Thyroid neoplasms, as well as adrenal and neuroendocrine tumors have the potential to metastasize to bone. About 3% of patients with well-differentiated thyroid carcinomas develop secondary bone lesions, while adrenal and neuroendocrine tumors have 10% and 13% bone metastases rates, respectively. Spinal metastases are associated to a worst prognosis. The progressive systemic disease, the post-operative complications, and the pre-operative neurologic impairment were associated to a worst global survival rate in the thyroid cancer. Additionally, extensive spinal instrumentation of metastatic thyroid carcinoma was associated to greater complication rates. Interventional radiology offers promising techniques for the minimally invasive approach of bone metastases. Image-guided percutaneous radiofrequency ablation and cryoablation techniques have been studied in clinical trials and are considered effective options in pain palliation of patients with bone metastatic disease. These techniques may be associated with conventional treatment, as well as radiation therapy and percutaneous embolization, avoiding major surgical interventions and its complications.

Inclusion Criteria:

• patients with bone metastases from thyroid, adrenal or neuroendocrine tumor diagnosis, associated to one of the following: pain; risk fracture; risk of compression of spinal cord; hypercalcemia; performance status (ECOG) 0-3; mean life expectancy over one month;

Exclusion Criteria:

• age < 18 years
• active anticoagulant therapy or uncorrectable coagulopathy
• pregnancy or breast feeding

De-identified individual participant data for all primary and secondary outcome measures will be made available.

Supporting information: Study protocol; Statistical Analysis Plan (SAP); Informed Consent Form (ICF); Clinical Study Report (CSR); Analytic Code; Time frame: Data will be available within 18 months of study completion. Access Criteria: Data access requests will be reviewed by an external Independent Review Panel. Requestors will be required to sign a Data Access Agreement.

Data will become available within 18 months of study completion and for 6 months.

Data access requests will be reviewed by an external Independent Review Panel. Requestors will be required to sign a Data Access Agreement.