Radiofrequency thermal ablation of abdominal tumors: lessons learned from complications

On-demand reprogramming of immunosuppressive microenvironment in tumor tissue via multi-regulation of carcinogenic microRNAs and RNAs dependent photothermal-immunotherapy using engineered gold nanoparticles for malignant tumor treatment

The frequent immune escape of tumor cells and fluctuating therapeutic efficiency vary with each individual are two critical issues for immunotherapy against malignant tumor. Herein, we fabricated an intelligent core-shell nanoparticle (SNAs@CCMR) to significantly inhibit the PD-1/PD-L1 mediated immune escape by on-demand regulation of various oncogenic microRNAs and perform RNAs dependent photothermal-immunotherapy to achieve precise and efficient treatment meeting the individual requirements of specific patients by in situ generation of customized tumor-associated antigens. The SNAs@CCMR consisted of antisense oligonucleotides grafted gold nanoparticles (SNAs) as core and TLR7 agonist imiquimod (R837) functionalized cancer cell membrane (CCM) as shell, in which the acid-labile Schiff base bond was used to connect the R837 and CCM. During therapy, the acid environment of tumor tissue cleaved the Schiff base to generate free R837 and SNAs@CCM. The SNAs@CCM further entered tumor cells via CCM mediated internalization, and then specifically hybridized with over-expressed miR-130a and miR-21, resulting in effective inhibition of the migration and PD-L1 expression of tumor cells to avoid their immune escape. Meanwhile, the RNAs capture also caused significant aggregation of SNAs, which immediately generated photothermal agents within tumor cells to perform highly selective photothermal therapy under NIR irradiation. These chain processes not only damaged the primary tumor, but also produced plenty of tumor-associated antigens, which matured the surrounding dendritic cells (DCs) and activated anti-tumor T cells along with the released R837, resulting in the enhanced immunotherapy with suppressive immune escape. Both in vivo and in vitro experiments demonstrated that our nanoparticles were able to inhibit primary tumor and its metastasis via multi-regulation of carcinogenic microRNAs and RNAs dependent photothermal-immune activations, which provided a promising strategy to reprogram the immunosuppressive microenvironment in tumor tissue for better malignant tumor therapy.

Radiofrequency ablation versus stereotactic body radiotherapy for recurrent hepatocellular carcinoma: a multicenter, propensity score matching analysis

PURPOSE

This study aimed at analyzing and comparing the clinical efficacy and prognosis of stereotactic body radiotherapy (SBRT) and radiofrequency ablation (RFA) in the treatment of recurrent hepatocellular carcinoma (RHCC).

METHODS

Clinicopathological data of RHCC patients who underwent RFA or SBRT as treatment from three medical centers were retrospectively reviewed. The survival outcomes of patients who underwent SBRT were compared with those who underwent RFA. Using the Kaplan-Meier method, survival curves for the two groups of patients were generated, and the log-rank test was used to compare survival differences. Propensity score matching (PSM) analysis was used to match patients of the SBRT and RFA groups in a 1:1 ratio.

RESULTS

The SBRT group had a significantly better overall survival (OS) than the RFA group and no statistical differences were found in disease-free survival (DFS) in the two groups before and after PSM. After PSM, subgroup analysis demonstrated that, compared with the RFA group, the SBRT group had a significantly better OS in terms of tumor location in the subphrenic or subcapsular area, tumor size > 2.5 cm, and tumor proximity to major vessels ≤ 1 cm.

CONCLUSIONS

SBRT appears to be an effective priority to RFA for RHCC patients especially when RFA is not feasible due to tumor location, size, and proximity to major vessels.

Repeat laparoscopic hepatectomy versus radiofrequency ablation for recurrent hepatocellular carcinoma: A multicenter, propensity score matching analysis

This study aimed at analyzing and comparing the clinical efficacy and prognosis of repeat laparoscopic hepatectomy (r-LH) and radiofrequency ablation (RFA) in treating recurrent hepatocellular carcinoma (RHCC). Clinicopathological data of RHCC patients who underwent r-LH or RFA as treatment from three medical centers were retrospectively reviewed. Baseline characteristics at the recurrence time after initial hepatectomy and clinical outcomes following treatment of RHCC were compared between the two groups. Using the Kaplan-Meier method, survival curves for the two groups of patients were generated, and the log-rank test was used to compare survival differences. Propensity score matching (PSM) analysis was used to match patients of the r-LH and RFA groups in a 1:1 ratio. A total of 272 patients were enrolled, including 133 patients who underwent r-LH and 139 patients who received RFA. After PSM, 76 patients were matched in each study group. Compared with the r-LH group, the RFA group had shorter hospitalization and fewer postoperative complications. However, the r-LH group had significantly better overall survival (OS) and disease-free survival (DFS) than the RFA group before and after PSM. Subgroup analysis demonstrated that RHCC patients with solitary tumor or those with tumors located near the diaphragm, visceral surface or vessels, had survival benefits from r-LH. When tumor diameter ≤ 5 cm, r-LH appears to be an effective priority to RFA with a significantly higher OS and DFS rate in treating RHCC patients, especially for patients with solitary tumor and those with tumors located near the diaphragm, visceral surface or vessels.

Clinical outcomes after 2-year follow-up of transvaginal radiofrequency ablation of symptomatic uterine fibroids

AIM

The aim of this study was to evaluate the efficacy after 2 years follow-up of transvaginal radiofrequency ablation (TVRA) to treat myomas, and to identify factors predictive of the response to the treatment.

METHODS

This is a prospective cohort study of a 2-year follow-up of 65 patients who underwent TVRA for the treatment uterine fibroids at Virgen de las Nieves University Hospital in Granada, Spain. Ultrasound mean fibroid volume, symptom severity scale, total bleeding days, complications, pregnancy outcomes were recorded.

RESULTS

Statistically significant improvements in symptoms and bleeding were observed at 6, 12, and 24 months after the procedure. The mean myoma volume (cc) was significantly lower (p < 0.05) at 12 and 24 months, with a mean reduction in myoma volume of more than 80% and 60%, respectively. After a 24-month follow-up, 5 patients (7.7%) required additional surgical treatment to control symptoms. Patient age (>40 years), initial myoma size, and the timing of radiofrequency were identified as factors related to outcomes in the bivariate analysis.

CONCLUSIONS

Transvaginal radiofrequency ablation is an effective and safe technique for the treatment of myomas after 2 years of follow-up, which improves the symptoms of the patients and decreases the final volume of the myoma.

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

Gastrointestinal tract perforation after radiofrequency ablation for hepatic tumor: Incidence and risk factors

OBJECTIVE

We analyzed the incidence and mortality rate of gastrointestinal (GI) tract perforation after radiofrequency ablation (RFA) for hepatic tumors and assess its risk factors.

