Radiofrequency ablation of unresectable primary and metastatic hepatic malignancies: results in 123 patients

Thermoablation of colorectal liver metastasis

Thermoablation is a local therapy that is effective in in situ destruction of colorectal liver metastasis while preserving surrounding normal liver tissue. It is less invasive compared to surgery, easy to use, and can be repeated. The therapy provides local control of unresectable disease and is an alternative therapy for small resectable lesions in patients with insufficient hepatic reserve after resection or coexistent comorbid conditions. It can artificially increase the resection margin thus increasing the number of patient candidate for resection. When used in conjunction with liver resection it clears the liver of multiple lesions that are surgically inaccessible or unresectable. Main limitations of the treatment are local recurrence of the disease, treatment-related complications, and questionable impact on patient. Outcome of therapy can be improved when used as part of multimodality treatment.

Locoregional management of hepatic metastasis from primary uveal melanoma

Uveal melanoma is the most common primary ocular malignancy in adults and has a significant predilection for metastasis to the liver. Despite successful treatment of the primary uveal melanoma, up to 50% of patients will subsequently develop a systemic metastasis, with the liver involved in up to 90% of these individuals. Metastatic uveal melanoma has proven to be resistant to currently available systemic chemotherapies. Recognition of the poor prognosis associated with liver metastasis has led to the evaluation of various locoregional treatment modalities primarily designed to control tumor progression in the liver, including surgical resection, hepatic arterial chemotherapy, transarterial chemoembolization (TACE), immunoembolization, radiosphere, drug-eluting beads, isolated hepatic perfusion (IHP), and percutaneous hepatic perfusion. This article reviews the efficacies, and morbidities of currently available locoregional therapies.

Results of single-probe microwave ablation of metastatic liver cancer

AIMS

Microwave ablation (MWA) is the most recent development in the field of local ablative therapies. The aim of this study was to evaluate the variability and reproducibility of single-probe MWA vs. radiofrequency ablation (RFA) of liver metastases smaller than 3cm in patients without underlying liver disease.

METHODS

Sixteen liver metastases were treated using MWA, and matched for size and localisation with 13 metastases treated by RFA. Tumour diameters and postoperative ablation diameters were recorded (D1 transverse; D2 antero-posterior; D3 cranio-caudal; mm) on computed tomography scans.

RESULTS

Median D1, D2, and D3 ablation diameters after MWA vs. RFA were 18.5 (12-64) vs. 34 (16-41)mm (p=0.003), 26 (14-60) vs. 35 (28-40)mm (p=0.046), and 20 (10-73) vs. 32 (20-45)mm (p=0.025), respectively. As compared to RFA, the variability between the lesions after MWA was significantly higher for D2 (p<0.0001) and D3 (p=0.002) but not for D1 (p=0.15). The ablation diameters were less uniform after MWA than after RFA (p<0.001).

CONCLUSION

Ablation diameters after single-probe MWA of metastatic liver tumours are highly variable and suboptimal. Improvements are needed before MWA can be implemented routinely.

Interstitial thermal ablation with a fast rotating dual-mode transducer

Interstitial ultrasound applicators can be a minimally invasive alternative for treating targets that are unresectable or are inaccessible by extracorporeal methods. Dual-mode transducers for ultrasound imaging and therapy were developed to address the constraints of a miniaturized applicator and real-time treatment monitoring. We propose an original treatment strategy that combines ultrasound imaging and therapy using a dual-mode transducer rotating at 8 revolutions per second. Real-time B-mode imaging was interrupted to emit high-intensity ultrasound over a selected therapy aperture. A full 360 degrees image was taken every 8th rotation to image the therapy aperture. Numerical simulations were performed to study the effect of rotation on tissue heating, and to study the effect of the treatment sequence on transducer temperature. With the time-averaged transducer surface intensity held at 12 W/cm(2) to maintain transducer temperature below 66 degrees C, higher field intensities and deeper lesions were produced by narrower therapy apertures. A prototype system was built and tested using in vitro samples of porcine liver. Lesions up to 8 mm were produced using a time-averaged transducer surface intensity of 12 W/cm(2) applied for a period of 240 s over a therapy aperture of 40 degrees. Apparent strain imaging of the therapy aperture improved the contrast between treated and spared tissues, which could not be differentiated on B-mode images. With appropriate limits on the transducer output, real-time imaging and deep thermal ablation are feasible and sustainable using a rotating dual-mode transducer.

Radiofrequency ablation of unresectable liver tumors: factors associated with incomplete ablation or local recurrence

BACKGROUND

Radiofrequency ablation (RFA) of liver tumors is associated with a risk of incomplete ablation or local recurrence.

METHODS

One hundred sixty-eight patients with 311 unresectable liver tumors were included. Effects of different variables on incomplete ablation and local recurrence were analyzed.

RESULTS

There were 132 hepatocellular carcinomas and 179 liver metastases. Tumor size was 24 (±13) mm. Two hundred twenty-six tumors were treated percutaneously, and 85 through open approach (associated with liver resection in 42 cases). There was no mortality. Major morbidity rate was 7%. Incomplete ablation and local recurrence rates were 14% and 18.6%. Follow-up was 29 months. On multivariate analysis, factors associated with incomplete ablation were tumor size (>30 mm vs ≤30 mm, P = .004) and approach (percutaneous vs open, P = .0001). Factors associated with local recurrence were tumor size (>30 mm vs ≤30 mm, P = .02) and patient age (>65 years vs ≤65 years, P = .05).

