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

Thermal ablation for hepatic tumors in high-risk locations

Thermal ablative techniques such as radiofrequency and microwave ablation are minimally invasive and cost-effective approaches that are currently being adopted as alternatives to surgical resection for primary and metastatic liver malignancies. However, they are considered to be relatively contraindicated for tumors in high-risk locations due to technical difficulties and a perceived increased risk of perioperative complications. Several techniques, including artificial ascites, non-touch multibipolar ablation, and laparoscopically assisted ablation, can be used to improve the outcomes of ablation for high-risk tumors. This review aims to provide a comprehensive summary of the techniques currently used to improve thermal ablation outcomes for high-risk liver tumors.

Outcomes of laparoscopic radiofrequency ablation versus percutaneous radiofrequency ablation for hepatocellular carcinoma

BACKGROUND

Few studies have compared the therapeutic outcomes in patients with HCC who underwent laparoscopic radiofrequency ablation (LRFA) versus percutaneous radiofrequency ablation (PRFA) for hepatocellular carcinoma (HCC). Therefore, this study compared the recurrence and survival outcomes of the two RFA methods in patients with HCC.

METHODS

Recurrence and overall survival outcomes were evaluated in 307 patients who underwent LRFA (n = 151) or PRFA (n = 156) as a treatment method for de novo HCC. Inverse probability of treatment weighting (IPTW) analysis was performed to reduce the impact of treatment selection bias.

RESULTS

There were no significant differences in major baseline characteristics between the LRFA and PRFA groups. However, the proportion of cirrhotic patients was higher in the LRFA group, whereas the LRFA group had more tumors and a more advanced tumor-node-metastasis stage. Moreover, the mean tumor size was significantly larger in the LRFA group than in the PRFA group. In a multivariate analysis, serum albumin level, more than three tumors, and the RFA method were identified as significant predictors of recurrence-free survival. Moreover, for the overall survival of HCC patients, serum albumin levels, days of hospital stay during RFA, and the RFA method were independent predictors. In the IPTW-adjusted analysis, the LRFA group showed significantly higher recurrence-free survival and overall survival.

CONCLUSIONS

Our study revealed that compared with PRFA, LRFA was associated with longer recurrence-free survival and favorable overall survival in patients with HCC. Therefore, LRFA should be considered the primary therapy in patients with HCC eligible for RFA.

A meta-analysis and systematic review of the comparison of laparoscopic ablation to percutaneous ablation for hepatic malignancies

BACKGROUND

The optimal access for thermal ablation of the liver has not been evaluated in the literature for the laparoscopic versus percutaneous techniques. The aim of this manuscript was to determine the optimal ablation technique and patient selection for hepatic malignancies by comparing the efficacy and recurrence-free survival of laparoscopic and percutaneous thermal ablation.

METHODS

A detailed literature search was made in PubMed, Web of Science, Google scholar, and EMBASE for related research publications. The data were extracted and assessed by two reviewers independently. Analysis of pooled data was performed, and Odds Ratio (OR) or Hazard Ratio (HR) with corresponding confidence intervals (CIs) was calculated and summarized respectively.

RESULTS

A total of 10 articles were included with 1916 ablation patients. Laparoscopic ablation success (Median 100%) was found to be higher than percutaneous ablation success (median 89.4%) (p = ns). There was a higher percentage of both local and non-local hepatic recurrence in the patients treated with percutaneous ablation versus laparoscopic ablation. Meta-analysis indicated no difference in the adjusted hazard rate of recurrence by procedure type (p = 0.94). Laparoscopic ablation had a higher percentage of complications compared to percutaneous ablation (median lap 14.5% vs. perc 3.3%).

CONCLUSIONS

While laparoscopic and percutaneous ablation are both effective interventions for hepatic malignancies, laparoscopic ablation was found to have improved ablation success and less local and non-local hepatic recurrence compared to percutaneous ablation.

Meta-analysis of Percutaneous vs. Surgical Approaches Radiofrequency Ablation in Hepatocellular Carcinoma

Background: Radiofrequency ablation (RFA) is a curative modality for hepatocellular carcinoma (HCC) patients who are not suitable for resection. It remains controversial whether a surgical or percutaneous approach is more appropriate for HCC.

Method: A search was performed on the PubMed, Web of Science, Embase, and Cochrane Library databases from the date of database inception until April 17, 2021. Studies reporting outcomes of comparisons between surgical RFA (SRFA) and percutaneous RFA (PRFA) were included in this study. The meta-analysis was performed using the Review Manager 5.3 and Stata 12.0 software.

