Cryoablation Group Research Articles

Cryoablation Versus Radiofrequency Ablation for Hepatic Malignancies: A Systematic Review and Literature-Based Analysis.

The aim of this study is to summarize and quantify the current evidence on the therapeutic efficacy of cryoablation compared with radiofrequency ablation (RFA) in patients with hepatic malignancies in a meta-analysis.Data were collected by searching PubMed, Scopus, and Cochrane databases for reports published up to May 26, 2015. Studies that reported data on comparisons of therapeutic efficacy of cryoablation and RFA were included. The random effects model was used to estimate the pooled relative risks of events comparing cryoablation to RFA for therapy of hepatic malignancies.Seven articles met the inclusion criteria and were included in the meta-analysis. The meta-analysis showed that there was no statistically significant difference in mortality of at least 6 months (odds ratio [OR] = 1.00, 95% confidence interval [CI]: 0.68–1.49) and local tumor progression according to both patients (OR = 1.64, 95% CI: 0.57–4.74) and tumors (OR = 1.81, 95% CI: 0.74–4.38) between cryoablation group and RFA group. However, the risk of complications was significantly higher in the cryoablation group than that in the RFA group (OR = 2.93, 95% CI: 1.15–7.46). When considering the specific complications, only thrombocytopenia (OR = 51.13, 95% CI: 2.92–894.21) and renal impairment (OR = 4.19, 95% CI: 1.34–13.11) but not other complications were significantly higher in the cryoablation group.In conclusion, the 2 methods had almost equal mortality and nonsignificant difference in local tumor progression, with higher risk of complications in cryoablation. Further large-scale, well-designed randomized controlled trials are needed to identify the current findings and investigate the long-term effects of cryoablation compared with RFA for therapy of hepatic malignancies.

Treatment of Solitary Painful Osseous Metastases with Radiotherapy, Cryoablation or Combined Therapy: Propensity Matching Analysis in 175 Patients.

Purposeaim of this study was to identify outcomes in pain relief and quality of life in patients with a solitary painful osseous metastasis treated by radiotherapy, cryoablation or the combination using a propensity score matching study design.Materials and Methods175 patients with painful bone metastases were included in the study. Twenty-five of them underwent a radiation course (20 Gy in five daily fractions) 15 days after the cryoablation. These subjects were retrospectively matched by propensity analysis with a group of subjects treated by radiotherapy (125 subjects) and with a group treated byCryoablation (25 subjects). The pain relief in terms of complete response, rate of subjects requiring analgesics after treatments and the changes in self-rated quality of life were measured. Informed consent was obtained from the subject and the study was approved by the local Ethical Committee.ResultsAn higher proportion of subjects treated by cryoablation (32%) or cryoablation followed by RT (72%;) experienced a complete response compared with patients treated by radiotherapy alone (11.2%). After Bonferroni correction strategy, the addition of radiotherapy to cryoablation significantly improved the rate of complete response compared with cryoablation alone (p = 0.011) and this paralleled with an improved self-rated quality of life. Seventeen subjects (13.6%) of patients in the radiotherapy group, 9 (36%) in the cryoablation group, and 19 (76)% in the cryoablation- radiotherapy group did not require narcotic medications.ConclusionsThe addition of radiotherapy to cryoablation favorably impacts on perceived pain, with a favorable toxicity profile. However, our data should be interpreted with caution and could serve as a framework around which to design future trials.

Endostar combined with cryoablation for subcutaneous xenografted tumor model of lung adenocarcinoma cell line A549 in BALB/c nude mice: An experimental study