CONCLUSIONS

RFA is effective to treat unresectable liver tumors. However, there is a risk of incomplete ablation when percutaneously treating tumors >30 mm. When tumor ablation is completely achieved, the main factor associated with local recurrence is tumor size >30 mm.

[Radiofrequency ablation as a palliative therapy option in ENT tumors: in vivo and in vitro testing]

BACKGROUND

High frequency thermotherapy (HFTT) is an established palliative therapy for hepatic malignancies. An in vivo and in vitro trial examined the preconditions for the application of HFTT with liquid-cooled wet electrodes for minimally invasive palliation of head and neck tumors.

MATERIAL AND METHOD

HFTT was applied with needle electrodes, cooled with isotonic saline solution, and a high-frequency generator (Elektrotom HiTT 106, Berchtold, Tuttlingen) to porcine tongue and narcotized, juvenile domestic pigs to the tongue and neck, and monitored in realtime by B-mode ultrasound.

RESULTS

The direction of spread of the hyperthermic zone is well observed using ultrasound. Determining the direction of spread is not possible with cooled-tip electrode needles. Severe complications were not observed during the application.

CONCLUSION

RFA with liquid-cooled needle applicators is not safely applicable for the therapy of head and neck tumors.

Radioembolisation using yttrium 90 (Y-90) in patients affected by unresectable hepatic metastases

PURPOSE

This study was done to evaluate the effectiveness of radioembolisation of liver metastases with yttrium 90 (Y-90) in patients with no response to chemotherapy.

MATERIALS AND METHODS

From February 2005 to January 2008, we treated 110 patients affected by liver metastatic disease from colorectal, breast, gastric, pancreatic, pulmonary, oesophageal and pharyngeal cancers and from cholangiocarcinoma and melanoma. We excluded patients with bilirubin level >1.8 mg/dl and pulmonary shunt >20% but not patients with minor extrahepatic metastases.

RESULTS

We obtained a complete /partial response in 45 patients, stable disease in 42 patients and progressive disease in 23 patients. In 90 cases, we obtained a decrease in specific tumour marker level. The technical success rate was 96%, and technical effectiveness estimated at 3 months after treatment was 83.6%. Side effects were grade 4 hepatic failure in one case, grade 2 gastritis in six cases and grade 2 cholecystitis in two cases. The median survival and progression-free survival calculated by Kaplan-Meier analysis were 323 days and 245 days, respectively.

CONCLUSIONS

According to our 3-year experience, Y-90 radioembolisation (SIR-spheres) is a feasible and safe method to treat liver metastases with an acceptable level of complications and a good response rate.

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.

Two-surgeon technique of parenchymal transection contributes to reduced transfusion rate in patients undergoing major hepatectomy: analysis of 1,557 consecutive liver resections

BACKGROUND

Blood transfusions are an independent risk factor for adverse outcomes after hepatectomy. In-hospital transfusions are still reported in one third of patients in major series. Data on factors affecting blood transfusions in large series of liver resection are limited. The aim of this study was to evaluate factors predictive of blood transfusion in hepatectomies performed at a tertiary referral center.

METHODS

Records of 1,477 patients who underwent 1,557 liver resections between 1998 and 2007 were reviewed. Multivariate analysis of risk factors for red cell transfusion was performed.

RESULTS

Median intra-operative blood loss was 250 cc, and 30-day peri-operative red cell transfusion rate was 27%. On multivariate analysis, factors that significantly predicted increased red cell transfusion rates were female sex, pre-operative hematocrit<30%, platelet count<100,000/mm3, simultaneous resection of other organs, major hepatic resection, use of the Pringle maneuver, and tumors>10 cm. Parenchymal transection technique was an independent risk factor for perioperative red cell transfusion; the usage of the 2-surgeon technique (combined saline-linked cautery and ultrasonic dissection) was associated with a lower transfusion rate than other techniques, including ultrasonic dissection alone, finger fracture, and stapling (P<.001).

CONCLUSION

Although most factors that affect the red cell transfusion rate for liver resection are patient- or tumor-related, the parenchymal transection technique is under the surgeon's control. The decrease in transfusion rate associated with the use of the 2-surgeon technique emphasizes the important role of the hepatobiliary surgeon in determining outcomes after liver resection.

Interventional navigation systems for treatment of unresectable liver tumor

Most patients with liver tumors are not candidates for surgical resection. A number of local treatment methods for unresectable liver tumors have recently received considerable interests. The major task of these procedures is accurate needle placement with the aim of complete tumor removal and minimal damage to surrounding normal liver parenchyma. In this article, we review the current status of interventional navigation system (INS) for treatment of unresectable liver tumors in terms of overall workflow, tracking systems, and research development. The conceptual design of INS consists of pre-operative and intra-operative modules. The tracking system falls into three types: optical, electromagnetic, and MR gradient based. The current INS, according to their image modalities, can be classified into four categories: MRI based, CT based, U/S based, and multimodalities based. The article also discusses the future research direction for enhanced performance of INS with real time imaging, high accuracy, high resolution, and friendly user-interface.

