Laparoscopic radiofrequency ablation of primary and metastatic liver tumors. Technical considerations

Generic surgical process model for minimally invasive liver treatment methods

Surgical process modelling is an innovative approach that aims to simplify the challenges involved in improving surgeries through quantitative analysis of a well-established model of surgical activities. In this paper, surgical process model strategies are applied for the analysis of different Minimally Invasive Liver Treatments (MILTs), including ablation and surgical resection of the liver lesions. Moreover, a generic surgical process model for these differences in MILTs is introduced. The generic surgical process model was established at three different granularity levels. The generic process model, encompassing thirteen phases, was verified against videos of MILT procedures and interviews with surgeons. The established model covers all the surgical and interventional activities and the connections between them and provides a foundation for extensive quantitative analysis and simulations of MILT procedures for improving computer-assisted surgery systems, surgeon training and evaluation, surgeon guidance and planning systems and evaluation of new technologies.

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.

The value of intra-operative ultrasonography on safety margin and outcome during liver resection and radio-frequency ablation in the management of hepatocellular carcinoma patients

Background

Hepatocellular carcinoma (HCC) is an important health issue worldwide. Liver resection is the optimal management for early compensated HCC patients, but the majority of HCC patients are not candidates for resection. Several nonsurgical treatment modalities such as radio-frequency ablation (RFA), microwave ablation (MWA), trans-arterial chemoembolization, and immune therapy have been established. Intra-operative ultrasound (IOUS) is essential for accurate staging and secures both resection and RFA. We aimed to detect the value of using IOUS on safety margin and outcome during liver resection and RFA in the management of HCC patients. In the current study, 76 HCC patients, 58 males and 18 females, were included. Patients' age ranged from 49 to 69 years. Patients were divided into two groups: 52 open surgery liver resections (open resection group) and 24 laparoscopic-assisted RFA guided with laparoscopic IOUS (LARFA group). The open resection group was further subdivided into 32 cases for whom IOUS was performed and 20 patients studied retrospectively without IOUS. Surgical decisions were based on preoperative ultrasonography, computed tomography, and/or magnetic resonance imaging (MRI). We determined the size, number of lesions, and location by IOUS and compared them with preoperative imaging. Histopathology was done for resected lesions and follow-up CT for all patients.

Results

In the open resection group, the 32 cases of 52 for whom IOUS was performed, all had free surgical margin (100%) while 18 of 20 patients studied retrospectively without IOUS had free surgical margin (90%). Patients operated guided by IOUS had less morbidity and mortality with less operative time and hospital stay. In the LARFA group (24 patients with 37 lesions), the one-month follow-up showed complete ablation for all lesions in the 24 patients, while 12-month follow-up proved two cases of recurrence.

Conclusions

IOUS is a cornerstone in liver surgery. It improves outcomes with less morbidity and mortality and helps to achieve free surgical margin. Using IOUS allows the performance of radical but conservative hepatic resection.

Laparoscopic Versus Open Thermal Ablation of Colorectal Liver Metastases: A Propensity Score-Based Analysis of Local Control of the Ablated Tumors

BACKGROUND

Laparoscopic ablation (LA) of colorectal liver metastases (CRLMs) is frequently performed in combination with laparoscopic liver resection or as a stand-alone procedure. However, LA is technically demanding and whether the results are comparable with those of open ablation (OA) has not been determined to date. This study compared the effectiveness of LA and OA in achieving local tumor control of CRLMs.

METHODS

Patients undergoing LA or OA of CRLMs at Ghent University Hospital between June 2007 and February 2018 were identified from a prospective database. Lesions treated by LA and OA were matched 1:1 using a propensity score based on lesions (liver segment, size, deepness, proximity to a vessel), patients, and procedural characteristics. Ablation sites were followed up with computed-tomography or magnetic resonance imaging to assess the completeness of the ablation and ablation-site recurrence (ASR). Analysis of ASR was performed with the Kaplan-Meier method and Cox regression.

RESULTS

In this study, 163 patients underwent the surgical ablation (78 LA, 85 OA) of 333 CRLMs (143 LA, 190 OA). After matching, 220 lesions (110 LA, 110 OA) were analyzed. Ablation was complete in 93.7% (LA) and 97.3% (OA) of the sites (p = 0.195). No difference in ASR was observed (p = 0.351), with a cumulative risk of ASR at 12 months of 9.1% (LA) and 8.2% (OA). After multivariable analysis, ASR was confirmed to be independent of the surgical approach.

CONCLUSION

The findings showed that LA and OA achieve a comparable local control of CRLMs. This result further supports the adoption of a laparoscopic approach for the treatment of CRLMs.

Early experience with laparoscopic treatment of liver tumors using a separable cluster electrode with a no-touch technique

Introduction

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. Laparoscopic RFA has the benefit of direct visual control of the RFA procedure. Cluster electrodes (Octopus RF electrodes) can create a common ablation zone.

Aim

Using these two methods (laparoscopic approach and no touch technique), this present study evaluated the technical and clinical outcomes of early experience with laparoscopic RFA and a no-touch technique.

Material and methods

Between November 2015 and November 2018, 21 patients underwent laparoscopic RFA for hepatocellular carcinoma with a no-touch technique using cluster electrodes. Laparoscopic RFA is recommended for patients with a contraindication for surgical resection, patients wants and a relative contraindication for conventional percutaneous RFA, such as lesions adjacent to the gastrointestinal tract, gallbladder, bile duct, or heart.

Results

In the 21 tumors, 2 were treated with a single electrode, 12 with 2 electrodes, and 7 tumors with 3 electrodes. The mean time of ablation per lesion was 20.43 ±8.77 min. There was no mortality, local tumor progression, delayed destructive biliary damage, or liver abscess at the follow-up computed tomography. No technical failures occurred.

Conclusions

Laparoscopic RFA can access lesions for which percutaneous RFA is contraindicated or risky. Cluster electrodes can create sufficient ablation zones without contact and can achieve a sufficient margin with a low complication rate and no tumor dissemination. Therefore, laparoscopic RFA with a no-touch technique might be a safe and feasible treatment for HCC tumor in selected patients.

Role of thermal ablation in the management of colorectal liver metastasis

With a recent randomized prospective trial revealing that thermal ablative therapy as local tumor control improved overall survival (OS) in patients with unresectable colorectal cancer liver metastases (CRLM), thermal ablation continues to remain as an important treatment option in this patient population. Our aim of this article is to review the current role of the ablative therapy in the management of CRLM patients. Main indications for thermal ablation include (I) unresectable liver lesions; (II) in combination with hepatectomy; (III) in patients with significant medical comorbidities or poor performance status (PS); (IV) a small (<3 cm) solitary lesion, which would otherwise necessitate a major liver resection; and (V) patient preference. There are several approaches and modalities for ablative therapy, including open, percutaneous, and laparoscopic approaches, as well as radiofrequency ablation (RFA) and microwave ablation (MWA). Each approach and ablation modality have its own pros and cons. Percutaneous and laparoscopic approaches are preferred due to minimally invasive nature, yet laparoscopic approach has more benefits from thorough intraoperative ultrasound (US) exam as well as complete peritoneal staging with laparoscopy. Similarly, whereas high local tumor failure rate has been a major concern with RFA, MWA or microwave thermosphere ablation (MTA) have demonstrated significantly improved local tumor control due to homogenous tissue heating, ability to reach higher tissue temperatures, and less susceptible to the "heat-sink" effect. Although liver resection is the standard of care for CRLM, there have been some retrospective studies demonstrating similar oncological outcome between ablative therapy and surgical resection in very selected populations with small (<3 cm) solitary CRLM. Lastly, ablative therapy and liver resection should not be mutually exclusive, especially in the management of bilobar liver metastases. Concomitant ablative therapy with hepatectomy may spare the patients from having two-stage hepatectomy with less morbidity. The role of the thermal ablation will continue to evolve in patients with resectable and ablatable lesions owing to newly emerging technology, in addition to new systemic treatment options, including immunotherapy for metastatic colorectal cancer (CRC).

