Increasing Role of Image-Guided Ablation in the Treatment of Musculoskeletal Tumors

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.

Combined thermal ablation and liposomal granulocyte-macrophage colony stimulation factor increases immune cell trafficking in a small animal tumor model

PURPOSE

To characterize intratumoral immune cell trafficking in ablated and synchronous tumors following combined radiofrequency ablation (RFA) and systemic liposomal granulocyte-macrophage colony stimulation factor (lip-GM-CSF).

METHODS

Phase I, 72 rats with single subcutaneous R3230 adenocarcinoma were randomized to 6 groups: a) sham; b&c) free or liposomal GM-CSF alone; d) RFA alone; or e&f) combined with blank liposomes or lip-GM-CSF. Animals were sacrificed 3 and 7 days post-RFA. Outcomes included immunohistochemistry of dendritic cells (DCs), M1 and M2 macrophages, T-helper cells (Th1) (CD4+), cytotoxic T- lymphocytes (CTL) (CD8+), T-regulator cells (T-reg) (FoxP3+) and Fas Ligand activated CTLs (Fas-L+) in the periablational rim and untreated index tumor. M1/M2, CD4+/CD8+ and CD8+/FoxP3+ ratios were calculated. Phase II, 40 rats with double tumors were randomized to 4 groups: a) sham, b) RFA, c) RFA-BL and d) RFA-lip-GM-CSF. Synchronous untreated tumors collected at 7d were analyzed similarly.

RESULTS

RFA-lip-GMCSF increased periablational M1, CTL and CD8+/FoxP3+ ratio at 3 and 7d, and activated CTLs 7d post-RFA (p<0.05). RFA-lip-GMSCF also increased M2, T-reg, and reduced CD4+/CD8+ 3 and 7d post-RFA respectively (p<0.05). In untreated index tumor, RFA-lip-GMCSF improved DCs, M1, CTLs and activated CTL 7d post-RFA (p<0.05). Furthermore, RFA-lip-GMSCF increased M2 at 3 and 7d, and T-reg 7d post-RFA (p<0.05). In synchronous tumors, RFA-BL and RFA-lip-GM-CSF improved DC, Th1 and CTL infiltration 7d post-RFA.

CONCLUSION

Systemic liposomal GM-CSF combined with RFA improves intratumoral immune cell trafficking, specifically populations initiating (DC, M1) and executing (CTL, FasL+) anti-tumor immunity. Moreover, liposomes influence synchronous untreated metastases increasing Th1, CTL and DCs infiltration.

Myofibroblasts: A key promoter of tumorigenesis following radiofrequency tumor ablation

Radiofrequency ablation (RFA) of intrahepatic tumors induces distant tumor growth through activation of interleukin 6/signal transducer and activator of transcription 3 (STAT3)/hepatocyte growth factor (HGF)/tyrosine-protein kinase Met (c-MET) pathway. Yet, the predominant cellular source still needs to be identified as specific roles of the many types of periablational infiltrating immune cells requires further clarification. Here we report the key role of activated myofibroblasts in RFA-induced tumorigenesis and successful pharmacologic blockade. Murine models simulating RF tumorigenic effects on a macrometastatic tumor and intrahepatic micrometastatic deposits after liver ablation and a macrometastatic tumor after kidney ablation were used. Immune assays of ablated normal parenchyma demonstrated significantly increased numbers of activated myofibroblasts in the periablational rim, as well as increased HGF levels, recruitment other cellular infiltrates; macrophages, dendritic cells and natural killer cells, HGF dependent growth factors; fibroblast growth factor-19 (FGF-19) and receptor of Vascular Endothelial Growth Factor-1 (VEGFR-1), and proliferative indices; Ki-67 and CD34 for microvascular density. Furthermore, macrometastatic models demonstrated accelerated distant tumor growth at 7d post-RFA while micrometastatic models demonstrated increased intrahepatic deposit size and number at 14 and 21 days post-RFA. Multi-day atorvastatin, a selective fibroblast inhibitor, inhibited RFA-induced HGF and downstream growth factors, cellular markers and proliferative indices. Specifically, atorvastatin treatment reduced cellular and proliferative indices to baseline levels in the micrometastatic models, however only partially in macrometastatic models. Furthermore, adjuvant atorvastatin completely inhibited accelerated growth of macrometastasis and negated increased micrometastatic intrahepatic burden. Thus, activated myofibroblasts drive RF-induced tumorigenesis at a cellular level via induction of the HGF/c-MET/STAT3 axis, and can be successfully pharmacologically suppressed.

Body Interventional MRI for Diagnostic and Interventional Radiologists: Current Practice and Future Prospects

Clinical use of MRI for guidance during interventional procedures emerged shortly after the introduction of clinical diagnostic MRI in the late 1980s. However, early applications of interventional MRI (iMRI) were limited owing to the lack of dedicated iMRI magnets, pulse sequences, and equipment. During the 3 decades that followed, technologic advancements in iMRI magnets that balance bore access and field strength, combined with the development of rapid MRI pulse sequences, surface coils, and commercially available MR-conditional devices, led to the rapid expansion of clinical iMRI applications, particularly in the field of body iMRI. iMRI offers several advantages, including superior soft-tissue resolution, ease of multiplanar imaging, lack of ionizing radiation, and capability to re-image the same section. Disadvantages include longer examination times, lack of MR-conditional equipment, less operator familiarity, and increased cost. Nonetheless, MRI guidance is particularly advantageous when the disease is best visualized with MRI and/or when superior soft-tissue contrast is needed for treatment monitoring. Safety in the iMRI environment is paramount and requires close collaboration among interventional radiologists, MR physicists, and all other iMRI team members. The implementation of risk-limiting measures for personnel and equipment in MR zones III and IV is key. Various commercially available MR-conditional needles, wires, and biopsy and ablation devices are now available throughout the world, depending on the local regulatory status. As such, there has been tremendous growth in the clinical applications of body iMRI, including localization of difficult lesions, biopsy, sclerotherapy, and cryoablation and thermal ablation of malignant and nonmalignant soft-tissue neoplasms. Online supplemental material is available for this article. ^©RSNA, 2021.