METHODS

This retrospective cohort study included 4799 patients with malignant tumors who underwent RFA (n = 7206). Sixty-nine cases of thermal injury to the GI tract were identified via a search of the electronic medical record system using index terms and divided into two groups according to the thermal injury with (n = 8) or without (n = 61) GI tract perforation based on follow-up CT reports. The risk factors for GI tract perforation were identified via multivariable logistic regression analysis using clinical, technical, and follow-up CT findings.

RESULTS

The incidence of thermal injury to the GI tract and GI tract perforation was 0.96 % (69/7206) and 0.11 % (8/7206), respectively. The type of adjacent GI tract and history of diabetes mellitus differed significantly between the two groups (p < 0.05). The index tumor being located around the small intestine was the only significant risk factor for GI tract perforation after ablation (Odds ratio, 22.69; 95 % confidence interval, 2.59-198.34; p = 0.005 [reference standard, stomach]). All perforations were not identified on CT images immediately after RFA. The median time to detection was 20 days (range, 3-41 days). Two patients (25 %, 2/8) died due to perforation-related complications.

CONCLUSION

GI tract perforation after RFA for hepatic tumors is rare; however, it is associated with high mortality. Thus, careful follow-up is required after RFA if the index tumor is located around the small intestine.

Diaphragmatic Liver Herniation after Radiofrequency Ablation of a Secondary Liver Tumor

Radiofrequency thermal ablation (RFA) is widely used and has been accepted for the treatment of unresectable tumors. The leading technique that is used is percutaneous RFA under CT or US guidance. Multicenter surveys report acceptable morbidity and mortality rates for RFA. The mortality rate ranges from 0.1% to 0.5%, the major complication rate ranges from 2% to 3%. Diaphragmatic injury is a rare complication and it is described after RFA of subdiaphragmatic tumors. Most of them are without clinical importance. There are some case reports about diaphragmatic herniation of the intestine into the pleural cavity. We present a case of diaphragmatic perforation resulting in the herniation of the liver into the pleural cavity. A thoracotomy was performed, the liver was lowered back into the peritoneal cavity and the perforation was closed with mesh.

Complications of transvaginal radiofrequency ablation of fibroids: A 5-year experience

Introduction

Transvaginal radiofrequency ablation is a relatively noninvasive approach for the treatment of fibroids in patients who do not wish to undergo conventional surgery. Information on potential complications of this novel technique is very scarce.

Methods

Retrospective, descriptive, epidemiological study of 115 patients who underwent transvaginal radiofrequency ablation of fibroids and for whom complications were recorded.

Results

We performed 115 transvaginal radiofrequency ablation procedures, we recorded a total of 11 complications (9.6%; 95% CI, 3.8-14.8). Of these, 8 (7.0%) were classified as Clavien-Dindo type I, 1 (0.9%,) as type II, and 2 (1.7%) as type IIIb (severe). No other complications were recorded in a year follow-up.

Conclusion

Transvaginal radiofrequency ablation is a treatment option that makes it possible to treat fibroids that are difficult to manage using other techniques. Few associated complications have been described, and most of them are mild.

An Unexpected Complication Resulting from Radiofrequency Ablation for Treating Facet Joint Syndrome: A Case Report

Lumbar facet joints have been identified as a potential source of chronic low back pain (LBP) in 15% to 45% of patients, with the prevalence of such pain varying based on specific populations and settings examined. Lumbar facet joint interventions are useful in the diagnosis as well as the therapeutic management of chronic LBP. Radiofrequency ablation (RFA) of medial branch nerves is recognized as a safe and effective therapy for chronic facet joint pain in the lumbosacral spine, and its efficacy has already been established. The use of RFA is currently widespread in the management of spinal pain, but it is noteworthy that there have been works in the literature reporting complications, albeit at a very low frequency. We present a case of third-degree skin burns following radiofrequency ablation (RFA) for the management of facet joint syndrome. Postoperatively, the patient's skin encircling the needle displayed a pallor and exhibited deterioration in conjunction with the anatomical anomaly. The affected area required approximately 5 months to heal completely. During RFA, heat can induce burns not only at the point of contact with the RF electrode but also along the length of the needle. Vigilant attention is necessary to ensure patient safety and to address any potential complications that may arise during the procedure, including the possibility of minor technical errors.

Magnetically Enhanced Intracellular Uptake of Superparamagnetic Iron Oxide Nanoparticles for Antitumor Therapy

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely employed in biomedical fields, including targeted delivery of antitumor therapy. Conventional magnetic tumor targeting has used simple static magnetic fields (SMFs), which cause SPIONs to linearly aggregate into a long chain-like shape. Such agglomeration greatly hinders the intracellular targeting of SPIONs into tumors, thus reducing the therapeutic efficacy. In this study, we investigated the enhancement of the intracellular uptake of SPIONs through the application of rotating magnetic fields (RMFs). Based on the physical principles of SPION chain disassembly, we investigated physical parameters to predict the chain length favorable for intracellular uptake. Our prediction was validated by clear visualization of the intracellular distributions of SPIONs in tumor cells at both cellular and three-dimensional microtissue levels. To identify the potential therapeutic effects of enhanced intracellular uptake, magnetic hyperthermia as antitumor therapy was investigated under varying conditions of magnetic hyperthermia and RMFs. The results showed that enhanced intracellular uptake reduced magnetic hyperthermia time and strength as well as particle concentration. The proposed method will be useful in the development of techniques to determine the optimized physical conditions for the enhanced intracellular uptake of SPIONs in antitumor therapy.

Phase-transition nanodroplets with immunomodulatory capabilities for potentiating mild magnetic hyperthermia to inhibit tumour proliferation and metastasis

BACKGROUND

Magnetic hyperthermia (MHT)-mediated thermal ablation therapy has promising clinical applications in destroying primary tumours. However, traditional MHT still presents the challenges of damage to normal tissues adjacent to the treatment site and the destruction of tumour-associated antigens due to its high onset temperature (> 50 °C). In addition, local thermal ablation of tumours often exhibits limited therapeutic inhibition of tumour metastasis.

RESULTS

To address the above defects, a hybrid nanosystem (SPIOs + RPPs) was constructed in which phase transition nanodroplets with immunomodulatory capabilities were used to potentiate supermagnetic iron oxide nanoparticle (SPIO)-mediated mild MHT (< 44 °C) and further inhibit tumour proliferation and metastasis. Magnetic-thermal sensitive phase-transition nanodroplets (RPPs) were fabricated from the immune adjuvant resiquimod (R848) and the phase transition agent perfluoropentane (PFP) encapsulated in a PLGA shell. Because of the cavitation effect of microbubbles produced by RPPs, the temperature threshold of MHT could be lowered from 50℃ to approximately 44℃ with a comparable effect, enhancing the release and exposure of damage-associated molecular patterns (DAMPs). The exposure of calreticulin (CRT) on the cell membrane increased by 72.39%, and the released high-mobility group B1 (HMGB1) increased by 45.84% in vivo. Moreover, the maturation rate of dendritic cells (DCs) increased from 4.17 to 61.33%, and the infiltration of cytotoxic T lymphocytes (CTLs) increased from 10.44 to 35.68%. Under the dual action of mild MHT and immune stimulation, contralateral and lung metastasis could be significantly inhibited after treatment with the hybrid nanosystem.

