Radiofrequency ablation permits an effective treatment for colorectal liver metastasis

Radiofrequency ablation versus surgical resection in colorectal liver metastasis: insight from an umbrella review

Introduction

Radiofrequency ablation (RFA) has emerged as a less invasive alternative to surgical liver resection (LR) for the treatment of colorectal liver metastasis (CRLM) in patients who are not candidates for surgery. This umbrella review aimed to compare the effectiveness of RFA and LR in managing CRLM by synthesizing evidence from multiple meta-analyses.

Methods

We conducted a comprehensive search across Medline, Epistemonikos, Scopus, and the Cochrane Library, focusing on survival outcomes, disease-free survival, perioperative complications, and recurrence rates.

Results

Eleven meta-analyses met the inclusion criteria. The results show that LR is superior to RFA in terms of overall survival and disease-free survival for resectable CRLM, although RFA demonstrated lower perioperative complications and mortality. In matched cohorts, the overall survival rates between RFA and LR were comparable. However, RFA was associated with higher intrahepatic recurrence.

Discussion

This review highlights the continued importance of LR for resectable CRLM, while RFA remains a valuable option for non-resectable cases, particularly in patients with higher morbidity. Future studies should focus on more balanced cohort comparisons to better assess the efficacy of these treatments.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024497886, identifier (CRD42024497886).

Non-Operating Room Anesthesia (NORA) for Ultrasound-Guided Liver Radiofrequency Ablation

INTRODUCTION

Percutaneous ultrasound-guided radiofrequency ablation (RFA) is a well-studied treatment option for locally non-advanced hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLMs). Sedation is of crucial interest as it enables safe and pain-free procedures. Whether the type of sedation has an impact on procedural outcome is still not well investigated.

METHODS

We retrospectively collected data on patients undergoing liver RFA for various oncological conditions. Procedures were conducted in a non-operating room anesthesia (NORA) setting. Procedural-related complications and short-term oncological outcomes were analyzed.

RESULTS

Thirty-five patients (mean age 71.5 y, 80% male) were treated for HCC (26), CRLM (6) and gastric cancer metastases (3). Mean lesion size was 21 mm (SD ± 10.1 mm), and the most common tumor localization was the right hepatic lobe. RFA was performed in a step-up sedation approach, with subcutaneous lidocaine injection prior to needle placement and subsequent deep sedation during ablation. No anesthesia-related early or late complications occurred. One patient presented with pleural effusion due to a large ablation zone and was treated conservatively. Local tumor-free survival after 1 and 6 months was 100% in all cases where a curative RFA approach was intended.

CONCLUSIONS

NORA for liver RFA comes with high patient acceptance and tolerance, and optimal postoperative outcomes and oncologic results.

The combined detection of carcinoembryonic antigen, carcinogenic antigen 125, and carcinogenic antigen 19-9 in colorectal cancer patients

BACKGROUND

Hepatic metastases are common and difficult to treat after colorectal cancer (CRC) surgery. The predictive value of carcinoembryonic antigen (CEA), cancer antigen (CA) 125 and CA19-9 combined tests for liver metastasis is unclear.

AIM

To evaluate predictive value of combined tests for CEA, CA125, and CA19-9 levels in patients with liver metastases of CRC.

METHODS

The retrospective study included patients with CRC alone (50 cases) and patients with CRC combined with liver metastases (50 cases) who were hospitalized between January 2021 and January 2023. Serum CEA, CA125 and CA19-9 levels were compared between the two groups, and binary logistic regression was used to analyze the predictive value of the combination of these tumor markers in liver metastasis. In addition, we performed receiver operating characteristic (ROC) curve analysis to assess its diagnostic accuracy.

RESULTS

The results showed that the serum CEA, CA125 and CA19-9 levels in the CRC with liver metastasis group were significantly higher than those in the CRC alone group. Specifically, the average serum CEA level in the CRC with liver metastasis group was 162.03 ± 810.01 ng/mL, while that in the CRC alone group was 5.71 ± 9.76 ng/mL; the average serum CA125 levels were 43.47 ± 83.52 U/mL respectively. and 13.5 ± 19.68 U/mL; the average serum CA19-9 levels were 184.46 ± 473.13 U/mL and 26.55 ± 43.96 U/mL respectively. In addition, binary logistic regression analysis showed that CA125 was significant in predicting CRC liver metastasis (P < 0.05). ROC curve analysis results showed that the areas under the ROC curves of CEA, CA125 and CA19-9 were 0.607, 0.692 and 0.586.

CONCLUSION

These results suggest that combined detection of these tumor markers may help early detection and intervention of CRC liver metastasis, thereby improving patient prognosis.

Advancements in the Management of Synchronous Colorectal Liver Metastases: A Comprehensive Review of Surgical, Systemic, and Local Treatment Modalities

PURPOSE OF REVIEW

This review addresses the current landscape of colorectal cancer (CRC) with a focus on liver metastases, the third most common cancer globally. It explores recent findings in treatment strategies, emphasizing the dynamic interplay between surgery, systemic chemotherapy, and local therapies for synchronous colorectal liver metastases (CRLMs).

RECENT FINDINGS

Highlighting the role of advanced imaging, the review underscores the significance of contrast-enhanced MRI in surgical planning for CRLMs. Surgical resection remains a primary choice for resectable cases, with considerations for oncologic scoring systems and tumor biology. Perioperative systemic chemotherapy plays a pivotal role, especially in conversion therapy for initially unresectable CRLMs. The review also explores various local therapies, including radiofrequency ablation, microwave ablation, stereotactic body radiotherapy, hepatic arterial infusional chemotherapy, selective internal radiation therapy, and transarterial chemoembolization for unresectable cases. A comprehensive approach, integrating surgery, systemic chemotherapy, and local therapies, is crucial for managing synchronous CRLMs. Surgical resection and perioperative chemotherapy are key players, guided by considerations of tumor biology and scoring systems. For unresectable cases, local therapies offer viable alternatives, emphasizing the need for tailored treatments. Multidisciplinary collaboration among medical oncologists, surgeons, and radiologists is essential. Ongoing research will refine treatment approaches, while emerging technologies hold promise for further advancements in managing colorectal liver metastases.

Reproducible spectral CT thermometry with liver-mimicking phantoms for image-guided thermal ablation

Objectives. Evaluate the reproducibility, temperature tolerance, and radiation dose requirements of spectral CT thermometry in tissue-mimicking phantoms to establish its utility for non-invasive temperature monitoring of thermal ablations.Methods. Three liver mimicking phantoms embedded with temperature sensors were individually scanned with a dual-layer spectral CT at different radiation dose levels during heating (35 °C-80 °C). Physical density maps were reconstructed from spectral results using varying reconstruction parameters. Thermal volumetric expansion was then measured at each temperature sensor every 5 °C in order to establish a correlation between physical density and temperature. Linear regressions were applied based on thermal volumetric expansion for each phantom, and coefficient of variation for fit parameters was calculated to characterize reproducibility of spectral CT thermometry. Additionally, temperature tolerance was determined to evaluate effects of acquisition and reconstruction parameters. The resulting minimum radiation dose to meet the clinical temperature accuracy requirement was determined for each slice thickness with and without additional denoising.Results. Thermal volumetric expansion was robustly replicated in all three phantoms, with a correlation coefficient variation of only 0.43%. Similarly, the coefficient of variation for the slope and intercept were 9.6% and 0.08%, respectively, indicating reproducibility of the spectral CT thermometry. Temperature tolerance ranged from 2 °C to 23 °C, decreasing with increased radiation dose, slice thickness, and iterative reconstruction level. To meet the clinical requirement for temperature tolerance, the minimum required radiation dose ranged from 20, 30, and 57 mGy for slice thickness of 2, 3, and 5 mm, respectively, but was reduced to 2 mGy with additional denoising.Conclusions. Spectral CT thermometry demonstrated reproducibility across three liver-mimicking phantoms and illustrated the clinical requirement for temperature tolerance can be met for different slice thicknesses. The reproducibility and temperature accuracy of spectral CT thermometry enable its clinical application for non-invasive temperature monitoring of thermal ablation.

