Value of 18F-FDG PET/MR Imaging in the Early Evaluation of Treatment Response following Radiofrequency Ablation of Liver Cancer in a Rabbit Model

PurposeTo test the hypothesis that ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging can detect early residual tumor following radiofrequency (RF) ablation of liver cancer using a VX2 tumor model.Materials and MethodsTwenty-four rabbits with VX2 liver tumors were randomly divided into 3 groups (n = 8/group): Group 1 without RF ablation treatment, Group 2 with complete ablation, and Group 3 with partial ablation. An ¹⁸F-FDG PET/MR imaging scan was obtained within 2 hours after RF ablation. The maximum standardized uptake values (SUV) of the nontreated liver tumor, benign periablational enhancement (BPE), residual tumor, ablated tumor, and adjacent liver parenchyma and mean SUV of the normal liver were measured. The ratios of maximum SUV for these targets to the mean SUV of the normal liver (TNR) were calculated and compared.ResultsThe mean TNR of the nontreated liver tumors in Group 1 was significantly greater than that of the adjacent liver parenchyma (8.68 ± 0.71 vs 1.89 ± 0.26, P < .001). In Group 2, the mean TNR of BPE was significantly greater than that of the adjacent liver parenchyma (2.85 ± 0.20 vs 1.86 ± 0.25, P < .001). In Group 3, the mean TNR of the residual tumor was significantly greater than that of BPE (8.64 ± 0.59 vs 2.78 ± 0.23, P < .001), which was significantly greater than that of completely ablated tumor (2.78 ± 0.23 vs 0.50 ± 0.06, P < .001).Conclusions¹⁸F-FDG PET/MR imaging may serve as a promising imaging tool for the early detection of viable residual tumors due to incomplete tumor ablation.     

Correlation and Agreement of Yttrium-90 Positron Emission Tomography/Computed Tomography with Ex Vivo Radioembolization Microsphere Deposition in the Rabbit VX2 Liver Tumor Model

PurposeTo demonstrate a stronger correlation and agreement of yttrium-90 (⁹⁰Y) positron emission tomography (PET)/computed tomography (CT) measurements with explant liver tumor dosing compared with the standard model (SM) for radioembolization.Materials and MethodsHepatic VX2 tumors were implanted into New Zealand white rabbits, with growth confirmed by 7 T magnetic resonance imaging. Seventeen VX2 rabbits provided 33 analyzed tumors. Treatment volumes were calculated from manually drawn volumes of interest (VOI) with three-dimensional surface renderings. Radioembolization was performed with glass ⁹⁰Y microspheres. PET/CT imaging was completed with scatter and attenuation correction. Three-dimensional ellipsoid VOI were drawn to encompass tumors on fused images. Tumors and livers were then explanted for inductively coupled plasma (ICP)-optical emission spectroscopy (OES) analysis of microsphere content. ⁹⁰Y PET/CT and SM measurements were compared with reference standard ICP-OES measurements of tumor dosing with Pearson correlation and Bland-Altman analyses for agreement testing with and without adjustment for tumor necrosis.ResultsThe median infused activity was 33.3 MBq (range, 5.9–152.9). Tumor dose was significantly correlated with ⁹⁰Y PET/CT measurements (r = 0.903, P < .001) and SM estimates (r = 0.607, P < .001). Bland-Altman analyses showed that the SM tended to underestimate the tumor dosing by a mean of ?8.5 Gy (CI, ?26.3–9.3), and the degree of underestimation increased to a mean of ?18.3 Gy (CI, ?38.5–1.9) after the adjustment for tumor necrosis.Conclusions⁹⁰Y PET/CT estimates were strongly correlated and had better agreement with reference measurements of tumor dosing than SM estimates.     

Computed Tomography Evaluation of In Vivo Pulmonary Cryoablation Zone Sizes

PurposeTo evaluate ablation zone sizes in patients undergoing pulmonary tumor cryoablation with 14-gauge cryoablation probes.Materials and MethodsA single-center retrospective analysis of all consecutive patients who underwent cryoablation of pulmonary tumors with 1 or more 14-gauge probes (August 2017 to June 2020) was performed. Intraprocedural and 1–2-month postprocedural chest computed tomography (CT) scans were evaluated to characterize pulmonary lesions, ice balls, and ablation zones. Single-probe 14-gauge ablation zone volumes were compared with manufacturer reference isotherms and single- and 2-probe ablation zones from a prior investigation of 17-gauge probes. Overall survival and local recurrence–free survival were calculated to 3 years.ResultsForty-seven pulmonary malignancies in 42 patients (women, 50%; mean age, 75.2 years ± 11.5) underwent cryoablation with 1 (n = 35), 2 (n = 10), or 3 (n = 2) cryoablation probes. One- to 2-month follow-up CT images were available for 30 of the 42 patients. The mean cryoablation zone volumes at 1–2 months when 1 (n = 21), 2 (n = 8), and 3 (n = 1) probes were used were 5.0 cm³ ± 2.3, 37.5 cm³ ± 20.5, and 28.4 cm³, respectively. The mean single-probe follow-up ablation zone volume was larger than that previously reported for 17-gauge probes (3.0 cm³ ± 0.3) (P < .001) but smaller than manufacturer-reported isotherms (11.6 cm³ for ?40 °C isotherm) and the 2-probe ablation zone volume with 17-gauge devices (12.9 cm³ ± 2.4) (for all, P < 001). The 3-year overall survival and local recurrence–free survival were 69% (95% confidence interval [CI], 53%–89%) and 87% (95% CI, 74%–100%), respectively.ConclusionsFourteen-gauge probes generate larger ablation volumes than those generated by 17-gauge probes. Manufacturer-reported isotherms are significantly larger than actual cryoablation zones. Cryoablation can attain low rates of local recurrence.     

