Therapeutic efficacy and safety of percutaneous radiofrequency ablation of hepatocellular carcinoma abutting the gastrointestinal tract

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Percutaneous cryoablation for the treatment of liver cancer at special sites: an assessment of efficacy and safety

Background

To assess the safety and efficacy of cryoablation (CA) devices for the treatment of liver cancer at special sites in a retrospective study.

Methods

Special site liver cancer was defined as the tumors directly abutting surrounding structures (such as the liver capsule, gallbladder, vessel, diaphragm, intestine, and adrenal gland) with a maximum distance of 1.0 cm between the tumor and these organs. Sixty-six patients (49 men, 17 women; mean age, 60.8 years; age range, 27-82 years) were included. CA procedure was performed to treat 69 tumors under the guidance of computed tomography or ultrasound. Local tumor progression was assessed during the follow-up. A visual analog scale (VAS) evaluated the pain degree. Complications were assessed during and after every procedure.

Results

The number of tumors under the liver capsule and adjacent to the gallbladder, portal or hepatic vein, diaphragm, intestine, and adrenal gland were 29, 5, 8, 14, 7, and 6, respectively. The median follow-up time was 14 months (range, 2-28 months). In the 69 procedures, the technical success rate was 100%. The cumulative local tumor progression rates at 6, 9, 15, and 24 months were 10.2%, 16.5%, 20.9%, and 30.5%, respectively. No cases of serious complications occurred. During operation, the occurrence rates of subcapsular hemorrhage and pneumothorax were 2.9% and 1.4%, respectively. After the operation, the occurrence rate of biloma, capsular injury, subcapsular planting metastasis, and pneumothorax were 1.4%, 18.8%, 1.4%, and 2.8%, respectively. The average score of 66 patients with a VAS was 2.15±0.63 during the operation.

Conclusions

Percutaneous CA is safe and effective for patients with special site liver cancer.

Efficacy and Safety of Microwave Ablation (MWA) for Hepatocellular Carcinoma (HCC) in Difficult Anatomical Sites in Egyptian Patients with Liver Cirrhosis

Background and aim: Imaging guided microwave ablation (MWA) for hepatocellular carcinoma (HCC) has become a widely used method over recent years. Tumors close to the diaphragm, gastrointestinal tract, gallbladder, pancreas, hepatic hilum and major bile duct or vessels are generally considered relative contraindications for microwave ablation. This study was conducted to assess the effectiveness and safety of ultrasonography-guided MWA in treating patients with HCC in difficult anatomical sites in comparison to those in conventional sites. Patients and methods: Eighty-eight patients were included and divided into two groups: the study group of 44 with 46 lesions lying <5mm from the diaphragm, hepatic capsule, gall bladder (GB) or large vessel; and the control group of 44 patients with 50 lesions in non-risky sites. Each lesion was ablated using an ultrasound guided microwave probe using a detailed protocol. Results: Most of the patients were males, with a mean age of 57.8 years. In the study group, two patients had lesions adjacent to the GB, twelve were perivascular and 32 were subcapsular. The overall successful ablation rates were 84.8% and 92% in the study and control groups, respectively. Within the study group, ablation rates were 100%, 75% and 87.5% for lesions close to the GB, perivascular lesions and subcapsular lesions, respectively. One patient developed a subcutaneous abscess, with good outcome after proper treatment. Fever, pain and asymptomatic pleural effusion were reported after ablation without statistically significant difference between the groups or among subgroups. In conclusion: MWA for HCC in difficult anatomical sites is as effective and safe as for ordinary sites.

Safety and Efficacy of Percutaneous Thermal Ablation of Juxta-Cardiac Hepatic Tumours

INTRODUCTION

To evaluate the safety and efficacy of percutaneous thermal ablation of liver tumours in a juxta-cardiac (JC) location.

MATERIALS AND METHODS

From January 2010 to December 2014, out of 274 cases of hepatic ablation, 33 consecutive patients who received thermal ablation (radiofrequency or microwave) to left hepatic lobe tumours were included in this study. Patients were divided into two groups: JC or non-juxta-cardiac (NJC) (tumour margin ≤ 10 mm or > 10 mm from the cardiac border, respectively). Imaging follow-up was performed at 6-week and 3-monthly intervals. Technical success, 30-day complications and local tumour control/recurrence were recorded. Statistical analysis was performed with t test and Fisher's test. Univariate and multivariate survival analyses were performed using Cox regression.

RESULTS

Patients comprised of 23 men and 10 women (mean age 67.0 years). Mean tumour size was 2.2 ± 0.9 cm (28 hepatocellular carcinoma and 5 metastases). Mean follow-up time was 21.2 months (range 2-72 months). There were no differences between the JC and NJC groups in the rates of complete ablation (86.7 vs 83.3% P = 1.0), tumour recurrence (20.0 vs 22.2%, P = 0.95) or complication rates (6.7 vs 11.1% P = 1.0). Metastatic lesions were associated with a higher rate of recurrent disease (hazard ratio 3.86, 95% CI 1.0-14.8%, P = 0.05).

DISCUSSION

Percutaneous thermal ablation of JC tumours has similar rates of local tumour control and safety profile when compared to tumours in a NJC location. Tumours in a JC location should not be considered a contraindication for thermal ablation.

Safety assessment and therapeutic efficacy of percutaneous microwave ablation therapy combined with percutaneous ethanol injection for hepatocellular carcinoma adjacent to the gallbladder

OBJECTIVE

This study sought to evaluate the safety and efficacy of ultrasound-guided (US-guided) percutaneous microwave (MW) ablation combined with percutaneous ethanol injection (PEI) to treat liver tumours adjacent to the gallbladder.

MATERIALS AND METHODS

A total of 136 patients with hepatocellular carcinoma (HCC) adjacent to the gallbladder, who underwent ultra-sonographically-guided percutaneous MW ablation, which was combined with PEI in 132 patients, were retrospectively assessed. The patient population characteristics, tumour features, local tumour progression and treatment were compared and analysed. The safety and efficacy of the therapy were assessed by clinical data and imaging in follow-up examinations.