Objective To investigate the inhibitory effect of Endostar combined with cryoablation on lung adenocarcinoma cell line A549 in BALB/c nude mice, and to discuss its interaction mechanisms.Methods The lung adenocarcinoma A549 model in BALB/c nude mice were established. When the largest diameter of tumor reached 1.0 cm, a total of 24 mice were randomly and equally divided into 4 groups:control group, Endostar group, cryoablation group and cryoablation plus Endostar group. The largest diameter and the vertical diameter of the tumors were measured at different points of time after treatment. At the 21st day, the mice were sacrificed and the tumors were removed and the rate of tumor cell apoptosis, the microvessel density(MVD) and the expression level of vascular endothelial growth factor(VEGF) were determined by using immunohistochemistry method. The results were statistically analyzed. Results The tumor growth velocity of the control group, Endostar group, cryoablation group and cryoablation plus Endostar group was(236.68 ± 51.23)%,(220.02 ± 30.61)%,(159.46 ± 29.33)% and(103.34 ± 25.50)%,respectively(P 0.01). The rate of apoptosis of the four groups was(21.67 ± 2.34)%,(22.17 ± 1.47)%,(38.33 ± 1.37)% and(49.17 ± 1.72)%,respectively(P 0.01). The MVD and the expression levels of VEGF of the cryoablation plus Endostar group were significantly lower than those of the other three groups(P 0.01). Statistical analysis revealed that a positive correlation existed between the express of VEGF and MVD. Conclusion Endostar can obviously enhance the therapeutic efficacy of cryoablation on lung adenocarcinoma A549 in BALB/c nude mice. The underlying mechanisms may be the Endostar-inhibited angiogenesis through down-regulating the expression of VEGF, and the cooperative effect of Endostar and cryoablation on the promotion of tumor cell apoptosis.

Experimental study of anti-tumor immunologic response induced by cryoablation for prostate cancer

To assess the anti-tumor immune response of cryoablation for prostate cancer. Mouse model of prostate cancer was established. And the tumor-bearing mice were divided into three groups: control group (Group A), surgery group (Group B) and cryoablation group (Group C). Blood samples were withdrawn before and at Days 7, 14, 21 post-treatment. IFN-gamma and IL-4 were analyzed by enzyme-linked immunosorbent assay (ELISA). Th1/Th2 ratio was estimated from the IFN-gamma/IL-4 ratio. Lymphocytes of draining lymph node (DLN) and spleen were isolated. And the post-therapeutical number of tumor-specific IFN-gamma+CD4+ Th cells was measured by the method of enzyme link immunological spot (ELISPOT). And tumor-specific cytolytic activity of CD8+ cytotoxic T lymphocyte (CTL) was measured by LDH assay. The rate of metastasis was assessed. At Day 7 post-treatment in Groups A, B and C, Th1/Th2 ratio was 4.97+/-0.31, 10.07+/-0.62 and 13.71+/-0.57 respectively (P<0.05); the number of IFN-gamma+ cells every 10(6) CD4+ Th cells in DLN 22.3+/-1.0, 24.0+/-1.2 and 243.4+/-46.2 respectively; cytolytic activity of cytotoxic T lymphocyte against prostate cancer cells (14.6+/-1.1)%, (15.2+/-0.8)% and (62.6+/-2.3)% respectively (P<0.05). But for T cells derived from spleen, there were no difference in IFN-gamma+CD4+ Th cells or cytolytic activity of CTL among the groups. At Day 28 post-treatment, the rate of DLN metastasis was 100%, 80% and 40% respectively. And the rates of lung metastasis were all 100%. Cryoablation for prostate cancer can induce the Th1 advantage of anti-tumor immunity and generate the tumor-specific immune response in DLN. But the response remains limited. Further studies are warranted.

Non-extended cryoablation could be a new strategy in lung cancer management: An experiment on green fluorescent protein-labeled Lewis lung cancer-bearing mice

