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

The Landmark Series: Multimodal Management of Oligometastatic Sarcoma

The concept of "oligometastatic" disease suggests the presence of intermediate states between localized disease and widespread metastases, which may be potentially treatable with curative therapeutic strategies. Metastases local therapy (MLT) can be accomplished through various techniques such as stereotactic ablative radiotherapy (SABR), radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation, or surgical metastasectomy. The incorporation of MLT in the multidisciplinary treatment of patients with metastatic sarcoma is complex. Retrospective studies support consideration of MLT for selected patients based on factors such as patient condition, disease biology, histologic type, and disease burden. Decisions regarding type and timing of MLT should be made after multidisciplinary discussion including radiation oncologists, surgical and orthopedic oncologists, medical oncologists, and interventional radiology to explore all options before treatment decsions. All MLT techniques have advantages and disadvantages and should be performed in centers specialized in the care of complex oncology patients where various options can be explored concurrently or sequentially for each patient. Future studies evaluating quality of life and patient-reported outcomes are necessary to adequately align patient goals and optimal outcomes. This article reviews the medical scenarios that may benefit the use of MLT, evaluates the distinct advantages and disadvantages associated with these various techniques, and analyzes the findings from pivotal series to provide a comprehensive understanding of its role in clinical practice.

A Multidisciplinary Update on Treatment Modalities for Metastatic Spinal Tumors with a Surgical Emphasis: A Literature Review and Evaluation of the Role of Artificial Intelligence

Spinal metastases occur in up to 40% of patients with cancer. Of these cases, 10% become symptomatic. The reported incidence of spinal metastases has increased in recent years due to innovations in imaging modalities and oncological treatments. As the incidence of spinal metastases rises, so does the demand for improved treatments and treatment algorithms, which now emphasize greater multidisciplinary collaboration and are increasingly customized per patient. Uniquely, we discuss the potential clinical applications of AI and NGS in the treatment of spinal metastases. Material and Methods: A PubMed search for articles published from 2000 to 2023 regarding spinal metastases and artificial intelligence in healthcare was completed. After screening for relevance, the key findings from each study were summarized in this update. Results: This review summarizes the evidence from studies reporting on treatment modalities for spinal metastases, including minimally invasive surgery (MIS), external beam radiation therapy (EBRT), stereotactic radiosurgery (SRS), CFR-PEEK instrumentation, radiofrequency ablation (RFA), next-generation sequencing (NGS), artificial intelligence, and predictive models.

Update on Percutaneous Ablation for Sarcoma

PURPOSE OF REVIEW

To provide an update on the current state of percutaneous thermal ablation in the treatment of sarcoma.

RECENT FINDINGS

Data continue to accrue in support of ablation for local control and palliation of specific sarcoma subtypes such as extra-abdominal desmoid fibromatosis and for broader indications such as the treatment of oligometastatic disease. The synergistic possibilities of various combination therapies such as cryoablation and immunotherapy represent intriguing areas of active investigation. Histotripsy is an emerging non-invasive, non-thermal ablative modality that may further expand the therapeutic arsenal for sarcoma treatment. Percutaneous thermal ablation is a valuable tool in the multidisciplinary management of sarcoma, offering a minimally invasive adjunct to surgery and radiation therapy. Although there remains a paucity of high-level evidence specific to sarcomas, ablation techniques are demonstrably safe and effective for achieving local tumor control and providing pain relief in select patients and are of particular benefit in those with metastatic disease or requiring palliative care.

Directional microwave ablation in spine: experimental assessment of computational modeling

BACKGROUND

Despite the theoretical advantages of treating metastatic bone disease with microwave ablation (MWA), there are few reports characterizing microwave absorption and bioheat transfer in bone. This report describes a computational modeling-based approach to simulate directional microwave ablation (dMWA) in spine, supported by ex vivo and pilot in vivo experiments in porcine vertebral bodies.

MATERIALS AND METHODS

A 3D computational model of microwave ablation within porcine vertebral bodies was developed. Ex vivo porcine vertebra experiments using a dMWA applicator measured temperatures approximately 10.1 mm radially from the applicator in the direction of MW radiation (T1) and approximately 2.4 mm in the contra-lateral direction (T2). Histologic assessment of ablated ex vivo tissue was conducted and experimental results compared to simulations. Pilot in vivo experiments in porcine vertebral bodies assessed ablation zones histologically and with CT and MRI.

RESULTS

Experimental T1 and T2 temperatures were within 3-7% and 11-33% of simulated temperature values. Visible ablation zones, as indicated by grayed tissue, were smaller than those typical in other soft tissues. Posthumous MRI images of in vivo ablations showed hyperintensity. In vivo experiments illustrated the technical feasibility of creating directional microwave ablation zones in porcine vertebral body.

CONCLUSION

Computational models and experimental studies illustrate the feasibility of controlled dMWA in bone tissue.

Magnetic resonance-guided focused ultrasound versus percutaneous thermal ablation in local control of bone oligometastases: a systematic review and meta-analysis

BACKGROUND

The percutaneous thermal ablation techniques (pTA) are radiofrequency ablation, cryoablation, and microwave ablation, suitable for the treatment of bone oligometastases. Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive ablation technique.

OBJECTIVES

To compare the effectiveness and safety of MRgFUS and pTA for treating bone oligometastases and their complications.

METHODS

Studies were selected with a PICO/PRISMA protocol: pTA or MRgFUS in patients with bone oligometastases; non-exclusive curative treatment. Exclusion criteria were: primary bone tumor; concurrent radiation therapy; palliative therapy; and absence of imaging at follow-up. PubMed, BioMed Central, and Scopus were searched. The modified Newcastle-Ottawa Scale assessed articles quality. For each treatment (pTA and MRgFUS), we conducted two separate random-effects meta-analyses to estimate the pooled effectiveness and safety. The effectiveness was assessed by combining the proportions of treated lesions achieving local tumor control (LTC); the safety by combining the complications rates of treated patients. Meta-regression analyses were performed to identify any outcome predictor.

RESULTS

A total of 24 articles were included. Pooled LTC rate for MRgFUS was 84% (N = 7, 95% CI 66-97%, I2 = 74.7%) compared to 65% of pTA (N = 17, 95% CI 51-78%, I2 = 89.3%). Pooled complications rate was similar, respectively, 13% (95% CI 1-32%, I2 = 81.0%) for MRgFUS and 12% (95% CI 8-18%, I2 = 39.9%) for pTA, but major complications were recorded with pTA only. The meta-regression analyses, including technique type, study design, tumor, and follow-up, found no significant predictors.

