甲状腺癌および副腎皮質癌の骨転移に対する凍結融解療法

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 - SRE (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; 3, 6, 12 and 24 months post-cryoablation. Adverse events (AE), 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 hours 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 median±IQR 14.9±14.0 months follow-up. No grade 4 or 5 AE was reported. One grade 3 (5.9%) and two grade 2 AE (11.8%) occurred. PET/CT imaging showed 52% reduction in FDG uptake immediately after cryoablation. Cryoablation of bone metastases in thyroid and adrenocortical cancers was safe, effective, providing rapid and long-lasting pain relief, improving quality of life.