Cryoablation Of Liver Tumors Research Articles

Abstract No. 167 Thrombocytopenia following percutaneous microwave and cryoablation of liver tumors

Abstract No. 167 Thrombocytopenia following percutaneous microwave and cryoablation of liver tumors

Periprocedural factors associated with overall patient survival following percutaneous image-guided liver tumor cryoablation

Purpose To assess the impact of periprocedural factors, including adverse events, on overall patient survival following image-guided liver tumor cryoablation procedures. Methods In this retrospective single-institution study, 143 patients (73 male, 70 female, ages 29–88) underwent 169 image-guided liver tumor cryoablation procedures between October 1998 and August 2014. Patient, tumor and procedural variables were recorded. The primary outcome was overall survival post-procedure (Kaplan–Meier analysis). Secondary outcomes were the impact of 15 variables on patient survival, which were assessed with multivariate cox regression and log-rank tests. Results Mean tumor diameter was 2.5 ± 1.2 cm. 26 of 143 (18.2%) patients had primary hepatic malignancies; 117 of 143 (81.8%) had liver metastases. Survival analysis revealed survivor functions at 3, 5, 7, 10 and 12 years post-ablation of 0.54, 0.37, 0.30, 0.17 and 0.06, with mean survival time of 40.8 ± 4.9 months. Tumor size ≥4 cm (p = .018), pre-procedural platelet count <100 × 103/μL (p = .023), and prior local radiation therapy (p = .014) were associated with worse overall patient survival. Grade 3 or higher adverse events were not associated with reduced survival (p = .49). Conclusions All variables associated with overall survival were patient-related and none were associated with the cryoablation procedure. Pre-procedural thrombocytopenia, larger tumor size and history of prior local radiation therapy were independent risk factors for reduced overall survival in patients undergoing hepatic cryoablation. Adverse events related to hepatic cryoablation were not associated with decreased survival.

Percutaneous Cryoablation of Liver Tumors: Initial Experience from a Tertiary Care Center in India

Percutaneous ablation is an important part of management strategy for liver tumors. While radiofrequency ablation and microwave ablation are the most widely used ablative techniques, cryoablation (CA) has several technical advantages but has been underused till recently. In this study, we report the initial experience with percutaneous CA of liver tumors. This was a retrospective evaluation of consecutive patients with liver tumors who underwent percutaneous CA between October 2018 and August 2019. The ablation procedures were performed under combined ultrasound and computed tomography guidance using argon-helium-based CA systems. The baseline tumor characteristics (including size and location), Barcelona Clinic Liver Cancer stage, and Child-Pugh score were recorded. Each patient underwent a follow-up after 1 month and at 3 months subsequently. Technical success, complete response, local tumor progression, and overall survival were evaluated. Nine patients (mean age, 62.4 years, median age, 66 years, five men and four women) with 10 liver tumors (mean size, 2.22cm) underwent CA. Seven (77.8%) patients had hepatocellular carcinoma (HCC), and 2 patients had solitary liver metastasis. One patient with HCC had two lesions, while the rest had only one lesion. Of the two metastatic lesions, one was from carcinoma of the cervix and the other was from jejunal neuroendocrine tumor. Five tumors were located adjacent to the gallbladder, two lesions were adjacent to the right portal vein, two lesions were subcapsular, and one lesion was adjacent to the stomach. Technical success was achieved in all the patients. Complete response was achieved in 7 (77.8%) patients. The median follow-up period was 7 months (range, 3-12 months). There was no local tumor progression and no death during the follow-up period. No procedure-related complication was seen. Percutaneous CA of hepatic tumors is technically feasible and is a safe and effective ablative technique.