DISCUSSION

The effectiveness and safety of the two techniques were found comparable, even though MRgFUS is a noninvasive treatment that did not cause any major complication. Limited data availability on MRgFUS and the lack of direct comparisons with pTA may affect these findings.

CONCLUSIONS

MRgFUS can be a valid, safe, and noninvasive treatment for bone oligometastases. Direct comparison studies are needed to confirm its promising benefits.

Interventional management of malignant bone tumours

In the last few decades, interventional radiology (IR) has significantly increased its role in the management of bone tumours including bone metastases (BM) that represent the most common type of tumour involving the bone. The current IR management of BM is based on the 'palliative-curative' paradigm and relies on the use of consolidative (i.e. osteplasty, osteosynthesis) and/or ablation (i.e. cryoablation, radiofrequency ablation, electrochemotherapy) techniques. The present narrative review will overview the current role of IR for the management of BM.

Musculoskeletal oncology and thermal ablation: the current and emerging role of interventional radiology

The role of interventional radiology (IR) is expanding. With new techniques being developed and tested, this radiology subspecialty is taking a step forward in different clinical scenarios, especially in oncology. Musculoskeletal tumoral diseases would definitely benefit from a low-invasive approach that could reduce mortality and morbidity in particular. Thermal ablation through IR has already become important in the palliation and consolidation of bone metastases, oligometastatic disease, local recurrences, and treating specific benign tumors, with a more tailored approach, considering the characteristics of every patient. As image-guided ablation techniques lower their invasiveness and increase their efficacy while the collateral effects and complications decrease, they become more relevant and need to be considered in patient care pathways and clinical management, to improve outcomes. We present a literature review of the different percutaneous and non-invasive image-guided thermal ablation methods that are currently available and that could in the future become relevant to manage musculoskeletal oncologic diseases.

Ablative Techniques for Sarcoma Metastatic Disease: Current Role and Clinical Applications

Sarcomas are heterogenous mesenchymal neoplasms with more than 80 different histologic subtypes. Lung followed by liver and bone are the most common sites of sarcoma metastatic disease. Ablative techniques have been recently added as an additional alternative curative or palliative therapeutic tool in sarcoma metastatic disease. When compared to surgery, ablative techniques are less invasive therapies which can be performed even in non-surgical candidates and are related to decreased recovery time as well as preservation of the treated organ’s long-term function. Literature data upon ablative techniques for sarcoma metastatic disease are quite heterogeneous and variable regarding the size and the number of the treated lesions and the different histologic subtypes of the original soft tissue or bone sarcoma. The present study focuses upon the current role of minimal invasive thermal ablative techniques for the management of metastatic sarcoma disease. The purpose of this review is to present the current minimally invasive ablative techniques in the treatment of metastatic soft tissue and bone sarcoma, including local control and survival rates.

Assessing long-term locoregional control of spinal osseous metastases after microwave ablation

Osseous metastases to the spine result in significant pain and decreased quality of life. The purpose of this study was to evaluate the long-term efficacy of microwave ablation (MWA) for the treatment of spinal metastases regarding pain reduction and local control of disease progression. In this single center retrospective study, patients with osseous metastases to the spine undergoing MWA with vertebroplasty from 2013 to 2020 were included. Locoregional control of metabolic activity at the treated level was assessed using PET/CT scan both pre- and post-procedure. Pain reduction was measured using change in visual analog scale (VAS) pain score. Forty-eight spinal levels were treated with MWA in 28 patients (57 % male, mean age 68 ± 9 years). Median ablation time, energy, and temperature were 4 min and 13 s, 3.6 kJ, and 80 °C, respectively. Median pre-procedure maximum standard uptake value (SUVmax) was significantly reduced following ablation, from 4.55 (IQR 3.65-6.1) to 0 (IQR 0-1.8; p < 0.001), over an average of 29 ± 14.1 month follow up period. Pre-procedure VAS pain score was reduced from median (IQR) of 8 (6.5-9) to 1(1-2), 2(1-3) and 1(0.5-3) at 24 h, four weeks, and six months post-procedure, respectively (all p < 0.001 with respect to pre-procedure scores). In conclusion, this study supports microwave ablation as an effective technique for pain palliation and long-term locoregional tumor control of oligometastatic spinal disease as assessed by metabolic response.

The efficacy of adding hyperthermia to the treatment of advanced NSCLC patients based on the states of EGFR

Background: The study aims to explore the efficacy of adding hyperthermia to the treatment of advanced NSCLC patients based on the states of epidermal growth factor receptor (EGFR).

Patients and methods: We included 205 advanced NSCLC patients who were received hyperthermia plus other treatment (hyperthermia group) or non- hyperthermia and other treatments (non- hyperthermia group). The OS and progression free survival (PFS) were retrospectively estimated. Using Kaplan-Meier and the log-rank test compare the OS and PFS between the groups.

Results: The median follow-up was 22 months. The Univariate analysis have shown that 1-year OS and PFS_first rates in the hyperthermia group and non- hyperthermia group were 83.3% vs 71.5% (P=0.010) and 62.0% vs 42.7% (P=0.001). The subgroup analyses revealed that patients didn’t have EGFR mutant who received hyperthermia had significantly higher 1 year OS and PFS_first rates than those treated with non- hyperthermia (OS: 79.1% vs 65.2% P=0.037, PFS: 64.2% vs 36.5%, P=0.001). For patients with EGFR mutation, there was no significant difference between the two groups. The PFS_first in first-line and PFS_post in posterior-line was no significant difference between the groups.

Conclusions: This retrospective study revealed that adding hyperthermia to the treatment of NSCLC patients without EGFR mutation had better prognosis than those who did not adding hyperthermia to the regimen. Moreover, adding hyperthermia in first-line or in posterior-line treatment was no significant difference. However, these results need more prospective studies to confirm the conclusions.