Computed tomography-based thermography (CTT) in microwave ablation: prediction of the heat ablation zone in the porcine liver

OBJECTIVES

The aim of the study was to investigate computed tomography-based thermography (CTT) for ablation zone prediction in microwave ablation (MWA).

METHODS

CTT was investigated during MWA in an in vivo porcine liver. For CTT, serial volume scans were acquired every 30 s during ablations and every 60 s immediately after MWA. After the procedure, contrast-enhanced computed tomography (CECT) was performed. After euthanasia, the liver was removed for sampling and further examination. Color-coded CTT maps were created for visualization of ablation zones, which were compared with both CECT and macroscopy. Average CT attenuation values in Hounsfield units (HU) were statistically correlated with temperatures using Spearman's correlation coefficient. CTT was retrospectively evaluated in one patient who underwent radiofrequency ablation (RFA) treatment of renal cell carcinoma.

RESULTS

A significant correlation between HU and temperature was found with r =  - 0.77 (95% confidence interval (CI), - 0.89 to - 0.57) and p < 0.001. Linear regression yielded a slope of - 1.96 HU/°C (95% CI, - 2.66 to - 1.26). Color-coded CTT maps provided superior visualization of ablation zones.

CONCLUSION

Our results show that CTT allows visualization of the ablation area and measurement of its size and is feasible in patients, encouraging further exploration in a clinical setting.

CRITICAL RELEVANCE STATEMENT

CT-based thermography research software allows visualization of the ablation zone and is feasible in patients, encouraging further exploration in a clinical setting to assess risk reduction of local recurrence.

Reproducible spectral CT thermometry with liver-mimicking phantoms for image-guided thermal ablation

Objectives

Evaluate the reproducibility, temperature sensitivity, and radiation dose requirements of spectral CT thermometry in tissue-mimicking phantoms to establish its utility for non-invasive temperature monitoring of thermal ablations.

Materials and Methods

Three liver mimicking phantoms embedded with temperature sensors were individually scanned with a dual-layer spectral CT at different radiation dose levels during heating and cooling (35 to 80 °C). Physical density maps were reconstructed from spectral results using a range of reconstruction parameters. Thermal volumetric expansion was then measured at each temperature sensor every 5°C in order to establish a correlation between physical density and temperature. Linear regressions were applied based on thermal volumetric expansion for each phantom, and coefficient of variation for fit parameters was calculated to characterize reproducibility of spectral CT thermometry. Additionally, temperature sensitivity was determined to evaluate the effect of acquisition parameters, reconstruction parameters, and image denoising. The resulting minimum radiation dose to meet the clinical temperature sensitivity requirement was determined for each slice thickness, both with and without additional denoising.

Results

Thermal volumetric expansion was robustly replicated in all three phantoms, with a correlation coefficient variation of only 0.43%. Similarly, the coefficient of variation for the slope and intercept were 9.6% and 0.08%, respectively, indicating reproducibility of the spectral CT thermometry. Temperature sensitivity ranged from 2 to 23 °C, decreasing with increased radiation dose, slice thickness, and iterative reconstruction level. To meet the clinical requirement for temperature sensitivity, the minimum required radiation dose ranged from 20, 30, and 57 mGy for slice thickness of 2, 3, and 5 mm, respectively, but was reduced to 2 mGy with additional denoising.

Conclusions

Spectral CT thermometry demonstrated reproducibility across three liver-mimicking phantoms and illustrated the clinical requirement for temperature sensitivity can be met for different slice thicknesses. Moreover, additional denoising enables the use of more clinically relevant radiation doses, facilitating the clinical translation of spectral CT thermometry. The reproducibility and temperature accuracy of spectral CT thermometry enable its clinical application for non-invasive temperature monitoring of thermal ablation.

Evaluation of Different Registration Algorithms to Reduce Motion Artifacts in CT-Thermography (CTT)

Computed tomography (CT)-based Thermography (CTT) is currently being investigated as a non-invasive temperature monitoring method during ablation procedures. Since multiple CT scans with defined time intervals were acquired during this procedure, interscan motion artifacts can occur between the images, so registration is required. The aim of this study was to investigate different registration algorithms and their combinations for minimizing inter-scan motion artifacts during thermal ablation. Four CTT datasets were acquired using microwave ablation (MWA) of normal liver tissue performed in an in vivo porcine model. During each ablation, spectral CT volume scans were sequentially acquired. Based on initial reconstructions, rigid or elastic registration, or a combination of these, were carried out and rated by 15 radiologists. Friedman's test was used to compare rating results in reader assessments and revealed significant differences for the ablation probe movement rating only (p = 0.006; range, 5.3-6.6 points). Regarding this parameter, readers assessed rigid registration as inferior to other registrations. Quantitative analysis of ablation probe movement yielded a significantly decreased distance for combined registration as compared with unregistered data. In this study, registration was found to have the greatest influence on ablation probe movement, with connected registration being superior to only one registration process.

Development of a Three-Dimensional Multi-Modal Perfusion-Thermal Electrode System for Complete Tumor Eradication

Background: Residual viable tumor cells after ablation at the tumor periphery serve as the source for tumor recurrence, leading to treatment failure. Purpose: To develop a novel three-dimensional (3D) multi-modal perfusion-thermal electrode system completely eradicating medium-to-large malignancies. Materials and Methods: This study included five steps: (i) design of the new system; (ii) production of the new system; (iii) ex vivo evaluation of its perfusion-thermal functions; (iv) mathematic modeling and computer simulation to confirm the optimal temperature profiles during the thermal ablation process, and; (v) in vivo technical validation using five living rabbits with orthotopic liver tumors. Results: In ex vivo experiments, gross pathology and optical imaging demonstrated the successful spherical distribution/deposition of motexafin gadolinium administered through the new electrode, with a temperature gradient from the electrode core at 80 °C to its periphery at 42 °C. An excellent repeatable correlation of temperature profiles at varying spots, from the center to periphery of the liver tumor, was found between the mathematic simulation and actual animal tumor models (Pearson coefficient ≥0.977). For in vivo validation, indocyanine green (ICG) was directly delivered into the peritumoral zones during simultaneous generation of central tumoral lethal radiofrequency (RF) heat (>60 °C) and peritumoral sublethal RF hyperthermia (<60 °C). Both optical imaging and fluorescent microscopy confirmed successful peritumoral ICG distribution/deposition with increased heat shock protein 70 expression. Conclusion: This new 3D, perfusion-thermal electrode system provided the evidence on the potential to enable simultaneous delivery of therapeutic agents and RF hyperthermia into the difficult-to-treat peritumoral zones, creating a new strategy to address the critical limitation, i.e., the high incidence of residual and recurrent tumor following thermal ablation of unresectable medium-to-large and irregular tumors.

The Addition of Radiofrequency Tumor Ablation to Kyphoplasty May Reduce the Rate of Local Recurrence in Spinal Metastases Secondary to Breast Cancer

BACKGROUND

Approximately 10% of all cancer patients develop spinal metastases. When a symptomatic compression fracture occurs without associated deformity or neurologic deficit, it can be treated with kyphoplasty with or without radiofrequency ablation (RFA). Treatment with kyphoplasty is well established but does not address the underlying oncologic disease.