Microwave ablation for unresectable hepatic tumours: clinical results using a novel microwave probe and generator

BACKGROUND

Microwave ablation is an in situ method of tumour destruction used to treat patients with unresectable liver tumours. A new microwave generator and probe, designed to deliver high energy into solid tumours quickly has been developed at our institution. We report the results of its use in patients with unresectable liver tumours treated by a single surgeon in a single institution.

METHODS

Thirty-one patients with 89 unresectable liver tumours were recruited into the study and underwent microwave ablation in a single procedure.

RESULTS

There were no post-operative complications. At a median of 24 months post ablation, 15 patients were alive with 7 patients disease free. At a median of 26 months, 8 patients were alive with tumour recurrence but only 1 with local recurrence. The remaining 7 patients with recurrence were found to have new disease at locations remote from the ablation site. Fourteen patients died of disease progression at a median survival of 15 months, with only 1 patient with local and remote tumour recurrence. Of the total numbers of tumours treated (n=89), a local tumour recurrence rate of 2% was observed. Overall median survival was 29 months with 3 year survival of 40%.

DISCUSSION

Microwave tissue ablation using this novel generator and probe has a low local recurrence and complication rate. Overall survival is comparable to alternative ablation modalities and its ability to treat, even large tumours, with a single insertion of the probe makes it an extremely attractive treatment option.

American Society of Clinical Oncology 2009 clinical evidence review on radiofrequency ablation of hepatic metastases from colorectal cancer

PURPOSE

To review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM).

METHODS

The American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library.

RESULTS

Because data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches.

CONCLUSION

There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Early detection of local RFA site recurrence using total liver volume perfusion CT initial experience

RATIONALE AND OBJECTIVES

The aim of this study was to prospectively evaluate the feasibility of a novel total liver volume perfusion computed tomographic technique in demonstrating treatment-site recurrence of liver metastases after radiofrequency ablation (RFA).

MATERIALS AND METHODS

Eleven patients considered to be at increased risk for local RFA-site tumor recurrence underwent both positron emission tomography (PET) and perfusion computed tomography (CTP): a 12-phase scan of the entire liver acquired before and 11 times after contrast injection. After coregistration, blood flow maps were created using the maximum slope method.

RESULTS

In all cases, the CTP-derived blood flow maps fully paralleled the PET images in showing either the absence (nine of 13 lesions) or presence (four of 13 lesions) of local RFA-site recurrence. Marginal lesions with high hepatic arterial perfusion (>50 mL/min/100 g) and low portal venous perfusion (<10 mL/min/100 g) represented recurring vital tumor tissue (P < .05).

CONCLUSION

Total liver volume CTP seems feasible for the detection and localization of treatment-site recurrence after RFA.

Update and review of the multidisciplinary management of stage IV colorectal cancer with liver metastases

Background

The management of stage IV colorectal cancer with liver metastases has historically involved a multidisciplinary approach. In the last several decades, there have been great strides made in the therapeutic options available to treat these patients with advancements in medical, surgical, locoregional and adjunctive therapies available to patients with colorectal liver metastases(CLM). As a result, there have been improvements in patient care and survival. Naturally, the management of CLM has become increasingly complex in coordinating the various aspects of care in order to optimize patient outcomes.

Review

A review of historical and up to date literature was undertaken utilizing Medline/PubMed to examine relevant topics of interest in patients with CLM including criterion for resectability, technical/surgical considerations, chemotherapy, adjunctive and locoregional therapies. This review explores the various disciplines and modalities to provide current perspectives on the various options of care for patients with CLM.

Conclusion

Improvements in modern day chemotherapy as allowed clinicians to pursue a more aggressive surgical approach in the management of stage IV colorectal cancer with CLM. Additionally, locoregional and adjunctive therapies has expanded the armamentarium of treatment options available. As a result, the management of patients with CLM requires a comprehensive, multidisciplinary approach utilizing various modalities and a more aggressive approach may now be pursued in patients with stage IV colorectal cancer with CLM to achieve optimal outcomes.

Ultrasound-guided radiofrequency-assisted segmental liver resection: a new technique

Segmental hepatectomy is appealing for several reasons including preservation of liver parenchyma, reduction of intraoperative blood loss, and blood replacement by dividing tissues along the anatomic planes. A simple technique guided by intraoperative ultrasound is described here using radio-frequency energy to create coagulative desiccation of segmental or subsegmental arterial and portal vessels. Thirty patients underwent a segmental resection using this technique without mortality and with minor morbidity. This technique has a major advantage of being easy and safe to apply. We believe it has a potentially important role in both open and laparoscopic liver surgery.

Optimal management of localized renal cell carcinoma: surgery, ablation, or active surveillance

Radical nephrectomy is historically accepted as standard treatment for localized renal cell carcinoma (RCC). However, the presentation of RCC has changed dramatically over the past 3 decades. Newer alternative interventions aim to reduce the negative impact of open radical nephrectomy, with the natural history of RCC now better understood. This article discusses current surgical and management options for localized kidney cancer.

EUS-guided radiofrequency ablation with a prototype electrode array system in an animal model (with video)

BACKGROUND

Although previously reported in an animal model, the development of EUS-guided radiofrequency ablation (EUS-RFA) has been impeded because of a lack of a retractable needle electrode array that could safely and effectively ablate large areas.

OBJECTIVE

To evaluate the feasibility and safety of performing EUS-RFA with a 19-gauge FNA needle fitted with an umbrella-shaped retractable needle electrode array.

