Radiofrequency ablation versus stereotactic body radiotherapy for painful osseous metastases: A comparative correlation meta-analysis of pain relief.

Abstract

e24156 Background: Osseous metastases (OMs), a common cause of cancer pain, are only partially palliated by analgesics. Stereotactic body radiotherapy (SBRT) and radiofrequency ablation (RFA) are increasingly used, but the comparative effectiveness of SBRT vs. RFA for OMs has not been adequately evaluated. Herein we analyzed palliative benefits of SBRT and RFA in terms of pain relief from OMs. Methods: A systematic review was performed for all studies reporting palliative outcomes of SBRT (defined as five or fewer fractions of radiation) or RFA for palliation of OMs. Studies not reporting pain palliation were excluded. Random effects model determined the net Pearson correlation (R2) for post-SBRT and post-RFA pain reduction over time. The pooled correlation coefficient and 95% confidence interval were calculated using Fisher r-to- z transformation. Risk of bias was assessed using sunset plots; heterogeneity was assessed using I2 and meta-regression. Results: Seven full-text articles assessed a total of 1100 SBRT patients and 22 full-text articles assessed a total of 557 RFA patients. No studies directly compared SBRT to RFA. All included studies collected data on pain related to OM disease pre- and post-therapy. The scales used included the visual analog scale (2 SBRT, 15 RFA), brief pain inventory (4 SBRT, 4 RFA), numeric rating scale (0 SBRT, 2 RFA), QLQ-15 (1 SBRT, 0 RFA), or the memorial pain index card (0 SBRT, 1 RFA). Mean SBRT dose and fractions were 17.3 gy and 2.6. Median follow-up was 24 weeks for SBRT and 18 weeks for RFA, with median pain reduction of 59% (R2=0.83, 95%CI:0.80-0.87, I2=58.63%) and 64% (R2=0.52, 95%CI:0.41-0.62, I2=48.16%) respectively. Meta-regression by number of fractions and reporting metric fully accounted for heterogeneity in the SBRT and RFA data respectively. Sunset plots did not indicate significant publication bias. Conclusions: The published literature is predominately non-randomized, limiting the evidence level. Pain reduction and durability post-SBRT or post-RFA are comparable. Pre-SBRT or RFA therapies may obscure the full effect of either treatment modality. SBRT and RFA for painful OMs are associated with pain relief in a majority of patients, but the durability of this relief and the comparative efficacy of SBRT vs. RFA for this purpose has been inadequately reported in the literature. Future, combinatorial therapies as opposed to single-modality approaches may help to increase overall pain relief and durability as well as efficaciously palliating treatment-resistant patients.