Modern cryoablation has been performed in solid tumor management for more than two decades. Following the surgical spirits, it seems natural to pursue radical procedures in clinical practice, which results in unnecessary adverse effects. The attempt to use non-extended procedure made some marked achievements in practice but was criticized severely, because it was supposed to induce residual tumors, which would trigger the rapid development of cancer. Oncologists favored this procedure, however, claiming that non-extended cryoablation let lung cancer patients have higher quality of lives and longer survivals, in light of clinical observations. Therefore, this study was conducted trying to solve this controversy. In this study, fifty female C57BL/6J mice were grafted green fluorescent protein (GFP)-labeled Lewis lung cancer and randomized into two groups. The bidirectional diameters and fluorescence intensity of tumors, and the body weight of mice were recorded. Two weeks after the intervention, tumor volumes increased 20.95% in the cryoablation group, significantly different from that in the control group; the fluorescence intensity decreased 49.85% in the cryoablation group but increased 125.07% in the control group. Lung metastases could be observed in only 20% of mice in the cryosurgery group, contrasted to 64% in the control group. The non-extended lung cancer cryoablation does induce marginal tumor residuals, but will not trigger rapid tumor development. Inversely, the residual tumor cells are severely struck and the metastases are suppressed after the intervention. It could be a new strategy in lung cancer management, even for patients not in early stage.

Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis.

We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: −2.83; P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: −2.36; P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time.

Short-term safety and efficiency of cryoablation for renal sympathetic denervation in a swine model.

Background:Renal sympathetic nerves are involved in the reflective activation of the sympathetic nervous system in circulatory control. Catheter-based renal denervation (RDN) ameliorated treatment-resistant hypertension safely, but 10%–20% of treated patients are nonresponders to radiofrequency denervation. The purpose of this study was to investigate the safety and efficiency of cryoablation for sympathetic denervation in a swine model and to explore a new way of RDN.Methods:Seven swines randomly assigned to two groups: Renal cryoablation (CR) group and control group. The control group underwent renal angiogram only. The CR group underwent renal angiogram plus bilateral renal cryoablation. Renal angiograms via femoral were performed before denervation, after denervation and prior to the sacrifice to access the diameter of renal arterial and the pressure of aorta abdominalis. Euthanasia of the swine was performed on 28-day to access norepinephrine (NE) changes of the renal cortex and the changes of renal nerves.Results:Cryoablation did not induce severe complications at any time point. There was no significant change in diameter of renal artery. CR reduced systolic blood pressure (BP) from 145.50 ± 9.95 mmHg at baseline to 119.00 ± 14.09 mmHg. There was a slight but insignificant decrease in diastolic BP. The main nerve changes at 28-day consisted of necrosis with perineurial fibrosis at the site of CR exposure in conjunction with the nerve vacuolation. Compared with the control group, renal tissue NE of CR group decreased by 89.85%.Conclusions:Percutaneous catheter-based cryoablation of the renal artery is safe. CR could effectively reduce NE storing in the renal cortex, and the efficiency could be maintained 28-day at least.

Cryo-ablation improves anti-tumor immunity through recovering tumor educated dendritic cells in tumor-draining lymph nodes.

BackgroundIn addition to minimally invasive destruction of tumors, cryo-ablation of tumors to some extent modulated anti-tumor immunity. Cryo-ablated tumors in glioma mice models induced anti-tumor cellular immunologic response which increases the percentage of CD3+ and CD4+T cells in blood as well as natural killer cells. As a crucial role in triggering anti-tumor immunity, dendritic cells (DCs) were educated by tumors to adopt a tolerance phenotype which helps the tumor escape from immune monitoring. This study aims to study whether cryo-ablation could influence the tolerogenic DCs, and influence anti-tumor immunity in tumor-draining lymph nodes (TDLNs).MethodsUsing the GL261 subcutaneous glioma mouse model, we created a tumor bearing group, cryo-ablation group, and surgery group. We analyzed alteration in phenotype and function of tolerogenic DCs, and evaluated the factors of anti-tumor immunity inhibition.ResultsDCs in TDLNs in GL261 subcutaneous glioma mouse model expressed tolerogenic phenotype. In contrast to surgery, cryo-ablation improved the quantity and quality of these tolerogenic DCs. Moreover, the DCs decreased the expression of intracellular interleukin-10 (IL-10) and extra-cellular IL-10. In vitro, DCs from the cryo-ablation group recovered their specific function and induced potent anti-tumor immunity through triggering T cells. In vivo, cryo-ablation showed weak anti-tumor immunity, only inhibiting the growth of rechallenged tumors. But many IL-10-low DCs, rather than IL-10-high DCs, infiltrated the tumors. More importantly, Tregs inhibited the performance of these DCs; and depletion of Tregs greatly improved anti-tumor immunity in vivo.ConclusionCryo-ablation could recover function of tumor induced tolerogenic DCs in vitro; and depletion of Tregs could improve this anti-tumor effect in vivo. The Tregs/CD4+T and Tregs/CD25+T cells in TDLNs inhibit DCs’ activity and function.