Transcatheter CT Hepatic Arteriography Compared with Conventional CT Fluoroscopy Guidance in Percutaneous Thermal Ablation to Treat Colorectal Liver Metastases: A Single-Center Comparative Analysis of 2 Historical Cohorts

PurposeTo evaluate safety and efficacy of CT hepatic arteriography compared with conventional CT fluoroscopy guidance in percutaneous radiofrequency (RF) and microwave (MW) ablation to treat colorectal liver metastases (CRLM).Materials and MethodsThis single-center comparative, retrospective study analyzed data of 108 patients treated with 156 percutaneous ablation procedures (42 CT fluoroscopy guidance [25 RF ablation, 17 MW ablation]; 114 CT hepatic arteriography guidance [18 RF ablation, 96 MW ablation]) for 260 CRLM between January 2009 and May 2019. Local tumor progression-free survival (LTPFS) was assessed using univariate and multivariate Cox proportional hazard regression analyses. LTPFS and overall survival (OS) were estimated using the Kaplan-Meier method.ResultsThere were no complications related to the transarterial catheter procedure. CT hepatic arteriography proved superior to CT fluoroscopy regarding 2-year LTPFS (18/202 [8.9%] vs 19/58 [32.8%]; P < .001, respectively). CT hepatic arteriography versus CT fluoroscopy (hazard ratio = 0.28; 95% confidence interval, 0.15–0.54; P < .001) and MW ablation versus RF ablation (hazard ratio = 0.52; 95% confidence interval, 0.24–1.12; P = .094) were positive predictors for longer LTPFS. Multivariate analysis revealed that CT hepatic arteriography versus CT fluoroscopy (hazard ratio = 0.41; 95% confidence interval, 0.19–0.90; P = .025) was associated with a significantly superior LTPFS. OS was similar between the 2 cohorts (P = .3).ConclusionsWhile adding procedure time and marginal patient burden, transcatheter CT hepatic arteriography–guided ablation was associated with increased local disease control and superior LTPFS compared with conventional CT fluoroscopy. CT hepatic arteriography represents a safe and valid alternative to CT fluoroscopy, as it reduces the number of repeat ablations required without adding risk or detrimental effect on survival.     

Impact of the Ablative Margin on Local Tumor Progression after Radiofrequency Ablation for Lung Metastases from Colorectal Carcinoma: Supplementary Analysis of a Phase II Trial (MLCSG-0802)

PurposeTo explore what extent of ablative margin depicted by computed tomography (CT) immediately after radiofrequency (RF) ablation is required to reduce local tumor progression (LTP) for colorectal cancer (CRC) lung metastases.Materials and MethodsThis retrospective study was undertaken as a supplementary analysis of a previous prospective trial. Seventy patients (49 men and 21 women; mean age ± standard deviation, 64.9 years ± 10.6 years) underwent RF ablation for CRC lung metastases, and 95 tumors that were treated in the trial and followed up with CT at least 12 months after RF ablation were evaluated. The mean tumor size was 1.0 cm ± 0.5 cm. The ablative margin was estimated as the shortest distance between the outer edge of the tumor and the surrounding ground-glass opacity on CT obtained immediately after RF ablation. The impact of the ablative margin on LTP was evaluated using logistic regression analysis. Multivariate logistic regression analysis was also performed to identify the risk factors for LTP. The result was validated with multivariate logistic regression applying a bootstrap method (1,000 times resampling).ResultsThe mean ablative margin was 2.7 mm ± 1.3 (range, 0.4–7.3 mm). LTP developed in 6 tumors (6%, 6/95) 6–19 months after RF ablation. The LTP rate was significantly higher when the margin was less than 2 mm (P = .023). A margin of <2 mm was also found to be a significant factor for LTP (P = .048) on multivariate analysis and validated using the bootstrap method (P = .025).ConclusionsAn ablative margin of at least 2 mm is important to reduce LTP after RF ablation for CRC lung metastases.     