Minimally Invasive Interventional Procedures for Metastatic Bone Disease: A Comprehensive Review

Metastases are the main type of malignancy involving bone, which is the third most frequent site of metastatic carcinoma, after lung and liver. Skeletal-related events such as intractable pain, spinal cord compression, and pathologic fractures pose a serious burden on patients’ quality of life. For this reason, mini-invasive treatments for the management of bone metastases were developed with the goal of pain relief and functional status improvement. These techniques include embolization, thermal ablation, electrochemotherapy, cementoplasty, and MRI-guided high-intensity focused ultrasound. In order to achieve durable pain palliation and disease control, mini-invasive procedures are combined with chemotherapy, radiation therapy, surgery, or analgesics. The purpose of this review is to summarize the recently published literature regarding interventional radiology procedures in the treatment of cancer patients with bone metastases, focusing on the efficacy, complications, local disease control and recurrence rate.

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.

CIRSE Standards of Practice on Thermal Ablation of Bone Tumours

Background

Percutaneous thermal ablation is an effective, minimally invasive means of treating a variety of focal benign and malignant osseous lesions. To determine the role of ablation in individual cases, multidisciplinary team (MDT) discussion is required to assess the suitability and feasibility of a thermal ablative approach, to select the most appropriate technique and to set the goals of treatment i.e. curative or palliative.

Purpose

This document will presume the indication for treatment is clear and approved by the MDT and will define the standards required for the performance of each modality. CIRSE Standards of Practice documents are not intended to impose a standard of clinical patient care, but recommend a reasonable approach to, and best practices for, the performance of thermal ablation of bone tumours.

Methods

The writing group was established by the CIRSE Standards of Practice Committee and consisted of five clinicians with internationally recognised expertise in thermal ablation of bone tumours. The writing group reviewed the existing literature on thermal ablation of bone tumours, performing a pragmatic evidence search using PubMed to search for publications in English and relating to human subjects from 2009 to 2019. Selected studies published in 2020 and 2021 during the course of writing these standards were subsequently included. The final recommendations were formulated through consensus.

Results

Recommendations were produced for the performance of thermal ablation of bone tumours taking into account the biologic behaviour of the tumour and the therapeutic intent of the procedure. Recommendations are provided based on lesion characteristics and thermal modality, for the use of tissue monitoring and protection, and for the appropriately timed application of adjunctive procedures such as osseus consolidation and transarterial embolisation.

Results

Percutaneous thermal ablation has an established role in the successful management of bone lesions, with both curative and palliative intent. This Standards of Practice document provides up-to-date recommendations for the safe performance of thermal ablation of bone tumours.

Sporadic Desmoid Tumours: Systematic Review with Reflection on the Role of Cryoablation

Desmoid tumours (DT) are rare locally infiltrative soft-tissue tumours which do not metastasise. DT arise sporadically or are associated with familial syndromes, with different clinical and genetic patterns. In recent years there has been an increasing therapeutic role of cryoablation for the treatment of sporadic DT. Therefore, in this present review, we: (a) summarize all the main epidemiological, clinical, and therapeutic aspects of sporadic DT that are relevant to an interventional radiologists' practice; (b) present the results of a systematic review that has been conducted with the intent of highlighting the main clinical outcomes available thus far with cryoablation; and (c) discuss the current and future potential applications of cryoablation in this field. Five studies were included in the systematic review accounting for 146 patients. Only 18.5% patients received cryoablation as a first-line treatment. Overall, the volume of the DT undergoing cryoablation was very large (mean total DT volume of 237 cm³). Major complications were noted for 13.3-30% patients and following 2.4-6.7% interventional sessions. The rates of complete tumour response ranged between 0 and 43.3%. 1- and 3-year local progression-free survival rates were 85.1-85.8%, and 77.3-82.9%, respectively. Complete pain relief was reported in 40-66.7% symptomatic patients. In conclusion, cryoablation is currently proposed as a therapeutic strategy to very large DT, which is recognized to be associated with an increased procedure-related morbidity and reduced rates of complete tumour response. Proposing cryoablation as the first-line treatment may improve these clinical outcomes.

Radiofrequency Ablation of Spine Metastases: A Clinical and Technical Approach

Percutaneous radiofrequency ablation (RFA) is an integral component of the multidisciplinary treatment algorithm for both local tumor control and palliation of painful spine metastases. This minimally invasive therapy complements additional treatment strategies, such as pain medications, systemic chemotherapy, surgical resection, and radiotherapy. The location and size of the metastatic lesion dictate preprocedure planning and the technical approach. For example, ablation of lesions along the spinal canal, within the posterior vertebral elements, or with paraspinal soft tissue extension are associated with a higher risk of injury to adjacent spinal nerves. Additional interventions may be indicated in conjunction with RFA. For example, ablation of vertebral body lesions can precipitate new, or exacerbate existing, pathologic vertebral compression fractures that can be prevented with vertebral augmentation. This article reviews the indications, clinical work-up, and technical approach for RFA of spine metastases.

The Role of a Navigational Radiofrequency Ablation Device and Concurrent Vertebral Augmentation for Treatment of Difficult-to-Reach Spinal Metastases

Aims: The purpose of this study was to assess the effectiveness of a navigational radiofrequency ablation device with concurrent vertebral augmentation in the treatment of posterior vertebral body metastatic lesions, which are technically difficult to access. Primary outcomes of the study were evaluation of pain palliation and radiologic assessment of local tumor control. Materials and Methods: Thirty-five patients with 41 vertebral spinal metastases involving the posterior vertebral body underwent computed tomography-guided percutaneous targeted radiofrequency ablation, with a navigational radiofrequency ablation device, associated with vertebral augmentation. Twenty-one patients (60%) had 1 or 2 metastatic lesions (Group A) and fourteen (40%) patients had multiple (>2) vertebral lesions (Group B). Changes in pain severity were evaluated by visual analog scale (VAS). Metastatic lesions were evaluated in terms of radiological local control. Results: The procedure was technically successful in all the treated vertebrae. Among the symptomatic patients, the mean VAS score dropped from 5.7 (95% CI 4.9–6.5) before tRFA and to 0.9 (95% CI 0.4–1.3) after tRFA (p < 0.001). The mean decrease in VAS score between baseline and one week follow up was 4.8 (95% CI 4.2–5.4). VAS decrease over time between one week and one year following radiofrequency ablation was similar, suggesting that pain relief was immediate and durable. Neither patients with 1–2 vertebral metastases, nor those with multiple lesions, showed radiological signs of local progression or recurrence of the tumor in the index vertebrae during a median follow up of 19 months (4–46 months) and 10 months (4–37 months), respectively. Conclusion: Treatment of spinal metastases with a navigational radiofrequency ablation device and vertebral augmentation can be used to obtain local tumor control with immediate and durable pain relief, providing effective treatment in the multimodality management of difficult-to-reach spinal metastases.