S011: The effect of testicular cryoablation on testosterone level in rats: An experimental model of histopathological orchiectomy

To determine whether testicular cryoablation caused histopathological orchiectomy, and to show its effects on serum total testosterone (t-testosterone) levels in rats.A total of 12 Wistar albino male rats were used in this study. The animals were divided into two groups, as cryoablation (9 rats) and control (3 rats) groups. Bilateral cryoablation was performed in the cryoablation group. T-testosterone levels were measured in both groups before scrotal exploration. Bilateral or­chiectomy was performed in both groups 10 days after the cryoablation procedure. T-testosterone was measured immediately before orchiectomy. Mann-Whitney U test was used for intergroup comparisons.Baseline t-testosterone levels were 1.31 (0.78-2.45) ng/mL and 0.98 (0.91-2.05) ng/mL in the cryoab­lation and the control groups, respectively (P = .92). T-testosterone levels were 0.23 (0.07-1.12) ng/mL and 2.87 (0.63-3.06) ng/mL in the cryoablation and the control groups, respectively, in the blood samples obtained at the time of orchiectomy (P = .03). Histopathological examination of rat testes revealed varying degrees of paratestic­ular inflammation and necrosis in 13 of 18 testes in the cryoablation group. None of 6 testes showed necrosis in the control group.Our study showed that histopathological orchiectomy could be obtained by cryoablation in rat testes.

Effects of cryoablation and radiofrequency ablation on endothelial and blood clotting activation.

Cryoablation (CA) emerged as an alternative procedure to radiofrequency (RF). The aim of this study was to compare haemostatic system alterations in patients undergoing RF or CA for atrioventricular nodal reentrant tachycardia ablation. von Willebrand factor (vWF), spontaneous whole blood platelet aggregation, prothrombin fragment F1+2 (F1+2), thrombin-antithrombin complex (TAT), plasminogen activator inhibitor type-1 (PAI-1), and clot lysis time (CLT) were determined in 48 patients (27 CA; 21 RF; 19M/29F, mean age 49.6±17.6years). Blood samples were obtained before the procedure (T0), immediately after (T1), and 24h later (T2). At T1 both procedures were associated with a significant increase in levels of the endothelial activation marker vWF. At T2 vWF levels were lower in CA than in RF group. No changes in whole blood platelet aggregation before and after ablation procedures were observed. At T1 both groups determined an increase in blood clotting activation markers, F1+2, TAT, and DD. At T2 F1+2, TAT and DD levels were similar to baseline values. The comparison between RF and CA showed no significant differences in F1+2 and TAT levels, whereas at T1 DD levels were higher in CA group than in RF group. Both procedures induced a significant decrease in CLT, whereas no changes in PAI-1 levels were found. There were no significant differences in CLT and PAI-1 levels. The fibrinolytic efficiency analysis showed that at T1 DD/TAT and DD/F1+2 ratios were lower in RF group and remained lower in RF than in CA group at T2. CA procedure may be associated with a lower degree of endothelial damage and with a higher fibrinolytic capacity respect to RF.

