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

Radiofrequency Ablation with an Internally Cooled Monopolar Directional Electrode: Ex Vivo and in Vivo Experimental Studies in the Liver

PURPOSE

To evaluate the feasibility of using an internally cooled directional electrode (ICDE) to create sufficient directional ablation in the desired area and to investigate whether use of the ICDE reduces thermal injury to the adjacent organs.

MATERIALS AND METHODS

The animal care and use committee approved this animal study. In ex vivo studies of bovine livers and colons, temperature was measured in both ablation and nonablation directions with the ICDE, temperature at the liver-colon interface and the presence of burns on the colon were evaluated with each ICDE and internally cooled conventional electrode (ICCE), and the ablation area with the use of three ICDEs in the switching multichannel mode was evaluated. In an in vivo study of 10 pigs, 11 ablations were performed by using three ICDEs in the switching multichannel mode. In addition, the difference in thermal injury to the gallbladder and stomach was compared between use of the ICDE and the ICCE. Mann-Whitney test and the Fisher exact test were used for statistical analysis.

RESULTS

In the ex vivo study, the hepatic temperature in the nonablation direction was lower than 50°C; temperature higher than 47°C was maintained for less than 3 minutes, even 0.5 cm away from the ICDE; and the temperature at the liver-colon interface did not increase above 50°C. In the switching multichannel mode, a fused coagulation zone was created. In the in vivo study, confluent ablation was created in the inner circle of three ICDEs with a mean interelectrode distance of less than 2.6 cm. Use of the ICDE did not create a moderate-to-severe gallbladder wall injury in any of the pigs, but use of the ICCE caused injury in three of the five pigs (P > .05). The ICDE caused moderate-to-severe gastric wall injury at one of eight ablations, and the ICCE caused injury at eight of nine ablations (P < .05).

CONCLUSION

Use of an ICDE can create a sufficient ablation in the desired direction and can decrease thermal injury to the adjacent organs.

Percutaneous microwave ablation for liver tumours adjacent to the marginal angle

PURPOSE

This study was designed to describe the technical essentials of microwave ablation (MWA) for tumours adjacent to the liver marginal angle (LMA) and to determine the feasibility, safety and efficacy of this approach.

MATERIALS AND METHODS

A total of 22 patients with primary or metastatic liver tumours adjacent to the LMA were enrolled. There were 19 small tumours (≤3 cm) and three larger tumours (>3 cm) with maximum diameters ranging from 0.7-2.7 cm (mean 1.7 ± 0.6 cm) and 4.7-6.6 cm (mean 5.4 ± 1.0 cm), respectively. For small tumours the entire acute angle was segmentally blocked utilising MWA. For larger tumours, the feeding arteries were initially blocked with ethanol before conformal ablation. Artificial ascites, real-time monitoring, small ethanol doses, colour Doppler flow imaging or contrast enhanced ultrasound guidance was used as an additional technique to assist with ablation. Contrast imaging was performed to evaluate the ablative efficacy. Treatment responses, local tumour progression (LTP) and complications were recorded.

RESULTS

All patients achieved a complete response. LTP was identified in two cases (9.1%) during the 4.5 month median follow-up period (range 2-29 months). A total of five additional sessions were performed, and secondary effectiveness was achieved in patients with LTP. No major complications were observed.

CONCLUSIONS

Percutaneous MWA is a new promising technique for tumours adjacent to the LMA, especially in cases with small tumours. Technical improvements to this procedure are expected to improve the results for large tumours abutting the LMA.

Artificial Ascites for Pain Relief During Microwave Ablation of Subcapsular Liver Tumors

PURPOSE

To compare post-procedure pain of subcapsular hepatic metastasis treated with microwave ablation (MWA) with and without artificial ascites.

MATERIALS AND METHODS

During a 2-years period, 41 patients underwent MWA of 52 peripheral liver metastases including 20 patients (10 men and 10 women (mean ± SD age: 62 ± 9.3 years) who underwent MWA of 27 metastasis without artificial ascites (group 1), and 21 patients (12 men and 9 women (mean age: 63.5 ± 9.9 years) who underwent MWA of 25 metastasis with artificial ascites (group 2). Patient's pain assessment cores [10-point visual analog scale (VAS)] at 6, 24 h, and 4 days after the MWA procedure were compared among groups, as well as 24 h cumulative morphine dose was also compared among groups. Complications were reported. Statistical significance was evaluated by Fisher's exact test and Student's t test.

RESULTS

Pain VAS were 8.6 ± 2.7, 3.9 ± 1.4, and 0.6 ± 1.2 at 6, 24 h, 4 days, respectively, for group-I and 0.8 ± 1.9, 0.3 ± 0.9, and 6.6 ± 3.5 for group II. Pain VAS were significantly different at 6, 24 h, and 4 days between the two groups (p < 0.0001). The average 24 h dose of morphine was 5.8 ± 2.2 mg in group-I and 0.2 ± 0.6 mg in group-II (p < 0.0001). Complications occurred in two patients from group-I (10%), including one bilio-pleural fistula and one minor cutaneous burn. One patient (9.5%) in group-II developed a lobar infarction. No bleeding and no procedure-related death were reported.

CONCLUSION

Artificial ascites prevents immediate post-procedural pain, which re-appears intensively 4 days later.

