Painful metastases involving bone: percutaneous image-guided cryoablation--prospective trial interim analysis

To prospectively determine the safety and effectiveness of percutaneous cryoablation for the reduction of pain, improvement in the activities of daily life, and reduction in the use of analgesic medications for patients with painful metastatic lesions involving bone.

This study was compliant with HIPAA and was approved by the institutional review board. Written informed consent was obtained. During 18 months, 14 patients (eight men, six women; age range, 21-72 years; mean age, 54 years) with one or two painful metastatic lesions involving bone, with a score of 4 or greater out of 10 for worst pain in a 24-hour period, and who did not respond to or refused conventional radiation treatment or chemotherapy were treated with percutaneous cryoablation. Patient response was measured with the Brief Pain Inventory, and analgesic use was recorded before and after the procedure at days 1 and 4, weekly for 4 weeks, and then every other week for a total of 6 months. Complications were monitored. Analysis of the primary end points was undertaken with paired comparison procedures by using paired t tests across individual time points supplemented with repeated measures analysis of variance.

Treated lesions were 1-11 cm in diameter. Before cryoablation, the mean score for worst pain in a 24-hour period was 6.7 of 10; the score decreased to 3.8 (P = .003) 4 weeks after treatment. Mean pain interference with activities of daily living was 5.5 of 10 before treatment and decreased to 3.2 (P = .004) 4 weeks after treatment. All eight (100%) patients (exact 95% binomial confidence interval: 63%, 100%) for whom narcotics were prescribed prior to the procedure reported a reduction in these medications after cryoablation. No serious complications were observed.

Percutaneous cryoablation is a safe and effective method for palliation of pain due to metastatic disease involving bone.