P0076 Percutaneous cryoablation for stage iv lung cancer: A retrospective analysis

Background The aim of this study was to investigate the therapeutic effect of cryoablation treatment and palliative treatment in stage IV lung cancer. Methods Fifty-four patients with intrapulmonary and extrapulmonary tumours were enrolled into the study. 31 patients received cryoablation treatment and 23 patients had palliative treatment (no cryoablation). Both the safety of the procedure and overall survival (OS) for stage IV lung cancer were assessed during a 6.5-year follow-up period. The OS of patients in both groups and the effects of treatment timing and frequency were compared. Findings The OS in the cryoablation group was significantly longer than in the palliative group (median OS: 14 months versus 7 months, p = 0.0009). The OS of those who received delayed cryoablation treatment was longer than that observed for those who received timely treatment (median OS: 18.5 months versus 10 months, p = 0.0485), but this was not observed in those who received palliative treatment (median OS: 7 months versus 7.5 months, p = 0.9814). Multiple treatments compared with single treatments played an important part in improving the OS of patients who received cryoablation treatment (median OS: 18 months versus 14 months, p = 0.0376). Interpretation There was a significant difference between cryoablation and palliative treatment in terms of OS. In addition, multiple cryoablation treatments may have an advantage over single treatments.

Standardization of selection criteria for percutaneous image-guided cryoablation of recurrent soft-tissue sarcomas

Percutaneous image-guided cryoablation has not been validated for local management of recurrence of soft tissue sarcoma (STS) of the trunk or limbs. This study aims to identify selection criteria for cryoablation in order to standardize indications of this treatment. Between 2000 and 2010, 46 patients (57 tumors) presenting local recurrences of STS of the trunk or limbs and treated following standards of care were selected from our institutional database. Eligibility for cryoablation was assessed by two radiologists according to predefined criteria: maximal diameter size of the tumor ≤10cm, distance to skin >5mm, distance to neurovascular structures 3mm at least, absence of articular involvement and planned cryoablation covering the entire lesion volume. Characteristics and outcomes were compared. There was nearly perfect agreement for all criteria (k coefficient ranging from 0.83 to 0.98) between both readers. A subgroup of 13patients was identified as eligible for cryoablation. Locations to the trunk, pelvic girdle or shoulder were significantly more present in the cryoablation group (P=0.002). In this group, tumors were mainly located deeply (P=0.002) with great axes ≤5cm (P=0.044). High local tumor aggressiveness (P=0.016) and differentiated myxoid liposarcoma or myxofibrosarcoma (P=0.007) were more frequent in the eligible group. Based on these criteria, two groups of patients with local relapse of STS can be identified. These results may improve the standardization of selection of patients who could be candidates for cryoablation.

Comparison of Pulmonary Vein Isolation Using Cryoballoon Versus Conventional Radiofrequency for Paroxysmal Atrial Fibrillation

The aim of this study was to compare the results of pulmonary vein isolation using conventional irrigated radiofrequency (RF) approach versus the cryoballoon (CB) ablation. From January 2008 to December 2011, a total of 426 patients with drug-resistant symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation as the index procedure by conventional manual RF or CB ablation at our center. A final population of 396 patients was considered for analysis and divided into 2 groups: conventional RF ablation (n= 260) and CB ablation (n= 136). At a mean follow-up of 23 ± 13months (median 27, range 4 to 68), the success rate for RF ablation group was 57.3% (149 patients) and was 63.2% (86 patients) for cryoablation group (p= 0.25). Procedural times were significantly shorter in the cryoablation group (192 ± 49 vs 112 ± 58minutes, p <0.000001) but not fluoroscopy times (36 ± 14 vs 31 ± 17minutes, p= 0.45). No clinical predictors were found to predict atrial fibrillation recurrences. Complication rates were similar in both groups except for phrenic nerve palsy that was uniquely observed in the CB group (8.1%, p <0.00001). All phrenic nerve palsies resolved during follow-up. In conclusion, on a medium-term follow-up, conventional point-by-point RF ablation and CB ablation showed similar success rates. Procedural times were significantly shorter in the CB approach. The most frequent complication during CB procedures was phrenic nerve palsy, which occurred in 8.1% of patients and resolved in all during the follow-up period.

Tumor-specific immunity induced by cryoablation in a murine renal cell carcinoma model.

