Safety and Clinical Outcomes of Percutaneous Radiofrequency Ablation for Intermediate and Large Bone Tumors Using a Multiple-Electrode Switching System: A Phase II Clinical Study

Interventional Radiology in the Management of Metastases and Bone Tumors

Interventional Radiology (IR) has experienced an exponential growth in recent years. Technological advances of the last decades have made it possible to use new treatments on a larger scale, with good results in terms of safety and effectiveness. In musculoskeletal field, painful bone metastases are the most common target of IR palliative treatments; however, in selected cases of bone metastases, IR may play a curative role, also in combination with other techniques (surgery, radiation and oncology therapies, etc.). Primary malignant bone tumors are extremely rare compared with secondary bone lesions: osteosarcoma, Ewing sarcoma, and chondrosarcoma are the most common; however, the role of interventional radiology in this fiels is marginal. In this review, the main techniques used in interventional radiology were examined, and advantages and limitations illustrated. Techniques of ablation (Radiofrequency, Microwaves, Cryoablation as also magnetic resonance imaging-guided high-intensity focused ultrasound), embolization, and Cementoplasty will be described. The techniques of ablation work by destruction of pathological tissue by thermal energy (by an increase of temperature up to 90 °C with the exception of the Cryoablation that works by freezing the tissue up to -40 °C). Embolization creates an ischemic necrosis by the occlusion of the arterial vessels that feed the tumor. Finally, cementoplasty has the aim of strengthening bone segment weakened by the growth of pathological tissue through the injection of cement. The results of the treatments performed so far were also assessed and presented focused the attention on the management of bone metastasis.

Percutaneous Cryoablation of Large Tumors: Safety, Feasibility, and Technical Considerations

INTRODUCTION

Large tumors may prove unsuitable for surgical cure or other local therapies due to their size, involvement of critical structures, prior non-ablative treatment failure, or coexisting disease burden. This study was performed to assess the safety and feasibility of percutaneous cryoablation for treatment of large tumors exceeding 6 cm in size, and to highlight the key technical considerations inherent to such cases.

MATERIALS AND METHODS

This single-institution retrospective study identified 77 patients (42 male, 35 female; median age 55 years) who underwent 96 cryoablation procedures for treatment of 78 tumors (mean diameter 9.8 ± 3.6 cm) from 2008 through 2020. Technical success, procedure-related complications, mortality, oncologic outcomes, and procedural logistics were evaluated. Technical success was defined as ice ball extension at least 5 mm beyond the tumor margins.

RESULTS

Intentional subtotal ablations were performed in 32% of cases due to tumor encroachment on vulnerable structures or as part of staged/combined therapies. Of the 68% of cases that were planned for complete ablation, the technical success rate was 100%. Major complications occurred after 19/96 (20%) procedures, with hemorrhage and acute kidney injury each occurring in 6/96 (6%). Post-procedural myositis occurred in 24/96 (25%) cases and was not considered a major complication in the absence of acute kidney injury. Local recurrence occurred in 2/23 (8.7%) of patients undergoing ablation for cure or local control at a median follow-up duration of 13 months.

CONCLUSION

Percutaneous cryoablation may be used to treat large (> 6 cm) tumors with a high degree of technical success and an acceptable safety profile.

Feasibility of radiofrequency ablation as an alternative to surgical intervention in patients with huge multiloculated pyogenic liver abscesses: A retrospective cohort study

This retrospective cohort study investigated the feasibility of radiofrequency (RF) ablation as an alternative to surgical intervention in patients with huge multiloculated pyogenic liver abscesses (PLAs).From August 2010 to April 2016, 83 patients with PLA were admitted to Beijing Chao-Yang Hospital, China. Four of these patients had huge multiloculated PLAs and underwent RF ablation plus antibiotics. The inclusion criteria for RF ablation were as follows: multiloculated PLA confirmed by computed tomography (CT) or magnetic resonance imaging (MRI), widest diameter of the PLA ≥5 cm, failure to respond to or not suitable to treatment with percutaneous drainage (PD), and patient refusal of surgery. The safety and effectiveness of RF ablation were initially assessed. All patients were commenced on antibiotics on admission to our hospital. CT-guided percutaneous catheter drainage was attempted in one patient but was unsuccessful. The main organism isolated from cultures of these patients' blood or abscess samples was Klebsiella pneumoniae (3/4). RF ablation was performed as soon as eligibility according to the above criteria was established.RF ablation was technically successful in all 4 study patients, all PLAs being completely eradicated. The median duration of fever after RF ablation was 4.5 days. No abscesses recurred; thus, this strategy for managing PLA was 100% successful (4/4). No procedure-related deaths or major complications occurred. One patient had an asymptomatic right pleural effusion that resolved with conservative treatment including albumin infusion and diuretics.Our preliminary data indicate that RF ablation is a safe, feasible, and effective treatment for huge multiloculated PLAs. It should be considered as an alternative treatment for patients who fail to respond to or not suitable for PD plus antibiotics and refuse surgical intervention.