RESULTS

All patients were completely treated with two sessions; 120 patients underwent one session, 16 patients underwent two sessions. The primary technique was effective in 95.6% of the cases, according to the computed tomography (CT) or magnetic resonance imaging (MRI) in the one-month follow-up (132 of 138 sessions). PEI and other therapies were performed in the patients who had been incompletely treated (all six patients underwent PEI, and some underwent other therapies, including one transcatheter arterial chemoembolisation (TACE), one liver transplantation and two liver resections). There was a median follow-up period of 30.1 months and a range of 4 to 68 months. None of the patients had major complications. There were no treatment-related deaths. Twenty-six patients died of primary disease progression that was not directly attributable to MW ablation (19.1%, 26/136). Local tumour progression was noted in five patients (3.7%, 5/136), who had completely ablated tumours at follow-up. The patients with locally progressing tumours underwent additional therapy (three patients underwent PEI, one patient TACE, and one liver resection).

CONCLUSION

Ultrasound-guided percutaneous MW ablation, in combination with percutaneous ethanol injection and thermal monitoring, is a safe and effective treatment for HCC adjacent to the gallbladder.

Radiofrequency ablation of hepatocellular carcinoma in difficult locations: Strategies and long-term outcomes

AIM: To investigate the treatment strategies and long-term outcomes of radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) in difficult locations and to compare the results with non-difficult HCC.

METHODS: From 2004 to 2012, a total of 470 HCC patients underwent ultrasound-guided percutaneous RFA. Among these HCC patients, 382 with tumors located ≤ 5 mm from a major vessel/bile duct (n = 87), from peripheral important structures (n = 232) or from the liver capsule (n = 63) were regarded as difficult cases. There were 331 male patients and 51 female patients, with an average age of 55.3 ± 10.1 years old. A total of 235 and 147 patients had Child-Pugh class A and class B liver function, respectively. The average tumor size was 3.4 ± 1.2 cm. Individual treatment strategies were developed to treat these difficult cases. During the same period, 88 HCC patients with tumors that were not in difficult locations served as the control group. In the control group, 74 patients were male, and 14 patients were female, with an average age of 57.4 ± 11.8 years old. Of these, 62 patients and 26 patients had Child-Pugh class A and class B liver function, respectively. Regular follow-up after RFA was performed to assess treatment efficacy. Survival results were generated from Kaplan-Meier estimates, and multivariate analysis was performed using the Cox regression model.

RESULTS: Early tumor necrosis rate in the difficult group was similar to that in the control group (97.6% vs 94.3%, P = 0.080). The complication rate in the difficult group was significantly higher than that in the control group (4.9% vs 0.8%, P = 0.041). The follow-up period ranged from 6 to 116 mo, with an average of 28 ± 22.4 mo. Local progression rate in the difficult group was significantly higher than that in the control group (12.7% vs 7.1%, P = 0.046). However, the 1-, 3-, 5-, and 7-year overall survival rates in the difficult group were not significantly different from those in the control group (84.3%, 54.4%, 41.2%, and 29.9% vs 92.5%, 60.3%, 43.2%, and 32.8%, respectively, P = 0.371). Additionally, a multivariate analysis revealed that tumor location was not a significant risk factor for survival.

CONCLUSION: There was no significant difference in long-term overall survival between the two groups even though the local progression rate was higher in the difficult group.

New advances in local therapy for colorectal cancer metastases to the liver

SUMMARY 

The liver is the most common site of metastasis from primary colorectal cancer (CRC), and liver metastasis represents a major cause of morbidity and mortality for patients with primary CRC. Of patients with metastatic CRC that is confined to the liver, only a minority of patients are candidates for potentially curative surgical resection. In addition, to the very well-established modalities of surgery and thermal ablation, several newer locoregional therapies are available for the treatment of hepatic metastases, including stereotactic body radiotherapy, radioembolization and chemoembolization. Small prospective studies evaluating these treatments show promising response rates and local control in the first-line and salvage settings. Further randomized trials are required for a more rigorous assessment of the benefit and optimal setting in which these therapies should be used in patients with CRC liver metastases.

Limitation of repeated radiofrequency ablation in hepatocellular carcinoma: proposal of a three (times) × 3 (years) index

BACKGROUND AND AIM

Percutaneous radiofrequency ablation (RFA) has been shown to be a highly effective treatment for hepatocellular carcinoma (HCC). We investigated the controllability of HCC and explored the algorithm of therapeutic strategy for HCC in patients who met the RFA criteria.

METHODS

We enrolled 472 patients with HCC who met the RFA criteria (≤ 3 nodules, ≤ 3 cm) and underwent RFA for initial therapy. Patients who underwent repeated RFA were evaluated retrospectively when HCC exceeded the RFA criteria, or the functional hepatic reserve progressed to Child-Pugh grade C.

RESULTS

Overall survival rates were: 1 year, 96%; 3 years, 79%; and 5 years, 56%. In 5 years, 14% of patients progressed to Child-Pugh grade C. Meanwhile, 47% of patients exceeded the RFA criteria. Annually, 8% of patients deviated from the RFA criteria. The percentage of patients who were able to receive RFA significantly decreased at the fourth session compared with up to the third session. The survival rates decreased at the rate of 7% annually until the third year after the initial RFA. Afterwards, it shifted to a decrease at the rate of 12% annually. In a multivariate analysis, the presence of hepatitis C virus infection and the existence of a single tumor were identified as significant independent factors contributing to probabilities exceeding the RFA criteria.

CONCLUSIONS

HCC was controlled by RFA up to three RFA treatments and 3 years from the initial therapy. On this basis, we propose a "three (times) × 3 (years) index" for considering a shift from RFA to other treatment modalities.

Percutaneous radiofrequency ablation for malignant liver tumours in challenging locations

PURPOSE

To evaluate the treatment results of radiofrequency ablation (RFA) for primary and metastatic malignant liver tumours in challenging locations and also to present the treatment strategy that was used in these cases.