PurposeTo evaluate tumor-specific immunity and define the mechanisms involved in the cryoimmunologic response, we compared the tumor control efficacy and immunologic responses of cryoablation with those of surgical excision in a tumor rechallenge model.Materials and MethodsSixty BALB/c mice with RENCA tumors that were generated in the left flank area underwent cryoablation or radical excision. The mice successfully treated were rechallenged with RENCA or an undifferentiated colon carcinoma cell line, CT26, in the contralateral right flank area. The recurrence rate after tumor rechallenge in each group was then observed. To assess the immunologic response of each treatment modality, fluorescent-activated cell sorting (FACS) analysis and a cytotoxicity assay using 51Cr release were performed.ResultsAfter reinoculation of the RENCA cells, the rate of tumor growth was significantly higher in the surgical excision group than in the cryoablation group (94.4% vs. 11.1%, p=0.001). In the cryoablation group, the tumor growth rate was significantly increased after rechallenge of CT26 cells compared with RENCA (94.1% vs. 11.1%, p=0.001). The cryoablation group showed an elevated CD3, CD4, CD8 T, and natural killer cell count in the FACS analysis and also showed significantly increased cytotoxicity in the 51Cr release assay compared with the excision group.ConclusionsThese results showed that cryoablation, compared to surgical resection, was more effective in preventing tumor growth after rechallenge with RENCA cells and that this response was tumor-specific, because the CT26 cells did not have the same effect.

Experimental Study of Endostar Injection Concomitant with Cryoablation on Lung Adenocarcinoma A549 Xenografts

To explore the inhibiting effect and mechanism of Endostar injection concomitant with cryoablation on lung adenocarcinoma A549 xenografts in nude mice. A total of 24 nude mice with subcutaneous xenografts of the A549 cell line were established and divided into 4 groups when the maximal diameters of tumors became 1 cm: control group, Endostar group, cryoablation group and combination group (Endostar concomitant with cryoablation). The nude mice were sacrificed after 21-days treatment, tumour tissues were removed to measure their volume, in situ test of TdT-mediated dUTP nick end labeling (TUNEL) was adopted to determine the cellular apoptosis around freezing injury zones, and immunohistochemical SP test was applied for the detection of micro-vessel density (MVD) and vascular endothelial growth factor (VEGF) expression levels. At 21-days after treatment, the growth velocities of control group, Endostar group, cryoablation group and combination group were 236.7 ± 51.2%, 220.0 ± 30.6%, 159.5 ± 29.3% and 103.3 ± 25.5% (P<0.01), while cellular apoptosis rates of tumors were 21.7 ± 2.34%, (22.17 ± 1.47)%, 38.3 ± 1.37% and 49.2 ± 1.72%, (P<0.01), respectively, according to the immunohistochemical test. MVD and VEGF expression levels in the combination group were both lower than in other groups (P<0.01), also being positively related (r=0.925, P<0.01). Endostar can significantly improve the inhibitory effects of cryoablation on xenografts of lung adenocarcinoma A549, and the mechanism is probably associated with its function as an inhibitor of tumour neo-angiogenesis through down-regulating VEGF expression.

Cryoablation versus radiofrequency ablation of atrioventricular nodal reentrant tachycardia