CONCLUSION

Our work provides a novel strategy for enhanced mild magnetic hyperthermia immunotherapy and ultrasound imaging with great clinical translation potential.

Comparison of Ablation Performance between Octopus Multipurpose Electrode and Conventional Octopus Electrode

OBJECTIVE

To compare Octopus multipurpose (MP) electrodes, which are capable of saline instillation and direct tissue temperature measurement, and conventional electrodes for radiofrequency ablation (RFA) in porcine livers in vivo.

MATERIALS AND METHODS

Sixteen pigs were used in this study. In the first experiment, RFA was performed in the liver for 6 minutes using Octopus MP electrodes (n = 15 ablation zones) and conventional electrodes (n = 12 ablation zones) to investigate the effect of saline instillation. The ablation energy, electrical impedance, and ablation volume of the two electrodes were compared. In the second experiment, RFA was performed near the gallbladder (GB) and colon using Octopus MP electrodes (n = 12 ablation zones for each) with direct tissue temperature monitoring and conventional electrodes (n = 11 ablation zones for each). RFA was discontinued when the temperature increased to > 60\xe2\x84\x83 in the Octopus MP electrode group, whereas RFA was performed for a total of 6 minutes in the conventional electrode group. Thermal injury was assessed and compared between the two groups by pathological examination.

RESULTS

In the first experiment, the ablation volume and total energy delivered in the Octopus MP electrode group were significantly larger than those in the conventional electrode group (15.7 ± 4.26 cm³ vs. 12.5 ± 2.14 cm³, p = 0.027; 5.48 ± 0.49 Kcal vs. 5.04 ± 0.49 Kcal, p = 0.029). In the second experiment, thermal injury to the GB and colon was less frequently noted in the Octopus MP electrode group than that in the conventional electrode group (16.7% [2/12] vs. 90.9% [10/11] for GB and 8.3% [1/12] vs. 90.9% [10/11] for colon, p < 0.001 for all). The total energy delivered around the GB (2.65 ± 1.07 Kcal vs. 5.04 ± 0.66 Kcal) and colon (2.58 ± 0.57 Kcal vs. 5.17 ± 0.90 Kcal) were significantly lower in the Octopus MP electrode group than that in the conventional electrode group (p < 0.001 for all).

CONCLUSION

RFA using the Octopus MP electrodes induced a larger ablation volume and resulted in less thermal injury to the adjacent organs compared with conventional electrodes.

Bipolar Radiofrequency Ablation of the Adrenal Gland: In Vivo and Ex Vivo Experiments

Laparoscopic adrenalectomy is currently the standard treatment modality for unilateral aldosterone-producing adenoma (APA); however, a less-invasive treatment is needed for its treatment. A new bipolar ablation system that poses a lower risk of complications has been recently developed. This study aimed to evaluate the safety and performance of a novel bipolar radiofrequency ablation (RFA) system for the treatment of APAs. Ablations were performed in an ex vivo study using bovine adrenal glands [group A: n = 6, single-probe; group B: n = 6, two probes, interprobe distance (ID) = 12 mm; group C: n = 6, two probes, ID = 20 mm]. The in vivo study was conducted in groups A and B (n = 2 each) using porcine adrenal glands. For the ex vivo study, the mean vertical diameter (Dv) of the coagulative necrosis area and the mean transverse diameter (Dt) values were 11.99 mm and 10.96 mm for group A, 12.66 mm and 10.0 mm for group B, and 23.37 mm and 22.10 mm for group C, respectively. For the in vivo study, the mean Dv and Dt values were 12.23 mm and 9.03 mm for group A, and 16.38 mm and 9.52 mm for group B, respectively. No heat-induced damage to the adjacent organs was observed. To our best knowledge, this is the first study to evaluate the performance of the bipolar system in RFA of the adrenal gland. RFA using the new bipolar ablation system is safe and produces a sufficient coagulation area to treat APAs.

Emerging Indications for Interventional Oncology: Expert Discussion on New Locoregional Treatments

Interventional oncology (IO) employs image-guided techniques to perform minimally invasive procedures, providing lower-risk alternatives to many traditional medical and surgical therapies for cancer patients. Since its advent, due to rapidly evolving research development, its role has expanded to encompass the diagnosis and treatment of diseases across multiple body systems. In detail, interventional oncology is expanding its role across a wide spectrum of disease sites, offering a potential cure, control, or palliative care for many types of cancer patients. Due to its widespread use, a comprehensive review of the new indications for locoregional procedures is mandatory. This article summarizes the expert discussion and report from the "MIOLive Meet SIO" (Society of Interventional Oncology) session during the last MIOLive 2022 (Mediterranean Interventional Oncology Live) congress held in Rome, Italy, integrating evidence-reported literature and experience-based perceptions. The aim of this paper is to provide an updated review of the new techniques and devices available for innovative indications not only to residents and fellows but also to colleagues approaching locoregional treatments.

Long-term efficacy and safety of microwave ablation for hepatocellular carcinoma adjacent to the gallbladder with a diameter ≤ 5 cm: a multicenter, propensity score matching study

OBJECTIVE

To compare the long-term efficacy and safety of microwave ablation (MWA) as first-line therapy for hepatocellular carcinoma (HCC) adjacent versus nonadjacent to the gallbladder.

MATERIALS AND METHODS

From 2006 to 2018, 657 patients with ≤5 cm HCC who underwent percutaneous ultrasound-guided MWA as first-line therapy from 5 hospitals were enrolled in this retrospective study. Patients were grouped into the adjacent group (n = 49) and the nonadjacent group (n = 608) according to whether the tumor was adjacent to the gallbladder. Propensity score matching (PSM) was used to balance baseline variables between the two groups.

RESULTS

Forty-eight patient pairs were matched after PSM. For the PSM cohort, during a median follow-up time of 60 months, there were no differences in PFS (hazard ratio [HR], 1.011; 95% confidence interval [CI], 0.647-1.578; p = 0.963) or OS (HR 0.925; 95% CI 0.522-1.639; p = 0.789) between the adjacent and nonadjacent groups. Univariate and multivariate analyses revealed that the tumor adjacent to the gallbladder was not an independent risk factor for PFS or OS (all p > 0.05). Subgroup analysis showed comparable PFS and OS between the two groups in the <3 cm subgroup and the 3-5 cm subgroups (all p > 0.05). In addition to more use of assistive technology (p < 0.05), the adjacent group shared comparable local tumor progression, complications, technical success rate, and hospital stay (all p > 0.05) to the nonadjacent group.

CONCLUSION

There were comparable long-term efficacy and complications between patients with HCC adjacent and nonadjacent to the gallbladder treated with MWA.