PATIENTS AND METHODS

From January 2007 to January 2010, we performed CT-guided RFA on 528 lesions in 402 patients (265 men and 137 women; mean age 65.1 years, range 19-82 years) with liver tumours (primary and metastatic) of which 98 lesions in 84 patients (55 men and 29 women; mean age 67.8 years, range 33-82 years) were located in challenging locations, defined as less than 5 mm from a large vessel or an extrahepatic organ (heart, lung, gall bladder, right kidney or gastrointestinal tract). The sizes of the tumours ranged 1.5-6 cm. We used two different RFA systems with an expandable needle electrode (RITA; Rita Medical Systems, Inc, Mountain View, CA, USA and MIRAS; Invatec S.r.l., Roncadelle, Italy).The tumours were considered as ablated completely if no viability was found on dual-phase dynamic contrast-enhanced CT at 1 month after RFA.

RESULTS

Complete ablation was obtained in 89.7% (88/98) of the high-risk located lesions, while 10 (10.3%) of the lesions were managed with repeated RFA because of tumour residue. The 1-, 2- and 3-year survival rates were 82.6, 67.3 and 54.1%, respectively. Minor complications occurred in eight of the 84 patients (9.5%), including small sub-capsular haematoma in four, small pleural effusion in three and partial liver infarction in one. Local tumour progression rate was 9.2% (9/98).

CONCLUSION

RFA is a safe and effective method of treatment of primary and metastatic liver tumours even located in challenging locations when performed by a well-trained and experienced interventional radiologist.

Percutaneous radiofrequency thermal ablation of primary and metastatic hepatic tumors: current concepts and review of the literature

The liver is a common site for primary malignancy and hematogenous metastasis. Although surgical resection of primary or metastatic hepatic tumors is generally regarded as first-line therapy, the majority of patients with hepatic malignancy have disease that is not amenable to surgical resection because of tumor location, poor hepatic reserve, or medical comorbidities. This has led to significant interest in the development of nonsurgical image-guided therapies, including radiofrequency ablation (RFA). RFA is appealing as a minimally invasive therapy that may be performed on an outpatient basis. It enables ablation of an area 3 to 5 cm in diameter, with relatively low morbidity and mortality rates. The results concerning the use of percutaneous RFA in the treatment of hepatocellular carcinoma, colorectal metastases, and other hepatic metastases are reviewed in this article. Clinical and technical considerations and complications are also discussed.

Feasible temperature of percutaneous microwave ablation of dog liver abutting the bowel

PURPOSE

This study used a dog model to determine the optimal temperature of percutaneous microwave ablation that causes complete necrosis of liver but not the adjacent bowel, supporting the use of this method to specifically and effectively treat liver tumour abutting the bowel.

MATERIALS AND METHODS

Ultrasound-guided percutaneous microwave ablation of liver abutting the bowel was performed on healthy adult dogs. Temperature of the ablation margin was monitored and controlled through inserted thermal monitoring needles. Dogs were divided into three groups and received microwave ablation at 75-95°C, 65-75°C, or 55-65°C. Imaging and histological examination were used to evaluate the damage of the bowel adjacent to the ablated liver.

RESULTS

Within one hour of treatment, the bowel adjacent to the ablated liver was seriously burned in the group receiving 75-95°C microwave ablation. Inflammation and congestion were found in the submucosa of the bowel in the group receiving 65-75°C microwave ablation. Minor inflammation was found in the mucosa of the bowel in the group receiving 55-65°C microwave ablation. Moreover, in the group receiving 55-65°C microwave ablation, ablated liver areas were covered with omenta, and histological examination revealed inflammatory reaction of the omenta 28 days after ablation.

CONCLUSIONS

Microwave ablation at 55-65°C for 6 min is preferred for ablation of liver tissue abutting the bowel in dogs. These findings may provide some valuable reference for percutaneous microwave ablation of human liver tumour adjacent to the bowel.

Radiofrequency ablation of hepatocellular carcinoma: The feasibility of magnetic resonance imaging with gadolinium ethoxybenzyl diethylene triamine pentaacetic acid for evaluating the ablative margin

AIM

  The aim of this study was to evaluate the feasibility of gadolinium ethoxybenzyl diethylene triamine pentaacetic acid (Gd-EOB-DTPA) in magnetic resonance imaging (MRI) to assess the ablative margin of radiofrequency (RF) ablation to hepatocellular carcinoma (HCC).

METHODS

  RF ablation was performed in the livers of six pigs after the i.v. administration of Gd-EOB-DTPA 20 min before ablation. Three pigs were killed 2 h after administration (group A), and the other pigs were killed 7 days after ablation (group B). Thereafter, correlation between pathological findings and MRI was investigated. Moreover, the Gd concentrations were examined in ablated and non-ablated regions. An initial clinical evaluation was conducted for 28 HCC nodules. Percutaneous RF ablation was performed 20 min after administration, and T(1)-weighted images were taken 2, 24 and 72 h post-treatment.

RESULTS

  On T(1)-weighted images of the porcine liver, the RF ablated lesions showed hyperintense regions with hypointense rims, which histopathologically corresponded to sinusoidal congestion. The Gd concentrations in ablated regions in group A were significantly higher than those in non-ablated regions, while the concentrations in both regions in group B fell to nearly undetectable levels. In 27 of the 28 HCC nodules, the treated area consisted of a hypointense region, indicative of the tumor, and a surrounding hyperintense rim 2 h after ablation. Subsequently, a thin hypointense region was observed in the outermost layer 24 and 72 h after ablation.

CONCLUSION

  Administration of Gd-EOB-DTPA in conjunction with RF ablation of HCC may be feasible for the assessment of an accurate ablative margin.

