Percutaneous radiofrequency ablation of liver metastases in potential candidates for resection: the "test-of-time approach"

US-US Fusion Imaging in Radiofrequency Ablation for Liver Metastases

OBJECTIVE

Radiofrequency ablation (RFA) induces gas bubbles in ablation zones, and the ablative margin cannot be evaluated accurately on ultrasound (US) during and immediately after RFA. This study assessed the usefulness of US-US fusion imaging to visualize the ablative margin of RFA for liver metastasis.

METHODS

RFA guided by US-US fusion imaging was performed on 12 targeted tumors in 10 patients. Secondary hepatic malignancies included patients with colorectal cancer (n = 4), breast cancer (n = 2), lung cancer (n = 1), gastrointestinal stromal tumor (n = 1), pancreatic neuroendocrine tumor (n = 1), and adrenocortical carcinoma (n = 1). The maximal diameter of the tumors ranged from 0.8 to 4.0 cm (mean ± SD 1.6 ± 0.9 cm).

RESULTS

The mean number of electrode insertions was 1.6 per session (range 1-3). Technically, effective ablation was achieved in a single session in all patients, and safety ablative margins were confirmed on contrast-enhanced CT for early assessment of tumor response. There were no serious adverse events or procedure-related complications. During the follow-up period (median 220 days, range 31-417 days), none of the patients showed local tumor progression.

CONCLUSION

US-US fusion imaging could show the tumor images before ablation and the ablative area on US in real time. The image overlay of US-US fusion imaging made it possible to evaluate the ablative margin three dimensionally according to the US probe action. Therefore, US-US fusion imaging can contribute to RFA therapy with a safety margin, that is, the so-called precise RFA.

Monitoring of tissue optical properties during thermal coagulation of ex vivo tissues

BACKGROUND AND OBJECTIVE

Real-time monitoring of tissue status during thermal ablation of tumors is critical to ensure complete destruction of tumor mass, while avoiding tissue charring and excessive damage to normal tissues. Currently, magnetic resonance thermometry (MRT), along with magnetic resonance imaging (MRI), is the most commonly used technique for monitoring and assessing thermal ablation process in soft tissues. MRT/MRI is very expensive, bulky, and often subject to motion artifacts. On the other hand, light propagation within tissue is sensitive to changes in tissue microstructure and physiology which could be used to directly quantify the extent of tissue damage. Furthermore, optical monitoring can be a portable, and cost-effective alternative for monitoring a thermal ablation process. The main objective of this study, is to establish a correlation between changes in tissue optical properties and the status of tissue coagulation/damage during heating of ex vivo tissues.

MATERIALS AND METHODS

A portable diffuse reflectance spectroscopy system and a side-firing fiber-optic probe were developed to study the absorption (μa (λ)), and reduced scattering coefficients (μ's (λ)) of native and coagulated ex vivo porcine, and chicken breast tissues. In the first experiment, both porcine and chicken breast tissues were heated at discrete temperature points between 24 and 140°C for 2 minutes. Diffuse reflectance spectra (430-630 nm) of native and coagulated tissues were recorded prior to, and post heating. In a second experiment, porcine tissue samples were heated at 70°C and diffuse reflectance spectra were recorded continuously during heating. The μa (λ) and μ's (λ) of the tissues were extracted from the measured diffuse reflectance spectra using an inverse Monte-Carlo model of diffuse reflectance. Tissue heating was stopped when the wavelength-averaged scattering plateaued.

RESULTS

The wavelength-averaged optical properties, <μ's (λ)> and <μa (λ)>, for native porcine tissues (n = 66) at room temperature, were 5.4 ± 0.3 cm(-1) and 0.780 ± 0.008 cm(-1) (SD), respectively. The <μ's (λ)> and <μa (λ)> for native chicken breast tissues (n = 66) at room temperature, were 2.69 ± 0.08 cm(-1) and 0.29 ± 0.01 cm(-1) (SD), respectively. In the first experiment, the <μ's (λ)> of coagulated porcine and chicken breast tissue rose to 56.4 ± 3.6 cm(-1) at 68.7 ± 1.7°C (SD), and 52.8 ± 1 cm(-1) at 57.1 ± 1.5°C (SD), respectively. Correspondingly, the <μa (λ)> of coagulated porcine (140.6°C), and chicken breast tissues (130°C) were 0.75 ± 0.05 cm(-1) and 0.263 ± 0.004 cm(-1) (SD). For both tissues, charring was observed at temperatures above 80°C. During continuous monitoring of porcine tissue (with connective tissues) heating, the <μ's (λ)> started to rise rapidly from 13.7 ± 1.5 minutes and plateaued at 19 ± 2.5 (SD) minutes. The <μ's (λ)> plateaued at 11.7 ± 3 (SD) minutes for porcine tissue devoid of connective tissue between probe and tissue surface. No charring was observed during continuous monitoring of thermal ablation process.

CONCLUSION

The changes in optical absorption and scattering properties can be continuously quantified, which could be used as a diagnostic biomarker for assessing tissue coagulation/damage during thermal ablation. Lasers Surg. Med. 48:686-694, 2016. © 2016 Wiley Periodicals, Inc.

The interventional radiologist role in treating liver metastases for colorectal cancer

Interventional radiologists (IRs) have an expanding role in the treatment of liver metastases from colorectal cancer. Increasing data on the ability to treat liver metastases with locoregional therapies has solidified this position. Ablative approaches, such as radiofrequency ablation and microwave ablation, have shown durable eradication of tumors. Catheter-directed therapies-such as transarterial chemoembolization (TACE), drug-eluting beads (DEB), Y90 radioembolization, intra-arterial chemotherapy ports, and isolated hepatic perfusion (IHP)-are potential techniques for managing patients with unresectable liver metastases. Understanding the timing and role of these techniques in the multidisciplinary care of the patient is critical. Implementation of the IR clinic for consultation has enabled better integration of these therapies into the patient's overall care and has facilitated improved opportunities for clinical studies.

Evidence-based medical oncology and interventional radiology paradigms for liver-dominant colorectal cancer metastases

Colorectal cancer metastasizes predictably, with liver predominance in most cases. Because liver involvement has been shown to be a major determinant of survival in this population, liver-directed therapies are increasingly considered even in cases where there is (limited) extrahepatic disease. Unfortunately, these patients carry a known risk of recurrence in the liver regardless of initial therapy choice. Therefore, there is a demand for minimally invasive, non-surgical, personalized cancer treatments to preserve quality of life in the induction, consolidation, and maintenance phases of cancer therapy. This report aims to review evidence-based conceptual, pharmacological, and technological paradigm shifts in parenteral and percutaneous treatment strategies as well as forthcoming evidence regarding next-generation systemic, locoregional, and local treatment approaches for this patient population.

Treatment of Metastatic Lymph Nodes in the Neck from Papillary Thyroid Carcinoma with Percutaneous Laser Ablation

PURPOSE

To assess the effectiveness of percutaneous laser ablation (PLA) of cervical lymph node metastases from papillary thyroid carcinoma.

