ABSTRACT
Objective: To assess the efficacy and safety of CBCT-guided percutaneous cryoablation of bone metastases due to endocrine tumors. Outcomes included reduction of skeletal-related events and pain control. Method(s): This is a prospective, single arm, tertiary single-center study. Inclusion criteria included age >18 years;ECOG 0-3;mean life expectancy >one month;biopsy-proven bone metastases <7.0 cm in diameter from thyroid, adrenal and neuroendocrine tumors, with pain, hypercalcemia or at risk to develop fracture or spinal cord compression. Prior to ablation, all patients were evaluated by a pain specialist and a brief pain inventory (BPI) was obtained. Follow-up was carried out weekly for the first 8 weeks and then at 3, 6, 12 and 24 months when a BPI was obtained and observation of skeletal-related events. Result(s): This is an interim analysis of 17 patients,12 women and 5 men, mean age of 64.2+/- 12.3 years. Ten patients had papillary thyroid cancer (58.8%), 5 medullary thyroid cancer (29.4%) and 2 with adrenocortical cancer. A total of 24 lesions were treated (21 sessions);current mean follow-up time: 11.1+/- 7.3 months.Cementoplasty was carried out in three lesions;mean size lesions were 3.3 +/- 1.3 cm. Only one mild adverse event was observed (transient sciatic neuropraxia). From the group of patients included with bone pain (N= 14), a mean pre-procedural BPI was 8.3 +/- 2.1 (10 being highest score). After procedure, all patients had reduction of the pain score;complete pain relief was observed in 6 (31.6%) patients within 1-week and the other patients reported a significant reduction of BPI score: mean 2.8+/- 3.3 (1-week);0.9 +/- 1.8 (6-months). Eleven (64.7%) patients achieved complete ablation;radiation therapy was required in 2 patients and no patients required additional surgery. Pathologic fracture was observed in 2 treated lesionswhich recovered spontaneously within 1month. Six non-procedure related deaths were reported during follow-up (oncologic disease progression n = 5;Covid-19 infection n = 1);Discussion/Conclusion: Cryoablation proved to be safe and effective to treat bone metastases due to endocrine tumors, providing a rapid and durable pain palliation, local disease control, and should be considered an option to improve patient care in selected cases.