Clinical feasibility of radiofrequency ablation using novel adjustable separable electrodes with a multipurpose needle for treating small hepatocellular carcinomas: a prospective single center study

BACKGROUND

The novel separable clustered electrode system with two adjustable active tips (ICAEs) and a fine multipurpose needle (MPN) for in situ temperature monitoring and adjuvant agent injection was developed and validated in an animal study. The purpose of this study was to evaluate the technical efficacy and complication of the novel electrode system for patients who have small HCC.

METHODS

In this prospective, single-center clinical trial, ten participants with 14 small (≤ 2 cm, BCLC 0-A) HCCs referred for RFA were enrolled. A novel electrode system consisting of two ICAEs and one MPN with a thermometer and side holes was used for RFA. The RF energy was delivered using a multichannel RF system combining bipolar and switching monopolar modes. Technical success, efficacy, and complications were evaluated on immediate and one-month follow-up CT.

RESULTS

Technical success was achieved in 92.9% (13/14) of tumors. One participant withdrew consent after RFA, and technical efficacy was achieved in 91.7% (11/12) of tumors. None showed thermal injury to nontarget organs. All patients were discharged the day after RFA without major complications. The active electrode lengths were adjusted in 60% (6/10) of patients during the procedure to tailor the ablation zone (83.3%, n = 5) or treat two tumors with different sizes (16.7%, n = 1). MPN was capable of continuous temperature monitoring during all ablations (100%, 14/14).

CONCLUSIONS

RFA using a novel electrode system showed acceptable technical efficacy and safety in patients with small HCCs. Further comparative studies are needed for the investigation of the system's potential benefits compared to conventional electrodes.

Image-guided percutaneous ablation for lung malignancies

Image-guided percutaneous lung ablation has proven to be an alternative and effective strategy in the treatment of lung cancer and other lung malignancies. Radiofrequency ablation, microwave ablation, and cryoablation are widely used ablation modalities in clinical practice that can be performed along or combined with other treatment modalities. In this context, this article will review the application of different ablation strategies in lung malignancies.

Conservative treatment of gastric perforation after microwave ablation of a hepatocellular carcinoma: Case report

RATIONALE

Microwave ablation (MWA) has been proven to be an efficient and safe method for local tumor control of liver tumors. Reported complications are rare, but include liver abscess, hematoma, pleural effusion, and occasional thermal injury of the adjacent colon. Intestinal perforation usually requires immediate surgical treatment to prevent generalized peritonitis and sepsis.

PATIENT CONCERNS AND DIAGNOSIS

Herein, we describe a case of gastric perforation following percutaneous MWA for hepatocellular carcinoma as a bridging therapy prior to liver transplantation.

INTERVENTIONS

Due to the clinical condition of the patient, conservative treatment was considered sufficient. Nine months after MWA, successful liver transplantation followed. Intraoperative findings revealed a scar in the gastric wall with tight adhesions to the liver, requiring adhesiolysis and subsequent suturing. Postoperative recovery was uneventful.

OUTCOME

At present, the patient is doing well. No further gastrointestinal events occurred.

LESSON

To our knowledge, this is the first report of such a complication occurring after MWA. Moreover, in this case, the gastric perforation could be treated conservatively.

Third-degree full-thickness burns as a complication of cervical radiofrequency ablation

A 46-year-old woman underwent a cervical radiofrequency ablation (RFA) for chronic neck pain. Following the procedure, two areas surrounding the grounding pad in the lumbar region developed full thickness third-degree burns. Burn injuries following cervical RFA are rarely reported and are most often associated with cardiac and solid tumour RFA. Only one other case has been reported in literature with a similar outcome following a thoracic facet RFA. In our case, the lesion was directly from the ground pad and not from the radiofrequency electrode, which is more often the culprit. This is the first case reported in the literature of a full-thickness skin burn from a cervical RFA. Physicians should be aware of the potential for severe burns around the RF probe and ground pad as sequelae of RFA, and we caution the use of sedation during the procedure, as patients will unlikely be able to report any unusual sensation.

Microwave ablation for peribiliary hepatocellular carcinoma: propensity score analyses of long-term outcomes

OBJECTIVE

To compare the long-term outcomes of MWA as the first-line treatment for HCC in peribiliary versus non-peribiliary locations using propensity score matching analysis.

METHODS

The study participants were recruited between April 2012 and October 2016. In total, 236 patients with HCC <5 cm who underwent ultrasonography-guided percutaneous MWA as the first-line treatment were enrolled. The patients were grouped into two according to tumor location: peribiliary (n = 74) and non-peribiliary (n = 162). The progression-free survival (PFS) and overall survival (OS) rates were compared before and after propensity score matching. Subgroup analyses were conducted for the peribiliary group according to the biliary grading.

RESULTS

Propensity score matching yielded 63 matched pairs of patients. In the two matched groups, cumulative PFS rates were 29.0% and 14.0% in the peribiliary group, and 51.0% and 31.0% in the non-peribiliary group at 3 and 5 years, respectively. Corresponding OS rates were 51.0% and 49.0% in the peribiliary group, and 77.0% and 70.0% in the non-peribiliary group at 3 and 5 years, respectively. In addition, there were significant differences in major complication rates between the two groups (25.7% vs 8.0%; p < .001). In contrast to peribiliary HCCs adjacent to the second-degree branches of intrahepatic bile duct (67.1 ± 5.2 months), subgroup analysis indicated that the mean OS was significantly lower in peribiliary HCCs adjacent to the first-degree branches (51.2 ± 7.5 months) (p = .015).

CONCLUSION

The application of MWA for peribiliary HCC leads to a higher rate of complications and worse long-term tumor control than for non-peribiliary HCC.KEY POINTSThe application of MWA for peribiliary HCC leads to a higher rate of complications than for non-peribiliary HCC.The application of MWA for peribiliary HCC leads to worse long-term tumor control than for non-peribiliary HCC. Abbreviations: Hepatocellular carcinoma (HCC); microwave ablation (MWA); α-fetoprotein (α-FP); local tumor progression (LTP); intrahepatic distal recurrence (IDR); progression-free survival (PFS); overall survival (OS).

Mycotic pseudoaneurysm of the hepatic artery as a complication of radiofrequency ablation of hepatic metastases

Image-guided radiofrequency ablation is frequently used to treat small hepatocellular carcinoma and metastases. Complications associated with this thermal-based technology for liver cancers arise via direct mechanical injury by the electrodes or collateral thermal damage to surrounding structures. This case report describes an unusual presentation of hepatic arterial mycotic pseudoaneurysm as melaena after percutaneous image-guided radiofrequency ablation for liver metastases in a patient with a previous surgical history of hepaticojejunostomy for cholangiocarcinoma. The patient had a lifesaving procedure to treat the hepatic pseudoaneurysm with transarterial glue embolization.

Directional ablation in radiofrequency ablation using a multi-tine electrode functioning in multipolar mode: An in-silico study using a finite set of states

PURPOSE

To analyse the feasibility of directional ablation using a multi-tine electrode.

