Explore the vast range of titles available.

PurposeTo assess safety and outcome of radiofrequency ablation (RFA) and microwave ablation (MWA) as compared to systemic chemotherapy and partial hepatectomy (PH) in the treatment of colorectal liver metastases (CRLM).MethodsMEDLINE, Embase and the Cochrane Library were searched. Randomized trials and comparative observational studies with multivariate analysis and/or matching were included. Guidelines from National Guideline Clearinghouse and Guidelines International Network were assessed using the AGREE II instrument.ResultsThe search revealed 3530 records; 328 were selected for full-text review; 48 were included: 8 systematic reviews, 2 randomized studies, 26 comparative observational studies, 2 guideline-articles and 10 case series; in addition 13 guidelines were evaluated. Literature to assess the effectiveness of ablation was limited. RFA + systemic chemotherapy was superior to chemotherapy alone. PH was superior to RFA alone but not to RFA + PH or to MWA. Compared to PH, RFA showed fewer complications, MWA did not. Outcomes were subject to residual confounding since ablation was only employed for unresectable disease.ConclusionThe results from the EORTC-CLOCC trial, the comparable survival for ablation + PH versus PH alone, the potential to induce long-term disease control and the low complication rate argue in favour of ablation over chemotherapy alone. Further randomized comparisons of ablation to current-day chemotherapy alone should therefore be considered unethical. Hence, the highest achievable level of evidence for unresectable CRLM seems reached. The apparent selection bias from previous studies and the superior safety profile mandate the setup of randomized controlled trials comparing ablation to surgery.

Abstract Purpose of ReviewBased on good local control rates and an excellent safety profile, guidelines consider thermal ablation the gold standard to eliminate small unresectable colorectal liver metastases (CRLM). However, efficacy decreases exponentially with increasing tumour size. The preferred treatment for intermediate-size unresectable CRLM remains uncertain. This systematic review and meta-analysis compare safety and efficacy of local ablative treatments for unresectable intermediate-size CRLM (3–5 cm).Recent FindingsWe systematically searched for publications reporting treatment outcomes of unresectable intermediate-size CRLM treated with thermal ablation, irreversible electroporation (IRE) or stereotactic ablative body-radiotherapy (SABR). No comparative studies or randomized trials were found. Literature to assess effectiveness was limited and there was substantial heterogeneity in outcomes and study populations. Per-patient local control ranged 22–90% for all techniques; 22–89% (8 series) for thermal ablation, 44% (1 series) for IRE, and 67–90% (1 series) for SABR depending on radiation dose.SummaryFocal ablative therapy is safe and can induce long-term disease control, even for intermediate-size CRLM. Although SABR and tumuor-bracketing techniques such as IRE are suggested to be less susceptible to size, evidence to support any claims of superiority of one technique over the other is unsubstantiated by the available evidence. Future prospective comparative studies should address local-tumour-progression-free-survival, local control rate, overall survival, adverse events, and quality-of-life.

Microwave ablation (MWA) is a relatively new thermal modality for minimally invasive procedures compared with radiofrequency ablation. Although MWA and radiofrequency ablation are thermal modalities, their underlying physics and principles greatly differ. Consequently, it is imperative that clinicians be aware of how these differences impact realized ablation volumes to consistently ensure technical success and better patient outcomes. This paper will review the nuances specific to MWA technology (i.e., tissue properties, perfusion/heat sink effect, ablation assessment, imaging accuracy and tissue contraction) that are often overlooked based on familiarity with conventional thermal modalities to guide more accurate assessment of post-treatment MWA volumes.

To quantitatively assess the influence of target temperature and ablation duration on the quality of proton resonance frequency shift (PRFS)-based MR thermometry during microwave ablation (MWA) in a controlled ex vivo model, and to identify parameter ranges associated with improved thermometry performance. Thirty-two MWAs were performed in 10 ex vivo bovine livers in a 1.5-tesla MRI system with multi-slice volumetric real-time thermometry yielding temperature and thermal dose maps. The experiments were conducted twice using all combinations of four target temperatures (60; 80; 100; 120 °C) and four ablation times (5:00; 7:30; 10:00; 15:00 min). Thermometry quality was rated on a 5‑point Likert scale. Ablation areas were compared with histopathology (hematoxylin and eosin, H and nicotinamide adenine dinucleotide, NADH‑diaphorase) and correlated using Spearman coefficients. Likert scores were compared across temperatures using Kruskal-Wallis and Mann-Whitney U tests. All evaluations were performed independently by two readers. Lesion areas varied from 2.6 to 12.9 cm², increasing primarily with target temperature. Ablation areas from temperature and thermal dose maps correlated strongly with macroscopically visual necrosis ( p  < 0.01). Likert scores differed significantly across temperatures ( p  < 0.05). The highest image quality was achieved at 60 °C for 7:30 min, showing comparable scores as at 80° for 15:00 min, but significantly differing from 100 °C to 120 °C. In this controlled ex vivo setting, lower target temperatures were associated with improved MRI thermometry quality, providing more reliable visualization of ablation zones; however, ablation volumes decreased at lower temperatures. Furthermore, these empirical ex vivo observations suggest that a staged two-level approach may support a clinical workflow strategy aimed at balancing thermometry image quality and ablation volume. Given the absence of perfusion and motion effects, these findings require further validation before clinical translation.