Insufficient ablative margin determined by early computed tomography may predict the recurrence of hepatocellular carcinoma after radiofrequency ablation

Tumor recurrence in hepatocellular carcinoma (HCC) patients after radiofrequency ablation (RFA) remains common; some studies have reported that insufficient ablative margin after RFA might contribute to HCC recurrence. The aim of this study was to investigate whether insufficient ablative safety margins determined by early computed tomography (CT) predicts HCC recurrence after RFA. This retrospective study recruited patients with a single HCC lesion after RFA in our department between May 2013 and March 2014. Early follow-up CT was performed within 7 days after RFA. An adequate ablative margin assessed by follow-up CT was defined as (maximum post-RFA CT radius)(3)/(maximum pre-RFA CT radius + 5 mm)(3)> 1. All patients in whom complete ablation was achieved underwent a CT scan every 3 months for early detection of HCC recurrence. In total, 72 patients (48 male, mean age 69.4 years) were analyzed. Of these, eight patients had local tumor progression, four had intra-hepatic distant recurrence, and two had extra-hepatic metastasis. Insufficient ablative margin, defined as an ablative volume with a safety margin of less than 5 mm, was an important predictor of local tumor progression (LTP) (p = 0.015) and overall recurrence (p = 0.012). The sensitivity, specificity, and positive and negative predictive values of an insufficient ablative margin for predicting LTP and overall recurrence were 36.4%, 97.2%, 50.0%, and 87.9%, and 46.2%, 89.7%, 42.9%, and 87.9%, respectively. An ablative volume with an ablative margin of less than 5 mm is associated with higher rates of both LTP and overall recurrence in HCC after RFA.

Design and validation of a thermoreversible material for percutaneous tissue hydrodissection

Interventional oncology procedures such as thermal ablation are becoming routine for many cancers. Hydrodissection-separating tissues with fluids-protects tissues near the treatment zone to improve ablation's safety and facilitate more aggressive treatments. However, currently used fluids such as normal saline and 5% dextrose in water (D5W) migrate in the peritoneum, reducing their protective efficacy. As a hydrodissection alternative, we investigated a thermoreversible poloxamer 407 (P407) solution. Such a material can be injected as a liquid which then forms a semi-solid gel at body temperature without syneresis. The desired gelation temperature of 32°C was achieved with 15.4 wt/wt % P407. Viscosity analysis revealed the lowest viscosity and ideal injection point was at 14°C. Solution viscosity increased during gelation, to a peak of 65 kPa*s at 40°C. The electrical impedance of P407 was significantly greater than isotonic saline, but lower than D5W, indicating its potential for electrical protection. The P407 gel was similar to other hydrodissection fluids at ultrasound and CT imaging. Ex vivo liver ablations showed that P407 protects neighboring tissues, but may require a thicker barrier for comparable protection to D5W. Overall, we found that the P407 solution is a feasible alternative to traditional hydrodissection fluids and warrants additional study.

Various complications of percutaneous radiofrequency ablation for hepatic tumors: radiologic findings and technical tips

Radiofrequency ablation is a safe and effective treatment for primary and secondary liver malignancies and has a low complication rate; however, there are various radiofrequency ablation-related complications which can occur from the thorax to the pelvis. Although most of these complications are usually minor and self-limited, they may become fatal if diagnosis and treatment are delayed. It is important for radiologists performing radiofrequency ablation to have a perspective regarding the possible radiofrequency ablation-related complications and their risk factors as well as the radiologic findings for their timely detection and increase of the treatment efficacy, and thereby encouraging the use of the radiofrequency ablation technique. This article illustrates the various imaging features of common and rare radiofrequency ablation-related complications as well as offers technical tips in order to avoid these complications.

Cause-specific mortality associated with aging in patients with hepatocellular carcinoma undergoing percutaneous radiofrequency ablation

OBJECTIVE

The number of elderly patients diagnosed with hepatocellular carcinoma (HCC) is expected to increase. The aim of this study is to evaluate the efficacy of radiofrequency ablation (RFA) in elderly patients with HCC and to investigate cause-specific excess deaths associated with increasing number of elderly patients.

MATERIALS AND METHODS

We enrolled 1401 naive patients with HCC who were treated initially by RFA from 1999 to 2011. Patients below 75 years of age were categorized as 'younger' and those at least 75 as 'elderly'. Differences in the demographic and laboratory data of these patients were assessed, along with Kaplan-Meier analysis of survival using the log-rank test. In addition, we assessed the causes of death, defined as liver related and liver unrelated, by competing risk analysis and risk factors for respective causes of death by a proportional subdistribution model.

RESULTS

Overall, 353 patients were categorized as elderly. Elderly patients were more likely to be women, infected with hepatitis C virus, and score better in the Child-Pugh classification. The mortality at 5 years was lower in the elderly than in the younger patients (47.3 vs. 37.1%; P<0.001). Competing risk analysis showed a significant difference in liver-unrelated death (P<0.001) between the two groups, whereas there were no significant differences in liver-related death (P=0.64). By the proportional subdistribution model, age was a significant risk factor only for liver-unrelated death.

CONCLUSION

RFA provided satisfactory 5-year survival rates in elderly patients with HCC. The elderly tended to die from liver-unrelated causes.

Percutaneous radiofrequency ablation of hepatic tumours: factors affecting technical failure of artificial ascites formation using an angiosheath

AIM

To evaluate the technical feasibility of artificial ascites formation using an angiosheath before percutaneous radiofrequency ablation (RFA) for hepatic tumours and to determine predictive factors affecting the technical failure of artificial ascites formation.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. One hundred and thirteen patients underwent percutaneous RFA of hepatic tumours after trying to make artificial ascites using an angiosheath to avoid collateral thermal damage. The technical success rate of making artificial ascites using an angiosheath and conversion rate to other techniques after initial failure of making artificial ascites were evaluated. The technical success rate for RFA was assessed. In addition, potential factors associated with technical failure including previous history of transcatheter arterial chemoembolization (TACE) or RFA, type of abdominal surgery, and adjacent perihepatic structures were reviewed. Predictive factors for the technical failure of artificial ascites formation were analysed using multivariate analysis.