METHODS

A multi-tine electrode capable of operating in multipolar mode has been used to study the directional ablation. In addition to the basic design, similar to commercially available FDA approved multi-tine electrode, tines have been insulated from each other inside the probe base and tip using a thin insulating material of thickness 0.25 mm. A cylindrical single-compartment model of size 6 cm × 6 cm has been used to model normal liver tissue. The temperature-controlled radiofrequency ablation has been employed to maintain the tine-tips at different temperatures. Electro-thermal simulations have been performed by using a commercial multi-physics software package based on finite element methods. To make this study feasible a new approach to predict the ablations have been proposed and used in this study.

RESULTS

Asymmetric ablation zone with up to 5 mm difference in ablation boundary between the intended and non-intended direction has been observed along the transverse direction. Reduction in ablation up to 5 mm along the axial direction in comparison to the monopolar mode has also been observed.

CONCLUSION

Multi-tine electrode modified to operate in multipolar mode can create directional ablations of different shapes and can be used to target position and shape specific tumours.

Management of bleeding associated with radiofrequency ablation of benign thyroid nodules

OBJECTIVE

This study was performed to explore the effective management of bleeding associated with radiofrequency ablation (RFA) of benign thyroid nodules.

METHODS

Thirty-five patients with benign thyroid nodules who were treated with ultrasound-guided RFA from July 2015 to December 2016 at the Third Affiliated Hospital of Sun Yat-sen University were retrospectively reviewed. The technique efficacy, bleeding, and other complications were assessed during the follow-up period.

RESULTS

The mean technique efficacy was 55.6%±22.8% at 1 month and 24.1%±17.1% at 6 months after the procedure. One case of an intranodular haematoma and two cases of voice change (>1 month) were observed. All patients recovered with corresponding treatment.

CONCLUSION

Although the incidence of haemorrhage is low, serious haematomas are life-threatening. Therefore, having a comprehensive understanding of the potential complications, an accurate clinical strategy, and adequate technical skills may prevent or help to properly manage these complications.

Anticoagulation status post radiofrequency ablation in a patient with hepatocellular carcinoma and delayed bleeding event

Restarting anticoagulation is a tricky component of patient care. This is a case of a 65-year-old female presenting with hepatocellular carcinoma. A nonocclusive thrombus in the main portal vein was also identified. Six days postradiofrequency ablation (RFA), the patient's hemoglobin dropped to critical values and noncontrast computed tomography of the abdomen/pelvis revealed high density free fluid consistent with a bleed. The patient was medically managed and accepted for transfer to another hospital for IR-guided TIPS procedure. Patient recovered without any other complications. In conclusion, VTE prophylaxis be routinely initiated immediately following hepatectomy in hemodynamically stable patients without signs of active bleeding and should bleeding occur halt source then restart anticoagulation immediately.

Outcomes following minimally invasive imagine-guided percutaneous ablation of adrenal glands

Whilst surgery represents the gold standard for the treatment of adrenal primary malignant tumors, metastatic involvement of the adrenal glands is generally approached conservatively; however, surgery for local control has been controversial, and several reports have described the utility of surgical removal in terms of prolonged survival in selected patients. Different techniques, including radiofrequency ablation (RFA), microwave ablation (MWA), laser induced thermal therapy (LITT), cryoablation (CRA), and chemical ablation, are employed in percutaneous image-guided ablation for primary and metastatic malignancies of the adrenal glands, in case of patients with multiple comorbidities or who refuse surgery. Technical success, clinical success and safety were analysed and discussed in this systematic review. Tumor size was found a significant determinant for local disease control; histology of the primary malignancy and coexistence of tumor elsewhere were correlated with prognosis. These procedures resulted to be feasible and safe, with hypertensive crisis representing the most common complication. Although there is lack of evidence in the literature concerning outcomes compared with surgery, percutaneous ablation may represent a useful therapeutic option for controlling unresectable adrenal metastases, offering patients opportunities for improved survival.

Utility of Intraprocedural Contrast-Enhanced CT in Ablation of Renal Masses

OBJECTIVE. The purpose of this study was to evaluate the efficacy of radiofrequency ablation (RFA) of renal masses comparing a group who did not undergo intraprocedural CT and a group who did. MATERIALS AND METHODS. A retrospective review included 45 consecutively registered patients who underwent RFA of renal masses. If an adequate biopsy specimen was not obtained or follow-up was inadequate, the patient was eliminated from review from calculation of primary technical efficacy. The inclusion criterion was having undergone RFA with two cooled-tip electrodes. Baseline demographics (age, body mass index, and sex), renal mass characteristics (diameter, side, location, position, morphologic features, type of mass, and grade), technical details (repositioning and hydrodissection), and complications were evaluated. Follow-up images were evaluated to determine the presence of recurrence at the ablation site in the two groups. RESULTS. Among the 45 patients who underwent RFA, 13 did not undergo intraprocedural CT and 32 intraprocedural did. Thirty-five patients met the criteria for follow-up and positive biopsy results. For calculation of recurrence, 10 patients were in the group who did not and 25 were in group who did undergo intraprocedural contrast-enhanced CT. No correlation was found between baseline demographics, renal mass characteristics, and technical results of the two groups. There was an 89% overall technical efficacy rate with a 96% primary technical efficacy rate in the group who underwent intraprocedural CT compared with a 70% rate in the group who did not undergo intraprocedural CT. Negative correlation was found between the groups with respect to technical efficacy rate at p < 0.05. CONCLUSION. Intraprocedural contrast-enhanced CT yields important information about completeness of ablation during the procedure, allowing probe repositioning and thus better therapeutic effect.

Magnetically Actuated Degradable Microrobots for Actively Controlled Drug Release and Hyperthermia Therapy

Microrobots facilitate targeted therapy due to their small size, minimal invasiveness, and precise wireless control. A degradable hyperthermia microrobot (DHM) with a 3D helical structure is developed, enabling actively controlled drug delivery, release, and hyperthermia therapy. The microrobot is made of poly(ethylene glycol) diacrylate (PEGDA) and pentaerythritol triacrylate (PETA) and contains magnetic Fe₃ O₄ nanoparticles (MNPs) and 5-fluorouracil (5-FU). Its locomotion is remotely and precisely controlled by a rotating magnetic field (RMF) generated by an electromagnetic actuation system. Drug-free DHMs reduce the viability of cancer cells by elevating the temperature under an alternating magnetic field (AMF), a hyperthermic effect. 5-FU is released from the proposed DHMs in normal-, high-burst-, and constant-release modes, controlled by the AMF. Finally, actively controlled drug release from the DHMs in normal- and high-burst-release mode results in a reduction in cell viability. The reduction in cell viability is of greater magnitude in high-burst- than in normal-release mode. In summary, biodegradable DHMs have potential for actively controlled drug release and hyperthermia therapy.