Abstract No. 500 Cryoprobe factors associated with higher complication rates in patients undergoing percutaneous image-guided liver tumor cryoablation

The goal of this study was to evaluate possible associations between cryoablation probe factors and high-grade adverse events (AE) in patients undergoing percutaneous image-guided hepatic tumor cryoablation. In this IRB-approved retrospective study, a total of 204 patients were studied. Inclusion criteria included (1) age>18 years, (2) pathology-proven hepatic malignancy, and (3) and image-guided hepatic cryoablation performed between October 1998 and December 2018. The standard cryoablation protocol utilized the SeedNet system (Galil Medical, Inc) and included two 15-minute freeze applications separated by a 10-minute thaw. Procedure-related AE were graded using the CTCAE grading system. High-grade postprocedural AE were defined as CTCAE grades 3 or higher. Chi-squared analysis and ANOVA analysis were used to assess for statistically significant differences for categorical variables and continuous variables, respectively. Univariate analysis was used to assess the clinical and technical factors associated with high-grade AE. Factors assessed included demographic data, tumor type, number of cryoablation probes used and probe insulation. A total of 204 patients met inclusion criteria (52% female, age range 29 to 91, mean 62.4). Average tumor diameter was 2.4 ± 1.1 cm (range, 0.4-5 cm). 25% of tumors were primary hepatic malignancies with the remaining consisting of metastatic hepatic lesions. Insulated probes were used in 50% of the cases. The mean number of probes used was 3.6 ± 2.7. We observed an overall 28% AE rate during the study period, the high-grade AE rate was 6%. There were a total of 22 grade 1, 24 grade 2, 8 grade 3 and 3 grade 4 AE. No grade 5 AE occurred. A higher number of cryoablation probes (OR = 1.42, P <0.001) and lack of probe insulation (OR = 5.1, P = 0.042) were associated with increased likelihood of high-grade AE. None of the other assessed factors were associated with high-grade AE. The use of insulated cryoablation probes and the use of fewer probes (when feasible) may reduce the likelihood of high-grade AE in patients undergoing hepatic cryoablation.

04:03 PM Abstract No. 186 Periprocedural factors associated with worse overall patient survival following percutaneous image-guided liver tumor cryoablation

04:03 PM Abstract No. 186 Periprocedural factors associated with worse overall patient survival following percutaneous image-guided liver tumor cryoablation

Incidence and clinical sequelae of portal and hepatic venous thrombosis following percutaneous cryoablation of liver tumors

To assess the incidence and sequelae of portal and hepatic venous thrombosis after percutaneous cryoablation of hepatic tumors. From November 1998 through December 2010, 223 hepatic tumors were cryoablated during 170 ablation procedures in 135 patients. 24-h post-procedure MR images were reviewed retrospectively by two abdominal radiologists in consensus to identify tumor ablations that developed one or more new portal or hepatic venous thromboses in or outside the ablation zone. On follow-up MRI and CT examinations the outcomes of thromboses were classified as resolved, partially recanalized, persistent, or propagated. Venous thrombosis developed in association with 54 (24%) of 223 tumor ablations treated during 53 (31%) ablation procedures in 39 (28.8%) patients (15 women, 24 men; age range 40-82years, mean 59years). Of these 54 thromboses, 49 (91%) were located in portal vein branches, four (7%) in both portal and hepatic vein branches, and one (2%) in a hepatic vein branch. Thrombosed veins were outside but abutted the ablation zone in 36 (66.7%), and within it in 18 (33.3%). On follow-up imaging (n=49), thrombi resolved in 29 (59%), partially recanalized in two (4%), persisted in 18 (37%) and propagated from sub-segmental or segmental branches to the left or right portal branches in five (10%). No thrombus propagated to the main portal vein or inferior vena cava. Portal and hepatic vein branch thromboses are common in small branches following percutaneous cryoablation of hepatic tumors and most resolve spontaneously without sequelae.

Percutaneous Cryoablation for Liver Cancer.