A comparison of microwave thermosphere versus radiofrequency thermal ablation in the treatment of colorectal liver metastases

BACKGROUND

Microwave thermosphere ablation (MTA) is a new generation technology. The aim of this study was to compare the efficacy of MTA and radiofrequency ablation (RFA) in achieving local tumor control in patients with colorectal liver metastasis (CRLM).

METHODS

This was a retrospective study of a prospective ablation database. Fifty-four patients with 155 CRLM lesions underwent RFA and 51 patients with 121 lesions underwent MTA. Patients were managed by a multidisciplinary team. Clinical and oncologic data were analyzed. Kaplan-Meier and Cox Proportional Hazards model were used for statistical analysis.

RESULTS

Demographics were similar between the two groups. Total ablation and operative times were significantly shorter in MTA group (19 vs. 37 mins, p < 0.001, 154 vs. 202 mins, p = 0.009). With a similar hospital stay (median 1), 90-day morbidity was similar (8 vs. 10%, p = 0.848), without mortality. Local recurrence (LR) rate per lesion was 20% in RFA and 10% in MTA group (p = 0.020). On Cox Proportion Hazards model, ablation modality and tumor size were independent predictors of LR.

CONCLUSIONS

This is the first study comparing the efficacy of RFA and MTA on CRLM. The results suggest that compared to RFA, MTA improves local tumor control, while significantly shortening operative time.

Local recurrence after laparoscopic radiofrequency ablation of malignant liver tumors: Results of a contemporary series

INTRODUCTION

The aims of this study were to determine the incidence of Local recurrence (LR) in patients at long-term follow-up after laparoscopic RFA (LRFA) and also to determine the risk factors for LR from a contemporary series.

METHODS

Patients undergoing LRFA between 2005 and 2014 by a single surgeon were reviewed. Demographic and perioperative data were analyzed from a prospective database.

RESULTS

LRFA was performed on 316 patients with 901 lesions. Median follow-up was 25 months, with 76% of whom completed at least one year of follow-up. The LR rate was 18.4%. The LR in patients followed for less than 12 months was 13.8%, 20.3% for 12 months, and 19.7% for 18 months (P = 0.02). One-fourth of the LRs developed after the 1st year. Morbidity was 8.9% and mortality 0.3%. Tumor type, size, ablation margin, and surgeon experience affected LR, with tumor type, size, and ablation margin being independent.

CONCLUSIONS

This study shows that 14% of malignant liver tumors will develop LR within a year after LRFA. Additional 4% of the lesions will demonstrate recurrence within 1 cm of the ablation zone, mostly as part of a multifocal recurrence. Ablation margin is the only parameter that the surgeon can manipulate to decrease LR.

Stereotactic Radiofrequency Ablation for Metastatic Melanoma to the Liver

PURPOSE

To evaluate the outcome of patients with melanoma liver metastasis treated with stereotactic radiofrequency ablation (SRFA).

MATERIAL AND METHOD

Following IRB approval, a retrospective evaluation of the treatment of 20 patients with 75 melanoma liver metastases was performed.

RESULTS

A median number of 2 lesions (range 1-14) per patient with a median size of 1.7 cm (range 0.5-14.5 cm) were treated. 67 lesions were <3 cm (89.3 %) and 8 lesions were >3 cm (10.7 %). Per patient a median of 1 ablation session was performed (range: 1-4) totaling 34 sessions. There were no procedure-related deaths and all major complications (n = 3) could be easily treated by pleural drainages. The primary and secondary success rates were 89.3 and 93.3 %, respectively. The overall local recurrence rate was 13.3 %. Four of ten local recurrences were re-treated successfully by SRFA. During follow-up, 9/20 patients developed extrahepatic metastatic disease and 10/20 had liver recurrence at any location. The median OS from the date of SRFA was 19.3 months, with an OS of 64, 41, and 17 % at 1, 3, and 5 years, with no significant difference for patients with cutaneous and ocular melanoma. The median DFS after SRFA for all 20 patients was 9.5 months, with 37, 9, and 0 % at 1, 3, and 5 years.

CONCLUSIONS

Due to the high local curative potential and the promising long-term survival rates associated with minimal morbidity and mortality, radiofrequency ablation seems to be an attractive alternative to resection in patients with melanoma liver metastases.

Laparoscopic microwave thermosphere ablation of malignant liver tumors: An analysis of 53 cases

BACKGROUND AND OBJECTIVES

Microwave thermosphere ablation (MTA) is a new technology that is designed to create spherical zones of ablation using a single antenna. The aim of this study is to assess the results of MTA in a large series of patients.

METHODS

This was a prospective study assessing the use of MTA in patients with malignant liver tumors. The procedures were done mostly laparoscopically and ablation zones created were assessed for completeness of tumor response, spherical geometry and recurrence on tri-phasic CT scans done on follow-up.

RESULTS

There were a total of 53 patients with an average of 3 tumors measuring 1.5 cm. Ablations were performed laparoscopically in all but eight patients. Morbidity was 11.3% (n = 6), and mortality zero. On postoperative scans, there was 99.3% tumor destruction. Roundness indices A, B, and transverse were 1.1, 1.0, and 0.9, respectively. At a median follow-up of 4.5 months, incomplete ablation was seen in 1 of 149 lesions treated (0.7%) and local tumor recurrence in 1 lesion (0.7%).

CONCLUSIONS

The results of this series confirm the safety and feasibility of MTA technology. The 99.3% rate of complete tumor ablation and low rate of local recurrence at short-term follow up are promising.

Increased Duration of Heating Boosts Local Drug Deposition during Radiofrequency Ablation in Combination with Thermally Sensitive Liposomes (ThermoDox) in a Porcine Model

Introduction

Radiofrequency ablation (RFA) is used for the local treatment of liver cancer. RFA is effective for small (<3cm) tumors, but for tumors > 3 cm, there is a tendency to leave viable tumor cells in the margins or clefts of overlapping ablation zones. This increases the possibility of incomplete ablation or local recurrence. Lyso-Thermosensitive Liposomal Doxorubicin (LTLD), is a thermally sensitive liposomal doxorubicin formulation for intravenous administration, that rapidly releases its drug content when exposed to temperatures >40°C. When used with RFA, LTLD releases its doxorubicin in the vasculature around the zone of ablation-induced tumor cell necrosis, killing micrometastases in the ablation margin. This may reduce recurrence and be more effective than thermal ablation alone.