METHODS

Retrospective medical chart analysis of breast cancer patients (n = 23) with metastatic spinal fractures (n = 50 vertebral levels) who underwent RFA and kyphoplasty was undertaken. Key variables of interest included: fracture location, pain levels, and local recurrence. Local recurrence data were compared to published rates of recurrence in breast cancer-related metastatic spinal fractures treated with vertebroplasty or kyphoplasty alone. Data were analyzed using χ² and t test statistical analyses.

RESULTS

The mean preoperative pain level for this cohort was 6.9 on a 10-point visual analogue scale. Significant reductions in pain levels were observed postoperatively, at discharge (3.5; P < 0.05), at 1-month follow-up (2.8; P < 0.05), at 3-month follow-up (1.1; P < 0.05), and at 6-month follow-up (0.7 P < 0.05). Compared with published data of breast cancer patients with metastatic spinal fractures treated with vertebroplasty or kyphoplasty alone, the addition of RFA resulted in reduced local tumor recurrence (2% vs. 14%; P < 0.05). Average length of follow-up was 39 months.

CONCLUSIONS

The results suggest that the addition of RFA to kyphoplasty may reduce local tumor recurrence while providing similar pain relief benefits. The extrapolation of this added benefit to metastases from other primary cancers should be examined in future studies.

Radiofrequency versus microwave ablation for intraoperative treatment of colorectal liver metastases

INTRODUCTION

Intraoperative radiofrequency ablation (RFA) and the newer technique of microwave ablation (MWA) can both be of additional value in parenchyma preserving surgical treatment of colorectal liver metastases (CRLM). MWA is less influenced by the heat-sink effect of surrounding vessels and can generate more heat in less time but RFA is still widely used. True comparing studies are scarce.

METHODS

This single centre retrospective cohort study analyzed patients who underwent ultrasound guided intraoperative ablation as a part of the surgical treatment of CRLM between 2013 and 2018. In September 2015, MWA was substituted for RFA. Outcomes included unsuccessful ablation rates at 1-year postoperative, 30-days major complication rates, progression free survival (PFS) and overall survival (OS). Logistic regression models were used for univariable and multivariable analyses to identify predictors of unsuccessful ablation.

RESULTS

Forty-one patients underwent RFA of 98 lesions (median 2) and 79 patients underwent MWA of 193 lesions (median 2). The median diameter of the ablated lesions was 9 mm for both RFA and MWA. Unsuccessful ablation was observed in 7 metastases (7.1%) after RFA and 14 metastases (7.3%) after MWA (p = 1.000). Complications requiring re-intervention were observed after 8 procedures, 2 complications in the RFA group (4.9%) versus 6 complications in the MWA group (7.6%, p = 0.714), of which 6 were liver-related. Ninety-day mortality did not occur. Ablation technique was not associated with unsuccessful ablations. CRLM size was associated with unsuccessful ablation in the per lesion analysis (p < 0.001).

CONCLUSION

Intraoperative RFA and MWA were equally effective for treatment of small CRLM.

A novel use of biomechanical model-based deformable image registration (DIR) for assessing colorectal liver metastases ablation outcomes

Purpose:

Colorectal cancer is the third most common form of cancer in the United States, and up to 60% of these patients develop liver metastasis. While hepatic resection is the curative treatment of choice, only 20% of patients are candidates at the time of diagnosis. While percutaneous thermal ablation (PTA) has demonstrated 24%–51% overall 5-year survival rates, assurance of sufficient ablation margin delivery (5 mm) can be challenging, with current methods of 2D distance measurement not ensuring 3D minimum margin. We hypothesized that biomechanical model-based deformable image registration (DIR) can reduce spatial uncertainties and differentiate local tumor progression (LTP) patients from LTP-free patients.

Methods:

We retrospectively acquired 30 patients (16 LTP and 14 LTP-free) at our institution who had undergone PTA and had a contrast-enhanced pre-treatment and post-ablation CT scan. Liver, disease, and ablation zone were manually segmented. Biomechanical model-based DIR between the pre-treatment and post-ablation CT mapped the gross tumor volume onto the ablation zone and measured 3D minimum delivered margin (MDM). An in-house cone-tracing algorithm determined if progression qualitatively collocated with insufficient 5 mm margin achieved.

Results:

Mann–Whitney U test showed a significant difference (p < 0.01) in MDM from the LTP and LTP-free groups. A total of 93% (13/14) of patients with LTP had a correlation between progression and missing 5 mm of margin volume.

Conclusions:

Biomechanical DIR is able to reduce spatial uncertainty and allow measurement of delivered 3D MDM. This minimum margin can help ensure sufficient ablation delivery, and our workflow can provide valuable information in a clinically useful timeframe.

Consensus of Minimally Invasive and Multidisciplinary Comprehensive Treatment for Hepatocellular Carcinoma - 2020 Guangzhou Recommendations

In China, the majority of patients with hepatocellular carcinoma (HCC) result from long-term infection of hepatitis B. Pathologically, HCC is characterized by rich blood supply, multicentric origins, early vascular invasion and intrahepatic metastasis. Therefore, HCC is not a local disease but a systemic disease at the beginning of its occurrence. For this reason, a comprehensive treatment strategy should be adopted in the management of HCC, including local treatments (such as surgical resection, radiofrequency ablation, microwave ablation, chemical ablation and cryoablation, etc.), organ-level treatments [such as transcatheter arterial infusion of chemotherapy and transcatheter arterial chemoembolization (TACE)], and systemic treatments (such as immunotherapy, antiviral therapy and molecular targeted therapy, etc.). This consensus sets forth the minimally-invasive and multidisciplinary comprehensive guideline of HCC, focusing on the following eight aspects (1) using hepaticarteriography, CT hepatic arteriography (CTHA), CT arterial portography (CTAP), lipiodol CT (Lp-CT), TACE-CT to find the intrahepatic lesion and make precise staging (2) TACE combined with ablation or ablation as the first choice of treatment for early stage or small HCC, while other therapies are considered only when ablation is not applicable (3) infiltrating HCC should be regarded as an independent subtype of HCC (4) minimally-invasive comprehensive treatment could be adopted in treating metastatic lymph nodes (5) multi-level subdivision of M-staging should be used for individualized treatment and predicting prognosis (6) HCC with severe hepatic decompensation is the only candidate criterion for liver transplantation (7) bio-immunotherapy, traditional Chinese medicine therapy, antiviral therapy, and psychosocial and psychopharmacological interventions should be advocated through the whole course of HCC treatment (8) implementation of multicenter randomized controlled trials of minimally-invasive therapy versus surgery for early and intermediate stage HCC is recommended.

Image-Guided Peri-Tumoral Radiofrequency Hyperthermia-Enhanced Direct Chemo-Destruction of Hepatic Tumor Margins

Purpose

To validate the feasibility of using peri-tumoral radiofrequency hyperthermia (RFH)-enhanced chemotherapy to obliterate hepatic tumor margins.

Method and Materials

This study included in vitro experiments with VX2 tumor cells and in vivo validation experiments using rabbit models of liver VX2 tumors. Both in vitro and in vivo experiments received different treatments in four groups (n=6/group): (i) RFH-enhanced chemotherapy consisting of peri-tumoral injection of doxorubicin plus RFH at 42°C; (ii) RFH alone; (iii) doxorubicin alone; and (iv) saline. Therapeutic effect on cells was evaluated using different laboratory examinations. For in vivo experiments, orthotopic hepatic VX2 tumors in 24 rabbits were treated by using a multipolar radiofrequency ablation electrode, enabling simultaneous delivery of both doxorubicin and RFH within the tumor margins. Ultrasound imaging was used to follow tumor growth overtime, correlated with subsequent histopathological analysis.