Result: A total of 10 retrospective studies containing 12 cohorts, involving 740 patients in the PRFA group and 512 patients in the SRFA group, were selected. Although the tumor size in PRFA group was smaller than the SRFA group (p = 0.007), there was no significant difference in complete ablation rate between the SRFA and PRFA groups (95.63% and 97.33%, respectively; Odds ratio [OR], 0.56; 95% confidence intervals [CI], 0.26–1.24; p = 0.15). However, the SRFA group showed a significantly lower local tumor recurrence than the PRFA group in the sensitivity analysis (28.7% in the PRFA group and 21.79% in the SRFA group, respectively; OR, 1.84; 95% CI, 1.14–2.95; p = 0.01). Pooled analysis data showed that the rate of severe perioperative complications did not differ significantly between the PRFA and SRFA groups (14.28% and 12.11%, respectively; OR, 1.30; 95% CI, 0.67-2.53; p = 0.44). There was no significant difference in the 1-, 3-, and 5-year overall survival rates, as well as the 1- and 3-year disease-free survival (DFS) between the PRFA and SRFA groups. The 5-year DFS of the PRFA group was significantly lower than the SRFA group (hazard ratio 0.73; 95% CI 0.54–0.99).

Conclusion: Based on our meta-analysis, the surgical route was superior to PRFA in terms of local control rate. Furthermore, the surgical approach did not increase the risk of major complications.

Percutaneous thermal ablation of hepatic tumors: local control efficacy and risk factors for artificial ascites failure

OBJECTIVE

To investigate the risk factors affecting the technical failure of artificial ascites (AA) formation and to evaluate the local control efficacy of percutaneous thermal ablation assisted by the AA for hepatic tumors.

METHODS

A total of 341 patients with 362 hepatic tumors who underwent thermal ablation assisted by AA were reviewed retrospectively. The technical success of AA, the volume of liquid, and local efficacy after ablation were assessed. Predictive factors for the technical failure of AA formation and local tumor progression (LTP) were analyzed using univariate and multivariate analysis.

RESULTS

The technical success rate of AA formation was 81.8% (296/362). The amount of fluid was higher when the tumor was located in the left lobe of the liver than when it was located in the right lobe (median 950 ml versus 700 ml, p < 0.001). Previous hepatic resection (OR: 12.63, 95% CI: 2.93-54.45, p < 0.001), ablation (OR: 6.48, 95% CI: 1.36-30.92, p = 0.019) and upper-abdomen surgery (OR: 11.34, 95% CI: 1.96-65.67, p = 0.007) were the independent risk factors of AA failure. In the AA success group, the complete ablation rate was higher and the LTP rate was lower than that in the AA failure group (98.7 versus 92.4%, p = 0.012; 8.8 versus 21.2%, p = 0.004). Multivariate analysis identified AA failure (p = 0.004), tumor size (>3.0 cm) (p = 0.002) and metastatic liver tumor (p = 0.008) as independent risk factors for LTP.

CONCLUSION

History of hepatic resection, ablation and upper abdomen surgery were significant predictive factors affecting the technical failure of AA formation. Successful introduction of AA before thermal ablation can achieve better local tumor control efficacy.

Laparoscopic radiofrequency ablation of subcapsular hepatocellular carcinomas: risk factors related to a technical failure

BACKGROUND

This study aimed to evaluate the risk factors related to a technical failure after laparoscopic radiofrequency ablation (RFA) for subcapsular hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

A total of 110 patients with 114 HCCs who underwent laparoscopic RFA for HCCs (new HCC [n = 85] and local tumor progression [LTP] [n = 29]) between January 2013 and December 2018 were included. We evaluated the incidence of technical failure on immediate post-RFA CT images. Risk factors for a technical failure after laparoscopic RFA were assessed using univariable logistic regression analyses. The cumulative LTP rate was estimated using the Kaplan-Meier method.

RESULTS

Technical failure was noted in 3.5% (4/114) of the tumors. All four tumors that showed a technical failure were cases of LTP from previous treatment and were invisible on laparoscopy. On univariate analysis, LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as risk factors for a technical failure. The cumulative LTP rates at 1, 3, and 5 years were estimated to be 2.8%, 4.8%, and 4.8%, respectively.

CONCLUSIONS

LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as the risk factors for a technical failure after laparoscopic RFA.