Purpose

The purpose of this study was to optimize the RFA procedure used in combination with LTLD to maximize the local deposition of doxorubicin in a swine liver model. Pigs were anaesthetized and the liver was surgically exposed. Each pig received a single, 50 mg/m² dose of the clinical LTLD formulation (ThermoDox®). Subsequently, ablations were performed with either 1, 3 or 6 sequential, overlapping needle insertions in the left medial lobe with total ablation time of 15, 45 or 90 minutes respectively. Two different RFA generators and probes were evaluated. After the final ablation, the ablation zone (plus 3 cm margin) was dissected out and examined for doxorubicin concentration by LC/MS and fluorescence.

Conclusion

The mean Cmax of plasma total doxorubicin was 26.5 μg/ml at the end of the infusion. Overall, increased heat time from 15 to 45 to 90 minutes shows an increase in both the amount of doxorubicin deposited (up to ~100 μg/g) and the width of the ablation target margin to which doxorubicin is delivered as determined by tissue homogenization and LC/MS detection of doxorubicin and by fluorescent imaging of tissues.

Lung flooding enables efficient lung sonography and tumour imaging in human ex vivo and porcine in vivo lung cancer model

BACKGROUND

Sonography has become the imaging technique of choice for guiding intraoperative interventions in abdominal surgery. Due to artefacts from residual air content, however, videothoracoscopic and open intraoperative ultrasound-guided thermoablation of lung malignancies are impossible. Lung flooding is a new method that allows complete ultrasound imaging of lungs and their tumours.

METHODS

Fourteen resected tumourous human lung lobes were examined transpleurally with B-mode ultrasound before (in atelectasis) and after lung flooding with isotonic saline solution. In two swine, the left lung was filled with 15 ml/kg isotonic saline solution through the left side of a double-lumen tube. Lung tumours were simulated by transthoracic ultrasound-guided injection of 5 ml of purified bovine serum albumin in glutaraldehyde, centrally into the left lower lung lobe. The rate of tumour detection, the severity of disability caused by residual gas, and sonomorphology of the lungs and tumours were assessed.

RESULTS

The ex vivo tumour detection rate was 100% in flooded human lung lobes and 43% (6/14) in atelectatic lungs. In all cases of atelectasis, sonographic tumour imaging was impaired by residual gas. Tumours and atelectatic tissue were isoechoic. In 28% of flooded lungs, a little residual gas was observed that did not impair sonographic tumour imaging. In contrast to tumours, flooded lung tissue was hyperechoic, homogeneous, and of fine-grained structure. Because of the bronchial wall three-laminar structure, sonographic differentiation of vessels and bronchi was possible. In all cases, malignant tumours in the flooded lung appeared well-demarcated from the lung parenchyma. Adenocarcinoma, squamous, and large cell carcinomas were hypoechoic. Bronchioloalveolar cell carcinoma was slightly hyperechoic. Transpleural sonography identifies endobronchial tumour growth and bronchial wall destruction. With transthoracic sonography, the flooded animal lung can be completely examined in vivo. There is no residual gas, which interferes with ultrasound. Pulmonary vessels and bronchi are clearly differentiated. Simulated lung lesions can easily be detected inside the lung lobe.

CONCLUSIONS

Lung flooding enables complete lung sonography and tumour detection. We have developed a novel method that efficiently uses ultrasound for guiding intraoperative interventions in open and endoscopic lung surgery.

Laparoscopy in Liver Transplantation: The Future has Arrived

In the last two decades, laparoscopy has revolutionized the field of surgery. Many procedures previously performed with an open access are now routinely carried out with the laparoscopic approach. Several advantages are associated with laparoscopic surgery compared to open procedures: reduced pain due to smaller incisions and hemorrhaging, shorter hospital length of stay, and a lower incidence of wound infections. Liver transplantation (LT) brought a radical change in life expectancy of patients with hepatic end-stage disease. Today, LT represents the standard of care for more than fifty hepatic pathologies, with excellent results in terms of survival. Surely, with laparoscopy and LT being one of the most continuously evolving challenges in medicine, their recent combination has represented an astonishing scientific progress. The intent of the present paper is to underline the current role of diagnostic and therapeutic laparoscopy in patients waiting for LT, in the living donor LT and in LT recipients.

Ki-67 is a prognostic biomarker of survival after radiofrequency ablation of liver malignancies

PURPOSE

To assess the predictive value of examinations of tissue adherent to multitined electrodes on local tumor progression-free survival (LPFS) and overall survival (OS) after liver tumor radiofrequency ablation (RFA).

METHODS

An institutional review board-approved, Health Insurance Portability and Accountability Act-compliant review identified 68 liver tumors treated with RFA in 63 patients with at least 3 years' follow-up. Tissue adherent to the electrode after liver tumor RFA was evaluated with proliferation (Ki-67) and apoptotic (caspase-3) markers. LPFS and OS were evaluated by Kaplan-Meier methodology and the log-rank test. Multivariate analysis assessed the effect of tumor size, pathology, and post-RFA tissue characteristics on LPFS and OS.

RESULTS

Post-RFA tissue examination classified 55 of the 68 tumors as completely ablated with coagulation necrosis, with cells positive for caspase-3 and negative for Ki-67 (CN). Thirteen had viable Ki-67-positive tumor cells. Mean liver tumor size was larger in the viable (V) group versus the CN group (3.4 vs. 2.5 cm, respectively; P = .017). For the V and CN groups, respectively, local tumor progression occurred in 12 (92 %) of 13 and 23 (42 %) of 55 specimens. One, 3-, and 5-year LPFS was 8 %, 8 %, and 8 %, and 79 %, 47 %, and 47 % (P < .001) for the V and CN groups, respectively. During a 63-month median follow-up, 92 % of patients in the V group and 58 % in the CN group died, resulting in 1-, 3-, and 5-year OS of 92 %, 25 %, and 8 % vs. 92 %, 59 %, and 33 % (P = .032), respectively.

CONCLUSIONS

Ki-67-positive tumor cells on the electrode after liver tumor RFA is an independent predictor of LPFS and OS. Size, initially thought to be an independent risk factor for local tumor progression in tumors 3-5 cm, does not hold its significance at long follow-up.

Safety and efficacy of laparoscopic radiofrequency ablation for hepatic malignancies

Purpose

Radiofrequency ablation (RFA) is an accepted treatment option for primary and metastatic liver tumors. As percutaneous RFA has some limitations, laparoscopic RFA (LRFA) has been used as a therapeutic alternative for the treatment of hepatic malignancies.

Methods

Between March 2006 and September 2009, thirty patients with hepatic malignancies that were contraindicated for resection or percutaneous RFA underwent LRFA. Indications for this procedure were hepatocellular carcinoma (HCC, 21 patients), metastatic liver tumor (8 patients) and intrahepatic cholangiocarcinoma (1 patient).