MATERIALS AND METHODS

24 patients (62.3 ± 13.2 year; range 32-80) previously treated with thyroidectomy, neck dissection, and radioiodine ablation underwent ultrasound-guided PLA of 46 (18)FDG-PET/CT-positive metachronous nodal metastases. All patients were at high surgical risk or refused surgery and were unsuitable for additional radioiodine ablation. A 300 µm quartz fiber and a continuous-wave Nd-YAG laser operating at 1.064 mm were used. Technical success, rate of complications, rate of serological conversion, and local control at follow-up were derived. Fisher's exact test and Mann-Whitney U test were used and Kaplan-Meier curve calculated.

RESULTS

Technical success was obtained in all 46 lymph nodes (100 %). There were no major complications. Thyroglobulin levels decreased from 8.40 ± 9.25 ng/ml before treatment to 2.73 ± 4.0 ng/ml after treatment (p = 0.011), with serological conversion in 11/24 (45.8 %) patients. Overall, local control was obtained in 40/46 (86.9 %) lymph nodes over 30 ± 11 month follow-up, with no residual disease seen at imaging in 19/24 (79.1 %) patients. Local control was achieved in 40/46 (86.9 %) lymph nodes at 1 year and in all of the 25 nodes (100 %) followed for 3 years. Estimated mean time to progression was 38.6 ± 2.7 m.

CONCLUSION

Ultrasound-guided PLA is a feasible, safe, and effective therapy for the treatment of cervical lymph node metastases from papillary thyroid carcinoma.

Percutaneous Radiofrequency Ablation of Colorectal Cancer Liver Metastases: Factors Affecting Outcomes--A 10-year Experience at a Single Center

PURPOSE

To identify predictors of oncologic outcomes after percutaneous radiofrequency ablation (RFA) of colorectal cancer liver metastases (CLMs) and to describe and evaluate a modified clinical risk score (CRS) adapted for ablation as a patient stratification and prognostic tool.

MATERIALS AND METHODS

This study consisted of a HIPAA-compliant institutional review board-approved retrospective review of data in 162 patients with 233 CLMs treated with percutaneous RFA between December 2002 and December 2012. Contrast material-enhanced CT was used to assess technique effectiveness 4-8 weeks after RFA. Patients were followed up with contrast-enhanced CT every 2-4 months. Overall survival (OS) and local tumor progression-free survival (LTPFS) were calculated from the time of RFA by using the Kaplan-Meier method. Log-rank tests and Cox regression models were used for univariate and multivariate analysis to identify predictors of outcomes.

RESULTS

Technique effectiveness was 94% (218 of 233). Median LTPFS was 26 months. At univariate analysis, predictors of shorter LTPFS were tumor size greater than 3 cm (P < .001), ablation margin size of 5 mm or less (P < .001), high modified CRS (P = .009), male sex (P = .03), and no history of prior hepatectomy (P = .04) or hepatic arterial infusion chemotherapy (P = .01). At multivariate analysis, only tumor size greater than 3 cm (P = .01) and margin size of 5 mm or less (P < .001) were independent predictors of shorter LTPFS. Median and 5-year OS were 36 months and 31%. At univariate analysis, predictors of shorter OS were tumor size larger than 3 cm (P = .005), carcinoembryonic antigen level greater than 30 ng/mL (P = .003), high modified CRS (P = .02), and extrahepatic disease (EHD) (P < .001). At multivariate analysis, tumor size greater than 3 cm (P = .006) and more than one site of EHD (P < .001) were independent predictors of shorter OS.

CONCLUSION

Tumor size of less than 3 cm and ablation margins greater than 5 mm are essential for satisfactory local tumor control. Tumor size of more than 3 cm and the presence of more than one site of EHD are associated with shorter OS.

Percutaneous ablation of colorectal lung metastases

Lung metastasectomy can prolong survival in patients with metastatic colorectal carcinoma. Thermal ablation offers a potential solution with similar reported survival outcomes. It has minimal effect on pulmonary function, or quality of life, can be repeated, and may be considered more acceptable to patients because of the associated shorter hospital stay and recovery. This review describes the indications, technique, reported outcomes, complications and radiologic appearances after thermal ablation of colorectal lung metastases.

Comparison of Hepatic Resection and Radiofrequency Ablation for the Treatment of Colorectal Liver Metastasis

The liver is the major site of metastasis of primary colorectal cancer. Hepatic resection (HR) is considered the standard treatment for colorectal liver metastasis. In high-risk cases, radiofrequency ablation (RFA) can be attempted as an alternative treatment. This study compared the clinical profiles and overall and disease-free survival rates of patients with colorectal liver metastasis undergoing HR and RFA. From 1995 to 2009, we retrospectively analyzed clinical experiences of 43 and 17 patients who had undergone HR and RFA for primary colorectal cancer, respectively. To compare outcomes, we investigated the 3-year overall and disease-free survival rates. The 3-year overall survival rates of patients treated with HR and RFA were 53.5 and 47.1 %, respectively (p = 0.285); the disease-free survival rates were 35.0 and 26.9 %, respectively (p = 0.211). In the HR and RFA groups, 30 (60.2 %) and 13 (76.5 %) patients developed recurrence, respectively (p = 0.604). In the HR group, 1 patient died from postoperative liver failure, and 9 (20.9 %) developed postoperative complications, including wound infection, biliary leakage, intra-abdominal abscess, and pneumonia. In the RFA group, 1 patient (5.9 %) required prolonged inpatient care because of a procedure-related liver abscess. Although HR should be considered the first option for colorectal liver metastasis, RFA can be regarded as a primary treatment modality depending on the patient's characteristics, especially when a patient refuses surgery or has comorbidities.

Minimal invasive treatments for liver malignancies

Minimal invasive therapies have proved useful in the management of primary and secondary hepatic malignancies. The most relevant aspects of all these therapies are their minimal toxicity profiles and highly effective tumor responses without affecting the normal hepatic parenchyma. These unique characteristics coupled with their minimally invasive nature provide an attractive therapeutic option for patients who previously may have had few alternatives. Combination of these therapies might extend indications to bring curative treatment to a wider selected population. The results of various ongoing combination trials of intraarterial therapies with targeted therapies are awaited to further improve survival in this patient group. This review focuses on the application of ablative and intra-arterial therapies in the management of hepatocellular carcinoma and hepatic colorectal metastasis.

Oncogenesis: An "Off-Target" Effect of Radiofrequency Ablation

PURPOSE

To compare hepatocellular carcinoma (HCC) development after radiofrequency (RF) ablation, partial surgical hepatectomy, and a sham operation and to inhibit HCC recurrence after RF ablation in a mouse model of spontaneously forming HCC in the setting of chronic inflammation (ie, the MDR2 knockout model).

MATERIALS AND METHODS

Animal experiments were performed according to an approved animal care committee protocol. The authors compared the survival of MDR2 knockout mice (an inflammation-induced HCC model) that underwent RF ablation, 35% partial hepatectomy (ie, left lobectomy), or a sham operation (controls) by using Kaplan-Meier survival curve analysis. Tumor load and tumor frequency in mice that underwent sham operation were further compared with those of mice treated with RF ablation at 1 month after therapy by using a two-tailed Student t test. Liver slices from mice treated with RF ablation were stained for α-smooth muscle actin and Ki-67 to establish the role of liver regeneration in the tumorigenic effect of RF ablation. Finally, tumor load and tumor incidence were evaluated in mice treated with a c-met inhibitor after RF ablation by using the Mann-Whitney U test.