Laparoscopic thermoablation for hepatocellular carcinoma in patients with liver cirrhosis: an effective procedure for tricky tumors

The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are amenable to this option. Percutaneous radiofrequency interstitial thermal ablation (TA) proved to be effective in the treatment of unresectable HCC. Recent advances in laparoscopic ultrasound have improved the accuracy in detecting small intrahepatic HCC nodules missed by pre-operative imaging techniques. Our objective was to evaluate an operative combination of laparoscopic ultrasound with laparoscopic thermoablation (LTA) in the treatment of HCC not amenable to liver resection. The aim of our review was to evaluate the advantages and limits of the laparoscopic approach according the criteria of the evidence-based medicine. LTA of HCC proved to be a safe and effective technique both in the short- and long-term follow-up period. This technique may be indicated in selected cases when the percutaneous approach to the lesion is very difficult or contraindicated.

Hepatic resection vs percutaneous radiofrequency ablation of hepatocellular carcinoma abutting right diaphragm

BACKGROUND

It is usually difficult to adequately conduct percutaneous ultrasound-guided radiofrequency (RF) ablation for hepatocellular carcinomas (HCCs) abutting the diaphragm. Our hypothesis was that the subphrenic location of HCC could have an effect on the long-term therapeutic outcomes after hepatic resection and RF ablation.

AIM

To compare the long-term therapeutic outcomes of hepatic resection and percutaneous RF ablation for HCCs abutting the diaphragm.

METHODS

A total of 143 Child-Pugh class A patients who had undergone hepatic resection (n = 80) or percutaneous ultrasound-guided RF ablation (n = 63) for an HCC (≤ 3 cm) abutting the right diaphragm were included. Cumulative local tumor progression (LTP), cumulative intrahepatic distant recurrence (IDR), disease-free survival (DFS), and overall survival (OS) rates were estimated. Prognostic factors for DFS and OS were analyzed. Complications were evaluated.

RESULTS

The cumulative IDR rate, DFS rate, and OS rate for the hepatic resection group and RF ablation group at 5 years were “35.9% vs 65.8%”, “64.1% vs 18.3%”, and “88.4% vs 68.7%”, respectively. Hepatic resection was an independent prognostic factor for DFS (P ≤ 0.001; hazard ratio, 0.352; 95%CI: 0.205, 0.605; with RF ablation as the reference category); however, treatment modality was not an independent prognostic factor for OS. The LTP rate was 46.6% at 5 years for the RF ablation group. The major complication rate was not significantly different between the groups (P = 0.630). The rate of occurrence of peritoneal seeding was higher in the RF ablation group (1.3% vs 9.5%, P = 0.044).

CONCLUSION

Although OS was not significantly different between patients who had gone hepatic resection or percutaneous RF ablation for HCCs abutting the diaphragm, DFS was better in the hepatic resection group.

Advantages of Laparoscopic Radiofrequency Ablation Over Percutaneous Radiofrequency Ablation in Hepatocellular Carcinoma

BACKGROUND

Inoperable hepatocellular carcinoma (HCC) can be treated with laparoscopic radiofrequency ablation (LRFA), which is generally a more accurate and accessible procedure than percutaneous RFA (PRFA). However, few studies have compared survival outcomes between LRFA and PRFA in patients with HCC.

AIMS

This study aimed to compare the efficacy of LRFA and PRFA for HCC treatment.

METHODS

Patients who underwent PRFA or LRFA as an initial treatment modality between April 2005 and April 2016 were enrolled in this study. The overall and recurrence-free survival rates were examined for each patient. Additionally, propensity score matching was performed for both groups.

RESULTS

The baseline characteristics of patients in the PRFA and LRFA groups showed several minor differences. Multivariate analysis showed that the RFA method was not a critical determinant of recurrence-free or overall survival (p = 0.069 and p = 0.406). Among patients who underwent RFA as the initial treatment modality, there was no significant effect between either RFA procedures on survival. After propensity score matching, univariate analysis showed a significant difference in overall survival between PRFA and LRFA (p = 0.031). Multivariate analysis showed that LRFA is a strong factor that contributed to an improved overall survival in HCC patients (hazard ratio 0.108, p = 0.040). Furthermore, our data showed that LRFA was able to limit multiple intrahepatic recurrences, as well as prevent marginal recurrence.

CONCLUSIONS

LRFA appears to be superior to PRFA in terms of survival. LRFA may help reduce mortality in HCC patients.