DESIGN AND SETTING

Endoscopic experimental study in a porcine survival model at a tertiary referral center animal laboratory.

MAIN OUTCOME MEASURES

Evaluate the safety and efficacy of the retractable needle electrode array for performing EUS-RFA.

INTERVENTIONS

A 19-gauge EUS-FNA needle was modified and fitted with a retractable echogenic umbrella-shaped monopolar electrode array at its tip. The FNA needle was connected to a 200-W generator that has an impedance-based feedback system. EUS-RFA of the liver was attempted on 5 Yorkshire pigs. Although 1 pig was euthanized immediately after RFA to assess for immediate complications and pathological examination, the 4 others were kept alive for 7 days.

RESULTS

At EUS, the needle electrode was well visualized and could be deployed in the liver without technical difficulty. During ablation, a round hyperechoic focus gradually surrounded the electrode tip. Tissue ablation was attained within 7 minutes, and the electrode array could be easily withdrawn into the needle assembly. The vital signs of all pigs remained stable throughout the procedure and until they were euthanized. Histopathology in all pigs revealed a discrete, well-demarcated spherical focus of complete coagulation necrosis measuring 2.6 cm in diameter and without damage to the surrounding liver parenchyma or vasculature.

CONCLUSIONS

In this experimental study, EUS-RFA of the liver was performed safely by using the retractable umbrella-shaped electrode array with effective coagulation necrosis of large areas.

Technologic innovations in surgery: a philosophic reflection on their impact on operations for cancer

Technologic advances this past half-century have clearly had a positive effect on our ability to both diagnose and treat human cancer as well as on the operative treatment of other diseases. However, the impact of these innovations on the surgical treatment of cancer is not as clear as it is for many other problems that are managed surgically. This review is an "opinion piece" that attempts to assess the successes and failures of technologic innovations that have been introduced for the purpose of improving the operative treatment of cancer.

Radiofrequency ablation combined with KS-IL2 immunocytokine (EMD 273066) results in an enhanced antitumor effect against murine colon adenocarcinoma

PURPOSE

Radiofrequency ablation (RFA) is a common treatment modality for surgically unresectable tumors. However, there is a high rate of both local and systemic recurrence.

EXPERIMENTAL DESIGN

In this preclinical study, we sought to enhance the antitumor effect of RFA by combining it with huKS-IL2 immunocytokine [tumor-specific monoclonal antibody fused to interleukin-2 (IL2)] in mice bearing CT26-KS colon adenocarcinoma. Mice were treated with RFA, huKS-IL2 via intratumoral injection, or combination therapy.

RESULTS

Treatment of mice bearing s.c. tumors with RFA and huKS-IL2 resulted in significantly greater tumor growth suppression and enhanced survival compared with mice treated with RFA or huKS-IL2 alone. When subtherapeutic regimens of RFA or huKS-IL2 were used, tumors progressed in all treated mice. In contrast, the combination of RFA and immunocytokine resulted in complete tumor resolution in 50% of mice. Treatment of a tumor with RFA and intratumoral huKS-IL2 also showed antitumor effects against a distant untreated tumor. Tumor-free mice after treatment with RFA and huKS-IL2 showed immunologic memory based on their ability to reject subsequent challenges of CT26-KS and the more aggressive parental CT26 tumors. Flow cytometry analysis of tumor-reactive T cells from mice with complete tumor resolution showed that treatment with RFA and huKS-IL2 resulted in a greater proportion of cytokine-producing CD4 T cells and CD8 T cells compared with mice treated with RFA or huKS-IL2 alone.

CONCLUSIONS

These results show that the addition of huKS-IL2 to RFA significantly enhances the antitumor response in this murine model, resulting in complete tumor resolution and induction of immunologic memory.

Radiofrequency ablation of large size liver tumours using novel plan-parallel expandable bipolar electrodes: initial clinical experience

PURPOSE

Although radiofrequency ablation (RFA) is a promising method for local treatment of liver malignancies, with conventional monopolar systems recurrence rates for large size tumours (≥3.5 cm) remain high. The objective of this study was to evaluate the safety, feasibility and local effectiveness of a novel bipolar plan-parallel expandable system for these larger tumours.

METHODS AND MATERIALS

Eight consecutive patients with either unresectable colorectal liver metastases (CRLM in 6 patients), carcinoid liver metastases (1 patient) and hepatocellular carcinoma (HCC in 1 patient) of ≥3.5 cm were treated with bipolar RFA during laparotomy with ultrasound guidance. Early and late, major and minor complications were recorded. Local success was determined on 3-8 month follow-up CT scans of the upper abdomen.

RESULTS

Nine CRLM, one carcinoid liver metastases and one HCC (3.5-6.6 cm) were ablated with bipolar RFA. Average ablation time was 16 min (range 6-29 min.). Two patients developed a liver abscess which required re-laparotomy. In both cases bowel surgery during the same session probably caused bacterial spill. There were no mortalities. The patients were released from hospital between 5 and 29 days after the procedure (median 12 days). The 6-12 month follow-up PET-CT scans showed signs for marginal RFA-site tumour recurrence in three patients with CRLM (3/11 lesions).

CONCLUSION

Preliminary results suggest bipolar RFA to be a reasonably safe, fast and feasible technique which seems to improve local control for large size hepatic tumour ablations.