Stereotactic Body Radiotherapy for Stage I Renal Cell Carcinoma: National Treatment Trends and Outcomes Compared to Partial Nephrectomy and Thermal Ablation

PurposeTo assess use of stereotactic body radiotherapy (SBRT) for stage I renal cell carcinoma (RCC) and compare outcomes with thermal ablation and partial nephrectomy (PN).Materials and MethodsThe 2004–2015 National Cancer Database was investigated for histopathologically proven stage I RCC treated with PN, cryoablation, radiofrequency (RF) or microwave (MW) ablation, or SBRT. Patients were propensity score–matched to account for potential confounders, including patient age, sex, race, comorbidities, tumor size, histology, grade, tumor sequence, administration of systemic therapy, treatment in academic vs nonacademic centers, treatment location, and year of diagnosis. Overall survival (OS) was evaluated with Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models.ResultsA total of 91,965 patients were identified (SBRT, n = 174; PN, n = 82,913; cryoablation, n = 5,446; RF/MW ablation, n = 3,432). Stage I patients who received SBRT tended to be older women with few comorbidities treated at nonacademic centers in New England states. After propensity score matching, a cohort of 636 patients was obtained with well-balanced confounders between treatment groups. In the matched cohort, OS after SBRT was inferior to OS after PN and thermal ablation (PN vs SBRT, hazard ratio [HR] = 0.29, 95% confidence interval [CI] 0.19–0.46, P < .001; cryoablation vs SBRT, HR = 0.40, 95% CI 0.26–0.60, P < .001; RF/MW ablation vs SBRT, HR = 0.46, 95% CI 0.31–0.67, P < .001). Compared with PN, neither cryoablation nor RF/MW ablation showed significant difference in OS (cryoablation vs PN, HR = 1.35, 95% CI 0.80–2.28, P = .258; RF/MW ablation vs PN, HR = 0.64, 95% CI 0.95–2.55, P = .079).ConclusionsCurrent SBRT protocols show lower OS compared with thermal ablation and PN, whereas thermal ablation and PN demonstrate comparable outcomes.     

Percutaneous Radiofrequency Ablation of Appendicular Skeleton Chondroblastoma—an Experience from a Tertiary Care Cancer Center

PurposeTo evaluate safety and long-term efficacy of radiofrequency (RF) ablation in treatment of chondroblastoma.Materials and MethodsThis retrospective analysis comprised 27 consecutive patients with histopathologically proven chondroblastoma treated by RF ablation. The tumors were located in the proximal humerus (n = 6), proximal tibia (n = 8), proximal femur (n = 6), distal femur (n = 5), acromion process (n = 1), and lunate (n = 1). In 19 patients (70.3%), the tumor was in the weight-bearing area of the bone. Clinical response was assessed by comparing pain scores and functional assessment by Musculoskeletal Tumor Society (MSTS) score before and after ablation. Patients were followed for a minimum of 1 year to rule out complications and recurrence.ResultsTechnical success rate was 100%. Mean pain score before the procedure was 7.34 (range, 7–9); all patients experienced a reduction in pain, with 25 (92.6%) patients reporting complete pain relief at 6 weeks. Mean MSTS score before the procedure was 15.4, whereas mean MSTS score at 6 weeks after the procedure was 28.6, suggesting significant functional improvement (P < .0001). Two patients developed osteonecrosis and collapse of the treated bone. There were no recurrences.ConclusionsPercutaneous RF ablation is a safe and effective option for treating chondroblastoma of the appendicular skeleton.     

Use of a Glass Membrane Pumping Emulsification Device Improves Systemic and Tumor Pharmacokinetics in Rabbit VX2 Liver Tumor in Transarterial Chemoembolization

PurposeTo evaluate the phamacokinetics of epirubicin in conventional transarterial chemoembolization using a developed pumping emulsification device with a microporous glass membrane in VX2 rabbits.Materials and MethodsEpirubicin solution (10 mg/mL) was mixed with ethiodized oil (1:2 ratio) using the device or 3-way stopcock. Forty-eight rabbits with VX2 liver tumor implanted 2 weeks prior to transarterial chemoembolization were divided into 2 groups: a device group (n = 24) and a 3-way-stopcock group (n = 24). Next, 0.5 mL of emulsion was injected into the hepatic artery, followed by embolization using 100–300-μm microspheres. The serum epirubicin concentrations (immediately after, 5 minutes after, and 10 minutes after) and the tumor epirubicin concentrations (20 minutes after and 48 hours after) were measured after transarterial chemoembolization. Histopathologic evaluation was performed with a fluorescence microscope.ResultsThe area under the curve and maximum concentrations of epirubicin in plasma were 0.45 ± 0.18 μg min/mL and 0.13 ± 0.06 μg/mL, respectively, in the device group and 0.71 ± 0.45 μg min/mL and 0.22 ± 0.17 μg/mL, respectively, in the 3-way-stopcock group (P = .013 and P = .021, respectively). The mean epirubicin concentrations in VX2 tumors at 48 hours in the device group and the 3-way-stopcock group were 13.7 ± 6.71 and 7.72 ± 3.26 μg/g tissue, respectively (P = .013). The tumor necrosis ratios at 48 hours were 62 ± 11% in the device group and 51 ± 13% in the 3-way-stopcock group (P = .039).ConclusionsConventional transarterial chemoembolization using the pumping emulsification device significantly improved the pharmacokinetics of epirubicin compared to the current standard technique using a 3-way stopcock.     