Ablation Techniques in Cancer Pain

Painful bone metastases are a frequently encountered problem in oncology practice. The skeletal system is the third most common site of metastatic disease and up to 85% of patients with breast, prostate, and lung cancer may develop bone metastases during the course of their disease.

Current Management of Bone Metastases from Differentiated Thyroid Cancer

Simple Summary

Patients with bone metastases (BMs) from differentiated thyroid carcinoma (DTC) can live longer than those with BMs from other cancers. BMs from DTC create destructive lesions and easily cause intractable pain and neurological symptoms, including paralysis. These symptoms related to BMs affect mortality directly and indirectly by hampering the application of systemic therapies. Therefore, long-term local control of BMs in patients with DTC is desired, especially in patients with single or a small number of metastases. Local treatments for BMs have recently become advanced and sophisticated in surgery, radiotherapy, and percutaneous procedures. These therapies, either alone or in combination with other treatments, can effectively improve, or prevent the deterioration of, the performance status and quality of life of patients with DTC-BM. Among local therapies, complete surgical resection and stereotactic radiosurgery are the mainstay for achieving long-term control of DTC-BM.

Abstract

After the lung, the skeleton is the second most common site of distant metastases in differentiated thyroid carcinoma (DTC). Patients with osteolytic bone metastases (BMs) from thyroid carcinoma often have significantly reduced performance status and quality of life. Recent advancements in cancer therapy have improved overall survival in multiple cancer subtypes, including thyroid cancer. Therefore, long-term local control of thyroid BMs is desired, especially in patients with a single metastasis or oligometastases. Here, we reviewed the current management options for DTC-BMs and especially focused on local treatments for long-term local tumor control from an orthopedic tumor surgeon’s point of view. Metastasectomy and stereotactic radiosurgery can be performed either alone or in combination with radioiodine therapy and kinase inhibitors to cure skeletal lesions in selected patients. Percutaneous procedures have been developed in recent years, and they can also have a curative role in small BMs. Recent advancements in local therapies have the potential to provide not only long-term local tumor control but also a better prognosis.

Combined local treatments for vertebral metastases with limited epidural extension

OBJECTIVES

Vertebral metastases with limited epidural extension (VMLEE) are frequently encountered in cancer patients; they can cause severe and debilitating symptoms including pain and neurological impairment and are usually treated by radiotherapy. In this study, we mainly evaluated the safety of combined local treatments (CLT), associating radiofrequency ablation (RFA) with vertebroplasty and radiotherapy (RT) to treat VMLEE. Also, we aimed to evaluate the short-term efficacy of CLT on bone metastases palliation and long-term prevention of skeletal-related events.

METHODS

We retrospectively reviewed treatment complications, pain palliation, and skeletal complications after combined local treatments (CLT) for vertebral metastasis with limited epidural extension (VMLEE).

RESULTS

Eighteen consecutive patients had CLT for 24 VMLEE, between June 2016 and January 2021. No major post-treatment complication was recorded. Nine patients had pain before the initiation of CLT. One month after CLT, only 3 patients had residual pain with a significant decrease of visual analogue scale (VAS), from 7.3 ± 2.4 to 2 ± 0 (p = .008), as well as the mean morphine milligram equivalent dose from 196.6 ± 135.7 to 38.5 ± 26, p = .008. Mean follow-up was 16.7 ± 11.5 months. Only one vertebra showed an increase of a preexisting vertebral fracture. Nine VMLEE had evidence of residual disease, including 2 which resulted in spinal cord compression (2, 11 months).

CONCLUSION

CLT was safe and effective for pain palliation and long-term prevention of skeletal-related events for treatment of patients with VMLEE. The effectiveness of this combined treatment on tumor control and epidural involvement on the long term needs further investigation.

Anterior epidural carbon dioxide dissection during spine cryoablation

PURPOSE

Spine cryoablation (SC) of posterior vertebral lesions exposes to neuronal damages and incomplete treatment due to the proximity of the spinal canal. Carbon dioxide (CO₂) dissection is a nerve protective method that can be used during spine cryoablation that tends to distribute in non-dependent areas. The purpose of this technical note was to expose the feasibility of anterior epidural CO₂ dissection during SC in prone decubitus.

MATERIALS AND METHODS

Three consecutives patients underwent SC of metastases abutting the posterior wall of the vertebra with anterior epidural CO₂ dissection. A post-ablation MRI was performed after each cryoablation to state if the treatment was complete or incomplete. Complications were reported using the Common Terminology Criteria for Adverse Events v5.0 (CTCAE).

RESULTS

Peri-procedural anterior epidural injection of CO₂ was successful in all 3 procedures. Treatment was considered complete on all post-ablation MRI with ablation margins encompassing the targeted metastasis. No complication according to the CTCAE was reported.

CONCLUSION

CO₂ dissection of the anterior epidural space was successful in all 3 procedures allowing complete treatment on all post-ablation MRI.

Percutaneous management of bone metastases: State of the art

Interventional radiology is playing an increasingly important role in the local treatment of bone metastases; this treatment is usually done with palliative intent, although in selected patients it can be done with curative intent. Two main groups of techniques are available. The first group, centered on bone consolidation, includes osteoplasty/vertebroplasty, in which polymethyl methacrylate (PMMA) is injected to reinforce the bone and relieve pain, and percutaneous osteosynthesis, in which fractures with nondisplaced or minimally bone fragments are fixed in place with screws. The second group centers on tumor ablation. tumor ablation refers to the destruction of tumor tissue by the instillation of alcohol or by other means. Thermoablation is the preferred technique in musculoskeletal tumors because it allows for greater control of ablation. Thermoablation can be done with radiofrequency, in which the application of a high frequency (450 Hz-600 Hz) alternating wave to the tumor-bone interface achieves high temperatures, resulting in coagulative necrosis. Another thermoablation technique uses microwaves, applying electromagnetic waves in an approximate range of 900 MHz-2450 MHz through an antenna that is placed directly in the core of the tumor, stimulating the movement of molecules to generate heat and thus resulting in coagulative necrosis. Cryoablation destroys tumor tissue by applying extreme cold. A more recent, noninvasive technique, magnetic resonance-guided focused ultrasound surgery (MRgFUS), focuses an ultrasound beam from a transducer placed on the patient's skin on the target lesion, where the waves' mechanical energy is converted into thermal energy (65 °C-85 °C). Treatment should be planned by a multidisciplinary team. Treatment can be done with curative or palliative intent. Once the patient is selected, a preprocedural workup should be done to determine the most appropriate technique based on a series of factors. During the procedure, protective measures must be taken and the patient must be closely monitored. After the procedure, patients must be followed up.