Based on the primary tumor site, liver cancer can be divided into two categories: (1) primary liver cancer and (2) metastatic cancer to the liver from a distant primary site. Guided cryoablation via many imaging methods induces iceball formation and tumor necrosisand is an attractive option for treating unresectable hepatocellular carcinoma (HCC) and metastatic liver cancer. There are several advantages to using cryoablation for the treatment of liver cancer: it can be performed percutaneously, intraoperatively, and laparoscopically; iceball formation can be monitored; it has little impact on nearby large blood vessels; and it induces a cryo-immunological response in situ. Clinically, primary research has shown that percutaneous cryoablation of liver cancer is relatively safe and efficient, and it can be combined with other methods, such as radiation therapy, chemotherapy, and immunology, to control disease. Although research is preliminary, cryosurgery is fast becoming an alternative treatment method for HCC or liver tumors. Here, we review the mechanisms of liver tumor cryoablation, cryoablation program selection, clinical efficiency, and complications following treatment.

Percutaneous Imaging-Guided Cryoablation of Liver Tumors: Predicting Local Progression on 24-Hour MRI

The purpose of this study was to determine which MRI features observed 24 hours after technically successful percutaneous cryoablation of liver tumors predict subsequent local tumor progression and to describe the evolution of imaging findings after cryoablation. Thirty-nine adult patients underwent technically successful imaging-guided percutaneous cryoablation of 54 liver tumors (hepatocellular carcinoma, 8; metastases, 46). MRI features pertaining to the tumor, ablation margin, and surrounding liver 24 hours after treatment were assessed independently by two readers. Fisher exact or Wilcoxon rank sum tests (significant p values < 0.05) were used to compare imaging features in patients with and without subsequent local tumor progression. Imaging features of the ablation margin, treated tumor, and surrounding liver were evaluated on serial MRI in the following year. A minimum ablation margin of 3 mm or less was observed in 11 (78.6%) of 14 tumors with and 15 of 40 (37.5%) without progression (p = 0.012). A blood vessel bridging the ablation margin was noted in 11 of 14 (78.6%) tumors with and nine of 40 (22.5%) without progression (p < 0.001). The incidence of tumor enhancement 24 hours after cryoablation was similar for tumors with (10/14, 71.4%) or without (25/40, 62.5%) local progression (p = 0.75). MRI enabled assessment of the entire cryoablation margin in 49 of 54 (90.7%) treated tumors. MRI features at 24 hours after liver cryoablation that were predictive of local tumor progression included a minimum ablation margin less than or equal to 3 mm and a blood vessel bridging the ablation margin. Persistent tumor enhancement is common after liver cryoablation and does not predict local tumor progression.

Diagnosis and treatment of coagulopathy following percutaneous cryoablation of liver tumors: Experience in 372 patients

Coagulopathy after liver cryoablation was first reported many years ago; the cause is local platelet trapping and destruction within the margin of the cryolesion. However, the prognosis and therapeutic effects of coagulopathy remain unclear. This study retrospectively reviewed clinical data from 372 patients (525 sessions) who underwent liver cryoablation in our hospital during the past 4.5years. Small tumors (major diameter<6cm) were treated with a single complete ablation; massive tumors (major diameter 6–10cm or >10cm) were divided into two or three parts that were dealt with in turn. Platelet counts decreased to an average of (46.12±68.13)×109/L after each session of cryoablation. The decline was most evident in patients with high pretreatment platelet counts, while those with low pretreatment counts had the highest risk of coagulopathy. Change in platelet count was not correlated with the diameter of the tumor. Slight coagulopathy (platelet count (70–100)×109/L) can resolve without treatment within 1week and administration of recombinant human interleukin-11 can assist recovery from severe coagulopathy (platelet count<70×109/L).