Results

In in vitro experiments, MTS assay demonstrated the lowest cell proliferation, and apoptosis analysis showed the highest apoptotic index with RFH-enhanced chemotherapy, compared with the other three groups (p<0.01). In in vivo experiments, ultrasound imaging detected the smallest relative tumor volume with RFH-enhanced chemotherapy (p<0.01). The TUNEL assay further confirmed the significantly increased apoptotic index and decreased cell proliferation in the RFH-enhanced therapy group (p<0.01).

Conclusion

This study demonstrates that peri-tumoral RFH can specifically enhance the destruction of tumor margins in combination with peri-tumoral injection of a chemotherapeutic agent. This new interventional oncology technique may address the critical clinical problem of frequent marginal tumor recurrence/persistence following thermal ablation of large (>3 cm) hepatic cancers.

Clinical impact of radiofrequency ablation and stereotactic body radiation therapy for colorectal liver metastasis as local therapies for elderly, vulnerable patients

Background and Aim

Surgical resection is the standard local therapy for patients with colorectal liver metastases (CRLM). However, elderly and vulnerable patients sometimes have various organ dysfunctions. We have to conduct nonsurgical local therapies for those patients who might not tolerate surgery or systemic chemotherapy.

Methods

We retrospectively reviewed medical records of 254 patients who underwent local therapies, including surgery, radiofrequency ablation (RFA), and stereotactic body radiation therapy (SBRT), for CRLM from January 2010 to December 2016, at seven tertiary‐care institutions in Japan. This study was designed to include elderly, vulnerable patients who received local therapy for CRLM. For those undergoing liver resection, only those having one or more points of the Charlson comorbidity index (CCI) were enrolled.

Results

Of the total 169 enrolled patients, 122 patients underwent surgery, 42 RFA, and 5 SBRT as the first local therapy for CRLM. Median overall survival from the first local therapy was 5.9 years for the surgery group, 2.7 years for the RFA group, and 3.8 years for the SBRT group. The proportion of the patients with CCI ≧3 was significantly higher in the group of RFA/SBRT than surgery (P < 0.0001). In selected patients with CCI ≧3, there was no difference of the median survival time between the surgery group and the RFA group.

Conclusions

We could have other treatment options to provide nonsurgical local therapies (RFA/SBRT) for elderly, vulnerable CRLM patients who have risks for surgery.

Stereotactic body radiation therapy and radiofrequency ablation for the treatment of liver metastases: How and when?

Limited liver metastases represent a clinical challenge. Surgical approach is the most frequently reported treatment option, however, some patients are not eligible for surgical interventions. Relatively recent technologic advances have permitted the safe use of ablative techniques employed in the cure of hepatic metastases. Among these, radiofrequency ablation (RFA) and stereotactic body radiotherapy (SBRT) have emerged as valid treatments in a significant proportion of patients with intrahepatic oligometastatic disease. This review offers an up-to-date of current available literature on this issue focusing on the use and outcomes of RFA and SBRT, according to the PICO (Population, Intervention, Comparison and Outcomes) criteria.

Can we ablate liver lesions close to large portal and hepatic veins with MR-guided HIFU? An experimental study in a porcine model

OBJECTIVES

Invasive treatment of tumors adjacent to large hepatic vessels is a continuous clinical challenge. The primary aim of this study was to examine the feasibility of ablating liver tissue adjacent to large hepatic and portal veins with magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU). The secondary aim was to compare sonication data for ablations performed adjacent to hepatic veins (HV) versus portal veins (PV).

MATERIALS AND METHODS

MRgHIFU ablations were performed in six male land swine under general anesthesia. Ablation cells of either 4 or 8 mm diameter were planned in clusters (two/animal) adjacent either to HV (n = 6) or to PV (n = 6), with diameter ≥ 5 mm. Ablations were made using 200 W and 1.2 MHz. Post-procedure evaluation was made on contrast-enhanced MRI (T1w CE-MRI), histopathology, and ablation data from the HIFU system.

RESULTS

A total of 153 ablations in 81 cells and 12 clusters were performed. There were visible lesions with non-perfused volumes in all animals on T1w CE-MRI images. Histopathology showed hemorrhage and necrosis in all 12 clusters, with a median shortest distance to vessel wall of 0.4 mm (range 0-2.7 mm). Edema and endothelial swelling were observed without vessel wall rupture. In 8-mm ablations (n = 125), heat sink was detected more often for HV (43%) than for PV (19%; p = 0.04).

CONCLUSIONS

Ablations yielding coagulative necrosis of liver tissue can be performed adjacent to large hepatic vessels while keeping the vessel walls intact. This indicates that perivascular tumor ablation in the liver is feasible using MRgHIFU.

KEY POINTS

• High-intensity focused ultrasound ablation is a non-invasive treatment modality that can be used for treatment of liver tumors. • This study shows that ablations of liver tissue can be performed adjacent to large hepatic vessels in an experimental setting. • Liver tumors close to large vessels can potentially be treated using this modality.

Stereotactic body radiotherapy for lung metastases from colorectal cancer: a single institution experience

Aim: Stereotactic body radiotherapy (SBRT) has been used as an alternative to surgical intervention to treat primary malignanices of the lung as well as lesions from other primaries. In this study, we evaluate the safety and efficacy of SBRT in treating lung metastases from colorectal cancer (CRC). Materials & methods: We reviewed 22 patients that underwent lung SBRT for metastases from CRC. Almost all patients received chemotherapy before and after undergoing SBRT. Outcomes that were analyzed included overall survival, distant failure and progression-free survival, as well as the effects of biologically effective dose (BED) and KRAS status on local control. Results: Seven females and 15 males underwent SBRT to lung metastases from CRC. The median Eastern Cooperative Oncology Group status was one (0–2). The median dose was 48 Gy (40–54 Gy) in 5 fx (4–8 fx) and the median number of nodules treated with SBRT was one (1–3). Median follow-up was 28.5 months from SBRT and 79 months (9–145) from primary diagnosis. Local control at 1 and 3 years was 75 and 58%, respectively. There was a trend toward improved local control with increasing biologically effective dose (BED10 > 100; p = 0.07). Cancers that were positive for the KRAS mutation had increased local control at 12 months, 100 versus 75% (p = 0.0199). Median OS from the primary diagnosis of CRC and from SBRT was 79 and 31 months, respectively. There were no predictors for OS. There were no episodes of acute or late grade 3 or higher toxicity. Conclusion: The results of this study add to the growing body of literature to support SBRT for lung metastases, specifically those patients with limited lung metastases from CRC. The choice of radiation dose remains important, even in metastatic disease, as highlighted by the trend toward improved local control with increasing BED10.

Radiofrequency ablation for colorectal cancer liver metastases initially greater than 25 mm but downsized by neo-adjuvant chemotherapy is associated with increased rate of local tumor progression

BACKGROUND

Radiofrequency ablation (RFA) is a valid treatment for liver metastases from colorectal cancer (CRLM) smaller than 25 mm and unsuitable for surgical resection. Tumor size is predictive for local tumor progression (LTP). The aim of this study was to evaluate whether RFA is indicated for lesions >25 mm at presentation but <25 mm after chemotherapy.

METHOD

Patients who underwent RFA for CRLM after chemotherapy (January 2004-December 2012) were reviewed. Metastases were classified according to their size. Group 1: ≤25 mm before and after chemotherapy. Group 2A: >25 mm before but ≤25 mm after chemotherapy. Group 2B: >25 mm before and after chemotherapy.