Liver Tumor Ablation Procedure Duration and Estimated Patient Radiation Dose: Comparing Positron Emission Tomography/CT and CT Guidance

PurposeTo compare procedure duration and patient radiation dose in positron emission tomography/computed tomography (PET/CT) and CT-guided liver tumor ablation procedures.Materials and MethodsIn this retrospective, case-control study, 275 patients underwent 368 image-guided ablation procedures to treat 537 tumors. Radiologists used PET/CT guidance for 117 procedures and CT guidance for 251 procedures. PET/CT-guided procedures were performed by one radiologist (C: P.B.S.). All 3 radiologists (A: J.G.S., B: a radiologist who is not an author on this article, and C: P.B.S.) performed CT-guided procedures. Potential confounders included patient demographics, clinical and tumor characteristics, and procedural variables.ResultsThe mean duration and estimated patient radiation dose of PET/CT-guided procedures performed by radiologist C were 21.5 ± 4.9 minutes longer and 0.7 ± 2.8 mSv higher than CT-guided procedures performed by all radiologists in an unadjusted comparison. Adjusting for confounding, mean duration and estimated dose of PET/CT-guided procedures performed by radiologist C were 28.3 ± 3.8 minutes longer (P < .0001) and 6.2 ± 2.9 mSv higher (P = .03) than CT-guided procedures performed by the same radiologist. Comparing CT-guided procedures performed by all 3 radiologists, adjusted mean durations and estimated patient doses of procedures by the least experienced radiologist, radiologist A, and the second most experienced radiologist, radiologist B, were 24.2 ± 5.1 (P < .0001) and 18.1 ± 8.9 (P = .04) minutes longer and 13.1 ± 3.7 (P < .001) and 14.5 ± 6.4 (P = .02) mSv higher, respectively, than procedures performed by the most experienced radiologist, radiologist C.ConclusionsPET/CT-guided liver ablations had a slightly longer duration with slightly higher estimated patient radiation dose than similar CT-guided liver ablations. Procedure duration and patient dose do not appear to be major impediments to the emerging field of PET/CT-guided tumor ablation.     

Idarubicin-Loaded ONCOZENE Drug-Eluting Bead Chemoembolization in a Rabbit Liver Tumor Model: Investigating Safety,Therapeutic Efficacy,and Effects on Tumor Microenvironment

PurposeTo investigate toxicity, efficacy, and microenvironmental effects of idarubicin-loaded 40-μm and 100-μm drug-eluting embolic (DEE) transarterial chemoembolization in a rabbit liver tumor model.Materials and MethodsTwelve male New Zealand White rabbits with orthotopically implanted VX2 liver tumors were assigned to DEE chemoembolization with 40-μm (n = 5) or 100-μm (n = 4) ONCOZENE microspheres or no treatment (control; n = 3). At 24–72 hours postprocedurally, multiparametric magnetic resonance (MR) imaging including dynamic contrast-enhanced (DCE), diffusion-weighted imaging (DWI), and biosensor imaging of redundant deviation in shifts (BIRDS) was performed to assess extracellular pH (pHe), followed by immediate euthanasia. Laboratory parameters and histopathologic ex vivo analysis included fluorescence confocal microscopy and immunohistochemistry.ResultsDCE MR imaging demonstrated a similar degree of devascularization of embolized tumors for both microsphere sizes (mean arterial enhancement, 8% ± 12 vs 36% ± 51 in controls; P = .07). Similarly, DWI showed postprocedural increases in diffusion across the entire lesion (apparent diffusion coefficient, 1.89 × 10⁻³ mm²/s ± 0.18 vs 2.34 × 10⁻³ mm²/s ± 0.18 in liver; P = .002). BIRDS demonstrated profound tumor acidosis at baseline (mean pHe, 6.79 ± 0.08 in tumor vs 7.13 ± 0.08 in liver; P = .02) and after chemoembolization (6.8 ± 0.06 in tumor vs 7.1 ± 0.04 in liver; P = .007). Laboratory and ex vivo analyses showed central tumor core penetration and greater increase in liver enzymes for 40-μm vs 100-μm microspheres. Inhibition of cell proliferation, intratumoral hypoxia, and limited idarubicin elution were equally observed with both sphere sizes.ConclusionsNoninvasive multiparametric MR imaging visualized chemoembolic effects in tumor and tumor microenvironment following DEE chemoembolization. Devascularization, increased hypoxia, coagulative necrosis, tumor acidosis, and limited idarubicin elution suggest ischemia as the predominant therapeutic mechanism. Substantial size-dependent differences indicate greater toxicity with the smaller microsphere diameter.     