Musculoskeletal Oncologic Interventions: Proceedings from the Society of Interventional Radiology and Society of Interventional Oncology Research Consensus Panel

Musculoskeletal interventions are increasingly used with palliative and curative intent in the multidisciplinary treatment of oncology patients with bone and soft-tissue tumors. There is an unmet need for high-quality evidence to guide broader application and adoption of minimally invasive interventional technologies to treat these patients. Therefore, the Society of Interventional Radiology Foundation and the Society of Interventional Oncology collaborated to convene a research consensus panel to prioritize a research agenda addressing the gaps in the current evidence. This article summarizes the panel's proceedings and recommendations for future basic science and clinical investigation to chart the course for interventional oncology within the musculoskeletal system. Key questions that emerged addressed the effectiveness of ablation within specific patient populations, the effect of combination of ablation with radiotherapy and/or immunotherapy, and the potential of standardization of techniques, including modeling and monitoring, to improve the consistency and predictability of treatment outcomes.

Percutaneous image-guided thermal ablation of bone metastases: a retrospective propensity study comparing the safety profile of radio-frequency ablation and cryo-ablation

OBJECTIVES

To retrospectively compare the safety profile of percutaneous image-guided radiofrequency ablation (RFA) and cryoablation (CA) of bone metastases (BM) with and without a propensity score analysis.

METHODS

Between January 2008 and April 2018, 274 consecutive patients (mean age 61.6 ± 12.1 years) with BM were treated at our Institution with RFA (53 patients; 66 BM) or CA (221 patients; 301 BM) and included in this study. Complications were assessed according to the type of ablation modality before and after applying a 1:1 propensity score method taking into account patient's demographics, BM features, procedural details and follow-up findings.

RESULTS

In the whole 9 BM (2.5%) reported major complications without significant difference between RFA (1/66; 1.5%) and CA (8/301; 2.7%; p = 1); 40 BM (10.9%) showed minor complications, which were more common with RFA (22/66; 33.3%) than with CA (18/301; 6.0%, p<.001) mainly due to post-procedural pain occurring more frequently with RFA than CA (20/66; 30.3% vs. 7/301; 2.3%, p<.001). Following 1:1 matching, similar results were obtained, since there were similar rates of major complications with RFA and CA (1/66 [1.5%] and 0/66 [0.0%], respectively; p = 1); and higher rates of minor complications with RFA compared to CA [33.3% (22/66) vs. 2/66 (3%); p<.001] due to preponderant postprocedural pain (90.9% [20/22] minor complications with RFA).

CONCLUSIONS

Similar low rates of major complications are expected with RFA and CA of BM. In the post-operative period, RFA appears more painful than CA, thus warranting for adoption of dedicated analgesic protocols for patients undergoing RFA.

Pain relief and local tumour control following percutaneous image-guided cryoablation for spine metastasis: a 12-year single-centre experience

AIM

To assess pain relief and local tumour control retrospectively in spinal metastases undergoing cryoablation.

MATERIALS AND METHODS

Between May 2008 and September 2020, 46 metastases in 41 consecutive patients (mean age 59.7±4.4 [SD] years; range 27-84) were treated with cryoablation in 42 interventional sessions. Patient demographics, procedural data, complications, pain, and local tumour control were analysed retrospectively.

RESULTS

Thirty-one patients (36 spine metastases; 32 sessions) were treated for pain relief and 10 (10 metastases; 10 sessions) for local tumour control. Clinical success was reached in 30/32 (93.8%) interventional palliative sessions. Mean pre-procedural numerical pain rate scale was 6.2±1.7 (SD), and dropped significantly to 3.5±1.8 (SD), 1.9±1.7 (SD), and 1.9±1.8 (SD) at 24-h, 1-month and at the last available follow-up (median 16.5±23.2 [SD] months), respectively. For patients requiring local tumour control, primary clinical success was reached in 6/10 (60%) spinal metastases at median 25-months follow-up. The overall complication rate was 8%, with no secondary fractures or iatrogenic thermal-mediated nerve injuries reported.

CONCLUSION

Percutaneous image-guided cryoablation of spinal metastases is safe and effective in achieving pain relief and local tumour control.

Percutaneous management of bone metastases: state of the art

Interventional radiology is playing an increasingly important role in the local treatment of bone metastases; this treatment is usually done with palliative intent, although in selected patients it can be done with curative intent. Two main groups of techniques are available. The first group, centered on bone consolidation, includes osteoplasty / vertebroplasty, in which polymethyl methacrylate (PMMA) is injected to reinforce the bone and relieve pain, and percutaneous osteosynthesis, in which fractures with nondisplaced or minimally bone fragments are fixed in place with screws. The second group centers on tumor ablation. Tumor ablation refers to the destruction of tumor tissue by the instillation of alcohol or by other means. Thermoablation is the preferred technique in musculoskeletal tumors because it allows for greater control of ablation. Thermoablation can be done with radiofrequency, in which the application of a high frequency (450 Hz-600Hz) alternating wave to the tumor-bone interface achieves high temperatures, resulting in coagulative necrosis. Another thermoablation technique uses microwaves, applying electromagnetic waves in an approximate range of 900MHz to 2450MHz through an antenna that is placed directly in the core of the tumor, stimulating the movement of molecules to generate heat and thus resulting in coagulative necrosis. Cryoablation destroys tumor tissue by applying extreme cold. A more recent, noninvasive technique, magnetic resonance-guided focused ultrasound surgery (MRgFUS), focuses an ultrasound beam from a transducer placed on the patient's skin on the target lesion, where the waves' mechanical energy is converted into thermal energy (65°C-85°C). Treatment should be planned by a multidisciplinary team. Treatment can be done with curative or palliative intent. Once the patient is selected, a preprocedural workup should be done to determine the most appropriate technique based on a series of factors. During the procedure, protective measures must be taken and the patient must be closely monitored. After the procedure, patients must be followed up.