Short-Term Results of Laparoscopic Radiofrequency Ablation Using a Multipolar System for Localized Hepatocellular Carcinoma

BACKGROUND AND AIM

Multipolar radiofrequency ablation (RFA) is feasible for the treatment of hepatocellular carcinoma (HCC) for which a large ablative area is planned, and it imposes a light physical burden on patients. Multipolar RFA via the percutaneous approach is performed in the majority of cases, but the efficacy of multipolar RFA with a laparoscopic approach has rarely been studied. This study aimed to evaluate the efficacy and safety of multipolar laparoscopic RFA (LRA) for localized HCC over the short term.

METHODS

From January 2014 to January 2016, 77 consecutive patients with 130 HCCs treated by multipolar LRA were assessed. One to three bipolar needle applicators were inserted under laparoscopic ultrasonography guidance, regardless of tumor location. We intended to achieve parallel insertions and no-touch ablation as much as possible.

RESULTS

The median size of the main tumor was 22 mm (range, 10-42 mm). The median follow-up time was 13.6 months (range, 3.1-24.8 months). In all cases, a sufficient ablative area was obtained as planned, without thermal injury of adjacent organs. During the follow-up period, all patients were alive with no local tumor progression, while intrahepatic recurrence distant from the primary site occurred in 7 patients. The 2-year local tumor progression-free survival rate and overall cancer-free survival rate were 100 and 81.6%, respectively. There were no procedural major complications caused prolonging the hospitalization, and all patients were discharged without subjective symptoms 4-7 days after LRA.

CONCLUSIONS

Multipolar LRA was efficacious in the treatment of localized HCCs by safely achieving a good ablative area.

Transpulmonary computed tomography-guided radiofrequency ablation of liver neoplasms abutting the diaphragm with multiple bipolar electrodes

BACKGROUND

Neoplasm abutting the diaphragm is one kind of the special sites of liver neoplasms treated with radiofrequency ablation (RFA), the purpose of this study is to evaluate the feasibility and safety of computed tomography (CT)-guided RFA of liver neoplasms abutting the diaphragm with multiple bipolar electrodes sequentially passing through the lung parenchyma.

MATERIALS AND METHODS

37 patients were treated with transpulmonary CT-guided RFA. Technical success rate, perioperative complications, and local tumor progression were investigated.

RESULTS

The number of electrode (s) sequentially passing through the lung parenchyma (NPLP) was 1 electrode in 20 patients, 2 electrodes in 14 cases, and 3 electrodes in 3 cases. Technical success rate was 100%. The most of the perioperative complications were self-limiting and mainly included pneumothorax (11 cases, 2 needed percutaneous drainage), hemorrhage of the electrode track in the lung parenchyma (6 cases), a small amount of hemoperitoneum in perihepatic space (8 cases) and discomfort of the right shoulder (7 cases). Local tumor progression occurred in 6 cases during the follow-up (3-12 months). Multivariate logistic regression analysis showed that the incidence of pneumothorax was not related to NPLP (P = 0.50), length of the electrode (s) in the lung parenchyma (P = 0.18), types of anesthesia (P = 0.10), and indwelling time of the electrode (s) in the lung parenchyma (P = 0.28).

CONCLUSION

CT-guided RFA of liver neoplasms abutting the diaphragm with multiple bipolar electrodes sequentially passing through the lung parenchyma is a feasible and safe therapeutic option.

A case of hepatocellular carcinoma treated by radiofrequency ablation confirming the adjacent major bile duct under hybrid contrast mode through a biliary drainage catheter

Bile duct injury is a potential complication of radiofrequency ablation (RFA). Bipolar RFA devices have recently become available. Because visibility of the bipolar RFA electrodes is not good on ultrasonography, more careful usage of the electrodes to avoid bile ducts is needed. We present a case with hepatocellular carcinoma (HCC) located near the B5 intrahepatic bile duct. To view the bile duct, we used contrast medium for ultrasonography, administered through a biliary drainage catheter for endoscopic nasobiliary drainage (ENBD). Infusing the contrast medium allowed clear visualization of the HCC adjacent to the major bile duct during RFA. We also used a navigation system for bipolar RFA to confirm positions of the electrodes and HCC. We confirmed complete ablation of the HCC while avoiding bile duct injury and late bile duct stenosis. Administration of contrast medium for ultrasonography through an ENBD tube appears useful to avoid bile duct injury during RFA.

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.