Quality initiatives: strategies for anticipating and reducing complications and treatment failures in hepatic radiofrequency ablation

Radiofrequency (RF) ablation is one of several local treatment strategies that can be used for the destruction of a variety of primary and secondary liver tumors. As experience with RF ablation grows, it becomes increasingly evident that successful ablation requires meticulous technique. In addition, knowledge of potential complications is critical for both the interventionalist and the radiologist, whose postablation interpretation can facilitate identification of complications and treatment failures. Hepatic RF ablation offers significant advantages in that it is less invasive than surgery and carries a low risk of major complications. Successful prevention of complications and treatment failures begins at initial consultation and continues with preablation evaluation of specific patient factors such as coagulation profiles, use of medications, and risk factors for infection. Other predisposing factors include background liver cirrhosis, prior hepatectomy, and portal hypertension. During ablation, careful attention must be given to tumor size, number, and location. For large or multiple ablations, separate ablation sessions can help reduce the prevalence of postablation syndrome, and clustered electrodes and multiple overlapping treatment zones may be used to reduce the risk of treatment failure. It is critical to reevaluate tumors during ablation to determine the best approach and to compensate for changes in size and relative location due to patient positioning. With use of these strategies, hepatic RF ablation can be performed with greater safety, better patient tolerance, and a reduced risk of complications and treatment failures.

Concurrent and subsequent radiofrequency ablation combined with hepatectomy for hepatocellular carcinomas

Partial hepatectomy has long been the standard treatment modality for patients with hepatocellular carcinoma (HCC), although the majority of patients with HCCs are not candidates for curative resection. Radiofrequency ablation (RFA) has been widely used as the preferred locoregional therapy. RFA and hepatectomy can be complementary to each other for the treatment of multifocal HCCs. Combining hepatectomy with RFA permits the removal of larger tumors while simultaneously ablating any smaller residual tumors. By using this combination treatment, more patients might become candidates for curative resection. For treating recurrent tumors involving the liver after hepatectomy, RFA has been performed recently instead of transcatheter arterial chemoembolization or ethanol ablation. Many retrospective studies on the combination of RFA and hepatectomy demonstrate favorable results of effectiveness and safety. However, further investigation of prospective design will be needed to confirm these encouraging results.

Percutaneous radiofrequency ablation of hepatocellular carcinomas adjacent to the gallbladder with internally cooled electrodes: assessment of safety and therapeutic efficacy

OBJECTIVE

The objective of this study was to evaluate the safety and therapeutic efficacy of percutaneous radiofrequency (RF) ablation for the treatment of hepatocellular carcinomas (HCCs) adjacent to the gallbladder with the use of internally cooled electrodes.

MATERIALS AND METHODS

We retrospectively assessed 45 patients with 46 HCCs (mean size, 2.2 cm) adjacent to the gallbladder (<or=1.0 cm) treated with RF ablation using an internally cooled electrode system. An electrode was inserted into the tumor either parallel (n = 38) or perpendicular (n = 8) to the gallbladder wall. The safety and therapeutic efficacy of the procedures were assessed with clinical and imaging follow-up examinations. Follow-up with the use of CT ranged from four to 45 months (mean, 19 months). The association between variables (electrode direction, electrode type, tumor size, tumor location, lobar location) and the presence of a residual tumor or local tumor progression was also analyzed.

RESULTS

There were no major complications and minor complications were noted in three patients (7%) including one case of vasovagal syncope and two cases of bilomas. Wall thickening of the gallbladder adjacent to the RF ablation zone was noted in 14 patients (41%) as determined on immediate follow-up CT imaging. Wall thickening showed complete disappearance on subsequent follow-up CT imaging. The primary technique effectiveness rate was 96% (44/46) based on one-month follow-up CT imaging. Local tumor progression was noted in six (14%) of 44 completely ablated tumors during the follow-up period. The direction of electrode insertion (perpendicular), tumor size (>or=3 cm) and tumor location (a tumor that abutted the gallbladder) were associated with an increased risk of early incomplete treatment. No variable was significantly associated with local tumor progression.

CONCLUSION

Percutaneous RF ablation of HCCs adjacent to the gallbladder using an internally cooled electrode is a safe and effective treatment. Significant risk factors that lead to early incomplete treatment include tumor size, tumor location and electrode direction.

Ultrasonography-guided percutaneous radiofrequency ablation of hepatocellular carcinomas: a feasibility scoring system for planning sonography

PURPOSE

This study was designed to evaluate whether a feasibility scoring system for planning sonography is a reliable predictor of a safe and complete ablation in ultrasonography (US)-guided percutaneous radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

We retrospectively evaluated the therapeutic outcomes of 108 consecutive patients (M:F, 78:30; mean age, 57.4 years) with a single nodular HCC (mean diameter, 2.0 cm) treated by percutaneous RFA. All patients were assessed for the feasibility of performing an RFA at planning sonography prior to the ablation. The feasibility scoring system consisted of five categories: the safe electrode path (P); the vital organs adjacent to the RFA zone (O); tumor size (S); tumor conspicuity (C); and the heat-sink effect (H). Each category was divided into a four-point scale [1-4]. If a score of 4 in any category was determined, the patient was not considered to be a suitable candidate for percutaneous RFA. We assessed if the score of each category, safety score (P+O), and curability score (S+C+H) correlated with a safe and complete ablation using the chi-squared test and likelihood ratio test for trend.

RESULTS

The technical success rate was 100% (108/108) based on CT images obtained immediately after ablation. There was no 30-day mortality after RFA. There were major complications (one case of severe vasovagal reflex, one case of hemoperitoneum and one case of a pseudoaneurysm) in three (2.7%) patients, and minor complications (one case of a biloma, one case of subsegmental infarction and one case of abscess) in three (2.7%) patients. Post-ablation syndrome as a side effect was noted in 38 (35.1%) of 108 patients. The primary technique effectiveness rate at 1 month was 95.1% (105/108). Local tumor progression was noted in eight (7.6%) of 105 patients during the follow-up period (range, 3.0-11.5 months; median, 5.8 months; mean, 5.7 months). There was no significant single category to predict complication and local tumor progression (Fisher's exact test, p>0.05). Contrary to the safety score for the probability of complication (p>0.05), the curability score was significantly associated with the probability of local tumor progression (likelihood ratio test for trend; p=0.03).

CONCLUSION

The new feasibility scoring system for planning US can be used as objective criteria to predict therapeutic efficacy rather than the safety of percutaneous RFA of an HCC.

Percutaneous radiofrequency ablation for the hepatocellular carcinoma abutting the diaphragm: assessment of safety and therapeutic efficacy

Objective

To assess the safety and therapeutic efficacy of a percutaneous radiofrequency (RF) ablation for the hepatocellular carcinoma (HCC) abutting the diaphragm.