RESULTS

The technical success rates of artificial ascites formation by angiosheath and that of RFA were 84.1% (95/113) and 97.3% (110/113), respectively. The conversion rate to other techniques after the failure of artificial ascites formation using an angiosheath was 15.9% (18/113). Previous hepatic resection was the sole independent predictive factor affecting the technical failure of artificial ascites formation (p<0.001, odds ratio = 29.03, 95% confidence interval: 4.56-184.69).

CONCLUSION

Making artificial ascites for RFA of hepatic tumours using an angiosheath was technically feasible in most cases. However, history of hepatic resection was a significant predictive factor affecting the technical failure of artificial ascites formation.

Radiofrequency ablation of liver tumors

Radiofrequency ablation (RFA) is an alternative therapy for hepatocellular carcinoma and liver metastases when resection cannot be performed or, in the case of hepatocellular carcinoma, when transplant cannot be performed in a timely enough manner to avoid the risk of dropping off the transplant list. RFA has the advantage of being a relatively low-risk minimally invasive procedure used in the treatment of focal liver tumors. This review article discusses the current evidence supporting RFA of liver tumors, as well as the indications, complications, and follow-up algorithms used after RFA.

Radiofrequency ablation for colorectal liver metastases

The management of hepatic metastases from colorectal cancer (HMCRC) is multimodal including chemotherapy, surgical resection, radiation therapy, and focused destruction technologies. Radiofrequency ablation (RFA) is the most commonly used focused destruction technology. It represents a therapeutic option that may be potentially curative in cases where surgical excision is contra-indicated. It also increases the number of candidates for surgical resection among patients whose liver metastases were initially deemed unresectable. This article explains the techniques, indications, and results of radiofrequency ablation in the treatment of hepatic colorectal metastases.

First-line radiofrequency ablation with or without artificial ascites for hepatocellular carcinomas in a subcapsular location: local control rate and risk of peritoneal seeding at long-term follow-up

AIM

To compare the long-term local control of hepatocellular carcinoma (HCC) and risk of peritoneal seeding via percutaneous radiofrequency ablation (RFA) using artificial ascites with those of RFA without artificial ascites.

MATERIALS AND METHODS

The Institutional Review Board approved this retrospective study. From April 2005 to February 2008, 160 patients (121 men, 39 women; age range 36-79 years) with a single subcapsular HCC (mean size 2.19 cm) were treated with ultrasonography-guided percutaneous RFA as a first-line therapy. Forty-four patients were treated with RFA using artificial ascites, whereas the other 116 patients were treated without artificial ascites. The cumulative local tumour progression (LTP) and peritoneal seeding were compared in both groups using follow-up computed tomography (CT). Cumulative LTP rates were analysed using the Kaplan-Meier method and the log-rank test. Risk of peritoneal seeding was investigated by means of multivariate analysis.

RESULTS

The overall median follow-up period was 52.5 months (range 13-76 months). The 1, 2, 4, and 6 year cumulative LTP rates were 17.1, 27.6, 35.2, and 35.2%, respectively, in the group with artificial ascites, and 8, 15.2, 26.6, and 34.4% in the group without artificial ascites, without significant difference (p = 0.332). The rates of peritoneal seeding were 6.8% (3/44) in the group with artificial ascites and 2.6% (3/116) in the group without artificial ascites, a non-significant difference (p = 0.347). The biopsy prior to RFA was the independent risk factor of peritoneal seeding regardless of the use of artificial ascites.

CONCLUSION

Long-term local tumour control and risk of peritoneal seeding were comparable for RFA with or without artificial ascites when used as a first-line therapy for subcapsular HCC.

Radiofrequency ablation for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related mortality worldwide. Unfortunately, only 20% of HCC patients are amenable to curative therapy (liver transplantation or surgical resection). Locoregional therapies such as radiofrequency ablation (RFA), percutaneous ethanol injection, microwave coagulation therapy, and transcatheter arterial chemoembolisation play a key role in the management of HCC. The choice of the treatment modality depends on the size of the tumour, tumour location, anatomic considerations and the number of tumours present and liver function. RFA therapy for HCC can be performed safely using a percutaneous, laparoscopic, or an open approach, even in patients with poor functional reserve. Since the introduction of RFA, several randomised controlled trials and non-randomised studies comparing RFA and other therapies for HCC have been conducted. In addition, in the last decade there have been technical advances in RFA therapy for HCC, resulting in significant improvement in the prognosis of HCC patients treated with this modality. In this review, we primarily focus on percutaneous RFA therapy for HCC and refer to current knowledge and future perspectives for this therapy. We also discuss new emerging ablation techniques.

Percutaneous radiofrequency ablation versus surgical radiofrequency ablation for malignant liver tumours: the long-term results

BACKGROUND

Radiofrequency ablation (RFA) has been used to treat hepatocellular carcinoma (HCC) and liver metastases for more than 10 years with promising early outcomes. Preliminary results comparing percutaneous and surgical approaches have shown no difference in short-term outcomes. In this study, the longer-term outcomes were presented.

METHODS

Patients with liver malignancies treated by RFA were prospectively studied from 2003 to 2011. Post-ablation assessment by computed tomography (CT) scan and serum biochemistry was performed at regular intervals. Recurrence rates and long-term survival were analysed.

RESULTS

A total of 233 patients with liver malignancies (75.5% HCC and 24.5% liver metastases) were analysed. Three RFA approaches were used (percutaneous 58.4%, laparoscopic 9.4% and open 32.2%). The median follow-up time was 29 months. Complete ablation was achieved in 83.7%, with no difference between the two approaches. More wound and chest complications were observed in the surgical group. Intra-hepatic recurrences were observed in 69.5%; extra-hepatic recurrences were detected in 22.3%, with no difference between the two groups. There was no statistical difference between the two approaches in overall 1-, 3- and 5-year survival.