Results

Among the 30 patients who underwent LRFA, 5 patients underwent concomitant laparoscopic liver resection. Intraoperative laparoscopic ultrasound detected new malignant lesions in 4 patients (13.3%). A total of 46 lesions were ablated by LRFA. There was no postoperative mortality. The three-year overall survival rate was 83.7% for the HCC group and 64.3% for the metastatic group.

Conclusion

LRFA for hepatic malignancies proved to be a safe and effective treatment. Also, this procedure is indicated for lesions that are not amenable to percutaneous RFA or liver resection.

A multimodal approach to the management of neuroendocrine tumour liver metastases

Neuroendocrine tumours (NETs) are often indolent malignancies that commonly present with metastatic disease in the liver. Surgical, locoregional, and systemic treatment modalities are reviewed. A multidisciplinary approach to patient care is suggested to ensure all therapeutic options explored.

Laparoscopic thermoablation of colorectal cancer metastases to the liver - new experience of the centre

Aim of the study

Thermoablation of metastatic lesions in the liver is very commonplace. At present there are 3 essential techniques of access to carry out the procedure: open surgery, percutaneous technique and laparoscopic method. Percutaneous thermoablation is criticised due to the possible lack of radicalism. On the other hand, thermoablation during open surgery is a big perioperative trauma for the patient. The laparoscopic technique seems to be a compromise between the aforementioned techniques. The aim of this study was to present the technique and preliminary results of thermoablation of the liver carried out by means of the laparoscopic technique.

Material and methods

Laparoscopic thermoablation was carried out in 4 patients with colorectal cancer metastases to the liver. In order to precisely locate the tumour and guarantee radicalism of the surgery, laparoscopic probe ultrasonography was carried out during the procedure.

Results

All the patients underwent the procedure without any difficulties. All the patients left the hospital department as soon as 3 or 4 days after the surgery. This was about 7 days earlier in comparison with the open surgery procedure, which had been carried out before. The patients required a supply of analgesics only during the first 48 hours – non-steroid anti-inflammatory drugs, which made a substantial difference between them and the patients treated with the open surgical technique. Thanks to the laparoscopic ultrasound technique one patient had an additional lesion located, which had not been described in preoperative examinations.

Conclusions

In combination with ultrasonography, laparoscopic access, which does not have a very invasive character, seems to be relatively simple and effective to carry out the procedure of thermoablation.

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

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

Laparoscopic radiofrequency ablation of liver tumors: comparison of MR guidance versus conventional laparoscopic ultrasound for needle positioning in a phantom model

Laparoscopic radiofrequency ablation (LapRFA) is an established procedure for liver tumors in patients who are unsuitable for resection. A novel technique of magnetic resonance (MR) guided needle positioning during LapRFA was developed and compared to conventional ultrasound (US) guidance in a phantom model. MR-guided procedures were conducted in a 1.0 tesla high field open MR using an MR compatible endoscope and camera. The ultrasound-guided procedure was performed with a clinically established laparoscopy setup and a 2D laparoscopic US probe. During both techniques an identical monopolar non-ferromagnetic RFA needle and a silicon-based phantom model were applied. Finally needle positioning was performed by two surgeons and one interventionalist. Time to needle placement and number of trials were recorded and statistically analyzed. MR-guided needle positioning under laparoscopic control was technically feasible. Average time to correct needle placement was 2' 6″ in the LapUS group and 1' 54″ in the MR group. The number of trials was 3.2 in the LapUS group and 2.6 in the MR group. Image quality was assessed by all participants. MR images showed a better tissue to tumor contrast and allowed an improved orientation due to multiplanar visualization. MR-guided laparoscopic RFA is a promising technique offering multiplanar needle positioning with high soft tissue contrast with immediate therapy control. In a phantom model it showed comparable results regarding needle positioning to the established technique of laparoscopic US guidance.

Laparoscopic ultrasound with radiofrequency ablation of hepatic tumors in cirrhotic patients

BACKGROUND

The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are operative candidates due to associated liver cirrhosis. Recent advances in laparoscopic ultrasound and laparoscopy have greatly improved the accuracy in detecting intrahepatic tumor nodules, many of which were missed by preoperative imaging modality.

OBJECTIVE

The aim of this work was for an evaluation of the safety and efficacy of laparoscopic radiofrequency ablation (RFA) guided with laparoscopic ultrasound in detecting and treatment of liver tumors in patient with liver cirrhosis.

METHODS

Seventy-two patients with liver tumors (58 HCC, 9 metastatic adencarcinoma, 2 neoendocrine metastasis, 3 other metastasis) were submitted to laparoscopic RFA under laparoscopic ultrasound guidance. Forty-four patients (61.1%) were classified Child A and 28 patients (38.9%) Child B. Patients with large tumor (>6 cm), portal vein thrombosis, or Child C class were excluded from the study.

RESULTS

Laparoscopic RFA was completed in all patients without any conversion rate. Laparoscopic ultrasound identified 19 new malignant lesions (18.4%), in comparison with the result of preoperative imaging. A total of 103 hepatic focal lesions were treated by RFA (45 patients had 1 lesion, 23 patients had 2 lesions, and 4 patients had 3 lesions). There was no mortality. Morbidity occurred in 4 patients (5.5%): 2 patients had liver abscesses, 1 patient had pleural effusion, and 1 patient had postoperative bleeding necessitating blood transfusion and surgery. After a mean follow-up of 14.3 +/- 11.6 months, a complete response with 100% necrosis was achieved in 93 of 103 lesions (90.3%). Three lesions (2.9%) showed local recurrences, 5 lesions (4.8%) showed remote recurrences, and 2 lesions (1.9%) showed both local and remote recurrences.

CONCLUSIONS

Laparoscopic RFA guided with laparoscopic ultrasound is an excellent use of existing technology in the improvement of safety and efficacy of detection and treatment of intrahepatic tumors in patients with liver cirrhosis.

Glutamine synthetase immunostaining correlates with pathologic features of hepatocellular carcinoma and better survival after radiofrequency thermal ablation

PURPOSE

Activation of the wnt pathway identifies a subgroup of hepatocellular carcinomas (HCC) with specific epidemiologic and genetic profiles. Wnt activation is predicted by mutation and/or nuclear translocation of beta-catenin and by glutamine synthetase (GS) immunoreactivity. We investigated whether GS staining associates with specific pathologic features of HCC and with survival after radiofrequency thermal ablation.

EXPERIMENTAL DESIGN

Monoistitutional retrospective-prospective study in a tertiary hospital setting. Two hundred and seven cirrhotics (mean age, 70 years; 63% males, 82.1% hepatitis C virus positive) with early HCC were consecutively treated with radiofrequency thermal ablation (RFTA). Mean tumor size was 2.7 cm; 20.3% of patients had multiple nodules; and median follow-up was 36 months with 54.6% overall mortality. Tumor samples were mainly obtained by biopsy (92,5%) and examined by H&E and immunostaining for beta-catenin and GS. Main outcome measures were overall and tumor-specific mortality by Kaplan-Meier analysis and Cox proportional hazard models corrected for competing risks.