Phantom experimental study on microwave ablation with a water-cooled antenna

Microwave ablation therapy using a water-cooled antenna was studied experimentally in a phantom. The development of the heating pattern induced by the microwave antenna was determined from the thermocouple-measured temperature field, and the influence of the cooling water flow within the antenna on temperature distribution and heating pattern was investigated. The shape of the heating pattern was pear-like, and the enlarging rate of the heating pattern decreased with heating time. Because of strong cooling effect, the heating pattern in the region with Z < 0 (where Z = 0 represents the position of radiator, Z < 0 and Z > 0 represent the backward direction of the antenna with cooling water and forward direction without water, respectively) was smaller in diameter than that with Z > 0, and the heating pattern with Z < 0 was slightly reduced when the velocity of the cooling water increased. The highest ablative temperature occurred with Z > 0 decreasing. Finally, the specific absorption rate distribution was also determined and investigated analytically. The present results can be helpful in clinical ablation therapy practice and will be applicable to multiple applicators for surgical planning.

Pilot study for a new bipolar radiofrequency ablation/aspirator device in the management of primary and secondary liver cancers

BACKGROUND

In the US, the thermal ablation workload for cancer involving the liver is predicted to more than double in the next 5 years, emphasising the need to develop and improve the current technology.

STUDY DESIGN

A multicentre nonrandomised prospective clinical trial (NCT00514930) was undertaken, to assess the efficacy and safety of a new bipolar radiofrequency ablation/aspirator device, in the treatment of primary and secondary cancers of the liver.

RESULTS

A total of 34 lesions in 16 patients were ablated at laparotomy and followed up at 4 weeks. The mean diameter of lesion before ablation was 3.2+/-2.22 (range 1-10) cm, the mean volume aspirated during ablation was 9.25+/-7.3 (range 0-25) ml and the mean operative time was 145.95+/-40.7 (range 60-215) min. There was one major complication of a pleural effusion, which required drainage. The mean length of stay was 8+/-3.2 (range 3-14) days. In 11 patients, the ablated tumour was resected. On histological assessment, there was no evidence of viable cancer at the tumour edge. On follow-up computed tomography, the ablation zone fully encompassed the targeted tumour and there were no local complications related to ablation.

CONCLUSION

Initial analysis of the data from this small cohort, with only a short-term follow-up, shows this device to be safe and effective.

Liver ablation techniques: a review

BACKGROUND

Ablation techniques for unresectable liver carcinomas have evolved immensely since their introduction. Results of studies involving these techniques are restricted to reports of patient case series, which are often not presented in a standardised manner. This review aims to summarise the major studies in ablation technologies and present them in a way that may make comparison between the major modalities easier.

METHODS

All major databases (Medline, Cochrane, Embase and Pubmed) were searched for studies using microwave, radiofrequency or cryoablation to treat unresectable liver tumours. Only studies with at least 30 patients and 3-year follow-up were included. Complication, recurrence and survival rates of all studies are summarised and presented.

RESULTS AND CONCLUSION

It is difficult to compare ablation modalities, as probe design and energy sources have evolved rapidly over the last decade. Ablation offers an invaluable palliative option and in some cases it may offer rates of cure approaching that of surgical resection with lower morbidity and mortality. Perhaps the time has come, therefore, for prospective large-scale randomised control trials to take place comparing ablation modalities to each other and surgical resection.

Hepatic resection versus radiofrequency ablation for hepatocellular carcinoma in cirrhotic individuals not candidates for liver transplantation: a Markov model decision analysis

BACKGROUND

Several observational studies have suggested that radiofrequency ablation (RFA) may have survival benefits similar to hepatic resection (HR) in cirrhotic patients affected by hepatocellular carcinoma (HCC) are not candidates for liver transplantation. A small randomized controlled trial confirmed these findings, although underpowered to detect a significant difference at 5-year interval.

METHODS

A Markov model was created to simulate a randomized trial comparing the quality of life-adjusted survival for individuals undergoing HR versus RFA for HCCs less than 5 cm in diameter.

RESULTS

HR was the best therapeutic option with 5.33 (standard deviation +/-.42) versus 3.91 (standard deviation +/-.38) quality-adjusted life years except for in individuals older than 75 years of age (P = .02, log rank test). One-way sensitivity analysis showed that RFA was the preferred strategy if the perioperative mortality of HR was more than 30%, if the percentage of patients with negative margins was less than 60%, and if RFA could be performed at least 60% of the time for recurrent disease after a previous ablation. The quality of life associated with both procedures did not influence the results of this model.

CONCLUSIONS

HR provided better quality of life-adjusted survival as ablation therapy was associated with increased risk of local recurrent disease requiring multiple sessions. For older individuals, RFA appears to be the best therapeutic option. If the probability of ablation for recurrent disease is equal in the 2 arms, survival benefits of RFA is similar to HR.

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

AIM

To evaluate the feasibility and efficacy of percutaneous radiofrequency ablation (RFA) of the feeding artery of hepatocellular carcinoma (HCC) in reducing the blood-flow-induced heat-sink effect of RFA.