CONCLUSION

An extended period of follow-up in patients with liver malignancies showed that RFA is an effective treatment. No difference was demonstrated between the percutaneous and surgical approach, in terms of recurrence and survival.

Percutaneous radiofrequency ablation guided by contrast-enhanced ultrasound in treatment of metastatic hepatocellular carcinoma after liver transplantation

This study evaluated the advantages and applications of contrast-enhanced ultrasound (CEUS)-supported percutaneous radiofrequency ablation (RFA) in the treatment of metastatic hepatocellular carcinoma after liver transplantation, based on clinical details. CEUS-supported percutaneous RFA was adopted to treat 12 patients with hepatic metastatic carcinomas after liver transplantation. The diameters of the metastatic carcinomas varied from 1 cm to 5 cm, and the foci were discovered after 3 months to 12 months. Each focus was diagnosed and localised by CEUS for RFA once or twice. Curative effects were evaluated by CEUS or contrast-enhanced CT after the treatment. The re-examination results at 2 weeks post-treatment showed that the foci of 11 patients were ablated completely, whereas one patient with the largest focus required retreatment by RFA because of a partial residue. No local recurrence was found one month later in the re-examination. CEUS-supported percutaneous RFA in the treatment of hepatic metastatic carcinoma after liver transplantation has the advantages of accurate localisation, good efficacy, easy operation, and minimal invasion without any complications. Therefore, it can be recommended as the preferred therapy for hepatic metastatic carcinoma after liver transplantation.

Local ablation for hepatocellular carcinoma in taiwan

Hepatocellular carcinoma (HCC) is the second commonest cancer in Taiwan. The national surveillance program can detect HCC in its early stages, and various curative modalities (including surgical resection, orthotopic liver transplantation, and local ablation) are employed for the treatment of small HCC. Local ablation therapies are currently advocated for early-stage HCC that is unresectable because of co-morbidities, the need to preserve liver function, or refusal of resection. Among the various local ablation therapies, the most commonly used modalities include percutaneous ethanol injection and radiofrequency ablation (RFA); percutaneous acetic acid injection and microwave ablation are used less often. RFA is more commonly employed than other local ablative modalities in Taiwan because the technique is highly effective, minimally invasive, and requires fewer sessions. RFA is therefore advocated in Taiwan as the first-line curative therapy for unresectable HCC or even for resectable HCC. However, current RFA procedures are less effective against tumors that are in high-risk or difficult-to-ablate locations, are poorly visualized on ultrasonography (US), or are large. Recent advancements in RFA in Taiwan can resolve these issues by the creation of artificial ascites or pleural effusion, application of real-time virtual US assistance, use of combination therapy before RFA, or use of switching RF controllers with multiple electrodes. This review article provides updates on the clinical outcomes and advances in local ablative modalities (mostly RFA) for HCC in Taiwan.

Case-control study of the RFA therapeutic effect of newly developed 4D US and conventional 2D US

PURPOSE

For radiofrequency ablation (RFA) therapy of hepatocellular carcinoma (HCC), accurate positioning of the inserted needle in the index tumor seems to be an important factor affecting therapeutic effect. In a case-control study, we compared the therapeutic effect of RFA using 4D and 2D ultrasonography (US) to evaluate whether 4D US is more effective.

METHODS

Twenty subjects treated with percutaneous RFA using 4D US (4D group) and 20 subjects using conventional 2D US (2D group), who were matched for age, sex, and HCC diameter, were enrolled in this study. Aplio XG was used as the US system and PVT-375MV as the newly developed 4D US probe. The therapeutic effect of RFA was classified into four grades (A-D: "Grade A" is "absolutely curative").

RESULTS

In the 2D group, Grade A was achieved in 12 subjects (60 %). In contrast, Grade A was achieved in 19 subjects (95 %) in the 4D group. The proportion of cases in which Grade A was achieved was significantly higher in the 4D group (P < 0.01).

CONCLUSIONS

By using a 4D US device for RFA, more accurate insertion could be achieved and more effective therapy could be performed.

Complications of radiofrequency ablation for hepatocellular carcinoma in a multicenter study: An analysis of 16 346 treated nodules in 13 283 patients

AIM

  We surveyed multiple centers to identify types and frequency of complications and mortality rate associated with radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC).

METHODS

  We distributed a questionnaire developed by members of the Chugoku-Shikoku Society for the Local Ablation Therapy of Hepatocellular Carcinoma to 20 centers and analyzed types and frequency of complications and mortality rate.

RESULTS

  In total, 16 346 nodules were treated in 13 283 patients between January 1999 and November 2010. Five patients (0.038%) died: two from intraperitoneal hemorrhage, and one each from hemothorax, severe acute pancreatitis and perforation of the colon. In 16 346 treated nodules, 579 complications (3.54%) were observed, including 78 hemorrhages (0.477%), 276 hepatic injuries (1.69%), 113 extrahepatic organ injuries (0.691%) and 27 tumor progressions (0.17%). The centers that treated a large number of nodules and performed RFA modifications, such as use of artificial ascites, artificial pleural effusion and bile duct cooling, had low complication rates.

CONCLUSION

  This study confirmed that RFA is a low-risk treatment for HCC and that sufficient experience and technical skill can reduce complications.

Radiofrequency ablation of a solitary liver metastasis complicated by colonic perforation

Radiofrequency ablation is used for the treatment of primary liver malignancies and liver metastases. In this case, the authors performed percutaneous radiofrequency ablation of a solitary esophageal carcinoma metastasis within the left hepatic lobe. Following the procedure, the patient developed a colonic perforation with a large right upper quadrant abscess. Although the abscess nearly resolved after intravenous antibiotics and percutaneous drainage, the patient ultimately developed a colocutaneous fistula that required surgical excision and right hemicolectomy. The risks for developing this complication as well as measures to minimize this risk are discussed.