Image-guided therapies in the treatment of hepatocellular carcinoma: A multidisciplinary perspective

A multidisciplinary approach to the treatment of patients with unresectable hepatocellular carcinoma (HCC) has led to improvements in screening, detection, and treatments. Interventional techniques include thermal ablation, transarterial chemoembolization, and radioembolization whilst stereotactic body radiation therapy also uses imaging to target the radiation. Both survival rates and cure rates have improved markedly since the introduction of these techniques. This review article describes the image guided techniques used for the treatment of HCC.

Local recurrence of hepatocellular carcinoma in the tumor blood drainage area following radiofrequency ablation

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. HCC is generally considered to spread via the bloodstream and local recurrence often occurs in the blood drainage area determined by computed tomography during hepatic arteriography (CTHA), despite complete ablation of the primary nodule. This study was conducted in order to prospectively assess the rate of local recurrence in the blood drainage area depicted by delayed-phase CTHA. The participants comprised 364 consecutive patients (260 men and 104 women; mean age, 67.4±8.6 years), enrolled between April, 2002 and December, 2011. The participants were divided into two groups, according to whether the ablation area covered the entire blood drainage area as defined by delayed-phase CTHA (group A) or not (group B). Local tumor progression was compared between the two groups. The median time to recurrence was significantly shorter for group B (434 days) compared to that for group A (1,474 days; P=0.0037). The cumulative local recurrence rates for group A were 0, 0 and 1.5% at 1, 3 and 5 years postoperatively, respectively, whereas the recurrence rates for group B were 3.8, 17.0 and 22.8% at 1, 3 and 5 years, respectively (P<0.0001). In conclusion, the safety margin for radiofrequency ablation should be defined as the blood drainage area and ablation should aim at acquiring adequate safety margins.

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.

Radiofrequency ablation of hepatocellular carcinoma: Current status

Ablation therapy is one of the best curative treatment options for malignant liver tumors, and can be an alternative to resection. Radiofrequency ablation (RFA) of primary and secondary liver cancers can be performed safely using percutaneous, laparoscopic, or open surgical techniques, and RFA has markedly changed the treatment strategy for small hepatocellular carcinoma (HCC). Percutaneous RFA can achieve the same overall and disease-free survival as surgical resection for patients with small HCC. The use of a laparoscopic or open approach allows repeated placements of RFA electrodes at multiple sites to ablate larger tumors. RFA combined with transcatheter arterial chemoembolization will make the treatment of larger tumors a clinically viable treatment alternative. However, an accurate evaluation of treatment response is very important to secure successful RFA therapy. Since a sufficient safety margin (at least 0.5 cm) can prevent local tumor recurrences, an accurate evaluation of treatment response is very important to secure successful RFA therapy. To minimize complications of RFA, clinicians should be familiar with the imaging features of each type of complication. Appropriate management of complications is essential for successful RFA treatment.

Recent advances of radiofrequency ablation for early hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of death in the malignant neoplastic diseases in the world. Surgical operation is sometimes not indicated because of complicated liver cirrhosis and extrahepatic disorders. Radiofrequency ablation has been developed as a less invasive treatment for HCC since 1999, and long-term outcome has been shown. There are several complications which should be paid attention, and to improve the prognosis, combination treatment with transarterial chemoembolization should be discussed. Overall survival after between RFA and surgical resection should be compared prospectively. Establishment of staging system for treatment allocation of HCC and prevention of HCC recurrence is important issue to be examined.

Radiofrequency ablation of hepatocellular carcinoma: Current status

Ablation therapy is one of the best curative treatment options for malignant liver tumors, and can be an alternative to resection. Radiofrequency ablation (RFA) of primary and secondary liver cancers can be performed safely using percutaneous, laparoscopic, or open surgical techniques, and RFA has markedly changed the treatment strategy for small hepatocellular carcinoma (HCC). Percutaneous RFA can achieve the same overall and disease-free survival as surgical resection for patients with small HCC. The use of a laparoscopic or open approach allows repeated placements of RFA electrodes at multiple sites to ablate larger tumors. RFA combined with transcatheter arterial chemoembolization will make the treatment of larger tumors a clinically viable treatment alternative. However, an accurate evaluation of treatment response is very important to secure successful RFA therapy. Since a sufficient safety margin (at least 0.5 cm) can prevent local tumor recurrences, an accurate evaluation of treatment response is very important to secure successful RFA therapy. To minimize complications of RFA, clinicians should be familiar with the imaging features of each type of complication. Appropriate management of complications is essential for successful RFA treatment.

[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.