RESULTS

Ablation of 3.5% ± 0.02 of the MDR2 knockout mice liver induced increased tumor load (P = .007) and reduced survival (P = .03) in comparison to that of controls, with no significant difference to the 10-fold volume removal of partial hepatectomy. Seven days after RF treatment, the border zone of the coagulation zone was surrounded by α-smooth muscle actin-positive activated myofibroblasts. A significant elevation of hepatocyte proliferation was also seen 7 days after RF ablation in the distant liver (ablated lobe: P = .003; untreated lobe: P = .02). A c-met inhibitor significantly attenuated HCC development in MDR2 knockout mice treated with RF ablation (P = .001).

CONCLUSION

Liver regeneration induced by RF ablation facilitates c-met/hepatocyte growth factor axis-dependent HCC tumor formation after treatment in the MDR2 knockout model. Blockage of the c-met/hepatocyte growth factor axis attenuates HCC recurrence, raising the potential for therapeutic intervention to reverse this potentially deleterious tumorigenic effect.

Ablative and catheter-directed therapies for colorectal liver and lung metastases

Increasing data on treatment of liver metastases with locoregional therapies have solidified the expanding role of interventional radiologists (IRs) in the treatment of liver metastases from colorectal cancer. Ablative approaches such as radiofrequency ablation and microwave ablation have shown durable eradication of tumors. Catheter-directed therapies such as transarterial chemoembolization, drug-eluting beads, yttrium-90 radioembolization, and intra-arterial chemotherapy ports represent potential techniques for managing patients with unresectable liver metastases. Understanding the timing and role of these techniques in multidisciplinary care of patients is crucial. Implementation of IRs for consultation enables better integration of these therapies into patients' overall care.

Thermal ablation of colorectal liver metastases: a position paper by an international panel of ablation experts, The Interventional Oncology Sans Frontières meeting 2013

Objectives

Previous attempts at meta-analysis and systematic review have not provided clear recommendations for the clinical application of thermal ablation in metastatic colorectal cancer. Many authors believe that the probability of gathering randomised controlled trial (RCT) data is low. Our aim is to provide a consensus document making recommendations on the appropriate application of thermal ablation in patients with colorectal liver metastases.

Methods

This consensus paper was discussed by an expert panel at The Interventional Oncology Sans Frontières 2013. A literature review was presented. Tumour characteristics, ablation technique and different clinical applications were considered and the level of consensus was documented.

Results

Specific recommendations are made with regard to metastasis size, number, and location and ablation technique. Mean 31 % 5-year survival post-ablation in selected patients has resulted in acceptance of this therapy for those with technically inoperable but limited liver disease and those with limited liver reserve or co-morbidities that render them inoperable.

Conclusions

In the absence of RCT data, it is our aim that this consensus document will facilitate judicious selection of the patients most likely to benefit from thermal ablation and provide a unified interventional oncological perspective for the use of this technology.

Key Points

• Best results require due consideration of tumour size, number, volume and location.

• Ablation technology, imaging guidance and intra-procedural imaging assessment must be optimised.

• Accepted applications include inoperable disease due to tumour distribution or inadequate liver reserve.

• Other current indications include concurrent co-morbidity, patient choice and the test-of-time approach.

• Future applications may include resectable disease, e.g. for small solitary tumours.

Management of oligometastatic rectal cancer: is liver first?

Twenty percent of patients with rectal cancer present with synchronous liver metastases at the time of initial diagnosis. These patients can be treated with a curative intent, although the choice and sequence of treatment modalities are not well established and are commonly debated in multi-disciplinary tumor boards. In this article we review clinical evidence for various treatment approaches and attempt to formulate a pathway for clinicians to use in evaluating and managing these patients.

Non-operative therapies for colorectal liver metastases

Locoregional therapies for colorectal liver metastases complement systemic therapy by providing an opportunity for local control of hepatic spread. The armamentarium for liver-directed therapy includes ablative therapies, embolization, and stereotactic body radiation therapy. At this time, prospective studies comparing these modalities are limited and decision-making relies on a multidisciplinary approach for optimal patient management. Herein, we describe multiple therapeutic non-surgical procedures and an overview of the results of these treatments.

Optimal management of colorectal liver metastases in older patients: a decision analysis

BACKGROUND

Comparative trials evaluating management strategies for colorectal cancer liver metastases (CLM) are lacking, especially for older patients. This study developed a decision-analytic model to quantify outcomes associated with treatment strategies for CLM in older patients.

METHODS

A Markov-decision model was built to examine the effect on life expectancy (LE) and quality-adjusted life expectancy (QALE) for best supportive care (BSC), systemic chemotherapy (SC), radiofrequency ablation (RFA) and hepatic resection (HR). The baseline patient cohort assumptions included healthy 70-year-old CLM patients after a primary cancer resection. Event and transition probabilities and utilities were derived from a literature review. Deterministic and probabilistic sensitivity analyses were performed on all study parameters.

RESULTS

In base case analysis, BSC, SC, RFA and HR yielded LEs of 11.9, 23.1, 34.8 and 37.0 months, and QALEs of 7.8, 13.2, 22.0 and 25.0 months, respectively. Model results were sensitive to age, comorbidity, length of model simulation and utility after HR. Probabilistic sensitivity analysis showed increasing preference for RFA over HR with increasing patient age.

CONCLUSIONS

HR may be optimal for healthy 70-year-old patients with CLM. In older patients with comorbidities, RFA may provide better LE and QALE. Treatment decisions in older cancer patients should account for patient age, comorbidities, local expertise and individual values.

Safety and Efficacy of Ultrasound-Guided Radiofrequency Ablation of Recurrent Colorectal Cancer Liver Metastases after Hepatectomy

INTRODUCTION

To assess the results and outcome of radiofrequency ablation in the treatment of recurrent colorectal liver metastases.

PATIENTS AND METHODS

Between January 2005 and September 2012, we treated 59 patients with recurrent colorectal metastases not amenable to surgery with 77 radiofrequency ablation procedures. Radiofrequency was indicated if oncologic resection was technically not possible or the patient was not fit for major surgery. A total of 91 lesions were treated. The mean number of liver tumors per patient was 1.5, and the mean tumor diameter was 2.3 cm. In 37.5% of the cases, lesions had a subcapsular location, and 34% were close to a vascular structure.

RESULTS

The morbidity rate was 18.7%, and there were no post-procedural deaths. Distant extrahepatic recurrence appeared in 50% of the patients. Local recurrence at the site of ablation appeared in 18% of the lesions. Local recurrence rate was 6% in lesions less than 3 cm and 52% in lesions larger than 3 cm. The size of the lesions (more than 3 cm) was an independent risk factor for local recurrence (p < 0.05). Survival rates at 1, 3, and 5 years were 94.5%, 65.3%, and 21.7%, respectively.

DISCUSSION

Radiofrequency ablation is a safe procedure and allows local tumor control in lesions less than 30 mm (local recurrence of 6%) and provides survival benefits in patients with recurrent colorectal liver metastases.

Radiofrequency ablation and breast cancer: a review

BACKGROUND

Radiofrequency ablation (RFA) use in breast cancer is a developing area of research. There have been a number of published studies over the last decade, which explores the feasibility of minimally invasive techniques in breast cancer treatment. In this review, we will discuss the most recent data on radiofrequency ablation and examine the current methods, outcomes, complications, and limitations of RFA in breast cancer therapy.

METHODS

Pub Med search for English Language articles on RFA in breast cancer.