Estimated effective dose of CT-guided percutaneous cryoablation of liver tumors

PurposeTo estimate effective dose during CT-guided cryoablation of liver tumors, and to assess which procedural factors contribute most to dose. Materials and methodsOur institutional review board approved this retrospective, HIPAA-compliant study. A total of 20 CT-guided percutaneous liver tumor cryoablation procedures were performed in 18 patients. Effective dose was determined by multiplying the dose length product for each CT scan obtained during the procedure by a conversion factor (0.015mSv/mGy-cm), and calculating the sum for each phase of the procedure: planning, targeting, monitoring, and post-ablation survey. Effective dose of each phase was compared using a repeated measures analysis. Using Spearman correlation coefficients, effective doses were correlated with procedural factors including number of scans, ratio of targeting distance to tumor size, anesthesia type, number of applicators, performance of ancillary procedures (hydrodissection and biopsy), and use of CT fluoroscopy. ResultsEffective dose per procedure was 72±18mSv. The effective dose of targeting (37.5±12.5mSv) was the largest component compared to the effective dose of the planning phase (4.8±2.2mSv), the monitoring phase (25.5±6.8mSv), and the post-ablation survey (4.1±1.9mSv) phase (p<0.05). Effective dose correlated positively only with the number of scans (p<0.01). ConclusionsThe effective dose of CT-guided percutaneous cryoablation of liver tumors can be substantial. Reducing the number of scans during the procedure is likely to have the greatest effect on lowering dose.

Multimodality Non-rigid Image Registration for Planning, Targeting and Monitoring During CT-Guided Percutaneous Liver Tumor Cryoablation

The aim of this study was to develop non-rigid image registration between preprocedure contrast-enhanced magnetic resonance (MR) images and intraprocedure unenhanced computed tomographic (CT) images, to enhance tumor visualization and localization during CT imaging-guided liver tumor cryoablation procedures. A non-rigid registration technique was evaluated with different preprocessing steps and algorithm parameters and compared to a standard rigid registration approach. The Dice similarity coefficient, target registration error, 95th-percentile Hausdorff distance, and total registration time (minutes) were compared using a two-sided Student's t test. The entire registration method was then applied during five CT imaging-guided liver cryoablation cases with the intraprocedural CT data transmitted directly from the CT scanner, with both accuracy and registration time evaluated. Selected optimal parameters for registration were a section thickness of 5 mm, cropping the field of view to 66% of its original size, manual segmentation of the liver, B-spline control grid of 5 × 5 × 5, and spatial sampling of 50,000 pixels. A mean 95th-percentile Hausdorff distance of 3.3 mm (a 2.5 times improvement compared to rigid registration, P < .05), a mean Dice similarity coefficient of 0.97 (a 13% increase), and a mean target registration error of 4.1 mm (a 2.7 times reduction) were measured. During the cryoablation procedure, registration between the preprocedure MR and the planning intraprocedure CT imaging took a mean time of 10.6 minutes, MR to targeting CT image took 4 minutes, and MR to monitoring CT imaging took 4.3 minutes. Mean registration accuracy was <3.4 mm. Non-rigid registration allowed improved visualization of the tumor during interventional planning, targeting, and evaluation of tumor coverage by the ice ball. Future work is focused on reducing segmentation time to make the method more clinically acceptable.

Biochemical and Hematologic Alterations Following Percutaneous Cryoablation of Liver Tumors: Experience in 48 Procedures