RESULTS

Ninety-one patients (43.9%) had GS-positive HCCs by immunostaining. These tumors had larger size (P = 0.012) and characteristic histology (low grade, pseudoacini, hydropic changes, bile staining, lack of steatosis, and fibrosis). Other clinical or treatment variables were similar between groups. Variables correlating with tumor-specific and overall mortality by univariate analysis were tumor recurrence, advanced disease, posttreatment alpha-fetoprotein levels, and GS staining. Yearly, overall mortality rate was lower in GS-positive patients (12.4 versus 20% yearly; P = 0.006). By multivariate analysis, GS immunostaining correlated with reduced specific (hazard ratio, 0.58; 95% confidence interval, 0.34-0.97) and overall mortality (hazard ratio, 0.62; 95% confidence interval, 0.40-0.96).

CONCLUSIONS

Standard histology and GS status identify a HCC subset with distinct clinical and pathologic features.

Thermal ablation of prostate diseases: advantages and limitations

Both benign and malignant conditions affecting prostate gland are very common in elderly men. However, the conventional treatment of these conditions can be associated with significant side effects and complications, and less invasive treatment alternative has been always searched for. Because of the anatomical location and easy accessibility of prostate, many newer treatment modalities using thermal ablation have been applied to the organ. These include not only heating of the pathological tissue but also freezing. Some of such treatment techniques have shown to be effective and safe and been clinically used widely. In this review article, various tissue ablation techniques using temperature change applied to prostate gland are covered. Each procedure's advantages and disadvantages are compared and discussed.

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.

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.

Histopathologic and immunohistochemical features of tissue adherent to multitined electrodes after RF ablation of liver malignancies can help predict local tumor progression: initial results

PURPOSE

To determine whether histopathologic and immunohistochemical features of tissue adherent to electrodes after radiofrequency (RF) ablation of liver malignancies can help predict local tumor progression (LTP).

MATERIALS AND METHODS

Institutional review board waiver and informed consent were obtained. Histologic and immunohistochemical examinations of tissue adherent to electrodes after RF ablation of liver malignancies were performed, with application of proliferation (Ki-67) and apoptosis (caspase-3) markers. Clinical and technical information were prospectively collected for an HIPAA-registered database. Medical records and imaging were reviewed to determine LTP for treated tumors smaller than 5 cm in diameter. LTP-free and survival rates were assessed with Kaplan-Meier method; differences between groups assessed with permutation log-rank test. Multivariate analysis assessed with Cox regression for factors related to LTP.

RESULTS

Sixty-eight malignant tumors treated with RF ablation were identified. Fifty-five tissue specimens were classified as coagulation necrosis (CN), thermal artifact only, or tumor cells positive for caspase-3/negative for Ki-67; and 13 as viable tumor cells (Ki-67 positive). Mean tumor size was larger in viable (3.4 cm) than in CN (2.5 cm) group before treatment (P = .01). For viable and CN groups, LTP occurred in 12 (92%) of 13 and 16 (29%) of 55 specimens, respectively; 1-year LTP-free rates were 0% and 74%, respectively (P < .001). Multivariate analysis confirmed that viable cells comprise independent risk factor for LTP (P < .001). The odds of LTP is six times greater in viable group compared with CN group for tumors 3-5 cm (hazard ratio: 5.9, 95% confidence interval: 2.4, 14.5) and 10 times greater for tumors smaller than 3 cm (hazard ratio: 10.1, 95% confidence interval: 1.7, 57.5). Median survival was 32.7 months.

CONCLUSION

Evidence of Ki-67-positive tumor cells on the electrode after hepatic RF ablation is an independent predictor of LTP.

Noninvasive radiofrequency ablation of cancer targeted by gold nanoparticles

INTRODUCTION

Current radiofrequency ablation (RFA) techniques require invasive needle placement and are limited by accuracy of targeting. The purpose of this study was to test a novel non invasive radiowave machine that uses RF energy to thermally destroy tissue. Gold nanoparticles were designed and produced to facilitate tissue heating by the radiowaves.

METHODS

A solid state radiowave machine consisting of a power generator and transmitting/receiving couplers which transmit radiowaves at 13.56 MHz was used. Gold nanoparticles were produced by citrate reduction and exposed to the RF field either in solutions testing or after incubation with HepG2 cells. A rat hepatoma model using JM-1 cells and Fisher rats was employed using direct injection of nanoparticles into the tumor to focus the radiowaves for select heating. Temperatures were measured using a fiber-optic thermometer for real-time data.

RESULTS

Solutions containing gold nanoparticles heated in a time- and power-dependent manner. HepG2 liver cancer cells cultured in the presence of gold nanoparticles achieved adequate heating to cause cell death upon exposure to the RF field with no cytotoxicity attributable to the gold nanoparticles themselves. In vivo rat exposures at 35 W using direct gold nanoparticle injections resulted in significant temperature increases and thermal injury at subcutaneous injection sites as compared to vehicle (water) injected controls.

DISCUSSION

These data show that non invasive radiowave thermal ablation of cancer cells is feasible when facilitated by gold nanoparticles. Future studies will focus on tumor selective targeting of nanoparticles for in vivo tumor destruction.

Local recurrence after laparoscopic radiofrequency ablation of liver tumors: an analysis of 1032 tumors

BACKGROUND

The best measure of the technical success of radiofrequency ablation (RFA) is local recurrence (LR). The aim of this prospective study is to identify factors that predict LR.

METHODS

Three hundred thirty-five patients with 1032 unresectable liver tumors underwent laparoscopic RFA between November 1999 and August 2005. All lesions were assessed prospectively regarding tumor type, size, liver segment, blood vessel proximity, and central or peripheral location in the operating room and size of ablation zone at 1-week computed tomographic (CT) scans. Lesions that recurred in follow-up CT scans were identified prospectively. LR was categorized as contiguous or adjacent. Univariate Kaplan-Meier and Cox proportional hazard models were used for statistical analysis.

RESULTS

LR was identified 21.7% of tumors on CT scans with a mean follow-up of 17 months (median, 12 months; range, 3-68 months). This was contiguous in 70% and adjacent in 30%. LR rate per tumor was highest for colorectal metastasis (34%), followed by noncolorectal, nonneuroendocrine metastasis (22%), hepatocellular carcinoma (18%), and neuroendocrine metastasis (6%). By univariate analysis, tumor type and size, ablation margin, liver segmental location, blood vessel proximity, and type of ablation (first time vs. repeat) were found to affect LR. The Cox proportional hazard model identified tumor type, tumor size, ablation margin, and blood vessel proximity to be independent predictors of LR.

CONCLUSION

LR after RFA is predicted by certain tumor characteristics and technical factors. This information can be used intraoperatively to identify those tumors at a higher risk for failure.

Current status of liver tumor ablation devices

The liver is a common site of disease for both primary and metastatic cancer. Since most patients have a disease that is not amenable to surgical resection, tumor ablation modalities are increasingly being used for treatment of liver cancer. This review describes the current status of ablative technologies used as alternatives for resection, clinical experience with these technologies, currently available devices and design rules for the development of new devices and the improvement of existing ones. It focuses on probe design for radiofrequency ablation, microwave ablation and cryoablation, and compares the advantages and disadvantages of each ablation modality.