RESULTS

More than 25 studies were reviewed and we searched for number of tumors, average size, electrode used, if they successfully ablated the tumor, when the tumor was then resected and if the patients experienced any complication from the ablation.

CONCLUSIONS

Radiofrequency ablation is an emerging minimally invasive therapy in small, localized breast cancer. Currently, no clinical trials have been published to directly compare RFA to the current standard of surgical resection. Ultimately, RFA will need clinical trials to evaluate oncologic outcomes involving long interval follow-up to determine survival, local control and disease progression before it becomes a reasonable alternative to surgical resection.

"How we do it" - a practical approach to hepatic metastases ablation techniques

Secondary liver malignancies are associated with significant mortality and morbidity if left untreated. Colorectal cancer is the most frequent origin of hepatic metastases. A multidisciplinary approach to the treatment of hepatic metastases includes medical, surgical, radiation and interventional oncology. The role of interventional oncology in the management of hepatic malignancies continues to evolve and applies to a large and continuous spectrum of metastatic disease, from the relatively small solitary metastasis to larger tumors and multifocal liver disease. Within the past 10 years, several publications of percutaneous image-guided ablation indicated the effectiveness and safety of this minimally invasive therapy for selected patients with limited number (arguably up to 4 metastases) of relatively small (less than 5cm) hepatic metastases. Different image-guided procedures such radiofrequency, microwave, and laser cause thermal ablation and coagulation necrosis or cell death of the target tumor. Cryoablation, causing cell death via cellular freezing, has also been used. Recently, irreversible electroporation, a nonthermal modality, has also been used for liver tumor ablation. In the following section, we review the different liver ablation techniques, as well as indications for ablation, specific patient preparations, and different "tricks of the trade" that we use to achieve safe and effective liver tumor ablation. We also discuss appropriate imaging and clinical patient follow-up and potential complications of liver tumor ablation.

Patterns of recurrence following selective intraoperative radiofrequency ablation as an adjunct to hepatic resection for colorectal liver metastases

BACKGROUND AND OBJECTIVES

The purpose of this study was to analyze the patterns of recurrence following intraoperative radiofrequency ablation (RFA) combined with hepatic resection for patients with colorectal liver metastases (CLM).

METHODS

Patients undergoing liver resection (with or without RFA) for CLM were examined. Rates and patterns of disease recurrence, as well as overall survival were assessed using Kaplan-Meier and Cox analyses.

RESULTS

A total of 174 patients underwent liver resection for CLM (150 without and 24 with intraoperative RFA). RFA was used to treat 41 tumors (median 1.6 cm). The 3-year overall survival was 65.5% and 61.4% (adjusted HR 1.02, 95% CI 0.55-1.88). Median recurrence-free survival was 7.4 versus 12.7 months with RFA versus non-RFA, respectively (adjusted HR 1.51, 95% CI 0.94-4.42). On multivariate analysis, neither survival nor recurrence-free survival was significantly associated with RFA. In total, there were two RFA ablation zone local failures. An ablation site recurrence was the sole site in one patient (4.2%).

CONCLUSION

RFA was used as an adjunct to resection in patients with greater disease burden. Despite this, RFA was not significantly associated with a higher risk of local failure and was not associated with worse survival, when compared with liver resection alone.

Microwave ablation (MWA) for the treatment of a solitary, chemorefractory testicular cancer liver metastasis

We present a case of a patient with stage IIIC metastatic seminoma with a persistent chemorefractory liver lesion. The patient was deemed a poor surgical candidate due to the tumor's aggressive biology with numerous other liver lesions treated with chemotherapy and a relatively high probability for additional recurrences. Further chemotherapy with curative intent was not a feasible option due to the fact that the patient had already received second-line high-dose chemotherapy and four cycles of third-line treatment complicated by renal failure, refractory thrombocytopenia, and debilitating neuropathy. After initial failure of laser, microwave ablation of the chemorefractory liver metastasis resulted in prolonged local tumor control and rendered the patient disease-free for more than 35 months, allowing him to regain an improved quality of life.

Impact of treatment modality and number of lesions on recurrence and survival outcomes after treatment of colorectal cancer liver metastases

BACKGROUND

Ablative strategies have been used to treat and facilitate hepatic resection (HR) in patients with otherwise unresectable colorectal liver metastases (CLM). We evaluated the efficacy of HR, concomitant HR and ablation and isolated ablation on recurrence and survival outcomes after treatment of CLM in patients with 1-4 and ≥5 lesions, respectively.

METHODS

A retrospective review of a prospectively collected hepatobiliary surgery database was performed on patients who underwent treatment for isolated CLM between 1990 and 2010. Pre-operative and treatment characteristics were compared between patients who underwent HR, concomitant HR and ablation and ablation alone. The impact of treatment modality on survival and recurrence outcomes was determined.

RESULTS

A total of 701 patients met inclusion criteria; 550 patients (78%) had 1-4 lesions and 151 patients (22%) had ≥5 lesions. Overall median survival for the entire cohort was 35 months with 5- and 10-year survival of 33% and 20%, respectively. Overall median and 5-year recurrence-free survival (RFS) was 13 months and 21%, respectively. For patients with 1-4 lesions, median survival was 37 months with 5-year survival of 36%. Stratified by procedure type, 5-year survival was 41% in patients who underwent HR, 35% in patients who underwent concomitant HR and ablation and 13% in patients who underwent ablation alone (P<0.001). For patients with ≥5 lesions, median survival was 28 months with 5-year survival of 23% without difference between treatment groups (P=0.078).

CONCLUSIONS

HR appears to be the most effective strategy for patients with 1-4 lesions. When ≥5 lesions are present, ablative strategies are useful in facilitating HR in otherwise unresectable patients.

Complementary use of resection and radiofrequency ablation for the treatment of colorectal liver metastases: an analysis of 395 patients

BACKGROUND

Liver resection and radiofrequency ablation (RFA) are two surgical options in the treatment of patients with colorectal liver metastases (CLM). The aim of this study was to analyze patient characteristics and outcomes after resection and RFA for CLM from a single center.

METHODS

Between 2000 and 2010, 395 patients with CLM undergoing RFA (n = 295), liver resection (n = 94) or both (n = 6) were identified from a prospective IRB-approved database. Demographic, clinical and survival data were analyzed using univariate and multivariate analyses.

RESULTS

RFA patients had more comorbidities, number of liver tumors and a higher incidence of extrahepatic disease compared to the Resection patients. The 5-year overall actual survival was 17 % in the RFA, 58 % in the Resection group (p = 0.001). On multivariate analysis, multiple liver tumors, dominant lesion >3 cm, and CEA >10 ng/ml were independent predictors of overall survival. Patients were followed for a median of 20 ± 1 months. Liver and extrahepatic recurrences were seen in 69 %, and 29 % of the patients in the RFA, and 40 %, and 19 % of the patients in the Resection group, respectively.

CONCLUSIONS

In this large surgical series, we described the characteristics and oncologic outcomes of patients undergoing resection or RFA for CLM. By having both options available, we were able to surgically treat a large number of patients presenting with different degrees of liver tumor burden and co-morbidities, and also manage liver recurrences in follow-up.