Percutaneous thermal ablation of sacral metastases: Assessment of pain relief and local tumor control

PURPOSE

To retrospectively report on safety, pain relief and local tumor control achieved with percutaneous ablation of sacral bone metastases.

MATERIALS AND METHODS

From February 2009 to June 2020, 23 consecutive patients (12 women and 11 men; mean age, 60±8 [SD] years; median, 60; range: 48-80 years) with 23 sacral metastases underwent radiofrequency (RFA) or cryo-ablation (CA), with palliative or curative intent at our institution. Patients' demographics and data pertaining to treated metastases, procedure-related variables, safety, and clinical evolution following ablation were collected and analyzed. Pain was assessed with numerical pain rating scale (NPRS).

RESULTS

Sixteen (70%) patients were treated with palliative and 7 (30%) with curative intent. Mean tumor diameter was 38±19 (SD) mm (median, 36; range: 11-76). External radiation therapy had been performed on five metastases (5/23; 22%) prior to ablation. RFA was used in 9 (39%) metastases and CA in the remaining 14 (61%). Thermo-protective measures and adjuvant bone consolidation were used whilst treating 20 (87%) and 8 (35%) metastases, respectively. Five (22%) minor complications were recorded. At mean 31±21 (SD) (median, 32; range: 2-70) months follow-up mean NPRS was 2±2 (SD) (median, 1; range: 0-6) vs. 5±1 (median, 5; range: 4-8; P<0.001) at the baseline. Three metastases out of 7 (43%) undergoing curative ablation showed local progression at mean 4±4 (SD) (median, 2; range: 1-8) months follow-up.

CONCLUSION

Percutaneous ablation of sacral metastases is safe and results in significant long-lasting pain relief. Local tumor control seems sub-optimal; however, further investigations are needed to confirm these findings due to paucity of data.

Musculoskeletal interventional oncology: current and future practices

Management of musculoskeletal (MSK) tumours has traditionally been delivered by surgeons and medical oncologists. However, in recent years, image-guided interventional oncology (IO) has significantly impacted the clinical management of MSK tumours. With the rapid evolution of relevant technologies and the expanding range of clinical indications, it is likely that the impact of IO will significantly grow and further evolve in the near future.

In this narrative review, we describe well-established and new interventional technologies that are currently integrating into the IO armamentarium available to radiologists to treat MSK tumours and illustrate new emerging IO indications for treatment.

Role of laser ablation in multimodal treatment of radioiodine- refractory bone metastases of thyroid cancer: a retrospective study

PURPOSE

To assess the efficacy, safety, and pain benefits of imaging-guided laser ablation (IGLA) in patients with radioiodine-refractory (RR) bone metastases from differentiated thyroid carcinoma (DTC).

PATIENTS AND METHODS

The institutional medical records of patients with bone metastases from DTC treated with laser ablation (LA) were reviewed retrospectively. Local response, complications, and effects on pain relief were investigated.

RESULTS

Six osteolytic lesions in five patients (one male, four females; mean age 65.4 ± 5.1 years, range 58-72) were treated with IGLA. All lesions were osteolytic and all have had previous treatments with high-dose radioiodine therapy followed by external radiotherapy (EBRT). All patients assumed opioid analgesics for severe pain. Overall, the lesions (mean size 5.8 ± 3.2 cm; median 5.0 cm, range 3.0-12.0 cm) underwent nine IGLA sessions (mean 1.8 ± 0.4 sessions; median 2.0 sessions, range 1-2). In four (80%) out five lesions, cross-sectional imaging showed a nearly complete response (CR) while the largest lesion was ablated by 80%. Pain changes were assessed with the Brief Pain Inventory-Short Form, that was administered before IGLA and during a 6-month follow-up. Patients experienced significant reduction in worst pain, average pain, and pain interference. Following IGLA, the average daily opioid requirement rapidly and progressively decreased. Treatments were well-tolerated and no major complications occurred.

CONCLUSIONS

IGLA is an effective and safe debulking procedure and provides significant pain relief in patients suffering from DTC bone metastases that are not responsive to standard treatments. So, IGLA could be considered as part of a multimodality management of advanced thyroid cancer with RR metastatic skeletal involvement.

French Multidisciplinary Approach for the Treatment of MSK Tumors

Several interventional treatments have recently been integrated into the therapeutic armamentarium available for the treatment of bone tumors. In some scenarios (e.g., osteoid osteoma), interventional treatments represent the sole and definitive applied treatment. Due to the absence of widely shared protocols and the complex multivariate scenarios underlying the clinical presentation of the remaining bone tumors including metastases, therapeutic strategies derived from a multidisciplinary tumor board are essential to provide effective treatments tailored to each patient. In the present review, we present the multidisciplinary therapeutic strategies commonly adopted for the most frequent bone tumors.

Spinal metastases treated with bipolar radiofrequency ablation with increased (>70°C) target temperature: Pain management and local tumor control

PURPOSE

To investigate the safety and clinical efficacy of bipolar radiofrequency ablation (b-RFA) with increased (>70°C) target temperature for the treatment of spine metastases with the intent of achieving pain relief or local tumor control.

MATERIALS AND METHODS

Thirty-one patients with a total of 37 metastases who were treated with b-RFA with increased temperature and vertebroplasty from January 2016 to May 2019 were retrospectively included. There were 20 women and 11 men with a mean age of 62.4±10.5 (SD) years (range: 40-78years). Patients and metastases characteristics, procedure details and clinical outcomes were analyzed.

RESULTS

Metastases were predominantly located in lumbar (22/37; 59.5%) or thoracic spine (13/37; 35.1%). Mean target temperature was 88.4±3.5 (SD) °C (range: 70-90°C). Technical success was 100% (37/37 metastases). One (1/37; 2.7%) major complication unrelated to b-RFA was reported. One (1/37; 2.7%) metastasis was lost to follow-up. Favorable outcome was noted in patients receiving b-RFA for pain management (16/20 metastases; 80%; mean follow-up, 3.4±2.9 [SD] months) or with oligometastatic/oligoprogressive disease (6/6 metastases; 100%; mean follow-up, 5.0±4.6 [SD] months). In patients receiving b-RFA to prevent complications, favorable outcome was noted in 6/10 metastases (60%; mean follow-up, 3.8±4.8 [SD] months).