Radiofrequency ablation for hepatocellular carcinoma: 10-year outcome and prognostic factors

OBJECTIVES

Radiofrequency ablation (RFA) is widely performed for hepatocellular carcinoma (HCC). However, there has been no report on 10-year outcome of RFA. The objective of this study was to report a 10-year consecutive case series at a tertiary referral center.

METHODS

We performed 2,982 RFA treatments on 1,170 primary HCC patients and analyzed a collected database.

RESULTS

Final computed tomography images showed complete tumor ablation in 2,964 (99.4%) of 2,982 treatments performed for the 1,170 primary HCC patients. With a median follow-up of 38.2 months, 5- and 10-year survival rates were 60.2% (95% confidence interval (CI): 56.7-63.9%) and 27.3% (95% CI: 21.5-34.7%), respectively. Multivariate analysis demonstrated that age, antibody to hepatitis C virus (anti-HCV), Child-Pugh class, tumor size, tumor number, serum des-γ-carboxy-prothrombin (DCP) level, and serum lectin-reactive α-fetoprotein level (AFP-L3) were significantly related to survival. Five- and 10-year local tumor progression rates were both 3.2% (95% CI: 2.1-4.3%). Serum DCP level alone was significantly related to local tumor progression. Five- and 10-year distant recurrence rates were 74.8% (95% CI: 71.8-77.8%) and 80.8% (95% CI: 77.4-84.3%), respectively. Anti-HCV, Child-Pugh class, platelet count, tumor size, tumor number, serum AFP level, and serum DCP level were significantly related to distant recurrence. There were 67 complications (2.2%) and 1 death (0.03%).

CONCLUSIONS

RFA could be locally curative for HCC, resulting in survival for as long as 10 years, and was a safe procedure. RFA might be a first-line treatment for selected patients with early-stage HCC.

Water-filled laparoendoscopic surgery (WAFLES): feasibility study in porcine model

PURPOSE

Recent surgical techniques have been advancing under endoscopic view and insufflation of carbon dioxide gas to expand the abdominal cavity. Isotonic fluid could be one candidate for expanding cavities to facilitate surgical maneuvering. We tested the feasibility and drawbacks of replacement of irrigating materials using a porcine model (water-filled laparoendoscopic surgery [WAFLES]).

MATERIALS AND METHODS

Laparoscopic cholecystectomy was performed in two porcine models using instillation of sorbitol solution as irrigant. Solution irrigation was performed through one of four ports, with drainage via another port. Conventional forceps equipped with a monopolar electrode for electrocautery, laparoscope, video processor, ultrasound, and transducer for measuring intraabdominal pressure were used.

RESULTS

Laparoscopic cholecystectomy was successfully undertaken with the following benefits: (1) clear observation of the dissecting plane throughout maneuvering; (2) control of oozing and spilled bile by irrigation and suction; and (3) ultrasonographic and laparoscopic images can be obtained simultaneously without any restriction to probe location. However, two disadvantages should be noted: (1) difficulties in managing floating organs and (2) interruption of vision by blood.

CONCLUSIONS

WAFLES provides some benefits for endoscopic surgery with proper devices, including apparatuses for irrigation and suction. Efficient irrigation and selection of proper irrigant and apparatuses are required to establish an acceptable procedure.

Utility of contrast-enhanced ultrasonography with Sonazoid in radiofrequency ablation for hepatocellular carcinoma

BACKGROUND AND AIMS

Kupffer imaging in contrast-enhanced ultrasonography (CEUS) with Sonazoid, which lasts for 60 min or longer, may be useful in ultrasound-guided percutaneous tumor ablation. The utility of Sonazoid in radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) was investigated in this study.

METHODS

We analyzed a total of 716 HCC nodules that were detected on dynamic computed tomography in 316 patients. Detectability of these nodules was compared between CEUS and conventional ultrasonography. The effectiveness in the treatment was assessed by comparing the mean numbers of treatment sessions of RFA in patients treated with CEUS and that in historical controls matched for tumor and background conditions.

RESULTS

Detectability of tumor nodule was 83.5% in conventional ultrasonography and 93.2% in CEUS (P=0.04). Sixty-nine nodules in 52 patients were additionally detected with CEUS. The number of additionally detected tumor nodules was positively correlated with serum albumin level (P=0.016). The number of RFA sessions was 1.33±0.45 with CEUS as compared to 1.49±0.76 in the historical controls (P=0.0019).

CONCLUSIONS

CEUS with Sonazoid is useful for HCC detection in patients with a well-conserved liver function reservoir. The decrease in RFA session numbers indicated the utility of Sonazoid in RFA treatment of HCC.

Intrahepatic bile duct dilatation after percutaneous radiofrequency ablation for hepatocellular carcinoma: impact on patient's prognosis

BACKGROUND

Percutaneous radiofrequency ablation (RFA) has been widely accepted as an alternative to surgery for small hepatocellular carcinoma (HCC). In RFA, a portion of liver tissue surrounding tumour is also ablated to achieve a safety margin. The intrahepatic bile duct may be injured and result in chronic bile duct dilatation upstream of the injured site. However, the impact of such an injury on the overall prognosis has been unclear.

METHODS

Patients who showed bile duct dilatation following RFA were identified by a retrospective review of imaging studies. Each dilatation was classified as mild (limited to one hepatic subsegment) or severe (affecting two or more subsegments). The relation between the incidence of intrahepatic bile duct dilatation and HCC recurrence or survival was analysed using proportional hazard models.

