Combined Microwave Ablation and Cementoplasty Eases Pain in Extra-Spinal Metastases

The combination of microwave ablation and cementoplasty may offer patients with extra-spinal metastases a minimally invasive option for pain reduction. The combined microwave ablation and cementoplasty treatment was safe and effective, according to an abstract presented at the World Conference on Interventional Oncology.

Radiation therapy is often offered as an option for patients with painful osseous metastases, but 40% of patients do not gain adequate pain relief. For these patients, the combination of microwave ablation and cementoplasty may provide an alternative pain-relieving treatment option. Cryoablation has typically been used for bone, but there are potential benefits to microwave ablation, such as shorter procedure times, less susceptibility to heat sink effects, and lack of reliance on bulky gas-cooling systems.

To assess the safety and efficacy of microwave ablation and cementoplasty, the researchers retrospectively analyzed procedures performed from February 2015 to September 2016 at a single institution. Seventy-two patients with 84 extra-spinal metastases located in the pelvis, femur, humerus, shoulder, and sternum were included in the study. All procedures were performed under general anesthesia using CT or fluoroscopic guidance.

During a single treatment session per patient, a single 14 g microwave ablation antenna (MedWaves, San Diego, CA) was coaxially inserted into each tumor and polymethylmethacrylate cementoplasty was performed within ablation zone.

Pain relief assessment occurred pre and postprocedure using Visual Analogue Scale pain scores, and cross-sectional imaging was used to evaluate locoregional tumor control. Procedural complications were also recorded.

The mean time per procedure was 7:43 minutes, with a range of 1:01 to 14:32 minutes, and the mean energy dose was 5.40 Kj. Two to 4 weeks prior to the procedure, patients had mean Visual Analogue Scale pain scores of 6.38. At 2 to 4 weeks, pain scores were 1.81, and at 3 to 6 months scores were 2.23. These changes represent statistically significant decreases in pre compared with postprocedural scores at each time point. Additionally, follow-up imaging conducted at 6 months showed no local disease progression in 93% of patients (67/72 patients). Ablation of all 84 lesions was technically successful, and no complications related to the procedure were reported.

“The degree and duration of pain reduction compare favorably to that of radiation therapy. Further prospective and cost comparative analysis to alternative treatment modalities may be warranted,” the authors concluded.

Reference

Dunlap RH, Moreland A, Bailey C, Hong K, Khan M. Safety and efficacy of combined microwave ablation and cementoplasty for painful extra-spinal metastases. Oral abstract presented at the World Conference on Interventional Oncology. June 2018. Boston, Massachusetts.