To retrospectively determine the frequency and severity of various abnormal laboratory test values following percutaneous cryoablation of liver tumors and to estimate the correlation between laboratory test values and tumor and ablation volumes. This HIPAA-compliant study had institutional review board approval. Informed consent was waived. Biochemical and hematologic laboratory values from 48 procedures in 39 patients (18 men and 21 women; age range, 29-86 years) who underwent magnetic resonance (MR) imaging-guided percutaneous cryoablation of 65 liver tumors (62 metastases, three hepatocellular carcinomas) were retrospectively reviewed. Changes in laboratory values at baseline and 0-6 hours and 1-2 weeks after the procedure were analyzed with respect to tumor and ablative margin volumes by using generalized estimating equations. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were correlated with percent maximal decrease in platelet count. Mean ablation zone volume was 67.3 cm(3) +/- 41.2 (standard deviation) (range, 7.3-191.4 cm(3)). AST and ALT values increased after all procedures and peaked at 6 hours (median change in AST value, +835 U/L; median change in ALT value, +614.5 U/L). Platelet count decreased after 47 procedures (mean maximal decrease, 92.3 x 10(9)/L [38%]), reaching a nadir at 12-24 hours after 24 procedures (50%) and returning to normal in 31 (84%) of 37 procedures at 1-2 weeks. One procedure was complicated by disseminated intravascular coagulation that necessitated transfusion and arterial embolization. Myoglobin values increased after 21 (44%) of 48 procedures and peaked at 6 hours (trimmed-mean value, 183.4 mug/L). Ablative margin volumes were predictive of changes at 0-6 hours in AST (P = .02), ALT (P = .003), and myoglobin (P < .001) values. Percent maximal decrease in platelet count correlated with peak change in AST (r = 0.72) (P < .001). Following percutaneous cryoablation of liver tumors, alterations in liver enzymes, myoglobin, and platelet count are common, are usually self-limited, and correlate with ablative margin volume--except for changes in platelet count, which correlate with changes in AST and ALT.

Liver tumor cryoablation: a commentary on the need of improved procedural monitoring.

Cryoablation is a method used for in situ destruction of liver tumors not eligible for surgical resection. Local recurrences following such treatment have been reported at rates of 5-44%. Insufficient procedural monitoring of the ablation is one plausible explanation for these recurrences. The cryoablative procedure is usually monitored by ultrasonography, but acoustic shadowing and loss of signals, compromise visualisation of the cryolesion circumference. Other monitoring modalities such as computer tomography and invasive methods like the use of thermocouples and impedance measurements have also been studied, but are not in common clinical use as single monitoring modalities. Thermodynamic conditions assumed adequate for tumor eradication are likely to occur only in parts of the cryolesion. This tumoricidal part of the cryolesion is not adequately depicted using any of these modalities. Magnetic resonance imaging (MRI) provides a clear delineation of the cryolesion circumference. Noninvasive temperature measurements assisted by MRI indicate which parts of the cryolesion that may be subject to complete necrosis. In this article MRI monitored cryoablation of liver tumors is discussed. Improved peroperative monitoring as offered by MRI may reduce the rates of local recurrences after treatment, but further technological improvements are required.

Hepatic vascular inflow occlusion enhances tissue destruction during cryoablation of porcine liver 1

Background Local recurrences after cryoablation of liver tumors have been reported at rates from 5% to 44% and can be caused by inadequate coverage of the tumor by the frozen region. Hepatic vascular inflow occlusion may facilitate ablation by enlarging the size of the frozen region and the tissue necrosis induced by freezing. Few studies have documented these effects of inflow occlusion during liver cryoablation. Materials and methods Two cryolesions were induced in the liver of 12 pigs in a standardized set-up. Vascular inflow occlusion was used in six pigs during freezing. Two freeze cycles were performed at each location. Ice-ball volume was estimated by intraoperative magnetic resonance imaging. Cryolesion volume was estimated from histopathologic examination of the lesions 4 days after ablation. Results The median volume of ice-balls produced during inflow occlusion was 107% larger than for ice-balls produced without occlusion ( P < 0.001). The median volume of cryolesions made during inflow occlusion was 195% larger than for cryolesions induced without occlusion ( P < 0.001). The geometry of the ice-balls was more regular if produced during inflow occlusion than if not. The ice-balls produced during the second freeze cycle were 17% and 20% larger than the ice-ball produced during the first freeze for lesions made with ( P = 0.01) and without ( P = 0.03) inflow occlusion. Conclusions Hepatic vascular inflow occlusion enables freezing of larger volumes of liver tissue andincreases the volume of tissue necrosis induced during cryoablation of porcine liver.