RESULTS

133 CRLM were ablated in 83 patients (median follow-up 56 months). At 1-year, the LTP rate was higher in group 2A than in group 1 (32% vs. 16%, p ≤ 0.001). The highest rate of 1-year LTP was 64% in group 2B. Time to LTP (TLTP) was shorter in group 2A than in group 1 (HR: 2.89; 95% CI [1.04-8.01]; p = 0.004). Following multivariate analysis, the group type was the only predictive factor for TLTP (p < 0.001).

CONCLUSIONS

RFA is not the optimal treatment for CRLM > 25 mm at presentation.

Local Control Outcomes Using Stereotactic Body Radiation Therapy for Liver Metastases From Colorectal Cancer

PURPOSE

To evaluate the effective dose and patterns of recurrence after stereotactic body radiation therapy (SBRT) for hepatic metastases that arise from colorectal cancer.

METHODS AND MATERIALS

A cohort of 70 patients with 103 colorectal liver metastases were treated with SBRT at a single institution. The prescribed doses were 45 to 60 Gy in 3 to 4 fractions, but these were modified according to the tolerance of the adjacent normal tissue. To allow for dose comparisons, a biological equivalent dose was calculated.

RESULTS

The median follow-up period was 34.2 months (range, 5.3-121.8 months). The 2-year overall survival and progression-free survival rates were 75% and 35%, respectively. In subgroups, the 2-year local control rates for biological equivalent dose ≤80 Gy (group 1), 100 to 112 Gy (group 2), and ≥132 Gy (group 3) were 52%, 83%, and 89%, respectively. Cox proportional hazards model revealed a significant difference between groups (hazard ratio 0.44, P=.03 for group 2; hazard ratio 0.17, P=.17 for group 3; P=.01 for total). The major pattern of failure was a new liver metastasis out of the SBRT field. There was no grade ≥3 toxicity.

CONCLUSIONS

Stereotactic body radiation therapy of liver metastases derived from colorectal cancer offers a locally effective treatment without significant complications. Longer local control can be expected if higher doses are used. Further studies will be needed to compare the efficacies of SBRT with those of surgical resection or radiofrequency ablation.

Planned Treatment of Advanced Metastatic Disease with Completion Ablation After Hepatic Resection

PURPOSE

The aim of this study is to describe a modified treatment strategy with image-guided percutaneous ablation after hepatic resection as a completion method to surgical eradication of liver metastases ("completion ablation [CA]").

METHODS

We conducted a retrospective analyses of patients who underwent CA within 180 days from the liver surgical resection to eradicate liver metastases present on the pre-surgical cross-sectional imaging or identified during intraoperative ultrasound that were not resected due to various reasons. Lesions treated with CA were evaluated for local tumor progression (LTP). Patients were evaluated for hepatic- and overall-recurrence-free survivals (hepatic-RFS and overall-RFS, respectively) and overall survival (OS).

RESULTS

Sixteen patients (10 females; median age 55 years, range 28-69) underwent CA of 21 lesions (median size 8 mm, range 6 to 22). Indications for the use of CA were small future liver remnant in 10 (63%), inability to identify the lesion during surgical exploration in 3 (19%), and technical difficulty of resection in 3 (19%) patients. No liver-related complications were recorded following the surgical resection or the CA procedures. Primary and secondary CA efficacy rates were 95 and 100%, respectively. LTP was 0% at a median clinical follow-up of 27 months (range 4.0-108 months). Five-year hepatic-RFS, overall-RFS, and OS were 36, 16, and 51%, respectively.

CONCLUSION

The use of CA as a complement to surgical resection is safe and effective. Such approach could potentially expand the surgical candidacy for patients with limited liver functional reserve and reduce postoperative morbidity and mortality in this selected patient population with more advanced disease.

Local tumour progression after percutaneous ablation of colorectal liver metastases according to RAS mutation status

BACKGROUND

Percutaneous ablation is a common treatment for colorectal liver metastasis (CLM). However, the effect of rat sarcoma viral oncogene homologue (RAS) mutation on outcome after ablation of CLMs is unclear.

METHODS

Patients who underwent image-guided percutaneous ablation of CLMs from 2004 to 2015 and had known RAS mutation status were analysed. Patients were evaluated for local tumour progression as observed on imaging of CLMs treated with ablation. Multivariable Cox regression analysis was performed to determine factors associated with local tumour progression-free survival.

RESULTS

The study included 92 patients who underwent ablation of 137 CLMs. Thirty-six patients (39 per cent) had mutant RAS. Rates of local tumour progression were 14 per cent (8 of 56) for patients with wild-type RAS and 39 per cent (14 of 36) for patients with mutant RAS (P = 0·007). The actuarial 3-year local tumour progression-free survival rate after percutaneous ablation was worse in patients with mutant RAS than in those with wild-type RAS (35 versus 71 per cent respectively; P = 0·001). In multivariable analysis, negative predictors of local tumour progression-free survival were a minimum ablation margin of less than 5 mm (hazard ratio (HR) 2·48, 95 per cent c.i. 1·31 to 4·72; P = 0·006) and mutant RAS (HR 3·01, 1·60 to 5·77; P = 0·001).

CONCLUSION

Mutant RAS is associated with an earlier and higher rate of local tumour progression in patients undergoing ablation of CLMs.

Radiofrequency Ablation Combined with Hepatic Arterial Chemoembolization Using Degradable Starch Microsphere Mixed with Mitomycin C for the Treatment of Liver Metastasis from Colorectal Cancer: A Prospective Multicenter Study

PURPOSE

This phase II prospective study investigates possible benefits of radiofrequency ablation (RFA) combined with hepatic arterial chemoembolization using degradable starch microsphere (DSM) mixed with mitomycin C (MMC) in non-surgical candidates with colorectal liver metastases.

MATERIALS AND METHODS

This study, approved by the respective institutional review board, included non-surgical candidates with 3 or fewer liver tumors of 3 cm or smaller, or a single lesion 5 cm or smaller. Percutaneous RFA was performed immediately after chemoembolization using DSM-MMC. Primary and secondary endpoints were the local tumor control rate, safety, and 2-year recurrence-free and overall survival rates.

RESULTS

This study examined 25 patients (22 males, 3 females) with 38 tumors of mean maximum diameter of 2.2 ± 0.9 cm (standard deviation) (range 1.0-4.2 cm). Their mean age was 70.2 ± 8.2 years (range 55-82 years). Local tumor progression developed in 3 tumors (7.9%, 3/38) of 3 patients (12%, 3/25) during the mean follow-up of 34.9 ± 9.2 months (range 18.3-50.1 months). The 2-year local tumor control rates were 92.0% [95% confidence interval (CI), 81.4-100%] on a patient basis and 94.6% (95% CI, 87.3-100%) on a tumor basis. The respective 2-year overall and recurrence-free survival rates were 88.0% (95% CI, 75.3-98.5%) and 63.3% (95% CI, 44.2-82.5%), with median survival time of 48.4 months. Fever was the only adverse event requiring treatments in 2 patients (8%).

CONCLUSIONS

This combination therapy is safe, exhibiting strong anticancer effects on colorectal liver metastasis, which might contribute to patient survival.

