Thermal ablation to relieve pain from metastatic bone disease: a systematic review

Objective

To review the efficacy of percutaneous thermal ablation (TA) of bone metastases (radiofrequency ablation [RFA], microwave ablation [MWA], cryoablation [CA], and MR-guided focused ultrasound [MRgFUS]) in reducing pain in patients with advanced stage cancer.

Materials and Methods

We searched MEDLINE/PubMed, MEDLINE In-Process, BIDS ISI, Embase, CINAHL, and the Cochrane database using the keywords "ablation," "painful," "bone," and "metastases" combined in multiple algorithms. Inclusion criteria were: original clinical studies published between 2001 and 2018; performance of RFA, MWA, CA or MRgFUS; and quantitative pain assessment before/after TA of bone metastasis.

Results

Eleven papers (3 on RFA, 1 on MWA, 2 on CA, and 5 on MRgFUS) involving 364 patients were reviewed. A technical success rate of 96–100% was reported, with follow-up for up to 6 months. At baseline, pain scores ranged from 5.4 to 8, at 1–4 weeks from 0.5 to 5, and at 12 weeks from 0.3 to 4.5. Mean pain reduction compared with baseline ranged from 26 to 91% at 4 weeks and from 16% to 95% at 12 weeks. MWA treatments caused no complications, whereas MRgFUS showed the highest complication rate. The number of minor complications observed ranged from 0 to 59 (complication ratio 0–1.17), whereas the number of significant adverse effects ranged from 0 to 4 (complication ratio 0–0.04).

Conclusion

All techniques achieved pain relief after 1 and 3 months, in up to 91% and 95% of patients respectively. MWA showed a negligible complication rate, whereas MRgFUS is associated with a noteworthy rate of adverse events. Future studies should adopt a standardized pain reporting scale to allow for meta-analysis.