Materials and Methods

We retrospectively assessed 80 patients who underwent a percutaneous RF ablation for a single nodular (< 4 cm) HCC over the last four years. Each patient underwent an ultrasound-guided RF ablation using internally cooled electrodes for the first-line treatment. We divided patients into two subgroups based on whether the index tumor was abutting (less than 5 mm) the diaphragm or not: group A (abutting; n = 31) versus group B (non-abutting; n = 49). We compared the two subgroups for complications and therapeutic efficacy using image and the review of medical records. The statistical assessment included an independent t-test, Fisher's exact test, and chi-square test.

Results

The assessment of the diaphragmatic swelling at CT immediately following the procedure was more severe in group A than group B (mean thickness change:1.44 vs. 0.46 mm, p = 0.00). Further, right shoulder pain was more common in group A than B (p = 0.01). Although minor complications (hemothorax 1 case, pleural effusion 1 case) were noted only in group A, no major thoracic complication occurred in either group. The technical success rate was lower in group A than group B (84% vs. 98%, p = 0.03). As well, the primary and secondary technique effectiveness rates in group A and group B were 90% versus 98% (p = 0.29) and 79% versus 91% (p = 0.25), respectively. The local tumor progression rate was higher in group A than in group B (29% vs. 6%, p = 0.02).

Conclusion

We found that the percutaneous RF ablation for the HCC abutting the diaphragm is a safe procedure without major complications. However, it is less effective with regard to technical success and local tumor control.

Percutaneous microwave ablation of liver cancer adjacent to the gastrointestinal tract

PURPOSE

The purpose of the study was to prospectively evaluate safety and effectiveness of percutaneous microwave ablation under temperature monitoring assisted with ethanol injection for liver cancer abutting gastrointestinal tract.

MATERIALS AND METHODS

One hundred seventy-nine hepatic tumors that underwent percutaneous microwave ablation with curative intention were included. Fifty-three lesions located less than 5 mm from gastrointestinal tract were in gastrointestinal group. One hundred twenty-six lesions located more than 5 mm from hepatic surface and first or second branch of hepatic vessels were in control group. The temperature of marginal ablation tissue proximal to gastrointestinal tract was monitored and controlled to fluctuating between 45 degrees C and 58 degrees C for more than 10 min for tumors in the gastrointestinal group. Ethanol (2-27 ml) was injected into marginal tissue in 33 of 53 lesions of the GI group.

RESULTS

Forty-seven of 53 tumors (88.7%) in the gastrointestinal group and 116 of 126 tumors (92.1%) in the control group achieved complete ablation (p > 0.05). There were neither immediate nor periprocedural complications in both groups. Tumor seeding happened in one of the gastrointestinal group and two of the control group. There was no delayed complication of bile ducts injury.

CONCLUSION

Under strict temperature monitoring, microwave ablation assisted with ethanol injection is safe and achieves a high complete ablation rate for hepatic tumors adjacent to gastrointestinal tract.

Radiofrequency ablation of hepatic tumors: lessons learned from 3000 procedures

Radiofrequency ablation has been accepted as the most popular local ablative therapy for unresectable malignant hepatic tumors. For 9 years from April 1999, we performed 3000 radiofrequency ablation procedures for hepatic tumors in our institution. Our results on the safety (mortality, 0.15%/patient) and therapeutic efficacy (5-year survival rate, 58%) are similar to those of previous studies reported, supporting the growing evidence of a clear survival benefit, excellent results for local tumor control and improved quality of life. The most important lesson learned from our 3000 procedures is that the best planning, safe ablation and complete ablation are key factors for patient outcome. Furthermore, multimodality treatment is the best strategy for recurrent hepatocellular carcinoma encountered after any kind of first-line treatment.

Radiofrequency ablation of the liver abutting stomach: in vivo comparison of gastric injury before and after intragastric saline administration in a porcine model

PURPOSE

To compare the in vivo gastric injury observed during radiofrequency (RF) ablation of the liver abutting the stomach before and after the intragastric administration of chilled saline.

MATERIALS AND METHODS

Twenty RF ablation zones were created in the livers of 10 pigs with a 1-cm-exposed active tip of an internally cooled electrode under ultrasound guidance for 10 min. Ten RF ablation zones were created before (non-saline group) and after (saline group) the intragastric administration of approximately 1000 mL of chilled saline, and 20 RF ablation zones were made in the posterior part of the left lobe abutting the stomach. The frequency and severity of the thermal injury observed in the stomach of the two groups were compared histologically.

RESULTS

All the resected gastric specimens showed thermal injuries of varying degrees of severity. The largest diameter of the gastric injury was significantly smaller in the saline group (mean 1.5 cm; range 1.3-1.8 cm) than in the non-saline group (mean 2.1cm; range 1.8-2.4 cm) (p=0.000). The saline group showed significantly less thermal injury to the muscular layer of the gastric wall by the histopathology (p=0.033).

CONCLUSIONS

The intragastric administration of chilled saline might be a useful technique for reducing the severity of gastric injury during RF ablation of the liver abutting the stomach.

Subcapsular liver tumors treated with percutaneous radiofrequency ablation: a prospective comparison with nonsubcapsular liver tumors for safety and effectiveness

PURPOSE

To assess the safety and effectiveness of percutaneous radiofrequency (RF) ablation of subcapsular liver tumors.

MATERIALS AND METHODS

The study protocol was approved by the institutional review board, and all patients gave written informed consent. One hundred eighty-one patients (79 men, 102 women; age range, 36-85 years) underwent ultrasonographically (US) guided percutaneous RF ablation of 361 primary or secondary (metastatic) liver tumors. Forty-four patients had one or more subcapsular nodules (group 1), and 137 had nonsubcapsular nodules only (group 2). Overall, 80 nodules were subcapsular and 281 were nonsubcapsular. The completeness of the ablation was assessed with contrast material-enhanced computed tomography (CT) 1 month after RF ablation. If residual tumor was documented, RF ablation was repeated. All patients in whom the ablation was complete after the first or second ablation session were monitored with CT or contrast-enhanced US every 3 months. Major complication, complete ablation, and local tumor progression rates were compared by using the chi(2) test or Fisher exact test.