The role of radiofrequency ablation for treatment of metachronous isolated hepatic metastasis from colorectal cancer

We investigated recurrence pattern and oncologic outcomes after treatment of metachronous isolated liver metastases from colorectal cancer according to treatment modality.We retrospectively analyzed 123 patients treated with hepatic resection and 82 patients treated with radiofrequency ablation (RFA) for metachronous isolated hepatic metastasis from colorectal cancer (HMCRC). We compared clinicopathological data, recurrence pattern, and recurrence-free survival (RFS) rates after the treatment of hepatic metastasis between patients treated with RFA and resection.The patients in the 2 groups were similar in gender, location of primary tumor, disease-free interval to hepatic metastasis, pathologic stage of primary tumor, and number of hepatic metastasis. The age was older in RFA group but it was not statistically different. The mean diameter of the largest hepatic mass was greater in the resection group than in the RFA group (3.1 vs 1.9 cm, P < 0.001). Chemotherapy after the treatment of hepatic metastasis was more commonly given in hepatic resection group (76.4% vs 62.2%, P = 0.04). Recurrence after the treatment of hepatic metastasis was not significantly different between the 2 groups (54.5% vs 65.9% in the resection and RFA groups). However, intrahepatic recurrence without extra-hepatic metastases was more common in the RFA group than in the resection group (47.5% vs 12.1%, P < 0.001). The RFS rate after the treatment of hepatic metastasis was significantly higher in resection group (48.6% vs 33.7%, P = 0.015). The size and number of hepatic metastasis, primary tumor stage, disease-free interval to hepatic metastasis, and the modality of treatment (RFA vs resection) for hepatic metastasis were confirmed as associated factors with re-recurrence after the treatment of hepatic metastasis. Among patients with solitary hepatic metastases of ≤3 cm, marginal recurrence was higher in the RFA group (3% vs 17.2%) and re-RFA was performed to achieve comparable recurrence rate (3% vs 5.2%, P = 0.662), the RFS rate was not different between the resection and RFA group (52.4% vs 53.4%, P = 0.491).Surgical resection for HMCRC showed higher RFS. However, the RFS rate in patients with a solitary hepatic metastasis of ≤3 cm was similar between the resection and RFA groups.

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.

"Edgeboost": A Novel Technique to Extend the Ablation Zone Lateral to a Two-Probe Bipolar Radiofrequency Device

BACKGROUND

The dual-electrode bipolar-RFA (B-RFA) is increasingly used to ablate large liver tumours (3-7 cm). However, the challenging aspect of B-RFA is the placement of the two electrodes around the tumour. Realignment often requires the electrodes to be extracted and reinserted.

AIM

The aim of this study is to examine "Edgeboost", a novel technique to increase the lateral ablation dimension without requiring any realignment of the electrodes.

METHODS AND MATERIALS

An egg-white model and an ex vivo calf liver model were used compare the standard bipolar mode ablation to Edgeboost-1 (reaching full impedance in bipolar mode initially, then cycling in unipolar mode between left and right probes) and Edgeboost-2 (similar to Edgeboost-1 but not reaching full impedance initially in bipolar mode in order to minimize charring and, thus, to increase total ablation time).

RESULTS

A significantly larger outer lateral ablation dimension to the probe was achieved with Edgeboost-1 compared to the standard method in the liver model (1.14 cm, SD: 0.16 vs. 0.44 cm, SD: 0.24, p = 0.04). Edgeboost-2 achieved the largest outer lateral ablation dimension of 1.75 cm (SD: 0.35). A similar association was seen in the egg model. Edgeboost-2 almost doubled the mass ablated with standard bipolar alone (mass ratio: 1:1.94 in egg white and 1:1.84 in liver).

CONCLUSION

This study demonstrates that the novel "Edgeboost" technique can increase the outer lateral ablation dimension without requiring the two inserted electrodes to be reinserted. This would be beneficial for interventionists who use the dual B-RFA.

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.

Hepatectomy vs radiofrequency ablation for colorectal liver metastasis: A propensity score analysis

AIM: To compare outcomes from radiofrequency ablation (RFA) and hepatectomy for treatment of colorectal liver metastasis (CRLM).

METHODS: From January 2000 to December 2009, 408 patients underwent curative intent treatment for CRLM. We excluded patients using the criteria: size of CRLM > 3 cm, number of CRLM ≥ 5, percutaneous RFA, follow-up period < 12 mo, double primary cancer, or treatment with both RFA and hepatectomy. We matched 51 patients who underwent RFA with 102 patients who underwent hepatectomy by propensity scores.

RESULTS: The median follow-up period was 45 mo (range, 12 mo to 158 mo). Hepatic recurrence was more frequent in the RFA than the hepatectomy group (P = 0.021) although extrahepatic recurrence curves were similar (P = 0.716). Survival curves of hepatectomy group were better than that of RFA for multiple, large (> 2 cm) CRLM (P = 0.034). However, survival curves were similar for single or small (≤ 2 cm) CRLM (P = 0.714, P = 0.740).

CONCLUSION: Hepatectomy is better than RFA for the treatment of CRLM. However, RFA might be suitable for selected patients with single, small (≤ 2 cm) CRLM.

Ablative technologies for hepatocellular, cholangiocarcinoma, and metastatic colorectal cancer of the liver

A wide array of ablation technologies, in addition to the progressive sophistication of imaging technologies and percutaneous, laparoscopic, and open surgical techniques, have allowed us to expand treatment options for patients with liver tumors. In this article, technical considerations of chemical and thermal ablations and their application in hepatic oncology are reviewed.

Liver-directed therapies in metastatic colorectal cancer

Colorectal cancer (CRC) is a major health concern in the United States (US) with over 140,000 new cases diagnosed in 2012. The most common site for CRC metastases is the liver. Hepatic resection is the treatment of choice for colorectal liver metastases (CLM), with a 5-year survival rate ranging from 35% to 58%. Unfortunately, only about 20% of patients are eligible for resection. There are a number of options for extending resection to more advanced patients including systemic chemotherapy, portal vein embolization (PVE), two stage hepatectomy, ablation and hepatic artery infusion (HAI). There are few phase III trials comparing these treatment modalities, and choosing the right treatment is patient dependent. Treating hepatic metastases requires a multidisciplinary approach and knowledge of all treatment options as there continues to be advances in management of CLM. If a patient can undergo a treatment modality in order to increase their potential for future resection this should be the primary goal. If the patient is still deemed unresectable then treatments that lengthen disease-free and overall-survival should be pursued. These include chemotherapy, ablation, HAI, chemoembolization, radioembolization (RE) and stereotactic radiotherapy.

Thermal ablation of liver metastases from colorectal cancer: radiofrequency, microwave and laser ablation therapies

Surgery is currently considered the treatment of choice for patients with colorectal cancer liver metastases (CRLM) when resectable. The majority of these patients can also benefit from systemic chemotherapy. Recently, local or regional therapies such as thermal ablations have been used with acceptable outcomes. We searched the medical literature to identify studies and reviews relevant to radiofrequency (RF) ablation, microwave (MW) ablation and laser-induced thermotherapy (LITT) in terms of local progression, survival indexes and major complications in patients with CRLM. Reviewed literature showed a local progression rate between 2.8 and 29.7 % of RF-ablated liver lesions at 12-49 months follow-up, 2.7-12.5 % of MW ablated lesions at 5-19 months follow-up and 5.2 % of lesions treated with LITT at 6-month follow-up. Major complications were observed in 4-33 % of patients treated with RF ablation, 0-19 % of patients treated with MW ablation and 0.1-3.5 % of lesions treated with LITT. Although not significantly different, the mean of 1-, 3- and 5-year survival rates for RF-, MW- and laser ablated lesions was (92.6, 44.7, 31.1 %), (79, 38.6, 21 %) and (94.2, 61.5, 29.2 %), respectively. The median survival in these methods was 33.2, 29.5 and 33.7 months, respectively. Thermal ablation may be an appropriate alternative in patients with CRLM who have inoperable liver lesions or have operable lesions as an adjunct to resection. However, further competitive evaluation should clarify the efficacy and priority of these therapies in patients with colorectal cancer liver metastases.

