Cryoablation of bone metastases in thyroid and adrenocortical cancers

The purpose of this study is to assess the feasibility, efficacy and safety of cone-beam computed tomography (CBCT)-guided cryoablation of bone metastases in thyroid and adrenocortical cancers. Adult patients with bone metastases and at least 1 skeletal-related event (pain, risk of fracture, spinal cord compression or hypercalcemia) at baseline were enrolled in a prospective, single-arm, single-center IRB-approved study (ClinicalTrials: NCT03986593). Brief Pain Inventory - Short Form (BPI-SF) and morphine-equivalent daily dose (M-EDD) were recorded at baseline and weekly during the first 8 weeks and 3, 6, 12 and 24 months post-cryoablation. Adverse events (AEs) and pre- and post-treatment cross-sectional (CT or MR) and functional imaging with PET/CT were analyzed. Seventeen patients (mean age of 58.3 ± 16.2 years old; 11 women) with either differentiated (n = 8; 47.1%) or medullary thyroid cancer (n = 6; 35.6%), or adrenocortical cancer (n = 3; 17.3%) were enrolled. CBCT-guided cryoablation of 24 bone metastases reached 100% technical success rate. An overall drop of 4.8 points (P < 0.05) in the worst pain in the last 24 h and M-EDD overall intake decrease (P < 0.05) were observed. In addition to pain improvement, no patients required surgery. Three patients (17.6%) required radiotherapy due to refractory or recurrent pain over a follow-up of 14.9 ± 14.0 (median ± IQR) months. No grade 4 or 5 AE was reported. One grade 3 AE (5.9%) and two grade 2 AEs (11.8%) occurred. PET/CT imaging showed a 52% reduction in FDG uptake immediately after cryoablation. Cryoablation of bone metastases in thyroid and adrenocortical cancers was safe and effective, providing rapid and long-lasting pain relief and improving quality of life. ClinicalTrials.gov: NCT03986593.

Cryoablation led to a sustained reduction in pain with a mean improvement of 7.2 points on a 1-10 scale of the Brief Pain Inventory - Short Form (BPI-SF) after 54 weeks. Pain relief and quality-of-life improvement (assessed by the BPI-SF) were observed in 81.3% of bone metastases just one week after cryoablation with an overall pain score reduction of 4.8 points. Cryoablation of bone metastases from endocrine cancers was safe and effective, providing long-lasting pain relief.