Veterinary Clinics: Tumor Ablation

Over the past decade, interventional oncology techniques have become integrated into the treatment plans of companion animals with cancer on a regular basis. Although procedures such as stenting are performed commonly, other less frequently utilized techniques for locoregional therapy, such as embolization and ablation, are emerging and demonstrating promise. Tumor ablation techniques are categorized into two subgroups: chemical ablation and energy-based ablation. Increased utilization of ablation will allow for the determination of specific indications and evaluation of outcomes for these techniques.

Pneumodissection during Percutaneous Renal Ablation Resulting in Air Embolism: Percutaneous Management and a Review of the Literature

Percutaneous renal ablation is a nephron-sparing approach for selected patients with renal cell carcinoma. Common complications include hemorrhage, injury to the urinary collecting system, and abscess formation. The purpose of this article is to present a case of vascular air embolism as a complication of pneumodissection performed during percutaneous ablation of renal cell carcinoma, discuss its successful percutaneous management, review common complications of renal ablation, and outline steps physicians can take to lessen these complications.

Septic Shock and Death after Microwave Ablation of Hepatocellular Carcinoma in a Liver Transplant Patient with a Bilioenteric Anastomosis

Percutaneous thermal ablation of hepatic tumors continues to play an integral role in the treatment of early-stage primary or secondary hepatic malignancies. Interventional radiologists must be familiar with potential complications of this procedure, associated risk factors, and methods for prevention. The authors report a devastating case of septic shock and death following percutaneous microwave ablation of a solitary hepatocellular carcinoma in a liver transplant patient with a bilioenteric anastomosis (BEA). We review the literature regarding prophylactic antibiotic regimens and bowel preparation prior to performing thermal ablation in patients with BEAs.

On the cooling effect of flowing blood on hepatic tumor ablation process

One method of removing malignant tissues from human organs is radiofrequency ablation. Thermal radiofrequency is a common technique of liver tumour therapy, which depends mainly on heating the infected region. This work proposes to investigate the thermal issue, which - in instance of excessive current - leads to extra lesion in liver tissues. However, the thermal lesions and the mistakes occurred in positioning the trocar instrument in the correct and accurate place arise the need to simulate and prediction of the thermal and electrical behaviour of the ablation operation. By using COMSOL multiphysics package, the process of hepatic tumour ablation has been simulated. Results show that by virtue of higher blood electrical conductivity, the nearby liver tissue around the electrode can be heated by rising its temperature due to electrical current from the radiofrequency probe according to the Joule law. Also, in this paper, different values of blood perfusion rate have been applied in the simulation process to investigate its effect on the ablation process. It is found that the increasing of mass flow rate of blood flow tends to bring down the fraction of necrotic tissue, which is contraindicated to the tumour ablation process.

Perforation of the esophagus due to thermal injury after laparoscopic radiofrequency ablation for hepatocellular carcinoma: a case for caution

Background

Several reported complications associated with radiofrequency ablation for liver tumors are due to thermal damage of neighboring organs. We herein report a first case of esophageal perforation due to thermal injury of laparoscopic radiofrequency ablation (RFA).

Case presentation

A 75-year-old woman was treated repeatedly with RFA (percutaneous and laparoscopic) and transcatheter arterial chemoembolization for hepatocellular carcinoma. One week after laparoscopic RFA for recurrent HCC located in segment 2 of the liver, dysphagia and thoracic pain occurred. Upper gastrointestinal endoscopy revealed a perforated esophageal ulcer at the esophago-gastric junction. Inflammation was localized because of severe intra-abdominal adhesion due to repeat surgery, so we decided to treat the patient conservatively. The perforation of the esophagus gradually scarred, and exacerbation did not occur after restarting oral intake.

Conclusions

When patients with a history of abdominal surgery or intra-abdominal inflammation undergo thermal ablation therapy, caution is required, as there is a possibility of thermal injury of unexpected organs.

Cooled tip radiofrequency ablation of benign thyroid nodules: preliminary experience with two different devices

Background

Thyroid nodules are very common in general population. Even if benign, they may require a treatment in case of symptoms or cosmetic concerns. In the last years, minimally invasive treatments alternative to surgery have been developed, in particular ultrasound (US) guided radiofrequency ablation (RFA).

Methods

Twenty-four patients (9 males; 15 females; mean age 57.9 years) were treated and divided in two groups (A and B) according to the RFA needle used (18 gauge needle, AMICA; 17 gauge needle, COVIDIEN). Nodules and patients characteristics, together with procedural data were registered pre-treatment and at 1-month follow-up. US visibility of the needle, volume of the nodules, symptoms and cosmetic concerns, complications were registered.

Results

Visibility of the needle was not significantly different in the two groups (P=0.0787). At 1 month the mean volume of the nodules dropped from 37.1 to 25 mL in group A and from 23.2 to 15.4 mL in group B; shrinkage rate (36.9% and 39.5%, respectively) was not significantly different (P=0.3137). Symptoms decreased from 3.1 to 1.4 in group A and from 4 to 1.6 in group B: no significant differences in reductions were observed (P=0.3305). Cosmetic score decreased from 3.7 to 3.4 in group A and from 3.9 to 3.6 in group B: no significant differences in reductions were observed (P=0.96). Total complication rate (18.2% in group A vs. 23.1% in group B) did not showed significant differences (P=0.5049).

Conclusions

The two systems used in our study resulted equivalent in terms of US needle visibility, efficacy, symptom/cosmetic relief, safety. More patients and a longer follow-up are necessary to confirm our results.

Novel temperature-controlled RFA probe for treatment of blocked metal biliary stents in patients with pancreaticobiliary cancers: initial experience

BACKGROUND AND STUDY AIMS

 Radiofrequency ablation (RFA) is used to treat blocked biliary stents in patients with pancreaticobiliary (PB) tumors with varying results. We report our experience with a novel temperature-controlled probe for treatment of blocked metal stents.

PATIENTS AND METHODS

 Patients with histologically proven PB cancers and a blocked biliary stents were treated using ELRATM electrode (Taewoong Medical) under fluoroscopic guidance. Demographics, clinical outcome, stricture diameter improvements, complications and mortality at 30 days were prospectively recorded.

RESULTS

 Nine procedures were performed on seven patients (4 male, 3 female); mean age 65.33 (range 56 - 82 years). Mean stricture diameter prior to RFA was 1.13 mm (SD ± 0.54) and 4.42 mm (SD ± 1.54) following RFA ( P  < 0.0001). Five of seven patients (71 %) required additional stents to ensure optimal drainage. There were no procedure-related complications. Mean follow-up was 193.55 days (range 31 - 540) and three of nine patients (33 %) died due to terminal cancer.

CONCLUSION

These are the first reported data on use of a temperature-controlled RFA catheter in humans to treat blocked metal biliary stents. The device is safe but further randomized trials are required to establish the efficacy and survival benefits of this probe.

Percutaneous microwave thermosphere ablation of pancreatic tumours

Background

In oncologic field, thermo-ablative procedures have spread more and more. Percutaneous microwave ablation (MWA) showed same benefits and some advantages over radiofrequency ablation (RFA). To date, a disadvantage of both was the not totally predictable size and shape of ablation volume. The aim of this study was to assess feasibility and safety of MWA in nonresectable pancreatic head cancer using a new technology of MW with high power (100 W) and frequency of 2,450 MH.