Surgical resection for local recurrence after radiofrequency ablation for colorectal liver metastasis is more extensive than primary resection

OBJECTIVE

As a minimally invasive modality, radiofrequency ablation (RFA) has been increasingly applied not only for the treatment of hepatocellular carcinoma, but also for that of colorectal liver metastasis (CLM). However, RFA for CLM has been shown to be associated with a high local recurrence rate, and no optimal treatment for RFA failure has been established yet. The aim of this study was to evaluate the feasibility and outcome of surgical resection for local recurrence after RFA.

MATERIAL AND METHODS

A retrospective study of 17 patients, who underwent surgery for local recurrence after RFA for resectable CLM, was carried out. The surgical procedures involved in the actual surgery were compared with those envisioned for the primary resection if RFA had not been selected.

RESULTS

Surgical resection for RFA recurrence was more invasive than the envisioned surgical procedure in 10 cases (58%). In addition, the proportions of cases that required technically demanding procedures among the patients receiving surgery for RFA recurrence were higher than those in envisioned operations; major hepatectomy, eight cases [47%] versus two cases [12%] (p<0.0205); excision and/or reconstruction of the major hepatic veins, three cases [18%] versus zero case [0%] (p=0.035); excision of diaphragm: three cases [18%] versus zero case [0%] (p=0.035). The 1-, 3- and 5-year overall survival rates were 92%, 45% and 45%, respectively.

CONCLUSIONS

Surgical resection for RFA recurrence for CLM required more invasive and technically demanding procedures. Thus, RFA for CLM should be limited to unresectable cases, and patients with resectable CLM should be thoroughly advised not to undergo RFA, but rather surgical resection.

Local recurrence rates after radiofrequency ablation or resection of colorectal liver metastases. Analysis of the European Organisation for Research and Treatment of Cancer #40004 and #40983

AIM

The aim of this study is to describe local tumour control after radiofrequency ablation (RFA) and surgical resection (RES) of colorectal liver metastases (CLM) in two independent European Organisations for Research and Treatment of Cancer (EORTC) studies.

BACKGROUND

Only 10-20% of patients with newly diagnosed CLM are eligible for curative RES. RFA has found a place in daily practice for unresectable CLM. There are no prospective trials comparing RFA to RES for resectable CLM.

METHODS

The CLOCC trial randomised 119 patients with unresectable CLM between RFA (±RES)+adjuvant FOLFOX (±bevacizumab) versus FOLFOX (±bevacizumab) alone. The EPOC trial randomised 364 patients with resectable CLM between RES±perioperative FOLFOX. We describe the local control of resected patients with lesions ≤4 cm in the perioperative chemotherapy arm of the EPOC trial (N=81) and the RFA arm of the CLOCC trial (N=55).

RESULTS

Local recurrence (LR) rate for RES was 7.4% per patient and 5.5% per lesion. LR rate for RFA was 14.5% per patient and 6.0% per lesion. When lesion size was limited to 30 mm, LR rate for RFA lesions was 2.9% per lesion. Non-local hepatic recurrences were more often observed in RFA patients than in RES patients, 30.9% and 22.3% respectively. Patients receiving RFA had a more advanced disease.

CONCLUSIONS

LR rate after RFA for lesions with a limited size is low. The local control per lesion does not appear to differ greatly between RFA and surgical resection. This study supports the local control of RFA in patients with limited liver metastases. Future studies should evaluate in which patients RFA could be an equal alternative to liver resection.

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.

Comparative analysis of radiofrequency ablation and resection for resectable colorectal liver metastases

AIM: To evaluate the therapeutic efficacy of radiofrequency ablation (RFA) for resectable colorectal liver metastases (CRLM) compared with that of resection.

METHODS: Between June 2004 and June 2009, we retrospectively analyzed 29 patients with resectable CRLMs; 17 patients underwent RFA, and 12 underwent hepatic resection. All of the patients were informed about the treatment modalities and were allowed to choose either of them. RFA including an intraoperative approach was performed by a radiologist; otherwise, hepatic resection was performed by a surgeon. Comparative analysis of the two groups was performed, including comparisons of gender, age, and clinical outcomes, such as primary tumor stage and survival rates.

RESULTS: The mean tumor size was significantly larger in the resection group (3.59 cm vs 2.02 cm, P < 0.01), and the 5-year overall survival (OS) rate for all patients was 44.7%. There was no difference in the 5-year OS rates between the RFA and resection groups (37.8% vs 66.7%). Univariate analysis indicated significantly lower 5-year OS rates for patients with a tumor size > 3 cm. The 5-year disease-free survival (DFS) rates were 17.6% and 22.2% in the RFA and resection groups, respectively (P = 0.119). Univariate analysis revealed that in cases of male gender, age > 65 years, T stage < IV, absence of lymphatic metastasis, and tumor size > 3 cm, RFA resulted in significantly inferior 5-year DFS rates compared with surgical resection.

CONCLUSION: Surgical resection revealed superior outcomes in the treatment of resectable CRLMs, particularly in cases with a hepatic tumor size > 3 cm.

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.

Clinically-translated silica nanoparticles as dual-modality cancer-targeted probes for image-guided surgery and interventions

Early diagnosis and treatment of melanoma are essential to minimizing morbidity and mortality. The presence of lymph node metastases is a vital prognostic predictor, and accurate identification by imaging has important implications for disease staging, prognosis, and clinical outcome. Sentinel lymph node (SLN) mapping procedures are limited by a lack of intraoperative visualization tools that can aid accurate determination of disease spread and delineate nodes from adjacent critical neural and vascular structures. Newer methods for circumventing these issues can exploit a variety of imaging tools, including biocompatible particle-based platforms coupled with portable device technologies for use with image-guided surgical and interventional procedures. We describe herein a clinically-translated, integrin-targeting platform for use with both PET and optical imaging that meets a number of key design criteria for improving SLN tissue localization and retention, target-to-background ratios, and clearance from the site of injection and the body. The use of such agents for selectively probing critical cancer targets may elucidate important insights into cellular and molecular processes that govern metastatic disease spread. Coupled with portable, real-time optical camera systems, we show that pre-operative PET imaging findings for mapping metastatic disease in clinically-relevant larger-animal models can be readily translated into the intraoperative setting for direct visualization of the draining tumor lymphatics and fluorescent SLN/s with histologic correlation. The specificity of this platform, relative to the standard-of-care radiotracer, (18)F-FDG, for potentially discriminating metastatic disease from inflammatory processes is also discussed in the setting of surgically-based or interventionally-driven therapies.

Percutaneous radiofrequency ablation (RFA) or robotic radiosurgery (RRS) for salvage treatment of colorectal liver metastases

BACKGROUND

Stereotactic radiation therapy is an evolving modality to treat otherwise unresectable liver metastases. In this analysis, two local therapies: 1) single session robotic radiosurgery (RRS) and 2) percutaneous radiofrequency ablation (RFA) were compared in a total of 60 heavily pretreated colorectal cancer patients.

METHODS

Thirty patients with a total of 35 colorectal liver metastases not qualifying for surgery that were treated in curative intent with RRS were prospectively followed. To compare efficacy of both treatment modalities, patients treated with RFA during the same period of time were matched according to number and size of the treated lesions. Local tumor control, local disease free survival (DFS), and freedom from distant recurrence (FFDR) were analyzed for efficacy. Treatment-related side effects were recorded for comparison.

