Cryoablation: Reviewing the Evidence for Pain Control
Cryoablation is an effective way to control pain from cancer without major side effects, according to the results of a systemic review.
Analgesics can control most cancer pain, but patients with bone metastases often struggle with quality-of-life issues from uncontrolled pain. However, cryoablation can be used to manage pain with a low complication rate in patients receiving palliative treatment. Cryoablation has only been used for about a decade for cancer pain, so the authors of the current study undertook a review to summarize the available evidence surrounding cryoablation for pain control.
The review included Scopus, Pubmed, and Cochrane databases and considered all 1,797 articles published prior to December 15, 2015 that focused on cancer pain control as an endpoint. Articles were excluded if they did not have an abstract or if they were non-systemic reviews.
There were 22 articles analyzed in the study after inclusion criteria were applied. There was 1 randomized controlled trial, 2 non-randomized controlled trials, 1 ambispective study, 9 retrospective studies, 2 non-specified cohort studies, 3 case series, and 4 case reports. These articles included 496 patients with 580 treated lesions.
The most common type of tumor treated was lung cancer, but 82.8% of the metastases were bone metastases, with or without soft tissue involvement. The authors found that mean pain scores decreased by 62.5% in the 24 hours following cryoablation and 70% at 3 months after cryoablation. By 6 months, pain scores had decreased by 80.9%.
Improvement in quality of life was also linked with cryoablation, with a 44.2% improvement after 4 weeks and 59.6% improvement after 8 weeks. Twenty-four hours after the cryoablation procedure, patients had a 75% decrease in the need for opioids. At 3 months, the decrease in need for opioids was 61.7%.
The review also found that combining cryoablation with radiotherapy, vertebroplasty or bisphosphonates led to better outcomes than cryoablation alone. No fatalities were reported among the studies reviewed, but complication rates varied greatly.
Although the study had limitations, the authors stated that, “the available evidence seems to suggest that analgesic cryoablation is effective in control pain with few major side effects, yielding high response rates in bone, soft tissues, and in hepatic metastases from a wide variety of primary tumours.” They added, “However, more clinical trials with larger samples are needed to compare cryoablation to other commonly-used interventional techniques such as radiofrequency ablation and EBRT. In addition, international criteria are needed to standardize measures used to evaluate pain and treatment response over time. Moreover, it is important to include patients with > 2 painful lesions, metastases or primary tumour, as such patients that are underrepresented in the studies performed to date.”
Ferrer-Mileo L, Luque Blanco AI, González-Barboteo J. Efficacy of cryoablation to control cancer pain. A systematic review. Pain Pract. 2018 May 7. doi: 10.1111/papr.12707. [Epub ahead of print].