Image-Guided Ablation of Recurrent or Unresectable Intrahepatic Cholangiocarcinoma

PurposeTo assess the safety and effectiveness of image-guided ablation of recurrent or unresectable intrahepatic cholangiocarcinoma (ICC).Materials and MethodsIn this retrospective study, 25 patients (14 women; age, 36–84 years) underwent 37 image-guided liver tumor ablation procedures to treat 47 ICCs (May 2004 to January 2022). At initial diagnosis, 20 patients had Stage 1 or 2 disease and 5 had Stage 3 or 4 disease. Before ablation, 19 (76.0%) of the 25 patients had progressed through prior treatments, including resection (n = 11), chemotherapy (n = 11), transarterial embolization (n = 3), or radiotherapy (n = 1); 6 (24.0%) of the 25 patients were treatment naïve. Ablation modality selection was based on patient and tumor characteristics and operator preference. Primary outcomes included local progression–free survival (LPFS) and overall survival (OS) after ablation. Statistical analysis included Kaplan-Meier (KM) survival analyses and Cox proportional hazards models.ResultsThe mean ablated tumor size was 2.0 cm ± 1.2 (range, 0.5–5.0 cm). The 1-, 2-, and 5-year LPFS rates were 84.0% (95% CI, 72.9–96.8), 73.0% (95% CI, 59.0–90.4), and 59.5% (95% CI, 41.6–85.1), respectively. The 1-, 2-, and 5-year secondary LPFS rates were 89.5% (95% CI, 80.2–99.9), 81.9% (95% CI, 69.4–96.6), and 75.6% (95% CI, 60.2–94.9). The 1-, 2-, and 5-year LPFS rates for tumors ≤2 cm in size were all 95.8% (95% CI, 88.2–100.0). The 1-, 2-, and 5-year OS rates were 78.5% (95% CI, 63.5–97.2), 68.4% (95% CI, 51.3–91.1), and 43.5% (95% CI, 23.5–80.5). Larger tumor size was associated with decreased time to local progression (hazard ratio, 1.93; P = .012).ConclusionsPercutaneous ablation provided favorable intermediate to long-term disease control for patients with recurrent or inoperable cholangiocarcinoma.     

CT Densitometry and Morphology of Radiofrequency-Ablated Stage IA Non–Small Cell Lung Cancer: Results from the American College of Surgeons Oncology Group Z4033 (Alliance) Trial

PurposeTo evaluate tumor and ablation zone morphology and densitometry related to tumor recurrence in participants with Stage IA non–small cell lung cancer undergoing radiofrequency ablation in a prospective, multicenter trial.Materials and MethodsForty-five participants (median 76 years old; 25 women; 20 men) from 16 sites were followed for 2 years (December 2006 to November 2010) with computed tomography (CT) densitometry. Imaging findings before and after ablation were recorded, including maximum CT attenuation (in Hounsfield units) at precontrast and 45-, 90-, 180-, and 300-s postcontrast.ResultsEvery 1-cm increase in the largest axial diameter of the ablation zone at 3-months’ follow-up compared to the index tumor reduced the odds of 2-year recurrence by 52% (P = .02). A 1-cm difference performed the best (sensitivity, 0.56; specificity, 0.93; positive likelihood ratio of 8). CT densitometry precontrast and at 45 seconds showed significantly different enhancement patterns in a comparison among pretreated lung cancer (delta = +61.2 HU), tumor recurrence (delta = +57 HU), and treated tumor/ablation zone (delta [change in attenuation] = +16.9 HU), (P < .0001). Densitometry from 45 to 300 s was also different among pretreated tumor (delta = −6.8 HU), recurrence (delta = −11.2 HU), and treated tumor (delta = +12.1 HU; P = .01). Untreated and residual tumor demonstrated washout, whereas treated tumor demonstrated increased attenuation.ConclusionsAn ablation zone ≥1 cm larger than the initial tumor, based on 3-month follow-up imaging, is recommended to decrease odds of recurrence. CT densitometry can delineate tumor versus treatment zones.     

Utility of the RENAL Nephrometry Scoring System in Predicting Adverse Events and Outcomes of Percutaneous Microwave Ablation of Renal Tumors

PurposeTo assess the utility of the radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines (RENAL) nephrometry scoring system at predicting adverse events and outcomes in percutaneous microwave ablation (MWA) of renal tumors.Materials and MethodsA retrospective review of 116 patients who underwent MWA from 2004 to 2018 at 2 large university hospitals was conducted. Patient demographics and tumor characteristics were collected. The RENAL nephrometry scores were calculated, and procedure-related adverse events were stratified into minor and major (the Society of Interventional Radiology classification of class C or higher). Technical and oncologic outcomes were based on follow-up magnetic resonance imaging and computed tomography scans after ablation.ResultsThe mean RENAL score was 6.6 (range, 4–11), and the mean tumor size was 24 mm. Follow-up ranged between 16 and 161 weeks (median, 50 weeks; mean, 65 weeks). Oncologic control was achieved in 96% (n = 111) of patients. The major and minor adverse event rates were 8.6% (n = 10) and 17% (n = 19), respectively. The mean RENAL score for patients with recurrent and/or residual tumor (8.2 ± 2.7) was higher than that for patients without disease recurrence (6.5 ± 3.5, P = .05). However, in a multivariate analysis, the RENAL score was not found to be an independent predictor of oncologic outcomes (odds ratio, 1.548; P = .092).ConclusionsThe RENAL nephrometry score has minimal utility for predicting outcomes and adverse events in MWA of renal tumors. The inconsistent nature of RENAL nephrometry scoring in percutaneous ablation procedures underscores the need for an ablation-specific risk stratification system.     