Methods

Five patients with pancreatic head cancer treated with percutaneous MWA under ultrasound guidance were retrospectively reviewed. Mean lesion diameter was 27.8 mm (range, 25-32 mm). Follow-up was performed by CT after 1, 3, 6 and, when possible, 12 months. The shape of the ablation volume was evaluated with multiplanar reformatting (MPR) using roundness index (RI): a value near 1 represents a more spherical ablation zone shape, and a value distant from 1 implies an oval configuration. Ablation and procedure times were registered, together with hospital stay. The feasibility, safety and quality of life (QoL) were reported.

Results

The procedure was feasible in all patients (100%). A spherical shape of ablation zone was achieved in all cases (mean RI =0.97). Mean ablation and procedure time were respectively of 2.48 and 28 minutes. Mean hospital stay was 4 days. No major complications were observed. Minor complications resolved during the hospital stay. An improvement in QoL was observed in all patients despite a tendency to return to preoperative levels in the months following the procedure.

Conclusions

Percutaneous MWA is a feasible and safe approach for the palliative treatment of advanced stage tumors of the head of the pancreas, despite its complex anatomic relations. The spherical shape of the ablation volume could be related with an improving of the effectiveness and safety.

Mechanical fractionation of tissues using microsecond-long HIFU pulses on a clinical MR-HIFU system

PURPOSE

High intensity focussed ultrasound (HIFU) can non-invasively treat tumours with minimal or no damage to intervening tissues. While continuous-wave HIFU thermally ablates target tissue, the effect of hundreds of microsecond-long pulsed sonications is examined in this work. The objective of this study was to characterise sonication parameter-dependent thermomechanical bioeffects to provide the foundation for future preclinical studies and facilitate clinical translation.

METHODS AND MATERIALS

Acoustic power, number of cycles/pulse, sonication time and pulse repetition frequency (PRF) were varied on a clinical magnetic resonance imaging (MRI)-guided HIFU (MR-HIFU) system. Ex vivo porcine liver, kidney and cardiac muscle tissue samples were sonicated (3 × 3 grid pattern, 1 mm spacing). Temperature, thermal dose and T2 relaxation times were quantified using MRI. Lesions were histologically analysed using H&E and vimentin stains for lesion structure and viability.

RESULTS

Thermomechanical HIFU bioeffects produced distinct types of fractionated tissue lesions: solid/thermal, paste-like and vacuolated. Sonications at 20 or 60 Hz PRF generated substantial tissue damage beyond the focal region, with reduced viability on vimentin staining, whereas H&E staining indicated intact tissue. Same sonication parameters produced dissimilar lesions in different tissue types, while significant differences in temperature, thermal dose and T2 were observed between the parameter sets.

CONCLUSION

Clinical MR-HIFU system was utilised to generate distinct types of lesions and to produce targeted thermomechanical bioeffects in ex vivo tissues. The results guide HIFU research on thermomechanical tissue bioeffects, inform future studies and advice sonication parameter selection for direct tumour ablation or immunomodulation using a clinical MR-HIFU system.

Renal Cell Carcinoma Perfusion before and after Radiofrequency Ablation Measured with Dynamic Contrast Enhanced MRI: A Pilot Study

Aim: To investigate if the early treatment effects of radiofrequency ablation (RFA) on renal cell carcinoma (RCC) can be detected with dynamic contrast enhanced (DCE)-MRI and to correlate RCC perfusion with RFA treatment time. Materials and methods: 20 patients undergoing RFA of their 21 RCCs were evaluated with DCE-MRI before and at one month after RFA treatment. Perfusion was estimated using the maximum slope technique at two independent sittings. Total RCC blood flow was correlated with total RFA treatment time, tumour location, size and histology. Results: DCE-MRI examinations were successfully evaluated for 21 RCCs (size from 1.3 to 4 cm). Perfusion of the RCCs decreased significantly (p < 0.0001) from a mean of 203 (±80) mL/min/100 mL before RFA to 8.1 (±3.1) mL/min/100 mL after RFA with low intra-observer variability (r ≥ 0.99, p < 0.0001). There was an excellent correlation (r = 0.95) between time to complete ablation and pre-treatment total RCC blood flow. Tumours with an exophytic location exhibit the lowest mean RFA treatment time. Conclusion: DCE-MRI can detect early treatment effects by measuring RCC perfusion before and after RFA. Perfusion significantly decreases in the zone of ablation, suggesting that it may be useful for the assessment of treatment efficacy. Pre-RFA RCC blood flow may be used to predict RFA treatment time.

Percutaneous High Frequency Microwave Ablation of Uterine Fibroids: Systematic Review

Uterine fibroids are the most common benign pelvic tumor of the female genital tract and tend to increase with age; they cause menorrhagia, dysmenorrhea, pelvic pressure symptoms, back pain, and subfertility. Currently, the management is based mainly on medical or surgical approaches. The nonsurgical and minimally invasive therapies are emerging approaches that to the state of the art include uterine artery embolization (UAE), image-guided thermal ablation techniques like magnetic resonance-guided focused ultrasound surgery (MRgFUS) or radiofrequency ablation (RF), and percutaneous microwave ablation (PMWA). The purpose of the present review is to describe feasibility results and safety of PMWA according to largest studies available in current literature. Moreover technical aspects of the procedure were analyzed providing important data on large scale about potential efficacy of PMWA in clinical setting. However larger studies with international registries and randomized, prospective trials are still needed to better demonstrate the expanding benefits of PMWA in the management of uterine fibroids.

A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors

Purpose

This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors.

Methods

This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed.

Results

The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups.

Conclusion

The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors.

Thermal ablation of hepatocellular carcinoma in patients with abnormal coagulation function

OBJECTIVE

To evaluate the safety of thermal ablation for hepatocellular carcinoma (HCC) in patients with abnormal coagulation function.

METHODS

Fifty-seven HCC tumours in 50 patients were treated with thermal ablation. All patients had a meted platelet count <50 × 10⁹/L or international normalised ratio (INR) ≥ 1.7. Gastroscopy before ablation, platelet concentrate or fresh frozen plasma transfusion during ablation and contrast enhanced ultrasoundgraphy (CEUS)-guided ablation to cease needle tract bleeding were performed to reduce haemorrhage. The incidences of haemorrhage and other major complications were recorded and patients were followed up to observe the local tumour progression (LTP), intrahepatic distant recurrence (IDR), overall survival (OS) and recurrence-free survival (RFS) rates.

RESULTS

Two incidences of needle tract bleeding and one needle tract bleeding together with bleeding at the suture of the spleen fossa were found. Three needle tract bleeding events were detected by CEUS and ceased after CEUS-guided complementary ablation. CEUS failed to detect bleeding at the suture of the spleen fossa. Therefore, a laparotomy was conducted for haemostasis. No other major complications were found after ablation. The median follow-up periods were 18.7 ± 12.0 months (range 1 ∼ 42 months) and 1 LTP and 15 IDRs occurred. The 1-, 2- and 3-year OS rates were 84.8%, 82.7% and 82.7%, and RFS rates were 67.9%, 64.0% and 64.0%, respectively.

