Thermal ablation for the treatment of bone metastases (BM) in patients (pts) with metastatic renal cell carcinoma (mRCC): Experience from IGR.

Abstract

437 Background: Local treatment of BM in mRCC pts comprises different approaches including thermal ablation techniques as well as radiofrequency ablation (RFA) and cryotherapy. We report our experience for the treatment of BM of mRCC pts using thermal ablation. Methods: The medical records of all pts with mRCC submitted to thermal ablation of BM from Feb 2008 to Oct 2013 were retrospectively analyzed. Intention of treatment was recorded in 3 categories: complete treatment of all BM in pts with oligometastatic disease or prevention of skeletal related events (SRE) risk and/or pain relief in pts with multimetastatic disease. The local control rate and prognostic factors for local failure (LF) were analyzed including patient characteristics, extension of disease, BM characteristics and type of treatment. Results: 22 pts with BM of mRCC were treated by thermal ablation techniques, with 32 procedures (3 pts had >=3 BM treated). Histology of primary tumor was clear cell in 20 and chromophobe carcinoma in 2 pts. At time of BM treatment, Heng prognostic score was good, intermediate and poor in 36, 59 and 5% of pts. Median age was 67 yrs (48-85). A majority of men were treated (16/22=73%). In 34%, pts had BM synchronous with the primary. BM presented cortical bone erosion in 69% and neurological structures in the vicinity in 50%. Intention of treatment was complete control of BM in 43% and prevention of risk of SRE and/or pain relief in 57% of pts. Cryotherapy was performed in 72% and RF in 28% of cases. Concomitant cimentoplasty and arterial embolization was performed in 70% and 30% respectively. Pain relief was achieved in 81% of pts. LF occurred in 19% of pts (n=6) (95% CI: 4-33%). The median follow-up was 13.4 months (95% CI: 11-21). Median OS was not reached. 86% of pts are still alive at 12 months. The unfavorable prognostic factors for LF were BM size >50 mm (p=0.035) and neurological structures in the vicinity (p=0.0083). Conclusions: Thermal ablation techniques are treatment options that should be considered in the curative and palliative treatment of BM in pts with mRCC. When indications are carefully discussed, these techniques have the potential to achieve good local control and acceptable survival.