RESULTS

Three (7%) major complications (intraperitoneal bleeding, skin burn, and tumor seeding) occurred in group 1, and two (1.5%) cases of tumor seeding occurred in group 2 (P = .093). No RF ablation-related deaths occurred. The complete ablation rate was 98% (43 of 44 patients) in group 1 and 98.5% (135 of 137 patients) in group 2 (P = .756). The local tumor progression rate after a median follow-up of 25 months (range, 13-54 months) was 16% (seven of 43 patients) in group 1 and 9.6% (13 of 135 patients) in group 2 (P = .355).

CONCLUSION

The difference in major complication rate between the subcapsular and nonsubcapsular liver tumors was not significant. The safety of RF ablation of subcapsular tumors seems acceptable, and the effectiveness is comparable to that of RF ablation of nonsubcapsular tumors.

Radiofrequency ablation of problematically located hepatocellular carcinoma: tailored approach

BACKGROUND

The challenge for radiofrequency ablation (RFA) of hepatocellular carcinomas (HCC) in problematic locations is that the outcome is limited due to insufficient ablation or injury of nearby structures. This study aimed to evaluate effective strategy and treatment results of RFA in these cases.

METHODS

Ultrasound guided percutaneous RFA was performed in 326 HCC patients. Among them, 249 tumors in 215 patients located at liver periphery, including 54 adjacent to GI tract, 110 close to the diaphragm, 49 close to the gallbladder, and 36 tumors close to liver surface. The sizes of the tumors ranged 1.2-7.0 cm (average 3.7 +/- 1.3 cm). Individualized treatment strategy was established for tumors in various locations, including "artificial ascites", "lift-expand" electrode placement, "draw-expand" electrode placement, "Supplementary ablation", and "accumulative multiple ablations" techniques. Treatment outcome was compared with another 64 central-located tumors (control group) in the same patients. One-month post-RFA contrast CT was used to evaluate early necrosis rate of the treated tumors.

RESULTS

Early tumor necrosis were obtained in 91.6% (228/249) of the problematically located HCC, including 90.7% (49/54) of the tumors adjacent to GI tract, 90.9% (100/110) near the diaphragm, 91.8% (45/49) by the gallbladder, and 94.4% (34/36) close to liver surface. The necrosis rate of control group was 98.4% (63/64), which was higher than the tumors close to diaphragm (P = 0.049). Local tumor recurrence was 8.4% (21/249), comparing with 3.1% (2/64) of the control group (P > 0.05). The 1-, 2- and 3-year survival rate of this group were 81.6%, 63.8%, and 53.6%, respectively. Major complications occurred in 3.2% (11/343) of the treatment sessions, including hemorrhage in two, nearby structure injury in five, and needle tract seeding in four patients.

CONCLUSIONS

Individualized treatment strategy for problematically located HCC is helpful in improving RFA outcome and expanding the application range of the therapy.

Hepatic Infarction after Radiofrequency Ablation of Hepatocellular Carcinoma with an Internally Cooled Electrode

PURPOSE

To elucidate the attributes of hepatic infarction after radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) with an internally cooled electrode.

MATERIALS AND METHODS

The authors retrospectively reviewed follow-up computed tomographic (CT) scans (follow-up period, 1-60.1 months; mean, 15.4 months) in 872 consecutive patients (male:female ratio, 672:200; mean age, 59.5 years) who had undergone 1,120 sessions of RFA for 1,335 HCCs with an internally cooled electrode. Diagnosis of hepatic infarction was made on the basis of CT findings. The authors evaluated the frequency of hepatic infarction, clinical features, initial and follow-up CT findings, accompanied complications, and prognosis. Potential risk factors were evaluated with multiple logistic regression analysis.

RESULTS

The frequency of hepatic infarction was 1.8% (20 of 1,120 sessions). Common presenting symptoms were abdominal pain (16 of 20 patients) and fever (11 of 20 patients). All infarctions were found at the first follow-up CT examination. Gas collections were noted in 65% of patients. All lesions showed progressive shrinkage. Accompanied complications were biloma (n = 2), abscess (n = 2), and portal vein thrombosis (n = 1). One patient with a lobar infarction died from hepatic failure. Older age (P = .048) and larger tumor size (P = .026) were statistically significant risk factors by multivariate analysis.

CONCLUSION

RFA complicated by hepatic infarction is uncommon. Although hepatic infarction can be managed conservatively in most cases, possible extensive involvement should be considered seriously because it may cause mortality.

Radiofrequency ablation of hepatocellular carcinoma: long-term outcome and prognostic factors

PURPOSE

To investigate the efficacy of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC), and the prognostic factors for post-RFA survival rate.

METHODS

From 1999 to 2006, 266 patients with 392 HCCs underwent ultrasound guided RFA treatment. They were 216 males and 50 females, average age 59.4+/-15.4 years (24-87 years). The HCC were 1.2-6.7 cm in diameters (average 3.9+1.3 cm). There were 158 patients with single tumor, and the rest had multiple (2-5) tumors. Univariate and multivariate analysis with 19 potential variables were examined to identify prognostic factors for post-RFA survival rate.

RESULTS

The overall post-RFA survival rates at 1st, 3rd, and 5th year were 82.9%, 57.9% and 42.9%, respectively. In the 60 patients with stage I HCC (AJCC staging), the 1-, 3-, 5-year survival rate were 94.8%, 76.4% and 71.6%, significantly higher than the 148 patients with stage II-IV tumors (81.8%, 57.6% and 41.2%, P=0.006). For the 58 patients with post-surgery recurrent HCC, the survival rates were 73.2%, 41.9% and 38.2% at the 1st, 3rd, and 5th year, which were significantly lower than those of stage I HCC (P=0.005). Nine potential factors were found with significant effects on survival rate, and they were number of tumors, location of tumors, pre-RFA liver function enzymes, Child-Pugh classification, AJCC staging, primary or recurrent HCC, tumor pathological grading, using mathematical protocol in RFA procedure and tumor necrosis 1 month after RFA. After multivariate analysis, three factors were identified as independent prognostic factors for survival rate, and they were Child-Pugh classification, AJCC staging and using mathematical protocol.