Clinical scenarios associated with local recurrence after laparoscopic radiofrequency thermal ablation of colorectal liver metastases

BACKGROUND

Over the last decade, radiofrequency thermal ablation (RFA) has been incorporated into the treatment algorithm of patients with unresectable colorectal liver metastases (CLM). For this population, the local recurrence (LR) rate is a key parameter used to assess the success of RFA. LR is defined as development of new tumor abutting and/or in 1 cm of an ablation zone. The aim of this study is to correlate LR with other hepatic or extrahepatic recurrence and patient survival.

METHODS

Between 2000 and 2011, 252 patients with CLM underwent laparoscopic RFA of 883 lesions. These patients were followed under a prospective protocol with quarterly liver computed tomography and blood work, including carcinoembryonic antigen levels quarterly for the first 2 years and then biannually. Clinical scenarios associated with LR were identified and categorized as being "isolated LR," "LR associated with new liver disease," or "LR associated with systemic disease." Demographic, clinical, and survival data were assessed using analysis of variance, Chi-square test, and univariate and multivariate Kaplan-Meier analysis.

RESULTS

One hundred eighteen patients (47%) developed LR after their initial laparoscopic RFA. These were 85 men (72%) and 33 women (28%), with a mean age of 70 ± 8 years. For this cohort, the mean of number of lesions was 3.1 ± 0.2 cm (range, 1-11) and dominant tumor size 2.9 ± 0.1 cm (range, 0.7-6.5) at the time of initial RFA. The LR rate per lesion was 29%. Of the patients who developed treatment failure at the RFA site, this was an isolated LR in 31 (26%) patients, associated with new liver disease in 51 (43%) and systemic metastases in 36 patients (31%). When patients with different clinical scenarios associated with LR were compared, no clinical predictors were identified to differentiate these subgroups. At a median follow up of 30 months (range, 3-113), the Kaplan-Meier median overall survival (OS) for patients with and without LR were 28 vs 31 months, respectively (P = .103). The OS for patients whose LR was isolated, associated with new liver and systemic recurrences was 39, 26, and 22 months, respectively (P = .009).

CONCLUSION

This study shows that, although the presence of LR does not negatively impact on survival, the pattern of recurrent disease does. LR after RFA for CLM is most often associated with new liver and systemic recurrences, reflecting the aggressive biology of cancer in patients channeled to this treatment modality.

Evaluation of YO-PRO-1 as an early marker of apoptosis following radiofrequency ablation of colon cancer liver metastases

Radiofrequency (RF) ablation (RFA) is a minimally invasive treatment for colorectal-cancer liver metastases (CLM) in selected nonsurgical patients. Unlike surgical resection, RFA is not followed by routine pathological examination of the target tumor and the surrounding liver tissue. The aim of this study was the evaluation of apoptotic events after RFA. Specifically, we evaluated YO-PRO-1 (YP1), a green fluorescent DNA marker for cells with compromised plasma membrane, as a potential, early marker of cell death. YP1 was applied on liver tissue adherent on the RF electrode used for CLM ablation, as well as on biopsy samples from the center and the margin of the ablation zone as depicted by dynamic CT immediately after RFA. Normal pig and mouse liver tissues were used for comparison. The same samples were also immunostained for fragmented DNA (TUNEL assay) and for active mitochondria (anti-OxPhos antibody). YP1 was also used simultaneously with propidium iodine (PI) to stain mouse liver and samples from ablated CLM. Following RFA of human CLM, more than 90 % of cells were positive for YP1. In nonablated, dissected pig and mouse liver however, we found similar YP1 signals (93.1 % and 65 %, respectively). In samples of intact mouse liver parenchyma, there was a significantly smaller proportion of YP1 positive cells (22.7 %). YP1 and PI staining was similar for ablated CLM. However in dissected normal mouse liver there was initial YP1 positivity and complete absence of the PI signal and only later there was PI signal.

CONCLUSION

This is the first time that YP1 was applied in liver parenchymal tissue (rather than cell culture). The results suggest that YP1 is a very sensitive marker of early cellular events reflecting an early and widespread plasma membrane injury that allows YP1 penetration into the cells.

Efficacy of laparoscopic radiofrequency ablation for the treatment of patients with small solitary colorectal liver metastasis

BACKGROUND

Although radiofrequency ablation (RFA) has been incorporated to the treatment algorithm of patients with unresectable colorectal liver metastasis (CLM), its utility in patients with resectable disease has not been well studied. The aims of this study were to define the clinical profile of patients with a solitary CLM who underwent laparoscopic RFA and to analyze their oncologic outcomes.

METHODS

Between 2000 and 2011, 44 patients underwent laparoscopic RFA and 60 patients resection of solitary CLM ≤3 cm. Data were analyzed from a prospectively maintained institutional review board-approved database using Student's t test, Chi-square, and Kaplan-Meier tests.

RESULTS

The indications for RFA were patient decision in 61% (n = 27), comorbidities in 34% (n = 15), and intraoperative findings in 5% (n = 2). In comparison with the resection group, RFA patients had a greater American Society of Anesthesiologists score (3.0 ± 0.1 vs 2.6 ± 0.1, respectively; P = .002), more frequent incidence of cardiopulmonary comorbidities (60% vs 38%, respectively; P = .045), and tumors located deeper in the liver parenchyma (39% vs 12%) that would have required a formal lobectomy. The 2 groups were otherwise similar for age, gender, carcinoembrradyogenic antigen, synchronous versus metachronous presentation of CLM, tumor size, and tumor and nodal status of primary colorectal cancer. The local recurrence rate was 18% after RFA and 4% after resection (P = .012). The overall Kaplan-Meier, cancer-specific, 5-year survival was 47% for RFA and 57% for resection (P = .464). Median disease-free survival was 25 months after RFA and 22 months after resection (P = .973).

CONCLUSION

Our results suggest that laparoscopic RFA might spare a number of patients at greater risk with a small solitary CLM the risk of morbidity from a formal liver resection. Furthermore, laparoscopic RFA might also be acceptable as the first line of therapy for patients with tumors that otherwise would have required a formal lobectomy or open resection. Nevertheless, the local recurrence rate of RFA should be kept in mind and the patients followed closely to treat failures promptly.

Current oncologic applications of radiofrequency ablation therapies

Radiofrequency ablation (RFA) uses high frequency alternating current to heat a volume of tissue around a needle electrode to induce focal coagulative necrosis with minimal injury to surrounding tissues. RFA can be performed via an open, laparoscopic, or image guided percutaneous approach and be performed under general or local anesthesia. Advances in delivery mechanisms, electrode designs, and higher power generators have increased the maximum volume that can be ablated, while maximizing oncological outcomes. In general, RFA is used to control local tumor growth, prevent recurrence, palliate symptoms, and improve survival in a subset of patients that are not candidates for surgical resection. It’s equivalence to surgical resection has yet to be proven in large randomized control trials. Currently, the use of RFA has been well described as a primary or adjuvant treatment modality of limited but unresectable hepatocellular carcinoma, liver metastasis, especially colorectal cancer metastases, primary lung tumors, renal cell carcinoma, boney metastasis and osteoid osteomas. The role of RFA in the primary treatment of early stage breast cancer is still evolving. This review will discuss the general features of RFA and outline its role in commonly encountered solid tumors.

