Feasibility of Controlling Metastatic Osseous Pain Using Three Kinds of Image-Guided Procedures for Thermal Microwave...

To evaluate the feasibility and safety of treating painful osseous metastases using image-guided percutaneous thermal microwave ablation.

This is a retrospective study of patients treated from December 2016 to December 2019 in one institute. A total of 50 patients (35 men, 15 women; mean age 55.24 ± 11.03 years) with 56 osseous metastatic lesions underwent image-guided percutaneous microwave ablation. There were 7 patients with multiple and 43 patients with single metastases. The numbers of patients with primary cancer were as follows: lung, 13; liver, 17; kidney, 10; prostate, 1; breast, 3; osteosarcoma, 1; and thyroid, 5. Seventeen patients had cancer combined with soft tissue masses. The radiological images for the ablative procedures were obtained by CT, fluoroscopy with ultrasound, and fluoroscopy alone in 16, 11, and 23 patients, respectively. Pain severity was estimated using the visual analogue scale before and after treatment (1 week, 1 month, and 3 months after treatment). Radiological evaluations were performed at baseline and 3 months after the procedure.

In all patients, pain reduction occurred from the first day after treatment. Pain did not recur during the 3 months of follow up. The mean total ablation time per microwave electrode was 3.99 ± 2.48 min (range, 1-15 min). The mean power of the microwave electrode was 66.40 ± 12.08 W. The average volume of bone (load-bearing bone, such as vertebra and acetabulum) cement after ablation was 2.82 ± 0.81 mL. There were no significant differences in visual analogue scale pain scores for different imaging techniques or ablation energies. No procedure-related complications occurred.

Image-guided percutaneous thermal microwave ablation of osseous metastases relieves pain and improves mobility. CT remains the first choice for percutaneous ablation. Fluoroscopy combined with ultrasound is effective for cases with soft tissue masses; fluoroscopy is also suitable for combination with vertebroplasty. However, further investigations are required.