Microwave ablation is a technique used to treat tumorous tissue. Its clinical use has been greatly expanding in the last few years. Because the design of the ablation antenna and the success of the treatment greatly depend on the accurate knowledge of the dielectric properties of the tissue being treated, it is highly valuable to have a microwave ablation antenna that is also able to perform in-situ dielectric spectroscopy. In this work, an open-ended coaxial slot ablation antenna design operating at 5.8 GHz is adopted from previous work, and its sensing abilities and limitations are investigated in respect of the dimensions of the material under test. Numerical simulations were performed to investigate the functionality of the floating sleeve of the antenna and to find the optimal de-embedding model and calibration option for obtaining accurate dielectric properties of the area of interest. Results show that, as in the case of the open-ended coaxial probe, the accuracy of the measurement greatly depends on the likeness between the calibration standards’ dielectric properties and the material under test. Finally, the results of this paper clarify to which extent the antenna can be used to measure dielectric properties and paves the way to future improvements and the introduction of this functionality into microwave thermal ablation treatments.

Purpose New technologies for microwave ablation (MWA) have been conceived, designed to achieve larger areas of necrosis compared with radiofrequency ablation (RFA). The purpose of this study was to report complications by using this technique in patients with focal liver cancer. Methods Members of 14 Italian centers used a 2.45-GMHz generator delivering energy through a cooled miniature-choke MW antenna and a standardized protocol for follow-up. They completed a questionnaire regarding number and type of deaths, major and minor complications and side effects, and likelihood of their relationship to the procedure. Enrollment included 736 patients with 1.037 lesions: 522 had hepatocellular carcinoma with cirrhosis, 187 had metastases predominantly from colorectal cancer, and 27 had cholangiocellular carcinoma. Tumor size ranged from 0.5 to 10 cm. In 13 centers, the approach used was percutaneous, in 4 videolaparoscopic, and in 3 laparotomic. Results No deaths were reported. Major complications occurred in 22 cases (2.9%), and minor complications in 54 patients (7.3%). Complications of MWA do not differ from those RFA, both being based on the heat damage. Conclusion Results of this multicenter study confirmed those of single-center experiences, indicating that MWA is a safe procedure, with no mortality and a low rate of major complications. The low rate of complications was probably due to precautions adopted, knowing in advance possible risk conditions, on the basis of prior RFA experience.

Objective To study the effect of percutaneous kyphoplasty (PKP) combined with microwave ablation (MWA) on pain and clinical outcomes in patients with spinal metastases. Methods Eighty-seven patients with spinal metastases were retrospectively collected and divided into the PKP group (40 cases), and PKP + MWA group (47 cases). The postoperative efficacy (Frankel grade classification) was assessed, and the height of the diseased vertebrae, pain indices [visual analogue scale (VAS) and analgesic use score (AUS)], dysfunction in daily activities [Oswestry disability index (ODI)], quality of life (quality of life scores for tumor patients), and physical status score [Eastern Cooperative Oncology Group performance status] were compared. The incidence rate of adverse events and the survival of both groups were also counted. Results Postoperatively, the PKP + MWA group had a higher total effective rate than the PKP group ( P  < 0.05). Versus the PKP group, the PKP + MWA group showed improved recovery of vertebral height, lower VAS, AUS, and ODI scores, higher QLS, and better physical status (all P  < 0.05). Postoperative adverse events were not significantly different between the two groups ( P  > 0.05). The disease-free survival rate and overall survival rate within 1 year were higher in the PKP + MWA group than in the PKP group ( P  < 0.05). Conclusion PKP combined with MWA elevates the height of the diseased vertebrae, alleviates the symptoms of pain and dysfunction, and promotes the quality of life and physical status in patients with spinal metastases.