Thermal Ablation and Transarterial Chemoembolization are Characterized by Changing Dynamics of Circulating MicroRNAs

PurposeTo determine whether the levels of circulating microRNAs (miRNAs) are altered in patients undergoing thermal ablation and chemoembolization and whether these changes are predictive of a clinical outcome.Material and MethodsThis prospective study consisted of 43 patients diagnosed with hepatocellular carcinoma (n = 15) and intrahepatic colorectal cancer metastases (n = 28) treated with thermal ablation (n = 23; radiofrequency [n = 6] or microwave [n = 19]), chemoembolization using drug-eluting embolics (n = 18), or both (n = 2). Four blood samples (immediately before the intervention and 60–90 minutes, 24 hours, and 7 days after the intervention) were taken to measure the plasma concentrations of miRNAs related to hypoxia (miR-21 and miR-210), liver injury (miR-122), epithelial–mesenchymal transition (miR-200a), and apoptosis (miR-34a) using miRNA-specific TaqMan assays and quantitative real-time polymerase chain reaction. Tumor burden and treatment response at 3 months were evaluated using the modified response evaluation criteria in solid tumors. The miRNA results were compared with clinical outcomes (Mann-Whitney U test, Wilcoxon matched-pair test).ResultsDynamic changes in the circulating miRNA levels were observed following both the interventions. For thermal ablation, significant increases in miR-21, miR-210, miR-122, miR-200a, and miR-34a concentrations peaked 60–90 minutes after the intervention (P < .01). However, for transarterial chemoembolization, maximum increases in the miRNA concentrations were observed at 24 hours after the intervention for miR-21, miR-210, miR-122, miR-200a, and miR-34a (P < .05). The increased concentrations of the circulating miRNAs were followed by a subsequent decline to baseline by 7 days. For the thermal ablation (but not chemoembolization) patients, elevations in the miR-210 and miR-200a levels were associated with early progressive disease at 3 months (P = .040 and P = .012, respectively).ConclusionsIncreased but dynamic levels of circulating miRNAs are present following interventional oncologic procedures and may prove useful as biomarkers for the monitoring of clinical outcomes.     

Transarterial Chemoembolization Followed by Radiofrequency Ablation for Hepatocellular Carcinoma: Impact of the Time Interval between the Two Treatments on Outcome

PurposeTo compare the efficacy of radiofrequency (RF) ablation after transarterial chemoembolization within or beyond 30 days for medium-large or multiple recurrent hepatocellular carcinomas (HCCs).Materials and MethodsIn this single-center retrospective study conducted from 2007 through 2015, 135 patients with a single recurrent HCC (>3 cm) or multiple (2–5 tumors) recurrent HCCs underwent transarterial chemoembolization plus RF ablation. A total of 62 patients underwent RF ablation after transarterial chemoembolization within 30 days (sequential group) and 73 patients underwent RF ablation after transarterial chemoembolization beyond 30 days (delayed group). Outcomes of interests included overall survival (OS), progression-free survival (PFS), and complete response (CR) rate.ResultsThe median OS and PFS were 49.8 and 38.0 months for sequential group, and 31.0 and 11.6 months for the delayed group. The sequential group experienced significantly better OS (hazard ratio [HR]: 0.517; P = .002) and PFS (HR, 0.621; P = .021). Among patients with multiple tumors or a single tumor >5 cm, the sequential group still had significantly longer OS (P = .022; P = .018, respectively) and PFS (P = 0.042; P = .036, respectively) than the delayed group, although no significant differences were observed among patients with solitary 3- to 5-cm tumors (P = .138; P = .803, respectively). The sequential group had a significantly better CR rate than the delayed group (85.4% vs. 68.5%, respectively; P = .035). Significant predictors of OS and PFS included maximum tumor size, number of tumors, and time interval between transarterial chemoembolization and RF ablation.ConclusionsTransarterial chemoembolization plus sequential RF ablation within 30 days was more effective for recurrent HCCs than transarterial chemoembolization plus delayed RF ablation. The time interval within 30 days is required for treating large or multiple HCCs but may not be necessary for solitary medium-sized HCC.     