CONCLUSION

With gastroscopy before ablation, platelet concentrate or fresh frozen plasma transfusion during ablation and CEUS-guided ablation to cease needle tract bleeding, thermal ablation is a safe treatment for HCC in patients with abnormal coagulation function.

[Percutaneous renal ablation: Pre-, per-, post-interventional evaluation modalities and adapted management]

OBJECTIVES

Ablative treatment (AT) rise is foreseen, validation of steps to insure good proceedings is needed. By looking over the process of the patient, this study evaluates the requirements and choices needed in every step of the management.

METHODS

We searched MEDLINE^®, Embase^®, using (MeSH) words and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance.

RESULTS

Explanations of AT proposal rather than partial nephrectomy or surveillance have to be discussed in a consultation shared by urologist and interventional radiologist. Per-procedure choices depend on predictable ballistic difficulties. High volume, proximity of the hilum or of a risky organ are in favor of general anesthesia, cryotherapy and computed tomography/magnetic resonance imaging (CT/MRI). Percutaneous approach should be privileged, as it seems as effective as the laparoscopic approach. Early and delayed complications have to be treated both by urologist and radiologist. Surveillance by CT/MRI insure of the lack of contrast-enhanced in the treated area. Patients and tumors criteria, in case of incomplete treatment or recurrence, are the key of the appropriate treatment: surgery, second session of AT, surveillance.

CONCLUSION

AT treatments require patient's comprehension, excellent coordination of the partnership between urologist and radiologist and relevant choices during intervention.

Emerging Nanotechnology and Advanced Materials for Cancer Radiation Therapy

Radiation therapy (RT) including external beam radiotherapy (EBRT) and internal radioisotope therapy (RIT) has been widely used for clinical cancer treatment. However, owing to the low radiation absorption of tumors, high doses of ionizing radiations are often needed during RT, leading to severe damages to normal tissues adjacent to tumors. Meanwhile, the RT efficacies are limited by different mechanisms, among which the tumor hypoxia-associated radiation resistance is a well-known one, as there exists hypoxia inside most solid tumors while oxygen is essential to enhance radiation-induced DNA damages. With the development in nanotechnology, there have been great interests in using nanomedicine strategies to enhance radiation responses of tumors. Nanomaterials containing high-Z elements to absorb radiation rays (e.g. X-ray) can act as radio-sensitizers to deposit radiation energy within tumors and promote treatment efficacy. Nanoscale carriers are able to deliver therapeutic radioisotopes into tumors for internal RIT, or chemotherapeutic drugs for synergistically combined chemo-radiotherapy. As uncovered in recent studies, the tumor microenvironment could be modulated by various nanomedicine approaches to overcome hypoxia-associated radiation resistance. Herein, the authors will summarize the applications of nanomedicine for RT cancer treatment, and pay particular attention to the latest development of 'advanced materials' for enhanced cancer RT.

CT-guided microwave ablation through the lungs for treating liver tumors near the diaphragm

Purpose

To explore the short-term efficacy and safety of CT-guided microwave ablation (MWA) for treating liver tumors near the diaphragm.

Results

The complete response (CR) rate for CT-guided MWA through the lung was 94.7% (124/131). The incomplete response (ICR) rate was 5.3% (7/131), of which 6 patients with ICRs achieved CRs after MWA. The CR rate for Group I was higher than Group II (99.0% vs. 80.0%, P=0.001). The mean follow-up time was 11.2 ±7.50 months. The total local recurrence (LR) rate was 15.3% (20/131). The complication rate was 26.5%, and no severe complications were recorded. All complications were controllable and treatable. The incidence of diaphragmatic thickening during the MWA was 18.8% (P>0.05); the incidence of exudative changes inside the lungs was 6.8% (P>0.05).

Conclusions

CT-guided MWA can detect changes in liver tissue, in the diaphragm and nearby lung tissues during the ablation process. It's safe and effective to treat tumors close to the diaphragm by CT-guided MWA through the lung.

Methods

CT-guided MWA was used on 131 tumors that were close to the diaphragm (distance between tumor and diaphragm ≤ 5 mm) in 117 patients with liver cancer. The tumors were divided into a < 3.0 cm group (Group I, n= 101) and a ≥ 3.0 cm group (Group II, n= 30) based on tumor diameters. The complications within 2 weeks following treatment were counted, and the safety and short-term efficacy of MWA were analyzed.

Sharma K, Chen H, Rossi CT, Kothapalli SVVN, Oetgen M, Kim A, H. Negussie A, Woods D, J. Wood B, C. W. Kim P, S. Yarmolenko P. Boiling histotripsy lesion characterization on a clinical magnetic resonance imaging-guided high intensity focused ultrasound system

Purpose

High intensity focused ultrasound (HIFU) is a non-invasive therapeutic technique that can thermally ablate tumors. Boiling histotripsy (BH) is a HIFU approach that can emulsify tissue in a few milliseconds. Lesion volume and temperature effects for different BH sonication parameters are currently not well characterized. In this work, lesion volume, temperature distribution, and area of lethal thermal dose were characterized for varying BH sonication parameters in tissue-mimicking phantoms (TMP) and demonstrated in ex vivo tissues.

Methods

The following BH sonication parameters were varied using a clinical MR-HIFU system (Sonalleve V2, Philips, Vantaa, Finland): acoustic power, number of cycles/pulse, total sonication time, and pulse repetition frequency (PRF). A 3×3×3 pattern was sonicated inside TMP’s and ex vivo tissues. Post sonication, lesion volumes were quantified using 3D ultrasonography and temperature and thermal dose distributions were analyzed offline. Ex vivo tissues were sectioned and stained with H&E post sonication to assess tissue damage.

Results

Significant increase in lesion volume was observed while increasing the number of cycles/pulse and PRF. Other sonication parameters had no significant effect on lesion volume. Temperature full width at half maximum at the end of sonication increased significantly with all parameters except total sonication time. Positive correlation was also found between lethal thermal dose and lesion volume for all parameters except number of cycles/pulse. Gross pathology of ex vivo tissues post sonication displayed either completely or partially damaged tissue at the focal region. Surrounding tissues presented sharp boundaries, with little or no structural damage to adjacent critical structures such as bile duct and nerves.

Conclusion

Our characterization of effects of HIFU sonication parameters on the resulting lesion demonstrates the ability to control lesion morphologic and thermal characteristics with a clinical MR-HIFU system in TMP’s and ex vivo tissues. We demonstrate that this system can produce spatially precise lesions in both phantoms and ex vivo tissues. The results provide guidance on a preliminary set of BH sonication parameters for this system, with a potential to facilitate BH translation to the clinic.