Magnetic Resonance Imaging-Estimated Three-Dimensional Temperature Distribution in Liver Cryolesions: A Study of Cryolesion Characteristics Assumed Necessary for Tumor Ablation

The goal of this study was to estimate the three-dimensional (3D) temperature distribution in liver cryolesions and assess the margin of the transition zone between the tumoricidal core of the lesion and the surrounding unfrozen tissue, using criteria proposed in the literature. Local recurrences after liver tumor cryoablation are frequent. Temperatures below −40°C and a 1-cm zone of normal tissue included in the cryolesion are considered necessary for adequate ablation. The 3D temperature distribution in 10 pig cryolesions was estimated by numerical solution of a simplified bioheat equation using magnetic resonance imaging data to establish cryolesion border conditions. Volumes encompassed by the −20, −40, and −60°C isotherms were estimated. The shortest distance from every voxel on the −40°C isotherm to the cryolesion edge was calculated and the mean and the maximal of these distances were defined for each cryolesion. Median cryolesion volumes with temperatures of −20, −40, and −60°C or colder were 53, 26, and 14% of the total cryolesion volume, respectively. The median cryolesion volume was 12.3 cm3. The median of the mean distances calculated between the −40°C isotherm and the cryolesion edge was 4.1 mm and increased with increasing cryolesion volume. The median of the largest of these distances calculated for each cryolesion was 8.1 mm. Temperatures claimed to be adequate for tumor destruction were obtained only in parts of the cryolesion. The adequacy of a 1-cm zone of normal liver tissue included in the cryolesion to ensure tumor ablation is questioned.

Impact of intraoperative sonography on resection and cryoablation of liver tumors

Impact of intraoperative sonography on resection and cryoablation of liver tumors

Impact of intraoperative sonography on resection and cryoablation of liver tumors.

We retrospectively analyzed the impact of intraoperative sonography (IOUS) on the management of patients referred for resection of liver tumors. Forty patients underwent IOUS with a 7-MHz curved-array sector transducer; in selected cases, a 5-MHz linear-array transducer attached to a color Doppler unit was also used. The number, size, and location of tumors on IOUS, including tumor proximity to or invasion of major vessels or invasion of the diaphragm, were compared to findings on preoperative imaging studies. The effect of these findings on surgical management was assessed. Unresectable lesions were treated by cryoablation under ultrasound guidance. IOUS detected preoperatively unsuspected lesions in 7 patients (18%). Metastases suspected on CT arterial portography were ruled out in 2 patients (5%), and indeterminate lesions were diagnosed as cysts by IOUS in 2 other patients (5%). Vascular proximity or vascular or diaphragmatic invasion detected by IOUS rendered lesions unresectable in 4 patients (10%). Cryoablation under IOUS guidance and monitoring was attempted in 11 patients (28%) and performed successfully in 10. IOUS changed the management in 38% of patients and guided cryoablation in 28% of patients. IOUS performed by an experienced sonologist is invaluable for the accurate assessment of liver tumor resectability; the detection of additional, preoperatively unknown lesions; and the guidance of cryoablation of unresectable tumors.

Realistic expectations for cryoablation of liver tumors.