Radiofrequency Ablation,Cryoablation, and Microwave Ablation for T1a Renal Cell Carcinoma: A Comparative Evaluation of Therapeutic and Renal Function Outcomes

PurposeTo compare the therapeutic and renal function outcomes of radiofrequency (RF) ablation, cryoablation, and microwave (MW) ablation for treatment of T1a renal cell carcinoma (RCC).Materials and MethodsA retrospective assessment of 297 patients (mean age 72 years range 24–90 years) with biopsy-proven RCC treated with image-guided percutaneous thermal ablation was performed between October 2006 and December 2016. Mean tumor size was 2.4 cm; mean radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, hilar tumor touching the main renal artery or vein, and location relative to polar lines; Preoperative Aspects and Dimensions Used for an Anatomical; and c-centrality scores were 6.0, 7.0, and 2.8, respectively. Assessments of adverse events, treatment efficacy, and therapeutic outcomes were performed among RF ablation, cryoablation, and MW ablation. The 2-year disease-free, metastatic-free, and cancer-specific survival rates were tabulated. Estimated glomerular filtration rate was used to assess for treatment related changes in renal function.ResultsA total of 297 T1aN0M0 biopsy-proven RCCs measuring 1.2–3.9 cm were treated with computed tomography–guided RF ablation (n = 244, 82%), cryoablation (n = 26, 9%), and MW ablation (n = 27, 9%). There were no significant differences in patient demographics among the 3 groups (P = .09). Technical success rates were similar among the 3 treatments (P = .33). Primary efficacy at 1 month postablation was more likely to be achieved with RF ablation and MW ablation than with cryoablation. At 2 years’ follow-up, there was no local recurrence, metastatic progression, or RCC-related death observed in the 3 groups. There was no significant change in estimated glomerular filtration rate among the 3 ablation groups compared with baseline at 2-year follow-up (P = .71).ConclusionRF ablation, cryoablation, and MW ablation are equivalent at 2 years for treatment of T1a RCC for therapeutic outcome, stability of renal function, and low adverse event rate.     

Image-Guided Percutaneous Thermal Ablation of Oligometastatic Ovarian and Non-Ovarian Gynecologic Tumors

PurposeTo assess the safety, feasibility, and efficacy of percutaneous thermal ablation (TA) in the treatment of metastatic gynecologic (GYN) tumors.Materials and MethodsA study cohort of 42 consecutive women (mean age, 59. years; range, 25–78 years) with metastatic GYN tumors (119 metastatic tumors) treated with radiofrequency (n = 47 tumors), microwave (n = 47 tumors), or cryogenic (n = 30 tumors) ablation from over 2,800 ablations performed from January 2001 to January 2019 was identified. The primary GYN neoplasms consisted of ovarian (27 patients; 77 tumors; mean tumor diameter [MTD], 2.50 cm), uterine (7 patients; 26 tumors; MTD, 1.89 cm), endometrial (5 patients; 10 tumors; MTD, 2.8 cm), vaginal (2 patients; 5 tumors; MTD, 2.40 cm), and cervical (1 patient; 1 tumor; MTD, 1.90 cm) cancers. In order of descending frequency, metastatic tumors treated by TA were located in the liver or liver capsule (74%), lungs (13%), and peritoneal implants (9%). Single tumors were also treated in the kidneys, rectus muscle, perirectal soft tissue (2.5%), and retroperitoneal lymph nodes (1.6%). All efficacy parameters of TA and definitions of major and minor adverse events are categorized by the latest Society of Interventional Radiology reporting standards.ResultsThe median follow-up of treated patients was 10 months. After the initial ablation, 95.6% of the patients achieved a complete tumor response confirmed by contrast-enhanced magnetic resonance imaging or computed tomography. On surveillance imaging, 8.5% of the ablated tumors developed local progression over a median follow-up period of 4.1 months. Five of 8 tumors with local recurrence underwent repeated treatment over a mean follow-up period of 18 months, and 4 of 5 tumors achieved complete eradication after 1 additional treatment session that resulted in a secondary efficacy of 80%. The overall technique efficacy of TA was 96.2% over a median follow-up period of 10 months.ConclusionsTA was safe and effective for the local control of metastatic GYN tumors in the lungs, abdomen, and pelvis, with an overall survival rate of 37.5 months and a local progression-free survival rate of 16.5 months, with only 4.8% of treated patients experiencing a major adverse event.     

Hepatic Hilar Nerve Block for Adjunctive Analgesia during Percutaneous Thermal Ablation of Hepatic Tumors: A Retrospective Analysis