Ablation of the slow pathway is an established cure for atrioventricular nodal reentrant tachycardia (AVNRT). Periprocedural damage to the conduction system is a major concern during AVNRT ablation, and cryoablation (CRYO) has been suggested to improve the procedural safety compared to standard radiofrequency (RF) ablation, without reducing the procedural success. We performed a systematic review and meta-analysis of studies comparing CRYO with RF ablation of AVNRT. We searched PubMed, CENTRAL, the BioMed Central, EMBASE, CardioSource, clinicaltrials.gov, and ISI Web of Science (January 1980 to July 2013). No language restriction was applied. Two independent reviewers screened titles and abstracts to identify studies that compared the procedural outcomes of AVNRT ablation with either CRYO or RF energy. Two independent reviewers assessed the risk of bias according to the Cochrane Collaboration, and extracted patient, study characteristics, and procedural outcome data. Results are expressed as odds ratio (OR) or as weighted mean difference (WMD) with their 95% confidence interval (CI). Fourteen studies (5 prospective randomized and 9 observational) with 2,340 patients (mean age range 13 to 53years, 1,522 (65%) females) were included in the analysis. RF ablation was performed in 1,262 (54%) patients, while CRYO in 1,078 (46%) patients. Acute success (abolition of dual atrioventricular node physiology or single echo beats) was achieved in 88% of patients treated with RF versus 83% of those treated with CRYO (OR = 0.72, 95% CI 0.46 to 1.13; P = 0.157). RF ablation was associated with shorter total procedure time (WMD = -13.7min, 95% CI -23 to -4.3min; P = 0.004), but slightly longer fluoroscopy time (WMD = +4.6min 95% CI +1.7 to +7.6min; P = 0.002). Permanent atrioventricular block occurred in 0.87% RF cases and in no CRYO case (OR = 3.60, 95% CI 1.09 to 11.81; P = 0.035). Over a median follow-up of 10.5months (range 6 to 12months), freedom from recurrent AVNRT was 96.5% in the RF group versus 90.9% in the CRYO group (OR = 0.40, 95% CI 0.28 to 0.58; P < 0.001). At meta-regression analysis, no clinical or procedural variable had a significant interaction with the results above. In patients undergoing AVNRT ablation, RF significantly reduces the risk of long-term arrhythmia recurrence compared to CRYO, but is associated with a higher risk of permanent atrioventricular block.

Renal Cryoablation Versus Robot-Assisted Partial Nephrectomy: Washington University Long-Term Experience

American Urological Association guidelines endorse partial nephrectomy as the preferred treatment for patients with small renal masses, while considering patients with significant comorbidities potential candidates for ablative therapy. We compared perioperative, renal functional, and oncologic outcomes of renal cryoablation and robot-assisted partial nephrectomy (RAPN) based on our long-term institutional experience. A retrospective review evaluated 267 patients who underwent laparoscopic or percutaneous cryoablation (July 2000-June 2011) and 233 patients who underwent RAPN (June 2007-September 2012) for enhancing renal masses at Washington University. The perioperative complication rate was 8.6% in the cryoablation group vs 9.4% in the RAPN group (P = 0.75). There was no significant difference in complication risk between the two treatment modalities on multivariate analysis. Estimated glomerular filtration rate (eGFR) at last follow-up was 6% lower than preoperative eGFR in the cryoablation group and 13% lower in the RAPN group (P<0.01). The advantage of cryoablation in preserving renal function persisted on multivariate analysis (P = 0.02). In patients with pathologically proven renal-cell carcinoma, 5-year Kaplan-Meier disease-free survival (DFS), cancer-specific survival (CSS), and overall survival was 83.1%, 96.4%, and 77.1% in the cryoablation cohort vs 100%, 100%, and 91.7% in the RAPN group. Mean time to recurrence was 16.2 months (range 0.03-42.0 mos). Cryoablation was associated with increased recurrence risk (hazard ratio [HR] = 11.4, P = 0.01) on multivariate analysis. Cryoablation and RAPN are safe alternatives for managing renal masses amenable to nephron-sparing interventions, offering acceptable morbidity and excellent renal preservation. While RAPN offers improved DFS, for those willing to undergo close postoperative monitoring and accept the potential need for re-treatment of recurrent disease, cryoablation offers excellent long-term CSS.

The COR trial: A randomized study with continuous rhythm monitoring to compare the efficacy of cryoenergy and radiofrequency for pulmonary vein isolation