ObjectiveTo evaluate the efficacy and safety of Y90 radiation segmentectomy (RS) vs. percutaneous microwave ablation (MWA) in patients with solitary HCC ≤ 4 cm.MethodsFrom 2014 to 2017, 68 consecutive treatment naïve patients were included (34 per treatment arm). Chi-square and t-test were used to evaluate differences in baseline demographics between groups. Objective response was evaluated using mRECIST and toxicity using CTCAE. Overall survival (OS) and progression free survival (PFS) in the targeted tumor and the remainder of liver from initial treatment was calculated using Kaplan–Meier estimation. Propensity score matching was then performed with n = 24 patients matched in each group. Similar outcome analysis was then pre-formed.ResultsIn the overall study population, both groups had similar baseline characteristics with the exception of larger lesions in the RS group. There was no difference in toxicity, objective tumor response, OS and non-target liver PFS between the MWA and RS group (p’s > 0.05). In the matched cohort, the objective tumor response was 82.6% in MWA vs. 90.9%% in RS (p = 0.548). The mean OS in the MWA group (44.3 months) vs RS (59.0 months; p = 0.203). The targeted tumor mean PFS for the MWA groups was 38.6 months vs. 57.8 months in RS group (p = 0.005). There was no difference overall PFS and toxicity between the 2 matched groups.ConclusionsOur data suggest Y90 RS achieves similar tumor response and OS with a similar safety compared to MWA in the management of HCC lesions ≤ 4 cm. Additionally, targeted tumor PFS appears to be prolonged in the RS group with similar non-target liver PFS between RS and MWA group.

Transbronchial microwave ablation (MWA) can be performed safely in patients with malignant central airway obstruction (MCAO), under moderate sedation and a high fraction of inspired oxygen. We retrospectively evaluated the difference in the overall survival (OS) after transbronchial interventions (TBIs) between MCAO patients with endoluminal or mixed-type obstruction who were treated by MWA (MWA group, n=34) and those with extraluminal obstruction who were treated by stent placement (STP) (STP group, n=27). The OS was longer in the MWA group than in the STP group (10.2 months vs. 4.5 months, p=0.001). A significant difference in the OS between the two groups was observed in the patients who received post-TBI anticancer therapy (27.2 months vs. 6.0 months, p=0.002). The OS tended to be longer in the MWA group than in the STP group, among the patients who received best supportive care alone (3.8 months vs. 1.8 months, p=0.068). Nine patients (26%) of the MWA group underwent additional MWA when tumor regrowth into the airway lumen was noted (median of TBI sessions, 3). Multivariate analysis identified the adoption of MWA as the initial treatment procedure to be independently associated with a reduced risk of death in patients with MCAO (hazard ratio=0.473, p=0.031). Adoption of MWA as the initial treatment procedure is beneficial in MCAO patients with endoluminal or mixed-type obstruction, regardless of whether patients receive post-TBI anticancer therapy or not.

Background/Objectives: To evaluate the prognostic value of easily obtainable biomarkers for patients undergoing percutaneous microwave ablation (MWA) for colorectal liver metastases (CLMs). Prior studies showed that simple biomarkers, such as the lymphocyte-to-monocyte ratio (LMR), albumin-to-globulin ratio (AGR), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR), as well as cancer-specific markers, like carcinoembryonic antigen (CEA), might have a prognostic role in various malignancies; however, none of these were assessed in patients undergoing MWA for CLMs. Methods: Based on the simple laboratory results, which were determined prior to the ablation, several biomarkers, including the LMR, AGR, PLR, and NLR, were calculated. The log-rank test’s optimal cutoff points for continuous variables were determined. Subsequently, univariable and multivariable Cox regression models were utilized to determine the association between various features and overall survival (OS). Results: This study included 57 CLM patients with a mean age of 63 ± 12.5 years at the time of ablation with a mean follow up of 30.9 months. The univariable model demonstrated that a high level of CEA (cutoff: 29.1 ng/mL; HR: 3.70) and a high LMR (cutoff: 5.32; HR: 4.05) were related to worse OS, whereas a high NLR (cutoff: 2.05; HR: 0.31) and primary left-sided colon cancer (HR: 0.36) were positive prognostic factors. The multivariable regression model confirmed these findings, with the exception of the LMR, which was no longer significantly associated with OS. Conclusions: This study demonstrates the feasibility of overall survival prediction and thus patient stratification based on easily obtainable biomarkers and clinicopathological features in CLM patients undergoing MWA.