CIO 2021-2 Radiofrequency Ablation in Radiation Naïve Patients for Palliation of Osseous Metastases: An OPuS One Sub-analysis

Purpose: To report the results from a prospective multicenter study of Radiofrequency Ablation (RFA) for the palliation of painful bone metastases for subjects that did not receive radiation therapy at the site of RFA before or after RFA treatment.

Material and Methods: Two-hundred six subjects were enrolled and treated with RFA across 15 sites (NCT03249584). Subject inclusion required worst pain ≥4/10 within 24 hours as measured by BPI (Brief Pain Inventory) at the target site. RFA was to be conducted with imaging at 1-2 levels and subsequent cementoplasty was optional. Pain and EQ-5D-5L index score were assessed at baseline and 3 days through12 months. Adverse events (AEs) related to device, procedure, and/or therapy were recorded. Subjects were included in the present sub-group analysis if they did not receive radiation therapy at the site(s) of RFA treatment from pre-RFA baseline through up to 12 months of follow-up.

Results: Eighty-one percent of RFA-treated subjects were free from radiation therapy (166/206). For this cohort, mean age ± SD was 63.5±13.6 years and 55.4% were female. The prevailing cancer pathologies were lung (23.5%), breast (21.7%), and renal (10.2%). Eighty-nine percent of subjects were treated for metastatic lesions involving the lumbar/thoracic spine; 11% were treated for metastatic lesions located in the iliac crest, periacetabulum, sacrum or mixed vertebral and pelvic location. Ninety-nine percent (209/210) of RFA procedures were technically successful and 97% were followed by cementoplasty. Prior to RFA, the mean score for worst pain was 7.8±1.7. Post ablation, worst pain improved with scores decreasing to 5.2±2.7, 4.4±2.8, 3.5±3.0, 3.2±3.1, 2.6±2.7, and 2.8±2.8 at 3 days (N=159), 1 week (n=153), 1 month (n=139), 3 months (n=122), 6 months (n=95), and 12 months (n=50) respectively (P <0.001 for all). Subjects experienced significant improvement at all follow up times in average pain (P <0.001), pain interference (P <0.001), and EQ-5D-5L (P <0.001). Six AEs were reported and 3 were serious: Respiratory failure, intra-abdominal fluid collection, and pneumonia. Sixty-two deaths were reported, but all were attributed to an underlying malignancy.

Conclusions: The results of this subgroup analysis from the OPuS One clinical study show swift and significant pain reduction for up to 12 months after RFA treatment for metastatic bone disease, without radiation therapy.