PurposeTo determine whether hepatic hilar nerve block techniques reduce analgesic and sedation requirements during percutaneous image-guided thermal ablation of hepatic tumors.Materials and MethodsA single-center retrospective cohort analysis was performed of 177 patients (median age, 67 years; range, 33–86 years) who underwent percutaneous image-guided thermal ablation of liver tumors. All patients were treated utilizing local anesthetic and moderate sedation between November 2018 and November 2021 at a tertiary level hospital, with or without the administration of a hepatic hilar nerve block. Univariable and multivariable linear regression analyses were performed to determine the relationship between the administration of the hilar nerve block and fentanyl and midazolam dosages.ResultsA total of 114 (64%) patients received a hilar nerve block in addition to procedural sedation, and 63 (36%) patients received procedural sedation alone. There were no significant differences in the baseline demographic and tumor characteristics between the cohorts. The procedure duration was longer in the hilar block cohort than in the unblocked cohort (median, 95 vs 82 minutes; P = .0012). The technical success rate (98% in both the cohorts, P = .93) and adverse event rate (11% vs 3%, P = .14) were not significantly different between the cohorts. After adjusting for patient and tumor characteristics, ablation modality, and procedure and ablation durations, hilar nerve blocks were associated with lower fentanyl (?18.4%, P = .0045) and midazolam (?22.7%, P = .0007) dosages.ConclusionsHepatic hilar nerve blocks significantly decrease the fentanyl and midazolam requirements during thermal ablation of hepatic tumors, without a significant change in the technical success or adverse event rates.     

Hypertensive Crisis during Microwave Ablation of Adrenal Neoplasms: A Retrospective Analysis of Predictive Factors

PurposeTo identify risk factors for hypertensive crisis (HC) during ultrasound-guided percutaneous microwave (MW) ablation of adrenal neoplasms.Materials and MethodsPatients who underwent MW ablation for adrenal tumors between April 2006 and November 2017 were retrospectively identified for this study (51 consecutive patients; 35 males, 16 females; mean age, 55 years; range, 15–85 years). A total of 77 MW ablation treatments were performed for 67 tumors (24 primary [9 pheochromocytomas, 8 adenomas, and 7 cortical carcinomas]; and 43 metastases [22 hepatocellular carcinoma, 8 renal cell carcinoma, 5 non-small cell lung cancer, 4 colorectal cancer, 3 liposarcoma, and 1 malignant fibrous histiocytoma]). The mean diameter of the adrenal tumors was 4.6 cm (range, 1.2–16.2 cm). Information about patient demographics, imaging studies, pathology and laboratory results, procedure records, and clinical outcomes was retrieved and analyzed. Statistical analysis was then performed to determine potential risk factors for HC.ResultsOf the 77 MW ablation procedures, HC occurred in 13 (16.9%). A significantly higher risk of HC was observed in patients with pheochromocytoma (odds ratio [OR], 9.037; 95% confidence interval [CI], 1.731–47.172; P = .009), body mass index <24 kg/m² (OR, 5.167; 95% CI, 1.060–25.194; P = .042), dominant tumor size ≤4.5 cm (OR, 4.023; 95% CI, 1.011–16.005; P = .048), and pre-procedural systolic blood pressure ≥130 mmHg (OR, 0.242; 95% CI, 0.068–0.861; P = .029).ConclusionHC can occur during MW ablation in patients with either primary or metastatic adrenal tumors. Pheochromocytoma, body mass index, tumor size, and pre-procedural systolic blood pressure appear to be significant risk factors for the occurrence of HC.     

Transarterial Radioembolization versus Transarterial Chemoembolization Plus Percutaneous Ablation for Unresectable,Solitary Hepatocellular Carcinoma of ≥3 cm: A Propensity Score–Matched Study

PurposeTo compare the safety and effectiveness of transarterial radioembolization (TARE) and transarterial chemoembolization with drug-eluting embolic agents combined with percutaneous ablation (transarterial chemoembolization [TACE] + ablation) in the treatment of treatment-naïve, unresectable, solitary hepatocellular carcinoma (HCC) of ≥3 cm.Materials and MethodsTwenty-nine patients with treatment-naïve, unresectable, solitary HCC of ≥3 cm received combined TACE + ablation, and 40 patients received TARE at a single institution. Local tumor response, tumor progression-free survival (PFS), overall survival, need for reintervention, bridge to transplant, and major complications were compared. Clinical variables and outcomes were compared before and after propensity score matching (PSM).ResultsBefore PSM, patients who underwent TARE had a larger tumor size (3.7 vs 5.5 cm; P = .0005) and were older (61.5 vs 69.3 years; P = .0014). After PSM, there was no difference in baseline characteristics between the 2 groups, with the mean tumor sizes measuring 3.9 and 4.1 cm in the TACE + ablation and TARE cohorts, respectively. After PSM (n = 19 in each group), no statistically significant difference was observed in local radiological response (disease control rates, 100% vs 94.7%; P = .31), survival (subdistribution hazard ratio [SHR], 0.71; 95% confidence interval [CI], 0.28–1.80; P = .469), PFS (SHR, 0.61; 95% CI, 0.21–1.71; P = .342), bridge to transplant (21.1% vs 31.6%, P = .46), and major adverse event rates (15.8% vs 10.5%, P = .63) between the 2 groups. The mean total number of locoregional interventions was higher in the TACE + ablation cohort (1.9 vs 1.3 sessions, P = .02), with an earlier median reintervention trend (SHR, 0.61; 95% CI, 0.20–1.32; P = .167).ConclusionsThe present study showed that TARE and the combination of TACE and ablation are comparable in safety and effectiveness for treating treatment-naïve, unresectable, solitary HCC of ≥3 cm.