CONCLUSIONS

B-RFA with increased target temperature has an excellent safety profile and results in high rates of pain relief and local metastasis control in patients with oligometastatic/oligoprogressive disease. Suboptimal results are achieved in patients receiving b-RFA to prevent complications related to the growth of the index tumor.

Bone metastases in thyroid cancer

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Osseous metastases (OMs) occur in only 4% of all thyroid cancer patients but are associated with greatly increased morbidity and mortality.

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OMs are about twice as frequent in follicular, hurthle cell, and medullary thyroid cancers as compared to papillary thyroid cancers.

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OMs are often lytic, triggered via activation of osteoclasts by tumor cells in a “vicious cycle”.

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OMs are often initially asymptomatic, but associated with eventual skeletal related events in >75%.

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Early identification of OMs, preemptive treatment with antiresorptive agents, and aggressive treatment of focal lesions before crisis are key.

Whereas preemptive screening for the presence of lymph node and lung metastases is standard-of-care in thyroid cancer patients, bone metastases are less well studied and are often neglected in thyroid cancer patient surveillance. Bone metastases in thyroid cancer are, however, independently associated with poor/worse prognosis with a median overall survival from detection of only 4 years despite an otherwise excellent prognosis for the vast majority of thyroid cancer patients. In this review we summarize the state of current knowledge as pertinent to bony metastatic disease in thyroid cancer, including clinical implications, impacts on patient function and quality of life, pathogenesis, and therapeutic opportunities, proposing approaches to patient care accordingly. In particular, bone metastasis pathogenesis appears to reflect cooperatively between cancer and the bone microenvironment creating a “vicious cycle” of bone destruction rather than due exclusively to tumor invasion into bone. Additionally, bone metastases are more frequent in follicular and medullary thyroid cancers, requiring closer bone surveillance in patients with these histologies. Emerging data also suggest that treatments such as multikinase inhibitors (MKIs) can be less effective in controlling bone, as opposed to other (e.g. lung), metastases in thyroid cancers, making special attention to bone critical even in the setting of active MKI therapy. Although locoregional therapies including surgery, radiotherapy and ablation play important roles in palliation, antiresorptive agents including bisphosphonates and denosumab appear individually to delay and/or lessen skeletal morbidity and complications, with dosing frequency of every 3 months appearing optimal; their early application should therefore be strongly considered.

Management of metastatic vertebral lesions by interventional techniques: Systematic review of outcomes

Vertebral metastases represent an important cause of cancer-related morbidity and mortality. Among all available treatments, interventional percutaneous techniques have recently emerged as potential strategies for the management of oncologic patients with vertebral lesions. Minimally invasive image-guided therapies include “ablative” and “consolidative” ones. According to the number of metastases and the patient's performance status, ablative techniques can be performed with a curative or a palliative purpose since necrosis induced by critic changes of intralesional temperature determines both tumor debulking and destruction of pain receptors. On the other hand, consolidative treatments are based on the injection of polymethylmethacrylate cement to improve structural vertebral integrity and obtain pain alleviation and prevention of skeletal-related events. This article reviews the current recommendations supporting the role of interventional radiology in the management of vertebral metastases, focusing on the last updates in literature.

Radiofrequency Coblation-Assisted Resection of Skull Base Neoplasms Using an Endoscopic Endonasal Approach

OBJECTIVES

We describe our early experiences with resecting skull base tumors using a radiofrequency ablation-assisted endoscopic endonasal approach. Ninety-seven patients with skull base tumors who were admitted to the Otorhinolaryngology department at Shanghai Jiaotong University Affiliated Shanghai Sixth People's Hospital between January 2014 and December 2016 were operated on using a radiofrequency ablation-assisted endoscopic endonasal approach. Complete resection was achieved in all patients. This paper describes the operative technique and presents the degree of resection, complications, and early clinical outcomes.

METHODS

We investigated the safety and feasibility of the technique and assessed preliminary treatment outcomes.

RESULTS

No patients experienced a new neurological deficit, cerebrospinal fluid leak, or meningitis after surgery. No deaths related to skull base tumors were observed during the follow-up period (14-50 months). The volume of intraoperative blood loss was 100-1,200 mL (median 350 mL), the duration of operation was 40-510 min (median 180 min), and the hospital stay was 6-65 days (median 18).

CONCLUSIONS

Our limited experience indicates that this technique is feasible and safe for complete resection of some skull base tumors in selected cases and in the future will have an increasing role to play in endoscopic sinonasal and skull base tumor dissection.

Bone Metastases in Neuroendocrine Neoplasms: From Pathogenesis to Clinical Management

Bone represents a common site of metastases for several solid tumors. However, the ability of neuroendocrine neoplasms (NENs) to localize to bone has always been considered a rare and late event. Thanks to the improvement of therapeutic options, which results in longer survival, and of imaging techniques, particularly after the introduction of positron emission tomography (PET) with gallium peptides, the diagnosis of bone metastases (BMs) in NENs is increasing. The onset of BMs can be associated with severe skeletal complications that impair the patient’s quality of life. Moreover, BMs negatively affect the prognosis of NEN patients, bringing out the lack of curative treatment options for advanced NENs. The current knowledge on BMs in gastro-entero-pancreatic (GEP) and bronchopulmonary (BP) NENs is still scant and is derived from a few retrospective studies and case reports. This review aims to perform a critical analysis of the evidence regarding the role of BMs in GEP- and BP-NENs, focusing on the molecular mechanisms underlining the development of BMs, as well as clinical presentation, diagnosis, and treatment of BMs, in an attempt to provide suggestions that can be used in clinical practice.

Thermal-ablation of vertebral metastases prevents adverse events in patients with differentiated thyroid carcinoma

PURPOSE

To evaluate a strategy that used thermal-ablation of vertebral metastases (VM) to prevent vertebral related events (VRE) in patients with differentiated thyroid cancer (DTC).

METHODS

This single center study retrospectively reviewed records and post-operative imaging of all DTC patients treated with thermal-ablation for asymptomatic VMs. Rate of local tumor control at first post-operative imaging, 12 and 24 months after thermal-ablation and rate of VREs at 12 and 24 months among the treated VMs were reported. New VMs that occurred during the follow-up and were not considered for additional thermal-ablation were moniroted and VREs were reported.

