Percutaneous image-guided cryoablation of painful metastases involving bone: multicenter trial

Abstract

Background: This study sought to describe the results of a single-arm multicenter clinical trial using image-guided percutaneous cryoablation for the palliation of painful metastatic tumors involving bone.

Methods: Over a 44-month period, 61 adult patients with 1 or 2 painful bone metastases with a score of 4 or more on a scale of 0 to 10 (≥4/10) worst pain in a 24-hour period who had failed or refused conventional treatment were treated with percutaneous image-guided cryoablation. Patient pain and quality of life was measured using the Brief Pain Inventory prior to treatment, 1 and 4 days after the procedure, weekly for 4 weeks, and every 2 weeks thereafter for a total of 6 months. Patient analgesic use was also recorded at these same follow-up intervals. Complications were monitored. Analysis of the primary endpoint was undertaken via paired comparison procedures.

Results: A total of 69 treated tumors ranged in size from 1 to 11 cm. Prior to cryoablation, the mean score for worst pain in a 24-hour period was 7.1/10 with a range of 4/10 to 10/10. At 1, 4, 8, and 24 weeks after treatment, the mean score for worst pain in a 24-hour period decreased to 5.1/10 (P < .0001), 4.0/10 (P < .0001), 3.6/10 (P < .0001), and 1.4/10 (P < .0001), respectively. One of 61 (2%) patients had a major complication with osteomyelitis at the site of ablation.

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

FIGURE 1

A) Noncontrast CT image of the upper chest with bone windows demonstrates an osteolytic metastasis in the medial head of the right clavicle (arrows). A cryoprobe (arrow head) is placed in the metastasis. B) Noncontrast CT image of the upper chest with body windows demonstrates an ice-ball, visible as a low-attenuation area about the cryoprobe with 0 °C at the ice-ball tissue boundary, extending beyond the margin of the clavicle and the osteolytic metastasis (arrows).

FIGURE 2

Treatment of a painful metastatic paraganglioma contained in a rib. Prior to treatment, the patient had 5/10 worst pain which was reduced to 2/10 by week 4 and 0/10 by week 8. Patient reported 0/10 pain at latest follow-up of 24 weeks. A) Contrast-enhanced CT image of the upper abdomen with body windows demonstrates an enhancing osteolytic metastasis in the left 10^th rib (arrow). B) Noncontrast CT image of the upper abdomen with bone windows demonstrates a cryoprobe (arrow) placed in the metastasis C) Noncontrast CT image of the upper abdomen with body windows demonstrates an ice-ball, visible as a low-attenuation area (arrow heads) extending beyond the margin of the target tumor. D) Contrast-enhanced CT image of the upper abdomen with body windows performed following the ablation procedure shows no residual enhancement of the mass contained in the left 10^th rib (arrow).

FIGURE 3

Mean BPI scores over time for patients treated with percutaneous cryoablation for (A) worst pain, (B) average pain, (C) pain interference, and (D) pain relief. Error bars represent the 95% confidence intervals. N=the number of patients completing BPI at each time point.