While cryoablation has been shown to be an effective method of destruction of primary and metastatic liver tumors, there is a disturbingly high incidence of recurrence at the cryoablated site and there are conflicting reports concerning long-term survival. For this reason, resection remains the preferred surgical treatment of liver tumors. However, there is a population of patients who, because of age, pre-existing liver disease, or likely systemic dissemination, present a higher risk for major resection, and for whom cryoablation may be favored. This study examined the safety and effectiveness of cryoablation in patients thought to be at higher risk for conventional hepatic resection, or in whom resection would not eradicate all known disease. Twenty-eight consecutive patients underwent cryoablation, with or without resection, of 39 hepatic tumors for primary (n = 9) or metastatic (n = 19) disease. Their postoperative course and long-term follow-up were examined for complications, survivability, and recurrence of disease. With the use of cryoablation, a major hepatic resection was avoided in 20 patients, 11 of whom were 70 years or older, 4 who likely had disseminated cancer even though the liver was the only site of detectable disease, 2 who were cirrhotic, and 2 with bilobar disease. An additional 7 patients had recurrence of disease in a previously resected liver, for whom additional resection would be hazardous. There was one operative death from an exaggerated systemic inflammatory response syndrome. Seven patients developed complications, including 2 patients with cryoablation-induced coagulopathy. Excluding 2 patients (including the postoperative death) the average hospital length of stay was 6.7 +/- 2.8 days. Seven patients required some intensive care unit (ICU) care. Three patients with primary liver cancer are alive 29 to 47 months after cryoablation. Two patients with metastatic disease are alive without recurrence at 12 and 16 months, and 9 are alive with disease from 13 to 58 months after cryoablation. Fifteen patients developed liver recurrence, 5/27 (19%) at the cryoablated site. Cryoablation appears to be a safe treatment modality for primary and metastatic liver cancer. It is particularly appealing in those patients who may be at higher risk for major hepatectomy because of age, pre-existing liver disease, type of metastatic disease, previous resection, or bilobar tumors. Most disturbing is the high incidence of recurrence at the cryoablated site, which may reflect problems with ultrasound localization or proximity of tumors to major vasculature. Disease-free survival is low. From this standpoint the procedure should be considered palliative, even though all hepatic tumors can be eradicated. However, these limitations should not deter the use of cryoablation in selected patients. There is the potential for long-term survival, just as there is with resection.

Intraoperative radiofrequency ablation or cryoablation for hepatic malignancies

Background: The majority of patients with primary or metastatic malignancies confined to the liver are not candidates for resection because of tumor size, location, multifocality, or inadequate functional hepatic reserve. Cryoablation has become a common treatment in select groups of these patients with unresectable liver tumors. However, hepatic cryoablation is associated with significant morbidity. Radiofrequency ablation (RFA) is a technique that destroys liver tumors in situ by localized application of heat to produce coagulative necrosis. In this study, we compared the complication and early local recurrence rates in patients with unresectable malignant liver tumors treated with either cryoablation or RFA.Patients and methods: Patients with hepatic malignancies were entered into two consecutive prospective, nonrandomized trials. The liver tumors were treated intraoperatively with cryoablation or RFA; intraoperative ultrasonography was used to guide placement of cryoprobes or RFA needles. All patients were followed up postoperatively to assess complications, treatment response, and local recurrence of malignant disease.Results: Cryoablation was performed on 88 tumors in 54 patients, and RFA was used to treat 138 tumors in 92 patients. Treatment-related complications, including 1 postoperative death, occurred in 22 of the 54 patients treated with cryoablation (40.7% complication rate). In contrast, there were no treatment-related deaths and only 3 complications after RFA (3.3% complication rate, P <0.001). With a median follow-up of 15 months in both patient groups, tumor has recurred in 3 of 138 lesions treated with RFA (2.2%), versus 12 of 88 tumors treated with cryoablation (13.6%, P <0.01).Conclusions: RFA is a safe, well-tolerated treatment for patients with unresectable hepatic malignancies. This study indicates that (1) complications occur much less frequently following RFA of liver tumors compared with cryoablation of liver tumors, and (2) early local tumor recurrence is infrequent following RFA.

Australian Experience of Cryoablation of Liver Tumors: Metastases

The authors' clinical experience of treating almost exclusively inoperable liver malignancy in 149 patients by cryotherapy is reviewed. There was only one 30-day death; morbidity was modest. Postoperative carcinoembryonic antigen (CEA) changes were extremely predictive of outcome in patients with liver metastases from colorectal cancer. For the group in which CEA levels returned to the normal range, median survival exceeded 1000 days. In addition, the authors reported encouraging results with cryotherapy as an adjunct to resection.