Laparoscopic radiofrequency of hepatocellular carcinoma using ultrasound-guided selective intrahepatic vascular occlusion

BACKGROUND

The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are operative candidates. The authors aimed to assess a novel operative combination of laparoscopic radiofrequency (LRF) with a selective intrahepatic vascular occlusion (SIHVO) to obtain an increased rate of total necrosis and a reduced rate of local HCC recurrences.

METHODS

For this study, 37 patients with HCC in liver cirrhosis were submitted to LRF with SIHVO. An LRF was indicated for patients not amenable to liver resection who evidenced at least one of the following criteria: severe impairment of the coagulation tests, large tumors (but <5 cm) or multiple lesions requiring repeated punctures, superficial lesions adjacent to visceral structures, deep-sited lesions with a very difficult or impossible percutaneous approach, and short-term recurrence of HCC after percutaneous loco-regional therapies.

RESULTS

Laparoscopic ultrasound identified seven new malignant lesions (19%) undetected by preoperative imaging. There was no operative mortality. Of the 37 patients, 31 experienced no complications (84%). Computed tomography (CT) evaluation 1 month after treatment showed that a complete response with 100% necrosis had been achieved for all the patients (100%). During the follow-up period (mean, 11.8 +/- 8.2 months), new malignant nodules developed in 14 patients (42%), and 36% of these recurrences were located in the same treated segment of the HCC.

CONCLUSIONS

The combined LRF and SIHVO procedure proved to be a safe and effective technique at least in the short and mid term. In fact, it permitted the treatment of lesions not treatable using the percutaneous approach with a complete clearance, and it had a low morbidity rate.

Survival after radiofrequency ablation of colorectal liver metastases: 10-year experience

OBJECTIVE

To assess factors affecting long-term survival of patients undergoing radiofrequency ablation (RFA) of colorectal hepatic metastases, with attention to evolving chemotherapy regimens.

METHODS

Prospective evaluation of 235 patients with colorectal metastases who were not candidates for resection and/or failed chemotherapy underwent laparoscopic RFA. Preoperative risk factors for survival and pre- and postoperative chemotherapy exposure were analyzed.

RESULTS

Two hundred and thirty-four patients underwent 292 RFA sessions from 1997 to 2006, an average of 8 months after initiation of chemotherapy. Twenty-three percent had extrahepatic disease preoperatively. Patients averaged 2.8 lesions, with a dominant diameter of 3.9 cm. Kaplan-Meier actuarial survival was 24 months, with actual 3 and 5 years survival of 20.2% and 18.4%, respectively. Median survival was improved for patients with <or=3 versus >3 lesions (27 vs. 17 months, P=0.0018); dominant size<3 versus >3 cm (28 vs. 20 months, P=0.07); chorioembryonic antigen<200 versus >200 ng/mL (26 vs. 16 months, P=0.003). Presence of extrahepatic disease (P=0.34) or type of pre/postoperative chemotherapy (5-FU-leucovorin vs. FOLFOX/FOLFIRI vs. bevacizumab) (P=0.11) did not alter median survival.

CONCLUSIONS

To our knowledge, this is both the largest and longest follow-up of RFA for colorectal metastases. The number and dominant size of metastases, and preoperative chorioembryonic antigen value are strong predictors of survival. Despite classic teaching, extrahepatic disease did not adversely affect survival. In this group of patients who failed chemotherapy, newer treatment regimens (pre- or postoperatively) had no survival benefit. The actual 5-year survival of 18.4% in these patients versus near zero survival for chemotherapy alone argues for a survival benefit of RFA.

Factors limiting complete tumor ablation by radiofrequency ablation

The purpose of this study was to determine radiological or physical factors to predict the risk of residual mass or local recurrence of primary and secondary hepatic tumors treated by radiofrequency ablation (RFA). Eighty-two patients, with 146 lesions (80 hepatocellular carcinomas, 66 metastases), were treated by RFA. Morphological parameters of the lesions included size, location, number, ultrasound echogenicity, computed tomography density, and magnetic resonance signal intensity were obtained before and after treatment. Parameters of the generator were recorded during radiofrequency application. The recurrence-free group was statistically compared to the recurrence and residual mass groups on all these parameters. Twenty residual masses were detected. Twenty-nine lesions recurred after a mean follow-up of 18 months. Size was a predictive parameter. Patients' sex and age and the echogenicity and density of lesions were significantly different for the recurrence and residual mass groups compared to the recurrence-free group (p < 0.05). The presence of an enhanced ring on the magnetic resonance control was more frequent in the recurrence and residual mass groups. In the group of patients with residual lesions, analysis of physical parameters showed a significant increase (p < 0.05) in the time necessary for the temperature to rise. In conclusion, this study confirms risk factors of recurrence such as the size of the tumor and emphasizes other factors such as a posttreatment enhanced ring and an increase in the time necessary for the rise in temperature. These factors should be taken into consideration when performing RFA and during follow-up.

Effect of hyperbarism on radiofrequency ablation outcome

OBJECTIVE

Our objective was to investigate whether increases in atmospheric or local tissue pressure would affect the outcome of radiofrequency ablation procedures and the size of the created thermal lesions.

MATERIALS AND METHODS

Thermal lesions were produced in specimens of explanted bovine liver inside a hyperbaric chamber at 101 (atmospheric), 141, 202, 273, and 364 kPa using radiofrequency power settings of 20, 30, 40, and 50 W. In subsequent in vivo experiments, thermal lesions were produced in the livers of anesthetized pigs with or without occlusion of the hepatic vein draining the ablation site.

RESULTS

At each radiofrequency power setting, progressive increases in applied pressure were paralleled by decreases in minimum impedance and increases in maximum tissue temperatures at the electrode tip (reflecting tissue-fluid boiling points), delivery time, total energy delivered, and thermal lesion volumes. Similar increases were observed in radiofrequency ablation procedures performed in vivo under occlusion of the vein draining the ablation site.

CONCLUSION

By elevating the tissue-fluid boiling point, increased pressure delays the desiccation of tissue in contact with the radiofrequency electrode tip and the related sharp increase in impedance. The result is prolonged delivery of larger amounts of radiofrequency energy and larger thermal lesions.

Histological, CT, and intraoperative ultrasound appearance of hepatic tumors previously treated by laparoscopic radiofrequency ablation

PURPOSE

The purpose of this paper is to compare intraoperative biopsy results of previously ablated liver tumors with their preoperative computed tomography (CT) and intraoperative laparoscopic ultrasound (LUS) appearances in patients undergoing repeat radiofrequency ablation (RFA).

METHODS

Seventy repeat RFA procedures were performed in 59 (13%) patients. Laparoscopically, suspected recurrent and stable appearing foci were biopsied using an 18 G biopsy gun. Preoperative CT and LUS appearances of the previously ablated lesions were compared with core biopsy results.