RESULTS

Among 589 consecutive HCC patients treated with RFA, 70 (11.9%) and 21 (3.6%) patients showed mild and severe bile duct dilatation respectively. Patients with severe dilatation, but not those with mild dilatation, had lower survival and higher HCC recurrence than patients without dilatation. Severe dilatation, but not mild dilatation, was significantly associated with death [hazard ratio (HR) 2.17, P=0.035] and recurrence (HR 2.89, P<0.001).

CONCLUSION

Whereas mild bile duct dilatation after RFA is clinically negligible, bile duct dilatation affecting two or more subsegments should be regarded as a complication that may affect the prognosis and should be observed carefully.

[Percutaneous radiofrequency ablation with artificial ascites for hepatocellular carcinoma adjacent to the diaphragm]

Surgical resection is the first-line curative treatment of hepatocellular carcinoma (HCC). However most patients are unable to undergo surgical resection because of advanced tumoral stage, severe liver dysfunction or poor clinical status. Therefore, image-guided tumor ablation techniques have been introduced for the treatment of unresectable HCC. Among them, radiofrequency ablation (RFA) has been demonstrated to be an effective alternative curative therapy. However, local ablative therapy for tumors located close to structures such as the diaphragm or gastrointestinal tract is technically challenging because of the risk of collateral thermal damage to nearby structures or incomplete treatment of the HCC resulting from poor visibility on sonography. The introduction of artificial ascites can separate adjacent organs from the tumor and improve the sonic window. The aim of this study was to evaluate the feasibility, safety and efficacy of RFA with artificial ascites for HCC adjacent to the diaphragm.

Radiofrequency ablation of hepatocellular carcinoma: pros and cons

Among locoregional treatments for hepatocellular carcinoma (HCC), radiofrequency ablation (RFA) has been accepted as the most popular alternative to curative transplantation or resection, and it shows an excellent local tumor control rate and acceptable morbidity. The benefits of RFA have been universally validated by the practice guidelines of international societies of hepatology. The main advantages of RFA include 1) it is minimally invasive with acceptable morbidity, 2) it enables excellent local tumor control, 3) it has promising long-term survival, and 4) it is a multimodal approach. Based on these pros, RFA will play an important role in managing the patient with early HCC (smaller than 3 cm with fewer than four tumors). The main limitations of current RFA technology in hepatic ablation include 1) limitation of ablation volume, 2) technically infeasible in some tumors due to conspicuity and dangerous location, and 3) the heat-sink effect. Many technical approaches have been introduced to overcome those limitations, including a novel guiding modality, use of artificial fluid or air, and combined treatment strategies. RFA will continue to play a role as a representative ablative modality in the management of HCC, even in the era of targeted agents.

Current status of radiofrequency ablation of hepatocellular carcinoma

Loco-regional treatments for hepatocellular carcinoma (HCC) are important alternatives to curative transplantation or resection. Among them, radiofrequency ablation (RFA) is accepted as the most popular technique showing excellent local tumor control and acceptable morbidity. The current role of RFA is well documented in the evidence-based practice guidelines of European Association of Study of Liver, American Association of Study of the Liver Disease and Japanese academic societies. Several randomized controlled trials have confirmed that RFA is superior to percutaneous ethanol injections in terms of local tumor control and survival. The overall survival after RFA is comparable to after surgical resection in a selected group of patients with smaller (< 3 cm) tumors. Currently, the clinical benefits of combined RFA with transarterial chemoembolization for intermediate stage HCC are increasingly being explored. Here we review the ongoing technical advancements of RFA and future potential.

Liver tumor ablation: percutaneous and open approaches

The global incidence of liver cancer is greater than a million cases a year. Surgical resection where applicable is still the standard of care for these patients. Various liver-directed regional therapies have been developed in an effort to treat the vast majority of unresectable liver tumors. This article reviews the principles behind various ablation therapies currently available for malignant liver tumors and their outcomes.

Inflammatory myofibroblastic tumor: a possible complication of percutaneous radiofrequency ablation for hepatocellular carcinoma

An inflammatory myofibroblastic tumor (IMT) is an uncommon, benign lesion characterized by the mesenchymal proliferation and infiltration of inflammatory cells composed primarily of lymphocytes and plasma cells. A percutaneous radiofrequency ablation (RFA) is an effective and safe therapeutic modality used for the management of liver malignancies. Here we report, for the first time, a case of IMT as a complication of RFA for hepatocellular carcinoma in a 61-year-old man with a Child's class A hepatitis B-related liver cirrhosis. Gastrohepatic fistula formation was pathologically proven and associated with the RFA. Such a longstanding inflammation of the fistula might have been a possible cause of the development of IMT in this case.

Percutaneous radiofrequency ablation of hepatocellular carcinoma in 14 patients undergoing regular hemodialysis for end-stage renal disease

OBJECTIVE

Management of hepatocellular carcinoma is a major problem in the care of patients undergoing regular hemodialysis treatments, mainly because of a high prevalence of hepatitis C virus infection. The purpose of this study was retrospective assessment of the safety and efficacy of percutaneous radiofrequency ablation of hepatocellular carcinoma in the care of patients with end-stage renal disease undergoing regular hemodialysis treatments.

MATERIALS AND METHODS

Between October 2004 and June 2008, 14 carefully selected hemodialysis patients with hepatocellular carcinoma (five naïve, nine recurrent) underwent a total of 19 radiofrequency ablation treatments. An internally cooled or expandable electrode was used. After tumor ablation, the insertion site at the liver surface was subjected to additional ablation to reduce the bleeding risk.