CONCLUSION

Identifying prognostic factors provides important information for HCC patient management before, during and after RFA. This long-term follow-up study on a large group of HCC patients confirmed that RFA could not only achieve favorable outcome on stage I HCC, but also be an effective therapy for stage II-IV or recurrent HCC.

Delayed Colonic Perforation After Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is an effective treatment for hepatocellular carcinoma. Colonic perforation secondary to RFA of the liver is an uncommon complication that has been reported to have an incidence between 0.1% and 0.3%. Lesions adjacent (within 1 cm) to the colonic wall and those in patients with history of upper abdominal surgery or chronic cholecystitis are particularly at risk. More importantly, thermal injury leading to colonic perforation has proved to have a fatal outcome. We present a case of percutaneous RFA in a patient with hepatocellular carcinoma that was abutting the colonic hepatic flexure. Colonic perforation was diagnosed on the eighth day postablation when the patient was readmitted with peritonitis.

MRI-Guided Percutaneous Cryotherapy for Soft-Tissue and Bone Metastases: Initial Experience

OBJECTIVE

We sought to determine the safety and feasibility of percutaneous MRI-guided cryotherapy in the care of patients with refractory or painful metastatic lesions of soft tissue and bone adjacent to critical structures.

MATERIALS AND METHODS

Twenty-seven biopsy-proven metastatic lesions of soft tissue (n = 17) and bone (n = 10) in 22 patients (15 men, seven women; age range, 24-85 years) were managed with MRI-guided percutaneous cryotherapy. The mean lesion diameter was 5.2 cm. Each lesion was adjacent to or encasing one or more critical structures, including bowel, bladder, and major blood vessels. A 0.5-T open interventional MRI system was used for cryoprobe placement and ice-ball monitoring. Complications were assessed for all treatments. CT or MRI was used to determine local control of 21 tumors. Pain palliation was assessed clinically in 19 cases. The mean follow-up period was 19.5 weeks.

RESULTS

Twenty-two (81%) of 27 tumors were managed without injury to adjacent critical structures. Two patients had transient lower extremity numbness, and two had both urinary retention and transient lower extremity paresthesia. One patient had chronic serous vaginal discharge, and one sustained a femoral neck fracture at the ablation site 6 weeks after treatment. Thirteen (62%) of the 21 tumors for which follow-up information was available either remained the same size as before treatment or regressed. Eight tumors progressed (mean local progression-free interval, 5.6 months; range, 3-18 months). Pain was palliated in 17 of 19 patients; six of the 17 experienced complete relief, and 11 had partial relief.

CONCLUSION

MRI-guided percutaneous cryotherapy for metastatic lesions of soft tissue and bone adjacent to critical structures is safe and can provide local tumor control and pain relief in most patients.

Percutaneous Radiofrequency Ablation for Recurrent Hepatocellular Carcinoma After Hepatectomy: Long-term Results and Prognostic Factors

BACKGROUND

We evaluated the long-term survival results and safety of percutaneous radiofrequency ablation (RFA) for recurrent hepatocellular carcinoma (HCC) after hepatectomy, and assessed the prognostic factors that can influence its long-term therapeutic results.

METHODS

One hundred and two patients, who had 119 recurrent HCC in their livers, underwent ultrasound-guided percutaneous RFA. All the patients had a history of hepatic resection as a first-line treatment modality for HCC. The mean diameter of the recurrent tumors was 2.0 cm (range, 0.8-5.0 cm). We evaluated the effectiveness rates, local tumor progression rates, survival rates, and complications. We also assessed the prognostic factors of the survival rates by using Cox proportional hazard models.

RESULTS

The primary effectiveness rate was 93.3% (111 of 119). The cumulative rates of local tumor progression at 1, 3, and 5 years were 6.0, 8.6, and 11.9%, respectively. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 93.9, 83.7, 65.7, 56.6, and 51.6%, respectively. Patients with a lower serum alpha-fetoprotein (AFP) level (<or=100 microg/L) before RFA or with small resected tumors (<or=5 cm) demonstrated better survival results (P < .05). There was only one major complication (liver abscess, 1.0% per treatment) during the follow-up period. There were no procedure-related deaths.

CONCLUSIONS

Percutaneous RFA is an effective and safe treatment modality for intrahepatic recurrent HCC after hepatectomy. Serum AFP level before RFA and resected tumor size were significant prognostic predictors of long-term survival.

The safety and efficacy of radiofrequency and electrolytic ablation created adjacent to large hepatic veins in a porcine model

INTRODUCTION

Immediately adjacent to large hepatic veins, tumour ablation by radiofrequency or electrolysis may be impaired by heat or current sink effects. Ablation may also cause vessel injury and thrombosis. The aim of this study was to evaluate the safety and efficacy of radiofrequency and electrolytic ablative techniques adjacent to large hepatic veins.

METHODS

Electrolytic and radiofrequency zones of ablation were created adjacent to hepatic veins in large white pigs. After 72 h the zones of ablation created were examined histologically for (a) the extent of tissue necrosis up to the vessel and (b) the presence of intimal damage and mural thrombus in the veins.

RESULTS

An unexpected complication of electrolysis near large veins was cardiac tamponade. This current related phenomenon could easily be avoided. In seven of nine electrolysis zones of ablation necrosis was completely adjacent to the vessel wall, but in only four of seven radiofrequency zones of ablation. All zones of ablation were associated with intimal necrosis, and most with mural thrombosis.

CONCLUSIONS

Ablation of hepatic tumours by radiofrequency and electrolysis is unreliable adjacent to hepatic veins. Both techniques are associated with mural thrombus formation, and so risk thrombo-embolic complication. These ablative modalities are not recommended for zones of ablation adjacent to hepatic veins.

Treatment strategy to optimize radiofrequency ablation for liver malignancies

PURPOSE

The purposes of this study were to investigate a treatment strategy to increase liver tumor necrosis and minimize complications with ultrasound-guided percutaneous radiofrequency (RF) ablation and to evaluate its therapeutic efficacy.