[Radiofrequency ablation of hepatocellular carcinoma]

Percutaneous radiofrequency ablation (RFA) is well established in the treatment of hepatocellular carcinoma (HCC). Due to its curative potential, it is the method of choice for non resectable BCLC (Barcelona Liver Clinic) 0 and A. RFA challenges surgical resection for small HCC and is the method of choice in bridging for transplantation and recurrence after resection or transplantation. The technical feasibility of RFA depends on the size and location of the HCC and the availability of ablation techniques (one needle techniques, multi-needle techniques). More recently, stereotactic multi-needle techniques with 3D trajectory planning and guided needle placement substantially improve the spectrum of treatable lesions including large volume tumors. Treatment success depends on the realization of ablations with large intentional margins of tumor free tissue (A0 ablation in analogy to R0 resection), which has to be documented by fusion of post- with pre-ablation images, and confirmed during follow-up imaging.

Computed tomography-guided interstitial high dose rate brachytherapy for centrally located liver tumours: a single institution study

OBJECTIVES

To evaluate the clinical outcome of computed tomography (CT)-guided interstitial (IRT) high-dose-rate (HDR) brachytherapy (BRT) in the treatment of unresectable primary and secondary liver malignancies. This report updates and expands our previously described experience with this treatment technique.

METHODS

Forty-one patients with 50 tumours adjacent to the liver hilum and bile duct bifurcation were treated in 59 interventions of CT-guided IRT HDR BRT. The tumours were larger than 4 cm with a median volume of 84 cm(3) (38-1,348 cm(3)). The IRT HDR BRT delivered a median total physical dose of 20.0 Gy (7.0-32.0 Gy) in twice daily fractions of median 7.0 Gy (4.0-10.0 Gy) in 19 patients and in once daily fractions of median 8.0 Gy (7.0-14.0 Gy) in 22 patients.

RESULTS

With a median follow-up of 12.4 months, the local control for metastatic hepatic tumours was 89 %, 73 % and 63 % at 6, 12 and 18 months respectively. The local control for primary hepatic tumours was 90 %, 81 % and 50 % at 6, 12 and 18 months respectively. Severe side effects occurred in 5.0 % of interventions with no treatment-related deaths.

CONCLUSIONS

CT-guided IRT HDR BRT is a promising procedure for the radiation treatment of centrally located liver malignancies.

KEY POINTS

• Interstitial high-dose-rate brachytherapy (IRT HDR BRT) is a promising treatment for central liver tumours • CT-guided IRT HDR BRT is safe for treating extensive tumours • CT-guided IRT HDR BRT could play a role in managing unresectable hepatic malignancies.

Locoregional surgical and interventional therapies for advanced colorectal cancer liver metastases: expert consensus statements

Selection of the optimal surgical and interventional therapies for advanced colorectal cancer liver metastases (CRLM) requires multidisciplinary discussion of treatment strategies early in the trajectory of the individual patient's care. This paper reports on expert consensus on locoregional and interventional therapies for the treatment of advanced CRLM. Resection remains the reference treatment for patients with bilateral CRLM and synchronous presentation of primary and metastatic cancer. Patients with oligonodular bilateral CRLM may be candidates for one-stage multiple segmentectomies; two-stage resection with or without portal vein embolization may allow complete resection in patients with more advanced disease. After downsizing with preoperative systemic and/or regional therapy, curative-intent hepatectomy requires resection of all initial and currently known sites of disease; debulking procedures are not recommended. Many patients with synchronous primary disease and CRLM can safely undergo simultaneous resection of all disease. Staged resections should be considered for patients in whom the volume of the future liver remnant is anticipated to be marginal or inadequate, who have significant medical comorbid condition(s), or in whom extensive resections are required for the primary cancer and/or CRLM. Priority for liver-first or primary-first resection should depend on primary tumour-related symptoms or concern for the progression of marginally resectable CRLM during treatment of the primary disease. Chemotherapy delivered by hepatic arterial infusion represents a valid option in patients with liver-only disease, although it is best delivered in experienced centres. Ablation strategies are not recommended as first-line treatments for resectable CRLM alone or in combination with resection because of high local failure rates and limitations related to tumour size, multiplicity and intrahepatic location.

Role of contrast enhanced ultrasound in radiofrequency ablation of metastatic liver carcinoma

OBJECTIVE

To investigate the application of contrast enhanced ultrasound (CEUS) in planning and guiding for radiofrequency ablation (RFA) for metastatic liver carcinoma (MLC).

METHODS

One hundred and thirty-five patients with clinically and pathologically diagnosed MLC (from gastrointestinal tumors) were included in the present study, and 104 of them had received CEUS prior to RFA to assess the number, size, shape, infiltration, location and enhancing features of the lesions. Among the 104 patients, 21 (20.1%) were excluded from RFA treatment due to too many lesions or large infiltrative range based on CEUS. The remaining 83 patients with 147 lesions underwent RFA (group A). During the same period, other 31 patients with 102 lesions serving as control group were treated based on findings of conventional ultrasound without contrast (group B). The patients underwent follow-up enhanced CT at the 1st month, and then every 3-6 months after RFA. The tumor was considered as early necrosis if no contrast enhancement was detected in the treated area on the CT scan at the 1st month.

RESULTS

In group A, 72 of 147 MLC lesions (48.9%) showed increased sizes on CEUS. Among them, 48 lesions (66.6%) appeared enlarged in arterial phase, and 24 (33.3%) showed enlarged hypoechoic area in parenchymal phase. CEUS showed total 61 additional lesions in 35 patients (42.1%) (ranged from 8 to 15 mm) compared with conventional ultrasound (US), and 42 (68.8%) of them were visualized in parenchymal phase only. There were total 208 lesions in group A underwent RFA with CEUS planning, and the tumor necrosis rate was 94.2% (196/208). In this group, local recurrence was found in 16 lesions (7.7%) during 3-42 months' following up, and new metastases were seen in 30 cases (36.1%). For group B, the tumor necrosis rate was 86.3% (88/102), local recurrence in 17 lesions (16.7%), and new metastases in 13 cases (41.9%). Tumor early necrosis and recurrence rates were significantly different between the two groups (P=0.018, P=0.016, respectively).

CONCLUSION

CEUS played an important role in RFA for liver metastases by candidate selecting and therapy planning, which helped to improve the outcome of the treatment.

Radiofrequency ablation of liver metastases from colorectal cancer: a literature review

Liver metastases occur in up to 60% of patients with colorectal cancer, and the control of liver metastases is considered to be of primary importance because it is a critical factor in determining prognosis. Radiofrequency ablation (RFA) therapy is one of the least invasive techniques for unresectable hepatic malignancies and can be performed safely using percutaneous, laparoscopic, or open surgical techniques. The local tumor progression rates after RFA for colorectal liver metastases range from 8.8% to 40.0%, and 5-year survival rates range from 20.0% to 48.5%. No prospective, randomized trials comparing the efficacy of RFA with that of surgical resection for colorectal liver metastases are currently available. However, some retrospective studies have reported that patients who received RFA had a survival rate similar to that observed in surgically treated groups, while other studies have reported better survival among patients who underwent surgical resection. The use of a laparoscopic or open surgical approach allows the repeated placement of RFA electrodes at multiple sites to ablate larger tumors. An accurate evaluation of treatment response is very important for the success of RFA therapy because a sufficient safety margin (at least 0.5 cm) can prevent local tumor progression. This review critically summarizes the current status of RFA for liver metastases from colorectal cancer.