RESULTS

There were 33 patients with colorectal cancer, 11 with hepatocellular cancer, 8 with neuroendocrine tumors, and 7 with other tumor types. Two hundred lesions were treated by RFA in these 70 repeat ablations. Suspected recurrent tumor foci were enhanced on CT and produced a more finely stippled echo pattern on LUS. Biopsy confirmed recurrent tumor in 72 of 84 such lesions. Previously ablated foci had a CT appearance of a hypodense, nonenhancing lesion without evidence of adjacent enhancing foci. Laparoscopic ultrasound appearance was of a hypoechoic lesion with a coarse internal pattern with the tracks of the ablation catheter probes often still visible. Biopsy found necrotic tissue in 21 of 22 such lesions appearing radiologically to be without recurrence. Biopsy of an ablated focus adjacent to an area of suspected recurrence showed necrotic tissue in 17 of 22 lesions and viable cancer in 5.

CONCLUSION

CT and LUS appearance of previously ablated foci showed good correlation with core biopsies. CT scan is reliable in following RFA lesions, without the need for routine biopsy. LUS reliably distinguished recurrent from ablated lesions in patients undergoing repeat ablation.

Japanese experience in ablation therapies for hepatocellular carcinoma

In the treatment of hepatocellular carcinoma, only 20-30% of patients are candidates for surgery. Still worse, even after curative surgical resection, 80% of patients develop recurrence within 5 years. Thus, various non-surgical therapies have developed. Among them, image-guided local ablation therapies, such as percutaneous ethanol injection, microwave coagulation and radiofrequency ablation, have been widely used for small hepatocellular carcinoma, because they are potentially curative, minimally invasive and easily repeatable. Percutaneous ethanol injection was a standard therapy. However, there has been a drastic shift from ethanol injection to radiofrequency ablation in recent years. In Japan, 1500 institutes have already introduced radiofrequency ablation in the treatment of liver tumors and the cool-tip electrode system has an 80% share of the market. Radiofrequency ablation can achieve complete tumor necrosis in most cases.Long-term survival seems considerably good, and complications are not frequent in radiofrequency ablation. Randomized controlled trials have proved that radiofrequency ablation is superior to ethanol injection in the treatment of small hepatocellular carcinoma from the viewpoint of, not only treatment response, but also long-term survival. Radiofrequency ablation seems feasible, efficacious and considerably safe. Radiofrequency ablation will be more widely performed in the treatment of primary and metastatic liver tumors in Japan.

Thermo-ablation par radiofréquence des tumeurs hépatiques

The basic principle of radiofrequency ablation is that the deposit of electromagnetic energy in a tumor causes heat ("cooks the tumor") and thereby destroys it. In the liver, this ablation may be performed percutaneously (by needles) or surgically (laparotomy, laparoscopy). Guidance by an imaging technique is necessary: ultrasound, CT or magnetic resonance imaging. The principal hepatic indications are hepatocellular carcinoma and hepatic metastases smaller than <5 cm. There is no associated mortality and only slight morbidity, due principally to hemorrhage, infection or stenosis of the bile ducts. Results show a 5-year survival rate of 40% for hepatocellular carcinoma and 22% for metastases.

Laparoscopic radiofrequency ablation of neuroendocrine liver metastases: a 10-year experience evaluating predictors of survival

BACKGROUND

A decade ago we reported the first use of laparoscopic radiofrequency thermal ablation (RFA) for the treatment of neuroendocrine hepatic metastases. This study analyzes our 10-year experience and determines characteristics predictive of survival.

METHODS

Eighty RFA sessions were performed in 63 patients with neuroendocrine hepatic metastases in a prospective trial. All patients had unresectable disease with computed tomography (CT) documented lesion and/or symptom progression. Perioperative morbidity, symptom relief, disease progression, and long-term survival were analyzed. Data are expressed as mean +/- standard error of the mean (SEM).

RESULTS

There were 22 women and 41 men, age 54.4 +/- 1.5 years followed for 2.8 +/- 0.3 years (range, 0.1 to 7.8). Tumor types included 36 carcinoid, 18 pancreatic islet cell, and 9 medullary thyroid cancer. RFA was performed 1.6 +/- 0.3 years after the diagnosis of liver metastases. Number of lesions treated was 6 +/- 0.5 (range, 1 to 16). Forty-nine patients underwent 1 ablation session, and 14 (22%) had repeat sessions caused by disease progression. Mean hospital stay was 1.1 days. Perioperative morbidity was 5%, with no 30-day mortality. Fifty-seven percent of patients exhibited symptoms. One week postoperatively 92% of these reported at least partial symptom relief, and 70% had significant or complete relief. Duration of symptom control was 11 +/- 2.3 months. CT follow-up demonstrated 6.3% local tumor recurrence. Larger dominant liver tumor size and male gender adversely impacted survival (P < .05). Median survival times were 11.0 years postdiagnosis of primary tumor, 5.5 years postdiagnosis of neuroendocrine hepatic metastases, and 3.9 years post-1st RFA. Survival for patients undergoing repeat ablation sessions was not significantly lower.

CONCLUSIONS

This study represents the largest series of neuroendocrine hepatic metastases treated by RFA. In this group of patients with aggressive neuroendocrine tumor metastases and limited treatment options, RFA provides effective local control with prompt symptomatic improvement.

Morbidity and mortality of laparoscopic vs. open radiofrequency ablation for hepatic malignancies

AIMS

Surgical radiofrequency ablation (RFA) of hepatic malignancies is associated with superior oncological outcome as compared to percutaneous RFA. The aim of this prospective non-randomized cohort study was to compare morbidity and mortality of laparoscopic (LRFA) vs. open (ORFA) radiofrequency ablation of liver cancer.

METHODS

Between October 1999 and November 2006, RFA was performed in 154 consecutive patients (percutaneous 12, LRFA 93, ORFA 49) for a total of 291 hepatic tumours (HCC 81, colorectal metastases 157, other 53). Seventy-four patients simultaneously underwent additional surgery. Laparoscopic RFA was performed in 45/54 patients with HCC, and in 44/54 patients with cirrhosis. Laparotomy was performed in 14/22 patients who underwent simultaneous colorectal resection, and in 12/22 patients with hepatic resection.

RESULTS

Postoperative complications occurred in 25 patients with subsequent mortality in 2. As compared with LRFA, ORFA was associated with significantly (p<0.01) higher intra-operative blood loss (median 20 (range 0-1700) vs. 10 (0-900) ml), longer duration of surgery (180 (25-440) vs. 75 (30-390) min), more postoperative complications (17 vs. 8), and longer postoperative hospital stay (8 (1-127) vs. 4 (1-51) d). According to the therapy-oriented severity grading system (TOSGS) classification, postoperative complications in the ORFA-group were more severe than those in the LRFA-group (p<0.01). These findings were consistent in patients without simultaneous colorectal and/or hepatic resection and in patients with liver tumours measuring 3cm or less. In univariate analysis the following factors were significantly (p<0.01) related to the presence of postoperative complications: simultaneous colorectal resection, laparotomy, duration of surgery, tumour location in right liver, liver segment 7 (p=0.01), absence of cirrhosis (p=0.02), liver segment 8 (p=0.03), and metastatic liver cancer (p=0.04).