METHODS

A total of 154 HCC patients with 177 pathologically confirmed hypervascular lesions participated in the study and were randomly assigned into two groups. Seventy-one patients with 75 HCCs (average tumor size, 4.3 +/- 1.1 cm) were included in group A, in which the feeding artery of HCC was identified by color Doppler flow imaging, and were ablated with multiple small overlapping RFA foci [percutaneous ablation of feeding artery (PAA)] before routine RFA treatment of the tumor. Eighty-three patients with 102 HCC (average tumor size, 4.1 +/- 1.0 cm) were included in group B, in which the tumors were treated routinely with RFA. Contrast-enhanced computed tomography was used as post-RFA imaging, when patients were followed-up for 1, 3 and 6 mo.

RESULTS

In group A, feeding arteries were blocked in 66 (88%) HCC lesions, and the size of arteries decreased in nine (12%). The average number of punctures per HCC was 2.76 +/- 1.12 in group A, and 3.36 +/- 1.60 in group B (P = 0.01). The tumor necrosis rate at 1 mo post-RFA was 90.67% (68/75 lesions) in group A and 90.20% (92/102 lesions) in group B. HCC recurrence rate at 6 mo post-RFA was 17.33% (13/75) in group A and 31.37% (32/102) in group B (P = 0.04).

CONCLUSION

PAA blocked effectively the feeding artery of HCC. Combination of PAA and RFA significantly decreased post-RFA recurrence and provided an alternative treatment for hypervascular HCC.

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

AIM: To evaluate the feasibility and efficacy of percutaneous radiofrequency ablation (RFA) of the feeding artery of hepatocellular carcinoma (HCC) in reducing the blood-flow-induced heat-sink effect of RFA.

METHODS: A total of 154 HCC patients with 177 pathologically confirmed hypervascular lesions participated in the study and were randomly assigned into two groups. Seventy-one patients with 75 HCCs (average tumor size, 4.3 ± 1.1 cm) were included in group A, in which the feeding artery of HCC was identified by color Doppler flow imaging, and were ablated with multiple small overlapping RFA foci [percutaneous ablation of feeding artery (PAA)] before routine RFA treatment of the tumor. Eighty-three patients with 102 HCC (average tumor size, 4.1 ± 1.0 cm) were included in group B, in which the tumors were treated routinely with RFA. Contrast-enhanced computed tomography was used as post-RFA imaging, when patients were followed-up for 1, 3 and 6 mo.

RESULTS: In group A, feeding arteries were blocked in 66 (88%) HCC lesions, and the size of arteries decreased in nine (12%). The average number of punctures per HCC was 2.76 ± 1.12 in group A, and 3.36 ± 1.60 in group B (P = 0.01). The tumor necrosis rate at 1 mo post-RFA was 90.67% (68/75 lesions) in group A and 90.20% (92/102 lesions) in group B. HCC recurrence rate at 6 mo post-RFA was 17.33% (13/75) in group A and 31.37% (32/102) in group B (P = 0.04).

CONCLUSION: PAA blocked effectively the feeding artery of HCC. Combination of PAA and RFA significantly decreased post-RFA recurrence and provided an alternative treatment for hypervascular HCC.

In vivo evaluation of a mechanically oscillating dual-mode applicator for ultrasound imaging and thermal ablation

Unresectable liver tumors are often treated with interstitial probes that modify tissue temperature, and efficacious treatment relies on image guidance for tissue targeting and assessment. Here, we report the in vivo evaluation of an interstitial applicator with a mechanically oscillating five-element dual-mode transducer. After thoroughly characterizing the transducer, tissue response to high-intensity ultrasound was numerically calculated to select parameters for experimentation in vivo. Using perfused porcine liver, B-mode sector images were formed before and after a 120-s therapy period, and M-mode imaging monitored the therapy axis during therapy. The time-averaged transducer surface intensity was 21 or 27 W/cm (2). Electroacoustic conversion efficiency was maximally 72 +/- 3% and impulse response length was 295 +/- 1.0 ns at -6 dB. The depth of thermal damage measured by gross histology ranged from 10 to 25 mm for 13 insertion sites. For six sites, M-mode data exhibited a reduction in gray-scale intensity that was interpreted as the temporal variation of coagulation necrosis. Contrast ratio analysis indicated that the gray-scale intensity dropped by 7.8 +/- 3.3 dB, and estimated the final lesion depth to an accuracy of 2.3 +/- 2.4 mm. This paper verified that the applicator could induce coagulation necrosis in perfused liver and demonstrated the feasibility of real-time monitoring.

Radiofrequency ablation of primary and metastatic lung cancers

Radiofrequency ablation is an accepted method of therapy for unresectable liver cancer. Most recently, interest in using this technology for treatment of primary and metastatic lung tumors has increased. Early animal studies have led to numerous human trials that suggest that radiofrequency ablation can play a major role in treatment of both early-stage primary lung cancer and metastatic lesions. Technical aspects of this therapy as well as areas of further research are discussed.

Surgical management of metastases to the adrenal gland: open, laparoscopic, and ablative approaches

The adrenal gland is a potential site of metastasis for various malignancies. Metastases to the adrenal gland are the second most common type of adrenal mass lesion after adenomas. Differentiation of a metastatic lesion from a primary adrenal lesion can be challenging and requires the selective use of radiologic imaging, serologic testing, and adrenal biopsy. In patients who present with an isolated adrenal metastasis, adrenalectomy is often considered to aid in cancer control. Numerous studies have reported improved survival with resection of solitary adrenal metastases for various types of primary tumors. Traditionally, open adrenalectomy was the preferred option for these patients. More recently, laparoscopic adrenalectomy has offered a minimally invasive approach, with its resultant advantages of improved perioperative parameters. Proper patient selection for the laparoscopic versus open approach remains paramount in deciding the best treatment for the individual patient.