Small liver colorectal metastases treated with percutaneous radiofrequency ablation: local response rate and long-term survival with up to 10-year follow-up

PURPOSE

To determine the long-term (10-year) survival of patients with colorectal liver metastases treated with radiofrequency (RF) ablation and systemic chemotherapy with intention to treat.

MATERIALS AND METHODS

Institutional review board approval was obtained for this study. From 1997 to 2006, 99 consecutive patients with 202 small (0.8-4.0 cm; mean: 2.2 cm ± 1.1) metachronous colorectal liver metastases underwent ultrasonography-guided percutaneous RF ablation with internally-cooled electrodes in association with systemic chemotherapy. Patients ineligible for surgery (n = 80) or whose lesions were potentially resectable and who refused surgery (n = 19) were included. Patients were followed up with contrast agent-enhanced computed tomography and/or magnetic resonance imaging for a minimum of 3 years to more than 10 years after RF ablation (n = 99, 67, 49, and 25 for 3, 5, 7, and 10 or more years, respectively). Overall local response rates and long-term survival rates were assessed. For each of these primary endpoints, Kaplan-Meier curves were generated and log-rank tests were used to assess for statistically significant differences.

RESULTS

Primary and secondary technical success rates were 93.1% (188 of 202) and 100% (14 of 14), respectively. Local tumor progression occurred in 11.9% (24 of 202) metastases, and 54.2% (13 of 24) of these were re-treated. Patient survival rates increased with re-treatment versus no re-treatment (P < .001). At follow-up, 125 new liver metastases were found, and of these 32.8% (41 of 125) were treated with RF ablation. Overall survival rates were 98.0%, 69.3%, 47.8%, 25.0%, and 18.0% (median: 53.2 months) at 1, 3, 5, 7, and 10 years, respectively. The major complication rate was 1.3% (two of 156), and there were no procedure-related deaths. At the time this article was written, 32.3% (32 of 99) of the patients were alive, and 67.7% (67 of 99) were deceased, with a median follow-up of 72 months.

CONCLUSION

Adding RF ablation to systemic chemotherapy achieved local control in a large majority of metachronous colorectal liver metastases. The 3- to 10-year survival rates of this relatively large series of patients were essentially equivalent to those of most surgical series reported in the literature.

Radiofrequency ablation versus resection for colorectal cancer liver metastases: a meta-analysis

Background

No randomized controlled trial (RCT) has yet been performed to provide the evidence to clarify the therapeutic debate on liver resection (LR) and radiofrequency ablation (RFA) in treating colorectal liver metastases (CLM). The meta-analysis was performed to summarize the evidence mostly from retrospective clinical trials and to investigate the effect of LR and RFA.

Methodology/Principal Findings

Systematic literature search of clinical studies was carried out to compare RFA and LR for CLM in Pubmed, Embase and the Cochrane Library Central databases. The meta-analysis was performed using risk ratio (RR) and random effect model, in which 95% confidence intervals (95% CI) for RR were calculated. Primary outcomes were the overall survival (OS) and disease-free survival (DFS) at 3 and 5 years plus mortality and morbidity. 1 prospective study and 12 retrospective studies were finally eligible for meta-analysis. LR was significantly superior to RFA in 3 -year OS (RR 1.377, 95% CI: 1.246–1.522); 5-year OS (RR: 1.474, 95%CI: 1.284–1.692); 3-year DFS (RR 1.735, 95% CI: 1.483–2.029) and 5-year DFS (RR 2.227, 95% CI: 1.823–2.720). The postoperative morbidity was higher in LR (RR: 2.495, 95% CI: 1.881–3.308), but no significant difference was found in mortality between LR and RFA. The data from the 3 subgroups (tumor<3 cm; solitary tumor; open surgery or laparoscopic approach) showed significantly better OS and DFS in patients who received surgical resection.

Conclusions/Significances

Although multiple confounders exist in the clinical trials especially the bias in patient selection, LR was significantly superior to RFA in the treatment of CLM, even when conditions limited to tumor<3 cm, solitary tumor and open surgery or laparoscopic (lap) approach. Therefore, caution should be taken when treating CLM with RFA before more supportive evidences for RFA from RCTs are obtained.

Radiofrequency ablation in the management of unresectable intrahepatic cholangiocarcinoma

PURPOSE

To evaluate the efficacy of radiofrequency (RF) ablation for treatment of unresectable intrahepatic cholangiocarcinoma (ICC) and to explore the impact of prognostic variables on outcomes.

MATERIALS AND METHODS

From 2000-2010, 17 patients with 26 ICCs underwent RF ablation at a single institution. None of the patients were surgery candidates. Seven patients had 15 primary ICCs, and 10 patients had 11 recurrent ICCs. The median largest diameter was 4.4 cm (range 2.1-6.8 cm). A percutaneous approach was used in 15 patients, and an open approach was used in 2 patients. Early tumor necrosis, recurrence-free survival, and overall survival were analyzed. Univariate analysis was performed to evaluate 12 clinicopathologic and treatment-related variables associated with recurrence-free survival and overall survival.

RESULTS

Early tumor necrosis was 96.2% (25 of 26 tumors). The median follow-up period after RF ablation was 29 months. The median recurrence-free survival and overall survival were 17 months and 33 months. The 1-year, 3-year, and 5-year survival rates were 84.6%, 43.3%, and 28.9%, with an overall complication rate of 3.6% (1 of 28 sessions). Three variables were found to be closely associated with recurrence-free survival: lymph node metastases (P = .023), tumor differentiation (P = .034), and tumor number (P = .035). The only variable significantly associated with overall survival was tumor differentiation (P = .033).

CONCLUSIONS

Preliminary results showed that RF ablation may be an effective treatment for ICC because it achieved an acceptable survival rate in a small population. Prognostic factors might allow better patient selection and outcomes.

Comparison of radiofrequency ablation and resection for hepatic metastasis from colorectal cancer

BACKGROUND/AIMS

Radiofrequency ablation (RFA) has been mostly used as a therapeutic alternative to hepatic resection for treating liver metastasis of colorectal cancer. The purpose of the present study was to determine whether there were differences in outcome between RFA and surgical resection in the treatment of colorectal cancer with liver metastases.

METHODS

We performed a retrospective analysis of 53 patients who underwent only hepatic resection or only RFA for colorectal liver metastases. Twenty-five patients who underwent hepatic resection were compared with 28 patients who underwent RFA for synchronous or metachronous liver metastases.

RESULTS

The median CEA level at the time of diagnosis of liver metastases was significantly higher in the resection group (14.2 ng/mL vs. 2.8 ng/mL, p=0.002). The median size of main liver metastases was significantly larger in the resection group (4.0 cm vs. 2.05 cm, p=0.002). There was no difference in the percentage of patients experiencing major complication (one patient in each group). The marginal recurrence rate was significantly higher in the RFA group (p=0.004). Disease-free and overall survival were longer in the resection group (p=0.008 and 0.017, respectively). In multivariate analysis, only the type of treatment was a factor associated with disease-free and overall survival (p=0.004 and 0.007, respectively).

CONCLUSIONS

Because of the high marginal recurrence rate, RFA shows an inferior outcome in comparison with surgical resection. Therefore, RFA should be considered for only selected patients with unresectable (by any means) disease or with high operative risk.