RESULTS

The Child-Pugh score was 6 or better in all patients but one. The number of tumors was one or two, and the tumor diameter was 35 mm or less in all treatments. No complication such as intraperitoneal hemorrhage was found in any treatment. Local tumor progression was found after one treatment and was successfully managed with subsequent radiofrequency ablation. During the mean observation period of 343 days, there was only one death, of heart failure, among the five patients with naïve tumors.

CONCLUSION

The safety and effectiveness of radiofrequency ablation were not compromised in this series of selected patients with hepatocellular carcinoma who were undergoing hemodialysis. Radiofrequency ablation is a promising option for small hepatocellular carcinomas in patients undergoing regular hemodialysis treatments.

Tumour ablation: technical aspects

Image-guided percutaneous radiofrequency ablation (RFA) is a minimally invasive, relatively low-risk procedure for tumour treatment. Local recurrence and survival rates depend on the rate of complete ablation of the entire tumour including a sufficient margin of surrounding healthy tissue. Currently a variety of different RFA devices are available. The interventionalist must be able to predict the configuration and extent of the resulting ablation necrosis. Accurate planning and execution of RFA according to the size and geometry of the tumour is essential. In order to minimize complications, individualized treatment strategies may be necessary for tumours close to vital structures. This review examines the state-of-the art of different device technologies, approaches, and treatment strategies for percutaneous RFA of liver tumours.

Radiofrequency ablation for hepatocellular carcinoma abutting the diaphragm: the value of artificial ascites

Ultrasound (US)-guided percutanoeus radiofrequency (RF) ablation is difficult to perform for treating a hepatic tumor abutting the diaphragm due to a poor sonic window and high risk of diaphragmatic thermal injury. RF ablation with assistance of the use of artificial ascites is a simple and safe technique for treating a hepatic dome tumor abutting the diaphragm. One can improve the sonic window and separate the RF ablation zone from the diaphragm by downward displacement of the liver with the use of a simple and inexpensive technique. Dextrose water solution is an ideal fluid due to its nonionic nature. Complications related to the use of artificial ascites including hemoperitoneum are rare. Peritoneal adhesion and tumor location in the bare area are the limitations for the application of this technique.

Percutaneous radiofrequency ablation of hepatocellular carcinoma abutting the diaphragm and gastrointestinal tracts with the use of artificial ascites: safety and technical efficacy in 143 patients

The purpose of this study was to assess the feasibility, safety and efficacy of radiofrequency ablation (RFA) with the use of artificial ascites for hepatocellular carcinoma (HCC) adjacent to the diaphragm and gastrointestinal tract. One hundred forty-three patients with 181 HCCs who underwent US-guided percutaneous RFA with the use of artificial ascites were retrospectively reviewed. Among the 181 HCCs, 148 HCCs were defined as problematic nodules for two major reasons: poor sonic window or possible thermal injury. We artificially induced ascites before performing RFA by dripping 5% dextrose in a water solution. We assessed the technical success of introducing artificial ascites, technical feasibility of the use of artificial ascites and complications. The technical success rate, as well as the primary and secondary technique success rate, was assessed by regular follow-up CT examinations. RFA with artificial ascites was successfully achieved in 130 of 143 patients. The primary technique effectiveness was 85.3%. During follow-up (mean, 20.4 months), remote intrahepatic recurrence occurred in 49 patients and local tumor progression occurred in 15 patients. Three (2.1%) of the 143 patients experienced major complications (hemoperitoneum, lobar infarction and biloma) related to the RFA procedure. The use of artificial ascites is a simple and useful technique to minimize collateral thermal injury and to improve the sonic window.

Efficacy of laparoscopic radiofrequency ablation for hepatocellular carcinoma compared to percutaneous radiofrequency ablation with artificial ascites

AIM

Hepatocellular carcinoma (HCC) nodules close to the liver surface exhibit high recurrence compared to those in distal parts of the liver. Moreover, when nodules remain adjacent to the gastrointestinal tract or gallbladder, severe complications such as perforation of those organs may occur due to invasive therapy. Percutaneous radiofrequency ablation (PRFA) with artificial ascites or laparoscopic radiofrequency ablation (LRFA) are used to treat these patients to avoid complications. The purpose of the present study was to assess the efficacy and safety of these two methods.

METHODS

Subjects comprised 74 patients (48 men, 26 women; mean age, 68.5 +/- 8.0 years; range, 46-89 years) with 86 HCC nodules. PRFA with artificial ascites was carried out for 37 patients (44 nodules) and LRFA was used for 37 patients (42 nodules). Clinical profiles were compared between groups.

RESULTS

No significant differences in clinical profiles were found between patients treated by PRFA or LRFA. Mean number of treatments was significantly lower for LRFA (1.0 +/- 0.0) than for PRFA (2.1 +/- 1.0, P < 0.001). Mean number of PRFA treatments was 2.2 +/- 1.0 in patients with HCC nodules >2 cm in diameter, whereas all tumors were completely ablated with only one session of LRFA. The safety margin was significantly wider for LRFA than for PRFA.

CONCLUSION

LRFA is a better treatment option for ablation of HCC nodules >2.0 cm in diameter.

Image-guided percutaneous ablation therapies for hepatocellular carcinoma

Image-guided percutaneous ablation therapies have been playing important roles in the treatment of hepatocellular carcinoma (HCC). In our department, we have treated 90% of previously untreated patients with ablation therapies. Among various local ablation therapies, radiofrequency ablation has been replacing ethanol injection as a standard therapy for patients who have unresectable HCC or who do not want surgery. Our randomized controlled trials and those of others proved that radiofrequency ablation is superior to ethanol injection. Radiofrequency ablation is potentially curative, minimally invasive, and easily repeated for recurrence. Long-term survival is notably high, and mortality and morbidity are low, in radiofrequency ablation. Further investigations are necessary to determine whether radiofrequency ablation can replace surgery for resectable hepatocellular carcinoma. In such trials, the primary endpoint must be overall survival. Recurrence-free survival can be misleading and cannot be a surrogate endpoint. There are still effective therapies after recurrence, and the first recurrence does not cause death in most cases. Furthermore, hepatectomy has theoretically better disease-free survival than radiofrequency ablation because it removes a larger amount of liver tissue. The better cure rate of resection can be canceled, however, by deterioration of liver function.