RESULTS

Thermal-ablation was used to achieve local control of 41 VMs in 28 patients. Median post-treatment follow-up was 22 months [range: 12-80] and the mean delay for first post-operative imaging was 2 months [range: 0.6-7.5]. Local control at first post-operative imaging, 12 and 24 months was achieved in 87.8%, 82.9% and 75.6%, respectively. Among the treated VMs the rates of VRE was 7.3% at 2 years, significantly lower if local control was achieved at first post-operative imaging than if it was not (0% vs 30%, p = 0.011, OR = 0.184 [95%CI = 0.094-0.360]). After thermal-ablation procedures, 19 news VMs occurred in 11 patients (39.2%) with a median interval of 8 months [range 1-26] and remained untreated. Among these untreated VMs, the rate of VREs at 2 years was significantly higher compared to the treated VMs: (36.8% vs. 7.3%, p = 0.008, OR = 0.135, [95%CI = 0.030-0.607]).

CONCLUSION

local tumor control of VMs using thermal-ablation decreases the risk of VREs in DTC patients.

Percutaneous image-guided ablation: From techniques to treatments

Image-guided ablation is performed by percutaneously introducing ablation probes to deliver energy into a tumor to destroy it in a controlled and localized fashion. Ablation modalities can be broadly classified as thermal or non-thermal based on the mechanism of tumor destruction and are performed using different types of image guidance for planning, delivering and follow-up of the treatment. Ablation is performed in a minimally invasive fashion, providing greater residual organ preservation with minimal morbidity to the patient. Image-guided ablation is being used in the clinic for the treatment of primary and metastatic tumors, and this article reviews state of the art for the treatment of malignancies in the liver, lung, kidney and musculoskeletal tissue.

Local ablative therapy of oligoprogressive TKI-treated thyroid cancer

Metastatic cancer patients generally respond well to treatment with tyrosine kinase inhibitors (TKIs). However, TKI resistance occurs in almost all cases and often leads to a change in treatment. Recent guidelines, including thyroid cancer, raised the possibility of locally treating TKI-resistant oligoprogressive disease, i.e., one or a few progressing lesions in an otherwise treatment-responsive metastatic cancer, thereby obviating the need to change the ongoing TKI. To determine the benefits of this intervention, we reviewed studies on the use of LAT for TKI-treated oligoprogressive cancers. We found that in non-small cell lung cancer at least, LAT prolongs disease control and the duration of exposure to a TKI irrespective of the LAT used. Moreover, we reviewed the local ablative therapies (LATs) that are feasible for the local control of oligoprogressive thyroid cancer. Lastly, we report two illustrative cases of patients with oligoprogressive thyroid cancer treated with two different LATs while on therapy with TKIs. Both LATs extended the duration of disease control and the time of exposure to the ongoing TKI, thereby indicating that LAT is a favorable option for TKI-treated oligoprogressive thyroid cancer. Prospective randomized studies are needed to verify the benefit of LATs in terms of progression-free and overall survival in this increasingly frequent clinical setting.

Basic Knowledge in Soft Tissue Sarcoma

Sarcoma is rare and heterogenous with various subtypes having a different prognostic. Desmoid is a tumour with a local aggressiveness; GIST with KIT mutation responds massively to target treatment as IMATINIB, whereas soft tissue sarcoma and leiomyosarcoma are very aggressive with poor response to systemic therapies. Interventional radiology plays an important role in the diagnosis of sarcomas with image-guided percutaneous core needle biopsy being the most commonly used biopsy technique in the diagnosis of sarcomas. Biopsy access routes discussed with the surgeon, and skin access is tattooed. Surgery is a mainstay of sarcoma treatment; the resection can be large. Indeed, resection objective is R0 because quality of surgical margins impacts local control and survival. Radiotherapy is possible in neoadjuvant or in adjuvant treatment to improve local control rate. Recently radiotherapy enhancer injected percutaneously in soft tissue sarcoma has proven benefit in increasing the rate of R0 complete surgical resection. Several studies showed better local control rate linked with post-operative radiotherapy. In patients affected by oligometastatic disease, complete surgical resection of all metastatic sites is in fact considered the primary treatment because complete remission is critical for cure. The decision making to use local therapies is complex, depends upon diverse presentations and histologies, and should always be taken in a multidisciplinary discussion. Today, percutaneous image-guided treatments with ablation technologies (radiofrequency ablation, cryotherapy, microwaves ablation) provide high rate of durable local control for small-sized malignant deposit in many organs including lung, liver and bones. Sarcoma must be managed by multimodality treatment in expert reference centres. Such management has a considerable impact on the prognosis.

Percutaneous Microwave Ablation and Cementoplasty: Clinical Utility in the Treatment of Painful Extraspinal Osseous Metastatic Disease and Myeloma

OBJECTIVE. The purpose of this study was to review the efficacy and durability of pain control and local tumor control using microwave ablation and cementoplasty in treating extraspinal osseous tumors. Painful osseous metastases are a common cause of cancer-related morbidity. Percutaneous thermal ablation presents an attractive minimally invasive option in this vulnerable patient group. MATERIALS AND METHODS. A retrospective review included 65 patients (35 men, 30 women) with 77 tumors who underwent image-guided microwave ablation and cementoplasty at a tertiary referral academic center over 18 months. Procedural efficacy was determined with a visual analog scale before the procedure and 24 hours, 2-4 weeks, and 20-24 weeks after the procedure. Locoregional control was assessed at follow-up cross-sectional imaging. RESULTS. The 77 tumors were in the following locations: ilium, 38; acetabulum on supraacetabular region, 23; femur, five; humerus, four; shoulder, four; sternum, three. The tumors were 15 multiple myelomas and metastases from cancers of the following organs: colon, nine; lung, 15; breast, 12; thyroid, seven; prostate, three; and kidney, four. Complete, successful ablation of all 77 tumors was achieved. Mean ablation time was 6 minutes 15 seconds (SD, 12 seconds), and mean energy used was 5.49 (SD, 2.97) kJ. The mean visual analog scale scores were 6.32 (SD, 1.94) before the procedure, 1.01 (SD, 1.24) at 24 hours, 1.71 (SD, 1.31) at 2-4 weeks, and 2.01 (SD, 1.42) at 20-24 weeks. Follow-up imaging at 20-24 weeks showed no local progression in 42 of 65 patients (64.6%). Six patients died 24-52 weeks after the procedure. No procedure-related complications were reported. CONCLUSION. Microwave ablation is efficacious in alleviating pain due to osseous metastases. The modality has promise for locoregional control of metastases, particularly in the context of oligometastatic (limited disseminated) disease.