Diagnostic efficacy of gadoxetic acid-enhanced MRI for the detection and characterisation of liver metastases: comparison with multidetector-row CT

OBJECTIVES

We compared the diagnostic performance of gadoxetic acid-enhanced MRI and 16-slice multidetector CT (MDCT) with respect to their abilities to detect hepatic metastases and differentiate hepatic metastases from hepatic cysts and haemangiomas.

METHODS

67 patients with 110 liver metastases (size 0.3-2.5 cm), 33 haemangiomas (size 0.5-1.5 cm) and 17 cysts (size 0.3-1.0 cm) underwent 4-phase MDCT and gadoxetic acid-enhanced MRI, including early dynamic phases, post-contrast T(2) weighted turbo spin echo sequences and 20 min hepatocyte-selective phases. Two observers independently analysed each image in random order. Sensitivity and diagnostic accuracy for lesion detection and differentiation for MDCT and gadoxetic acid-enhanced MRI were calculated using receiver operating characteristic analysis.

RESULTS

For both observers, the Az values of gadoxetic acid-enhanced MRI (mean, 0.982 and 0.981) were significantly higher than the Az values of MDCT (mean, 0.839 and 0.892) (p<0.05) for the detection of metastases and for the differentiation of metastases from haemangiomas and cysts. Sensitivities of gadoxetic acid-enhanced MRI with regard to the detection and characterisation of liver metastases (mean, 96.9% and 96.0%) were significantly higher than those of MDCT (mean, 78.7% and 75.0%) (p<0.05).

CONCLUSION

Gadoxetic acid-enhanced MRI showed higher diagnostic accuracy and sensitivity than did MDCT for the detection of hepatic metastases and for the differentiation between hepatic metastases and hepatic haemangiomas or cysts.

Radiofrequency ablation of metastatic lesions from breast cancer

INTRODUCTION

Breast cancer (BC) is the most common malignancy in women. Various studies [5,6] have shown that surgical resection of single liver or lung metastases in patients with metastases from BC increases survival. Radiofrequency ablation (RFA) can be an alternative to resection in some patients when resection is not feasible.

MATERIALS AND METHODS

From January 2002 to December 2008, 491 patients with liver metastases underwent US-guided percutaneous RFA. Of these patients 5 (5/491; 1%) had BC. In the same period, 32 patients with pulmonary metastases underwent CT-guided RFA. Of these patients 3 (3/32; 9%) had BC. Mean age was 61.3 years. All patients were postmenopausal and receiving polychemotherapy according to international guidelines. Inclusion criteria for RFA treatment of metastases from BC applied are identical or in some cases more restrictive than those reported in the literature.

RESULTS

There were no deaths or severe complications and no treatment failures. Disease free and overall median survival were respectively 7.65 and 25.7 months after US-guided RFA and 13.4 and 34.8 months after CT-guided RFA. During follow-up (mean follow-up 26 months, range 4-63 months) 5/8 (62.5%) patients exhibited recurrence: 3/5 (60%) had local recurrence and 2/5 (40%) had non-local recurrence; 4/5 patients with recurrence were re-treated.

DISCUSSION

The authors' experience confirms that RFA is an effective, safe and repeatable technique in the treatment of metastases from BC. Metastatic recurrence rate confirms that metastatic BC is a disease which requires a multidisciplinary approach and that the role of chemotherapy is indisputable. Effects on survival are promising but further confirmation is needed through prospective randomized studies.

18F-FDG PET/CT in evaluation of radiofrequency ablation of liver metastasis

Image-guided radiofrequency ablation (RFA) is a minimally invasive therapy option in the treatment of primary and secondary hepatic malignancies, which are not suitable for surgery/chemotherapy, and more recently, for tumors with limited hepatic involvement and solitary liver metastasis. Accurate assessment of treatment response after RFA remains a concern. Conventional imaging modalities have limitations of differentiation between residual/recurrence from post-RFA changes. We illustrate images of 3 patients in whom (18)F-FDG PET/CT was used for response assessment and restaging after RFA in liver tumors.

Long-term outcome of radiofrequency thermal ablation (RFA) of liver metastases from colorectal cancer (CRC): size as the leading prognostic factor for survival

PURPOSE

The aim of this study was to review some prognostic factors for survival after radiofrequency ablation (RFA) of metastases from colorectal cancer (CRC).

MATERIALS AND METHODS

From 1996 to 2009, 262 patients with metastases from CRC were treated with RFA. Fourteen were lost to follow-up. The following predictors were analysed in the remaining 248: synchronous/metachronous metastases, single/multiple metastases, diameter of largest metastasis and absence/presence of extrahepatic metastases. Survival was measured from the date of metastasis diagnosis and from the date of RFA.

RESULTS

Survival at 1, 2, 3 and 5 years was 93%, 78%, 62% and 35% from metastasis diagnosis, and 84%, 59%, 43% and 23% from the date of RFA. Median survival was 41 months in patients with largest metastasis ≤3 cm and 21.7 months for those with metastases >3 cm (p=0.0001); survival increased to 45.2 months in patients with largest metastasis ≤2.5 cm and fell to 18.5 months in those with metastasis >3.5 cm. Median survival of patients with extrahepatic metastases was significantly lower than that of patients without extrahepatic disease (23.3 vs. 32.6 months, p=0.018).

CONCLUSIONS

In light of our long-term results obtained with commonly used equipment, small lesion size (diameter of largest lesion ≤3 or 2.5 cm) proved to be the most favourable prognostic factor for survival in patients with CRC metastases to the liver treated with RFA. This conclusion is probably related to the possibility of obtaining radical ablation and points to the usefulness of devices allowing ablation of larger volumes. In the presence of extrahepatic metastases, RFA has less impact on survival, even though it is potentially useful in patients at a higher risk of death due to hepatic rather than extrahepatic metastases.

Radiofrequency ablation of hepatic metastases after curative resection of extrahepatic cholangiocarcinoma

OBJECTIVE

The objective of our study was to retrospectively evaluate local control and survival after radiofrequency ablation (RFA) in patients with liver metastases arising from extrahepatic cholangiocarcinoma who had previously undergone curative resection.

MATERIALS AND METHODS

From May 2003 to May 2009, RFA using an internally cooled electrode was performed on 29 metachronous liver metastases (mean number of tumors per patient, 1.6) arising from extrahepatic cholangiocarcinoma in 18 patients (mean age, 66 years). Tumor size ranged from 0.9 to 4.6 cm in maximum dimension (mean, 2.3 cm). As historical comparisons, we included 24 patients diagnosed with recurrent metastasis limited to the liver between February 1997 and April 2003 and who met the inclusion criteria for RFA: 16 patients received supportive therapy only and eight patients underwent chemotherapy with or without radiation.

RESULTS

Five patients had major complications (liver abscess, n = 4 patients; biliary stricture, n = 1; 17% per-treatment complication rate [5/29]), but there were no procedure-related deaths. Complete tumor necrosis was achieved in all 29 tumors after one session of RFA. The local tumor progression rate was 38% (median time to detection, 5 months). From the first diagnosis of liver metastasis, the median overall survival was 12.4 months and the 3-year survival rate was 10%. Patients who received RFA lived significantly longer than patients who received chemoradiotherapy (median survival, 5.6 months) and those who received supportive treatment (median survival, 5.3 months) (p < 0.001).

CONCLUSION

Percutaneous RFA results in effective local tumor control and may prolong survival in patients with recurrent hepatic metastases after curative resection for extrahepatic cholangiocarcinoma.