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.

Hepatocellular carcinoma in viral hepatitis: improving standard therapy

Hepatocellular carcinoma (HCC) is a common malignancy worldwide, and its incidence is increasing in the United States and elsewhere. The prognosis of HCC patients depends not only on tumour stage but also on the background liver function reservoir. Current options for the treatment of HCC are surgical resection, liver transplantation, transcatheter arterial embolization, chemotherapy, and percutaneous ablation therapy. The choice of optimal treatment for individual patients, especially those at an earlier cancer stage, is sometimes controversial. Short-term prognosis of HCC patients has been much improved recently due to advances in early diagnosis and treatment, although long-term prognosis is as yet far from satisfactory as indicated by the overall survival at 10 years after apparently curative treatment of only 22-35%. Prevention of HCC recurrence, or tertiary prevention, is one of the most challenging tasks in current hepatology.

Percutaneous radiofrequency ablation of liver cancer in the hepatic dome using the intrapleural fluid infusion technique

BACKGROUND

Intrapleural fluid infusion improves ultrasonographic visualization of tumours in the hepatic dome. The aim of this study was to assess the safety and long-term efficacy of ultrasonographically guided percutaneous radiofrequency ablation for tumours in the hepatic dome with intrapleural infusion.

METHODS

Of 2575 patients with hepatocellular carcinoma or hepatic metastases treated with radiofrequency ablation, intrapleural fluid infusion was performed in 587 patients for tumours in the hepatic dome. After the tip of a 14-G metallic needle was positioned in the pleural cavity under ultrasonographic guidance, 500-1000 ml of 5 per cent glucose solution was infused in 5-15 min. Radiofrequency ablation was performed using an internally cooled electrode. Long-term results were evaluated in 347 patients with a single hepatocellular carcinoma who were naive to any treatment.

RESULTS

Intrapleural fluid infusion was successfully performed in all 587 patients. The major complication rate on a per tumour basis was similar for patients treated with and without intrapleural infusion (1.6 versus 1.6 per cent; P = 0.924). The overall and recurrence-free survival were both similar for naive patients with a single hepatocellular carcinoma treated with and without intrapleural infusion (P = 0.429 and P = 0.109 respectively). Intrapleural infusion was not associated with lower overall survival in multivariable analysis.

CONCLUSION

With intrapleural fluid infusion, radiofrequency ablation for tumours in the hepatic dome was safe and effective, resulting in satisfactory overall and recurrence-free survival.

Perineural air injection as a means of prevention of thermal injury of the sciatic nerve during radio frequency ablation: a preliminary experimental study in rabbits

OBJECTIVE

The purpose of this study was to determine whether perineural air injection before radio frequency (RF) ablation of thigh muscles can minimize thermal injury to the sciatic nerve.

METHODS

Eighteen percutaneous RF ablation procedures were performed in the thighs of 9 rabbits (control, n = 9, right thigh; experimental, n = 9, left thigh) with an internally cooled electrode (1-cm active tip). In the control group, the tip of the electrode was located in posterior muscles 5 mm away from the sciatic nerve before ablation. In the experimental group, sonographically guided air injection into the perineural space was performed just before ablation. Animals were killed 7 days after ablation, and the presence or absence of pathologic changes of the sciatic nerves (axonal necrosis, myelin digestion, endoneurial fibrosis, perineurial fibrosis, and dystrophic calcification) in both groups were compared under an optical microscope.

RESULTS

Perineural air injection was achieved successfully with a single puncture in all rabbits in the experimental group. All of the pathologic findings were observed much more frequently in the control group, and the differences in the frequencies of axonal necrosis and myelin digestion of the sciatic nerve between the groups were clinically significant (P < .05).

CONCLUSIONS

Perineural air injection may be useful for reducing the frequency of thermal injury during RF ablation of lesions adjacent to nerves.

Minimizing abdominal wall damage during high-intensity focused ultrasound ablation by inducing artificial ascites

High-intensity focused ultrasound (HIFU) is becoming an important tool for tumor treatment [especially hepatocellular carcinoma (HCC)] in Asian countries. A HIFU system provides unique advantages of low invasiveness and absence of nonradiation. However, if the target HCC is close to the proximal surface of the liver, HIFU may overheat diaphragm, abdominal wall or skin. To avoid this complication, a method using artificial ascites in the abdominal cavity to separate the liver from the peritoneum, and to serve as a heat sink to cool overlying structures and thereby avoid inducing permanent damage was proposed. Target tissue that was 10 mm below the liver surface was ablated in 12 New Zealand white rabbits: 6 in the experimental group and 6 in the control group. Artificial ascites was established in the experimental group by injecting normal saline into the abdominal cavity until the pressure reached 150 mm H2O. Artificial ascites not only reduced the probability and extent of thermal damage to intervening structures, but also had no adverse affect on the efficacy of HIFU ablation.

Local tumor progression after radiofrequency ablation of liver tumors: analysis of morphologic pattern and site of recurrence

OBJECTIVE

The purpose of our study was to assess the morphologic pattern and exact site of local tumor progression with relation to various risk factors after radiofrequency ablation of liver tumors.

CONCLUSION

Local tumor progression after radiofrequency ablation shows mostly the peripheral nodular type. The site of local tumor progression shows a higher concordance rate with insufficient ablative margin than contiguous vessel and subcapsular location.