Minimally Invasive Image-Guided Ablation, Osteoplasty, Reinforcement, and Internal Fixation (AORIF) for Osteolytic Lesions in the Pelvis and Periarticular Regions of Weight-Bearing Bones

PURPOSE

To assess early outcome, safety, and complications of an alternative to open surgical treatments of osteolytic lesions in periarticular load-bearing bones.

MATERIALS AND METHODS

A single-center, prospective clinical cohort study of 26 lesions in 23 consecutive patients with painful osteolytic skeletal lesions was performed. Patients were followed for an average of 7 mo (1-18 mo). Lesions were targeted from the most intact bone via minimally invasive percutaneous approach for stable anchorage of internal fixation screws using fluoroscopic guidance. Cannulated screws served as universal portals for ablation, balloon osteoplasty, and delivery of bone cement in addition to internal fixation for cement anchoring and prophylactic stabilization of uninvolved bone.

RESULTS

There were 19 osteolytic lesions in the pelvis, 4 in the proximal femur, 2 in the proximal tibia, and 1 in the calcaneus. All defects were associated with severe pain or fractures. There were no conversions to open surgery and no infection or bleeding requiring transfusion, embolization, or additional procedures. There was significant improvement in visual analogue scale (VAS) pain score from 8.32 ± 1.70 to 2.36 ± 2.23, combined pain and functional ambulation score from 4.48 ± 2.84 to 7.28 ± 2.76, and Musculoskeletal Tumor Society score from 45% to 68% (P < .05).

CONCLUSIONS

Ablation, osteoplasty, reinforcement, and internal fixation is a safe and effective minimally invasive percutaneous image-guided treatment option for functional improvement or palliation of painful osteolytic lesions in the pelvis and periarticular loadbearing bones.

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.

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.

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.

Efficacy and Safety of Percutaneous Microwave Ablation and Cementoplasty in the Treatment of Painful Spinal Metastases and Myeloma

BACKGROUND AND PURPOSE

Painful spinal metastases are a common cause of cancer-related morbidity. Percutaneous ablation presents an attractive minimally invasive alternative to conventional therapies. We performed a retrospective review of 69 patients with 102 painful spinal metastases undergoing microwave ablation and cementoplasty to determine the efficacy and safety of this treatment.

MATERIALS AND METHODS

Procedures were performed between January 2015 and October 2016 with the patient under general anesthesia using image guidance for 102 spinal metastases in 69 patients in the following areas: cervical (n = 2), thoracic (n = 50), lumbar (n = 34), and sacral (n = 16) spine. Tumor pathologies included the following: multiple myeloma (n = 10), breast (n = 27), lung (n = 12), thyroid (n = 6), prostate (n = 5), colon (n = 4), renal cell (n = 3), oral squamous cell (n = 1), and adenocarcinoma of unknown origin (n = 1). Procedural efficacy was determined using the visual analog scale measured preprocedurally and at 2-4 weeks and 20-24 weeks postprocedure. Tumor locoregional control was assessed on follow-up cross-sectional imaging. Procedural complications were recorded to establish the safety profile.

RESULTS

The median ablation time was 4 minutes 30 seconds ± 7 seconds, and energy dose, 4.1 ± 1.6 kJ. Median visual analog scale scores were the following: 7.0 ± 1.8 preprocedurally, 2 ± 1.6 at 2-4 weeks, and 2 ± 2.1 at 20-24 weeks. Eight patients died within 6 months following the procedure. Follow-up imaging in the surviving patients at 20-24 weeks demonstrated no locoregional progression in 59/61 patients. Two complications were documented (S1 nerve thermal injury and skin burn).

CONCLUSIONS

Microwave ablation is an effective and safe treatment technique for painful spinal metastases. Further studies may be helpful in determining the role of microwave ablation in locoregional control of metastases.

Image-Guided Thermal Ablative Therapies in the Treatment of Sarcoma

OPINION STATEMENT

Percutaneous thermal ablation, including microwave ablation (MWA), radiofrequency ablation (RFA), and cryoablation, is a well-established focal treatment option for primary and metastatic malignancies. While published literature specific to ablation of sarcomas is relatively lacking compared with non-sarcomatous malignancies, what is available is promising. In situations where a focal treatment option is desired, strong consideration should be given to percutaneous thermal ablation, in addition to surgery and radiation therapy. A significant advantage of percutaneous thermal ablation over surgery and radiation includes the repeatability of ablation, as there is no absolute limit on the number of times an ablation can be performed. Compared with surgery, ablation offers the potential of decreased recovery time, a less invasive procedure, and is often performed in patients deemed not medically fit for surgery.