Thermal ablation techniques: a curative treatment of bone metastases in selected patients?

Abstract

Introduction: Thermal ablation techniques (radiofrequency-ablation/cryotherapy) can be indicated with a curative intent. The success rate and prognostic factors for complete treatment were analysed.

Material/methods: The medical records of all patients who had undergone curatively intended thermal ablation of bone metastases between September 2001 and February 2012 were retrospectively analysed. The goal was to achieve complete treatment of all bone metastases in patients with oligometastatic disease (group 1) or only of bone metastases that could potentially lead to skeletal-related events in patients with a long life expectancy (group 2). We report the rate of complete treatment according to patient characteristics, primary tumour site, bone metastasis characteristics, radiofrequency ablation/cryotherapy and the treatment group (group 1/group 2).

Results: Eighty-nine consecutive patients had undergone curatively intended thermal ablation of 122 bone metastases. The median follow-up was 22.8 months [IQR = 12.2-44.4]. In the intent-to-treat analysis, the 1-year complete treatment rate was 67% (95%CI: 50%-76%). In the multivariate analysis the favourable prognostic factors for complete local treatment were oligometastatic status (p = 0.02), metachronous (p = 0.004) and small-sized (p = 0.001) bone metastases, without cortical bone erosion (p = 0.01) or neurological structures in the vicinity (p = 0.002).

Conclusion: Thermal ablation should be included in the therapeutic arsenal for the cure of bone metastases.

Key points: • Thermal ablation techniques are currently performed to palliate pain caused by bone metastases. • In selected patients, thermal ablation can also be indicated with a curative intent. • Oligometastatic and/or metachronous diseases are good prognostic factors for local success. • Small-size (<2 cm) bone metastases and no cortical erosion are good prognostic factors.