Results from randomized trials designed to compare cryoenergy with radiofrequency for pulmonary vein (PV) isolation are lacking. To compare the efficacy of a simplified strategy for PV cryoablation (group C) vs PV isolation with open-irrigated radiofrequency catheters (group R). Fifty patients with paroxysmal atrial fibrillation (AF) and 4 independent PVs received a Reveal XT implantable cardiac monitor and were randomized to group C or group R. In group C, PV ablation was done with a single Arctic Front balloon (23 or 28 mm) per patient and two 300-second applications per PV. No further applications were delivered to close residual conduction gaps. In group R, bidirectional PV conduction block was pursued with Lasso and Navistar ThermoCool catheters and the CARTO system. The primary end point was the proportion of patients remaining free from AF recurrences ≥2 minutes without taking antiarrhythmic drugs 12 months after ablation. The primary end point was met by 12 (48%) patients in group C and 25 (68%) patients in group R (odds ratio 0.43; P = .05). This difference disappeared after adjustment for acute procedural outcome. In patients for whom all 4 PVs were blocked at the end of the procedure, there was no difference between group C and group R in the primary end point (67% vs 68%; P = .94). The efficacy of the simplified strategy for PV cryoablation tested in this study is inferior to PV isolation using open-irrigated radiofrequency catheters with electrophysiological and electroanatomical guidance. Complete PV conduction block is critical to the success of AF ablation.

Meta-analysis of cryoablation versus microwave ablation for small renal masses: is there a difference in outcome?

We aimed to compare local and metastatic recurrence of small renal masses primarily treated by cryoablation or microwave ablation. The MEDLINE, CINAHL, and PUBMED databases were searched to review the treatment of small renal masses with cryoablation or microwave ablation. Fifty-one studies met the inclusion criteria. Fifty-one studies representing 3950 kidney lesions were analyzed. No differences were detected in the mean patient age (P = 0.150) or duration of follow-up (P = 0.070). The mean tumor size was significantly larger in the microwave ablation group compared with the cryoablation group (P = 0.030). There was no difference between microwave ablation and cryoablation groups in terms of primary effectiveness (93.75% vs. 91.27%, respectively; P = 0.400), cancer-specific survival (98.27% vs. 96.8%, respectively; P = 0.470), local tumor progression (4.07% vs. 2.53%, respectively; P = 0.460), or progression to metastatic disease (0.8% vs. 0%, respectively; P = 0.120). Patient age was predictive of overall complications in the multivariate analysis (P = 0.020). Local tumor progression with cryoablation was predicted by the mean follow-up duration using univariate (P = 0.009) and multivariate regression (P = 0.003). Clear cell and angiomyolipoma were more frequent in the microwave ablation group (P < 0.0001 and P = 0.03328, respectively), and papillary, chromophobe, and oncocytoma were more frequent in the cryoablation group (P < 0.0001, P < 0.0001, and P = 0.0004, respectively). Open access was used more often in the microwave ablation group than in the cryoablation group (12.20% vs. 1.04%, respectively; P < 0.0001), and percutaneous access was used more frequently in the cryoablation group than in the microwave ablation group (88.64% vs. 37.20%, respectively; P = 0.0021). There is no difference in local or metastatic recurrence between cryoablation- and microwave ablation-treated small renal masses.

Percutaneous cryoablation for stage IV lung cancer: A retrospective analysis

The aim of this study was to investigate the therapeutic effect of cryoablation treatment and palliative treatment in stage IV lung cancer. Fifty-four patients were enrolled into the study. Thirty-one patients received cryoablation treatment (including intra- and extrapulmonary tumors), and 23 patients had palliative treatment (no cryoablation). Both the safety of the procedure and overall survival (OS) for stage IV lung cancer were assessed during a 6.5year follow-up period. The OS of patients in both groups and the effects of treatment timing and frequency were compared. The OS in the cryoablation group was significantly longer than in the palliative group (median OS: 14months vs. 7months, P=0.0009). The OS of those who received delayed cryoablation treatment was longer than that observed for those who received timely treatment (median OS: 18.5months vs. 10months, P=0.0485), but this was not observed in those who received palliative treatment (median OS: 7months vs. 7.5months, P=0.9814). Multiple treatments played an important role in improving the OS of patients who received cryoablation treatment (median OS: 18months vs. 14months, P=0.0376). There was a significant difference between cryoablation and palliative treatment, in terms of OS. In addition, multiple cryoablation treatments may have an advantage over single treatments.