Tolerance of radiofrequency ablation by patients of hepatocellular carcinoma

BACKGROUND

Radiofrequency ablation (RFA) is currently an effective method for ablation of hepatocellular carcinoma (HCC). Early reports have indicated that RFA is safe and virtually free from major complications. Unlike partial hepatectomy for HCC on patients with cirrhosis, there are no data on the safety limit of RFA. However, information is vital for selection of appropriate patients for the procedure. In this study, we analyzed results from use of RFA on HCC patients and determined the lower limit of liver function with which HCC patients can tolerate RFA.

METHOD

Preoperative variables of 310 patients who underwent RFA for HCC were analyzed to identify the risk factors in RFA intolerance in terms of morbidity associated with stress-induced complications.

RESULTS

Thirty-nine (12.6%) patients developed intolerance of RFA. Postoperative morbidity was mainly because of intractable ascites (n = 13), hyperbilirubinemia (n = 10), massive pleural effusion (n = 7), and other complications (n = 14). Multivariate analysis revealed that serum albumin level (P = 0.001), serum bilirubin level (P = 0.000), tumor number (P = 0.002), and RFA duration (P = 0.017) all played a role in this issue.

CONCLUSIONS

Simple data such as serum bilirubin, serum albumin level, and tumor number can be used to predict HCC patients' tolerance of RFA. Avoidance of excessive RFA time and careful monitoring of patients at risk are important means of reducing the postoperative morbidity rate.

Percutaneous ablation for small hepatocellular carcinoma

Hepatocellular carcinoma is increasingly detected at small size, usually 5 cm or smaller in diameter. For small hepatocellular carcinoma, percutaneous ablation is a potentially curative treatment. Ethanol injection is able to achieve a complete response of 70-80% and a 5-year survival of 40-60% in the treatment of hepatocellular carcinoma of 3 cm or less. Radiofrequency ablation has emerged as the more powerful alternative method. Randomized controlled trials show that radiofrequency ablation offers a higher complete response at fewer treatment sessions and better survival compared with ethanol injection. Microwave ablation has been demonstrated to be equivalent to radiofrequency ablation in both local efficacy and long-term outcome. Laser ablation is mainly applied in clinical settings in Europe. Nowadays, percutaneous ablation is commonly accepted as the best option for patients with small hepatocellular carcinoma who are not candidates for surgical resection or liver transplantation. However, whether it can compete with surgery as the first-line treatment has long been debated. There are some retrospective studies and only a few randomized controlled trials to compare the two modalities. The currently available data are not robust enough to draw a solid conclusion. This review article provides an overview of the current status of percutaneous ablation in management of small hepatocellular carcinoma and also focuses on comparison with surgical resection.

Current management of colorectal hepatic metastasis

In the USA, cancers of the colon and rectum are the third most common site of new cancer cases and cancer deaths. With improved screening and adjuvant therapy, the survival of patients has increased substantially over the last decade. However, patients with metastatic disease often have limited survival. Hepatic metastasis is one of the most frequent sites of metastatic disease. In fact, 35-55% of patients with colorectal cancer will develop hepatic metastasis at some time during the course of their disease. Patients who are able to undergo complete resection of their hepatic metastases have the best chance of long-term survival. The goal of hepatic resection is to achieve complete resection of all metastases with microscopically negative surgical margins while preserving sufficient hepatic parenchyma. Survival following hepatic resection of colorectal metastasis now approaches 35-50%. However, approximately 65% of patients will have a recurrence at 5 years. Increasingly chemotherapeutic agents are being offered in the preoperative setting prior to operation. At the time of operation, patients with extensive hepatic disease can sometimes be offered ablative therapies combined with resection or staged approaches. Modern management of hepatic colorectal metastases necessitates a multidisciplinary approach to effectively treat these patients and increase the number of patients who will benefit from resection.

Laparoscopic radiofrequency ablation for hepatocellular carcinoma

Radiofrequency ablation (RFA) is one of the best curative treatments for hepatocellular carcinoma in selected patients, and this procedure can be applied either percutaneously or laparoscopically. Although the percutaneous approach is less invasive and is considered the first choice, RFA with laparoscopic guidance is highly recommended for patients with a relative contraindication for percutaneous RFA, such as lesions adjacent to the gastrointestinal tract, gallbladder, bile duct and heart. Recent advances in laparoscopic ultrasound have widened the indication for laparoscopic ablation. In the present paper, we review the indications, advantages, prognosis and safety of laparoscopic RFA for hepatocellular carcinoma.

Radiofrequency ablation vs. resection for hepatic colorectal metastasis: therapeutically equivalent?

INTRODUCTION

The role of ablation for hepatic colorectal metastases (HCM) continues to evolve as ablation technology changes and systemic chemotherapy improves. Our aim was to evaluate the therapeutic efficacy of radiofrequency ablation (RFA) of HCM compared to surgical resection.

METHODS

A retrospective review of our 1,105 patient prospective hepatic database from August 1995 to July 2007 identified 192 patients with only hepatic resection or only ablation for HCM.