MATERIALS AND METHODS

A total of 332 patients with 503 liver malignancies underwent RF ablation according to a mathematical protocol with adjunctive measures. In the 332 patients, 205 had 308 hepatocellular carcinomas (HCCs) with a mean largest diameter of 4.1 cm and 127 had 195 metastatic liver carcinomas (MLCs) with a mean largest diameter of 3.9 cm. In patients with HCC, 60 (29.3%) had stage I/II disease and 145 (70.7%) had stage III/IV disease. Depending on tumor size, shape, and location, a defined treatment strategy was adopted that consisted of a mathematical protocol, an individualized protocol, and adjunctive measures. The mathematical protocol was followed for tumors larger than 3.5 cm. The individualized protocol was used for tumors located adjacent to the diaphragm, gastrointestinal tract, or gallbladder. Some adjunctive measures such as supplementary fine needle localization, local saline solution injection, and feeding vessel ablation were used to deal with different features of these liver tumors. Patients were followed regularly to assess treatment efficiency, and the tumor was considered to have early complete necrosis if no viability was found on enhanced computed tomography 1 month after RF ablation.

RESULTS

In this series, the early necrosis rates were 95.8% for HCC (295 of 308 tumors), 94.9% for MLC (185 of 195 tumors), 91.3% for tumors larger than 3.5 cm (189 of 207 tumors), 90.7% for tumors near the gastrointestinal tract (49 of 54 tumors), 91.5% for tumors near the diaphragm (86 of 94 tumors), and 90.6% for tumors near the gallbladder (48 of 53 tumors). The local recurrence rates were 10.7% for HCC (33 of 308 tumors) and 14.9% for MLC (29 of 195 tumors). The 1-, 2-, and 3-year overall survival rates were 89.6%, 69.4%, and 59.6%, respectively, for HCC and 80.3%, 52.8%, and 30.9%, respectively, for MLC. The 1-, 2-, and 3-year survival rates in 60 patients with stage I/II HCC were 93.7%, 87.1%, and 76.2%, respectively. The incidence of major complications was 1.4% (eight of 574 sessions), which included of three hemorrhages, four injuries to adjacent structures, and one case of needle tract seeding.

CONCLUSION

In RF ablation of hepatic tumors, application of a proper protocol and adjunctive measures play important roles in improving tumor necrosis rate and minimizing potential complications.

A case of biliary gastric fistula following percutaneous radiofrequency thermal ablation of hepatocellular carcinoma

Percutaneous radiofrequency thermal ablation (RFA) is an effective and safe therapeutic modality in the management of liver malignancies, performed with ultrasound guidance. Potential complications of RFA include liver abscess, ascites, pleural effusion, skin burn, hypoxemia, pneumothorax, subcapsular hematoma, hemoperitoneum, liver failure, tumour seeding, biliary lesions. Here we describe for the first time a case of biliary gastric fistula occurred in a 66-year old man with a Child’s class A alcoholic liver cirrhosis as a complication of RFA of a large hepatocellular carcinoma lesion in the III segment. In the light of this case, RFA with injection of saline between the liver and adjacent gastrointestinal tract, as well as laparoscopic RFA, ethanol injection (PEI), or other techniques such as chemoembolization, appear to be more indicated than percutaneous RFA for large lesions close to the gastrointestinal tract.

Thermal protection with 5% dextrose solution blanket during radiofrequency ablation

A serious complication for any thermal radiofrequency ablation is thermal injury to adjacent structures, particularly the bowel, which can result in additional major surgery or death. Several methods using air, gas, fluid, or thermometry to protect adjacent structures from thermal injury have been reported. In the cases presented in this report, 5% dextrose water (D5W) was instilled to prevent injury to the bowel and diaphragm during radiofrequency ablation. Creating an Insulating envelope or moving organs with D5W might reduce risk for complications such as bowel perforation.

Artificial ascites technique for percutaneous radiofrequency ablation of liver cancer adjacent to the gastrointestinal tract

Background

Percutaneous radiofrequency ablation (RFA) of liver tumours adjacent to the gastrointestinal tract is controversial. This study assessed the value of an intraperitoneal water infusion (artificial ascites) technique for percutaneous RFA of such tumours.

Methods

Before ablation in 52 patients (55 treatments, 58 tumours), between 250 and 3000 (mean 681) ml 5 per cent glucose solution was infused into the abdominal cavity using a 14-G needle, with the aim of preventing thermal injury by separating the liver from the gastrointestinal tract.

Results

There were no adverse events associated with the artificial ascites technique. In 43 (78 per cent) of the 55 treatments, the liver and gastrointestinal tract were separated successfully. In the other 12 treatments, in which the separation was not confirmed by real-time ultrasonography, there was one case of perforation of the ascending colon after RFA; adhesion of the liver and colon resulting from previous laparotomy may have been related to the injury.

Conclusion

Production of artificial ascites can be undertaken safely, making RFA safe and effective for hepatic tumours adjacent to the gastrointestinal tract. In patients with possible postoperative adhesions, confirmation of separation of the liver from surrounding organs is mandatory to avoid thermal injury.

Ultrasonography-guided percutaneous radiofrequency ablation for treatment of a huge symptomatic hepatic cavernous hemangioma

Hepatic cavernous hemangioma is the most common benign tumor of the liver. Appropriate management of this tumor remains a controversial topic. We have accumulated a number of cases with successful management of local hepatic tumors. Here we report a case where we performed an ultrasound-guided percutaneous radiofrequency ablation for the treatment of a symptomatic hemangioma. A 36-year-old female patient visited Kyungpook National University Hospital because of persistent right upper abdominal pain caused by an enlarging hemangioma. After two sessions of radiofrequency ablation, the hemangioma was significantly reduced in size. After 36 months, a follow-up abdominal CT revealed remarkably diminished necrotic areas of ablated hemangioma. The size of hemangioma was decreased to almost one third of the original longitudinal diameter. The patient remains asymptomatic in regards to the hemangioma.