CONCLUSION

LRFA for hepatic malignancies seems preferable above ORFA, provided good patient selection, surgical expertise, and long-term oncological control.

Perioperative outcome after laparoscopic radiofrequency ablation of liver tumors: an analysis of 521 cases

BACKGROUND

Radiofrequency thermal ablation (RFA) is gaining increased acceptance for the treatment of unresectable primary and metastatic liver tumors. Understanding the morbidity and laboratory changes after RFA is important for operative indications and perioperative management.

METHODS

The authors prospectively analyzed the 30-day morbidity and mortality rates of patients undergoing laparoscopic RFA for liver tumors in a 10-year period. Laboratory studies included a complete blood count, electrolytes, liver function tests, prothrombin time/international normalized ratio (INR), and tumor markers obtained preoperatively, on postoperative days (PODs) 1 and 7, then at 3 months.

RESULTS

A total of 521 RFA procedures were performed for 428 patients (286 men and 142 women) with a mean age of 61 years (range, 25-89 years). A total of 346 patients underwent a single operation, and 82 patients had two or more operations. The pathology was metastatic colon cancer for 244 patients (47%), hepatocellular cancer for 109 patients (21%), metastatic neuroendocrine cancer for 74 patients (14%), and other noncolorectal, nonneuroendocrine liver metastasis for 94 patients (18%). A total of 1,636 lesions (mean, 3.1 per patient; range, 1-16) were ablated. The mean tumor size was 2.7 +/- 1.6 cm (range, 0.3-11.5 cm). All cases were managed laparoscopically. The 30-day mortality rate was 0.4% (n = 2), and the morbidity rate was 3.8 % (n = 20). The average length of hospital stay was 1 day for RFA-only cases and 2.1 days when another surgical procedure was combined with RFA. Serum aspartate aminotransferase (AST) increased 14-fold, alanine aminotransferase (ALT) increased 10-fold, and bilirubin levels increased 2-fold on POD 1, with return to baseline in 3 months. Serum alkaline phosphatase and gamma-glutamyltransferase (GGT) levels showed a 25% increase on POD 7, with return to baseline in 3 months. There were no significant changes in platelet counts or prothrombin times postoperatively.

CONCLUSIONS

This large series provides valuable insight into the perioperative period and allows the expected morbidity of the procedure to be understood. Despite significant patient comorbidities, this procedure was tolerated with low morbidity and mortality rates. Postoperative coagulopathy was not observed. A postoperative rise in liver function tests is expected, reflecting the liver injury response to RFA. This information can be used to expand the patient population that may benefit from laparoscopic RFA.

Local release of dexamethasone from polymer millirods effectively prevents fibrosis after radiofrequency ablation

Recent studies show that after radiofrequency (RF) ablation, fibrosis occurs at the ablation boundary, hindering anticancer drug transport from a locally implanted polymer depot to the ablation margin, where tumors recur. The purpose of this study is to investigate strategies that can effectively deliver dexamethasone (DEX), an anti-inflammatory agent, to prevent fibrosis. Polymer millirods consisting of poly(D,L-lactide-co-glycolide) (PLGA) were loaded with either DEX complexed with hydroxypropyl beta-cyclodextrin (HPbeta-CD), or an NaCl and DEX mixture. In vitro release studies show that DEX complexed with HPbeta-CD released 95% of the drug after 4 days, compared to 14% from millirods containing NaCl and DEX. Rat livers underwent RF ablation and received either DEX-HPbeta-CD-loaded millirods, PLGA millirods with an intraperitoneal (i.p.) DEX injection, or control PLGA millirods alone. After 8 days in vivo, heightened inflammation and the appearance of a well-defined fibrous capsule can be observed in both the control experiments and those receiving a DEX injection (0.29 +/- 0.08 and 0.26 +/- 0.07 mm in thickness, respectively), with minimal inflammation and fibrosis present in livers receiving DEX millirods (0.04 +/- 0.01 mm). Results from this study show that local release of DEX prevents fibrosis more effectively than a systemic i.p. injection.

Thermoablation of colorectal liver metastases promotes proliferation of residual intrahepatic neoplastic cells

BACKGROUND

Resection of liver neoplasms is believed to promote growth of residual intrahepatic neoplastic cells. As the effects of radiofrequency thermoablation (RFA) are still unknown, we aimed to compare the influence of RFA versus liver resection on residual intrahepatic neoplastic cells.

METHODS

A primary metastasis was established by injection of syngenic CT-26 coloncarcinoma cells into the right liver lobe of Balb/C mice. Five days later, 3 x 10(5) GFP-transfected CT-26 tumor cells were injected intraportally, and the primary metastasis was treated by resection (group I, n = 7) or RFA (group II, n = 7). The effect of resection/RFA on the growth of single intrahepatic GFP neoplastic cells was evaluated by intravital microscopy 7 days later.

RESULTS

Resection of a primary metastasis enhanced the proliferation of residual intrahepatic neoplastic cells, compared with the control group. RFA led to an increased survival of residual neoplastic cells (5% +/- 2% vs 1% +/- 1% single cells) and significantly promoted the proliferation of neoplastic cells, compared with resection (13% +/- 4% vs 2% +/- 2% micrometastases).

CONCLUSIONS

RFA strongly promotes intrahepatic growth of residual neoplastic cells. On the basis of our findings, RFA should not be recommended as an alternative curative treatment to resection. Furthermore, if RFA is performed as palliative therapy, postinterventional chemotherapy may be advisable to overcome the stimulation of residual neoplastic cells by RFA.

Pattern of carcinoembryonic antigen drop after laparoscopic radiofrequency ablation of liver metastasis from colorectal carcinoma

BACKGROUND

Laparoscopic radiofrequency ablation (RFA) is being increasingly used for local control of hepatic metastasis from colorectal carcinoma (CRC). After surgical resection of colorectal liver metastasis, carcinoembryonic antigen (CEA) values fall within 2 weeks, making this a useful parameter to follow shortly after surgery. Little is known, however, about the expected pattern of the CEA drop after RFA.

METHODS

From September 1998 to October 2002, RFA to CRC liver metastasis was performed on 144 patients. A subset of 17 patients were studied who had no evidence of extrahepatic disease preoperatively, had all detectable tumor ablated intraoperatively, and who on long-term follow-up (up to 15 months) had no evidence of recurrent disease. Serum CEA was determined preoperatively, on the first postoperative day, at 1 week, and every 3 months afterwards. A computed tomography (CT) scan of the abdomen and pelvis was obtained every 3 months postoperatively.

RESULTS

Ten (58.8%) patients showed an increase in CEA on postoperative Day 1, averaging 38.3% compared with the preoperative value. CEA then fell to 50% of the preoperative value, on average, on Day 7 postoperatively and only reached its nadir at 3 months.

CONCLUSIONS

Unlike resection patients, those undergoing ablation show an initial rise in CEA, probably due to release from the ablated tissue. Although heating of RFA would be expected to destroy CEA, the initial rise and slow drop postoperatively argue for a release of immunoreactive CEA from the ablated zone. This slow decline in CEA indicates that several months should pass before assessing the extent of potential residual disease.