RESULTS

Patients who underwent RFA were similar to resection patients based on a similar Fong score (1.8 vs. 2.1 p = 0.28), presence of extrahepatic disease (15% vs. 9% p = 0.19), mean number of hepatic lesions (2.8 vs. 2.1 p = 0.14), and prior chemotherapy (67% vs. 60% p = 0.33). Median time to recurrence was shorter with ablation than resection (12.2 vs. 31.1 months; p < 0.001). Recurrence at the ablation-resection site was more common with ablation than resection occurring 17% vs. 2% (p < or = 0.001) of the time, respectively. Distant recurrence in the liver was also more common with ablation occurring in 33% of patients vs. 14% for resection (p = 0.002).

CONCLUSIONS

Surgical resection is associated with a lower chance of recurrence and a longer disease-free interval than RFA and should remain the treatment of choice in resectable HCM.

Correlation between high field MR images and histopathological findings of rat transplanted cancer immediately after partial microwave coagulation

PURPOSE

To investigate the immediate effects of microwave coagulation on rat tumors in various magnetic resonance (MR) images at high magnetic field strength using histopathological examinations as reference.

MATERIALS AND METHODS

Tumors implanted in rat femurs were partially thermocoagulated by microwave. Immediately after, T1- and T2-weighted images, diffusion-weighted images (DWIs), and contrast-enhanced T1 weighted images (CE-T1WIs) were acquired with a 7-tesla MR scanner. After measurements, tumors were examined histopathologically with hematoxylin-eosin (HE) staining and histochemically for acid phosphatase activity.

RESULTS

Without contrast, boundaries of coagulated areas were unclear on MR images, including apparent diffusion coefficient (ADC) maps. CE-T1WIs clearly showed immediate contrast enhancement of untreated areas of tumor, and the area of enhancement gradually enlarged in 5 min. Quantitative analyses were conducted by classifying tumor areas by contrast enhancement results. Signal intensities of the areas in the MR images showed no significant differences, but at the periphery, ADC values were significantly higher in areas with delayed enhancement than those with immediate enhancement. Compared with histopathological findings, with microwave thermocoagulation, increased ADC value seemed to derive from collection of extracellular fluid in the outer zone, where acid phosphatase activity was attenuated.

CONCLUSION

ADC values in the areas with delayed enhancement of CE-T1WIs were higher than those in non-affected areas, but MR images could not show areas of coagulation within tumors. Clear detection of the boundaries of coagulated areas required contrast enhancement, even at magnetic field strength of 7T.

Primary sclerosing cholangitis: the role of extrahepatic biliary resection

PSC is an idiopathic chronic cholestatic disease of the liver that has a variable clinical course. Patients should be managed based on the degree of liver dysfunction, as well as the degree of biliary obstruction and symptoms. Endoscopic biliary dilations provides symptomatic and biochemical relief with minimal morbidity and mortality. Endoscopic procedures, however, result in shorter overall and transplant-free survival than resection and may not decrease the incidence of cholangiocarcinoma. Dominant strictures that fail endoscopic management may harbor an underlying cholangiocarcinoma and surgical therapy should not be delayed. While transplantation is the option of choice in PSC patients with cirrhosis, extrahepatic biliary resection including the bifureation is a good therapeutic option in noncirrhotic patients. Resection of the extrahepatic biliary tree with the hepatic duct bifurcation should be considered in patients with a dominant extrahepatic stricture and preserved liver function. In the appropriately selected patient, extrahepatic biliary resection affords patients with survival rates equivalent to that of transplantation. In fact, extrahepatic biliary resection can potentially significantly delay or avoid transplantation. Extrahepatic biliary resection is a good durable option for noncirrhotic patients with PSC and a dominant extrahepatic stricture.

Neoplastic seeding after radiofrequency ablation for hepatocellular carcinoma

BACKGROUND

Neoplastic seeding reportedly occurs in up to 12.5% of patients treated with radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). The aim of this study is to assess the incidence, risk factors, and prognosis of neoplastic seeding after RFA among a large number of patients with a long-term follow-up.

METHOD

From February 1999 to December 2004, 1,031 patients underwent a total of 1,845 treatments with RFA for a total of 3,837 HCC nodules. The following variables were assessed to elucidate the risk factors of neoplastic seeding: age, sex, positivity for viral markers, tumor size, number of tumor nodules, number of RFA sessions, tumor location, percutaneous biopsy prior to RFA, alpha-fetoprotein (AFP), des-gamma-carboxy prothrombin (DCP) and lens culinaris agglutinin-reactive fraction of AFP (AFP-L3) levels, and the degree of tumor differentiation.

RESULTS

Neoplastic seeding was detected in 33 patients (3.2% per patient) at intervals of 4.8-63.8 (median, 15.2) months after RFA. On multivariate logistic regression analysis, only the poor differentiation degree was associated with the risk of neoplastic seeding (P= 0.012). Of tumor factors, tumor size, and AFP, DCP, and AFP-L3 levels were significantly associated with the poor differentiation degree. The cumulative survival rates 1 and 2 yr after the detection of neoplastic seeding were 86% and 47%, respectively.

CONCLUSION

Poor differentiation degree was the risk factor of neoplastic seeding after RFA for HCC. The surrogate markers for poor differentiation degree were larger tumor size and elevated tumor marker levels. Indication for RFA should be carefully considered for HCC patients under these conditions.