RESULTS

The median diameter of the treated lesions was 33 mm (7-53 mm). Baseline characteristics did not differ significantly between the groups. One- and two-year local control rates showed no significant difference but favored RRS (85% vs. 65% and 80% vs. 61%, respectively). A significantly longer local DFS of patients treated with RRS compared to RFA (34.4 months vs. 6.0 months; p < 0.001) was found. Both, median FFDR (11.4 months for RRS vs. 7.1 months for RFA p = 0.25) and the recurrence rate (67% for RRS and 63% for RFA, p > 0.99) were comparable.

CONCLUSION

Single session RRS is a safe and effective method to treat colorectal liver metastases. In this analysis, a trend towards longer DFS was seen in patients treated with RRS when compared to RFA.

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.

Interventional oncologic approaches to liver metastases

Metastatic liver disease is the most common cause of death in cancer patients. Complete surgical resection is currently considered the only curative treatment, with only about 25% of patients being amenable to surgery. Therefore, a variety of interventional oncologic techniques have been developed for treating secondary liver malignancies. The aim of these therapies is either to allow patients with unresectable tumors to become surgical candidates, provide curative treatment options in nonsurgical candidates, or improve survival in a palliative or even curative approach. Among these interventional therapies are transcatheter therapies such as portal vein embolization, hepatic artery infusion chemotherapy, transarterial chemoembolization, and radioembolization, as well as interstitial techniques, particularly radiofrequency ablation as the most commonly applied technique. The rationale, application and clinical results of each of these techniques are reviewed on the basis of the current literature. Future prospects such as gene therapy and immunotherapy are introduced.

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.

Assessment of thermal sensitivity of CT during heating of liver: an ex vivo study

OBJECTIVES

The purpose of this study was to assess the thermal sensitivity of CT during heating of ex-vivo animal liver.

METHODS

Pig liver was indirectly heated from 20 to 90 °C by passage of hot air through a plastic tube. The temperature in the heated liver was measured using calibrated thermocouples. In addition, image acquisition was performed with a multislice CT scanner before and during heating of the liver sample. The reconstructed CT images were then analysed to assess the change of CT number as a function of temperature.

RESULTS

During heating, a decrease in CT numbers was observed as a hypodense area on the CT images. In addition, the hypodense area extended outward from the heat source during heating. The analysis showed a linear decrease of CT number as a function of temperature. From this relationship, we derived a thermal sensitivity of CT for pig liver tissue of -0.54±0.03 HU °C(-1) with an r(2) value of 0.91.

CONCLUSIONS

The assessment of the thermal sensitivity of CT in ex-vivo pig liver tissue showed a linear dependency on temperature ≤90 °C. This result may be beneficial for the application of isotherms or thermal maps in CT images of liver tissue.

Surgical options for initially unresectable colorectal liver metastases

Although the frontiers of liver resection for colorectal liver metastases have broadened in recent decades, approximately 75% of these patients present with unresectable metastases at the time of their diagnosis. In the past, these patients underwent only palliative treatment, without the chance of a cure. In the previous two decades, several therapeutic strategies have been developed that render resectable those metastases that were initially unresectable, thus offering the chance of long-term survival and even a cure to these patients. The oncosurgical modalities that are available include liver resection following portal vein ligation/embolization, “two-stage” liver resection, one-stage ultrasonically guided liver resection, hepatectomy following conversion chemotherapy, and liver resection combined with thermal ablation. Moreover, in recent years, certain authors have recommended the revisiting of the concept of liver transplantation in highly selected patients with unresectable colorectal liver metastases and favorable prognostic factors. By employing such therapies, the number of patients with colorectal liver metastases who undergo a potentially curative treatment could increase to 40%. The safety profile of these approaches is acceptable (morbidity rates as high as 45%, mortality rates of less than 5%). Furthermore, the 5-year survival rates (approximately 30%) are significantly increased over those that were achieved with palliative treatment.

Retrospective review of efficacy of radiofrequency ablation for treatment of colorectal cancer liver metastases from a Canadian perspective

PURPOSE

A retrospective single-center review of ultrasound-guided radiofrequency ablation (RFA) treatment of colorectal cancer liver metastases was performed. This study reviews the primary and secondary technical effectiveness, overall survival of patients, recurrence-free survival, tumour-free survival, rates of local recurrence, and postprocedural RFA complications. Technical effectiveness and rates of complication with respect to tumour location and size were evaluated. Our results were compared with similar studies from Europe and North America.

METHODS

A total of 63 patients (109 tumours) treated with RFA between February 2004 and December 2009 were reviewed. Average and median follow-up time was 19.4 and 16.5 months, respectively (range, 1-54 months). Data from patient charts, pathology, and Picture Archiving and Communication System was integrated into an Excel database. Statistical Analysis Software was used for statistical analysis.

RESULTS

Primary and secondary technical effectiveness of percutaneous and intraoperative RFA were 90.8% and 92.7%, respectively. Average (SE) tumour-free survival was 14.4 ± 1.4 months (range, 1-43 months), and average (SE) recurrence-free survival was 33.5 ± 2.3 months (range, 2-50 months). Local recurrence was seen in 31.2% of treated tumours (range, 2-50 months) (34/109). Overall survival was 89.4% at 1 year, 70.0% at 2 years, and 38.1% at 3 years, with an average (SE) overall survival of 37.0 ± 2.8 months. There were 14 postprocedural complications. There was no statistically significant difference in technical effectiveness for small tumours (1-2 cm) vs intermediate ones (3-5 cm). There was no difference in technical effectiveness for peripheral vs parenchymal tumours.

CONCLUSIONS

This study demonstrated good-quality outcomes for RFA treatment of colorectal cancer liver metastases from a Canadian perspective and compared favorably with published studies.

Management of unresectable colorectal cancer by multimodality therapy: An analysis of 67 cases

AIM: To summary our experience with multimodality therapy of unresectable colorectal cancer.

METHODS: A total of 67 patients were included in this study, including 15 patients with right-sided colon cancer, 9 with left-sided colon cancer, and 43 with rectal cancer. All cases were assessed as unresectable by the multidisciplinary team and histologically confirmed as colorectal cancer. Multimodality therapy was performed by colorectal specialists and the multidisciplinary team.

RESULTS: Of all 67 patients, no patients achieved complete remission, 43 achieved partial remission, 16 had stable disease, and 8 had progressive disease. The short-term remission rate was 100%. The survival duration ranged from 10 to 38 months, with an average of 24 months. Nine (13.4%) patients underwent radical surgery. The total complication rate was 52.2% (35/67).

CONCLUSION: Multimodality therapy allows improving quality of life and prolonging survival time in patients with unresectable colorectal cancer.

Ablation of perivascular hepatic malignant tumors with irreversible electroporation

BACKGROUND

Ablation is increasingly used to treat primary and secondary liver cancer. Ablation near portal pedicles and hepatic veins is challenging. Irreversible electroporation (IRE) is a new ablation technique that does not rely on heat and, in animals, appears to be safe and effective when applied near hepatic veins and portal pedicles. This study evaluated the safety and short-term outcomes of IRE to ablate perivascular malignant liver tumors.

STUDY DESIGN

A retrospective review of patients treated with IRE between January 1, 2011 and November 2, 2011 was performed. Patients were selected for IRE when resection or thermal ablation was not indicated due to tumor location. Treatment outcomes were classified by local, regional, and systemic recurrence and complications. Local failure was defined as abnormal enhancement at the periphery of an ablation defect on post-procedure contrast imaging.

RESULTS

Twenty-eight patients had 65 tumors treated. Twenty-two patients (79%) were treated via an open approach and 6 (21%) were treated percutaneously. Median tumor size was 1 cm (range 0.5 to 5 cm). Twenty-five tumors were <1 cm from a major hepatic vein; 16 were <1 cm from a major portal pedicle. Complications included 1 intraoperative arrhythmia and 1 postoperative portal vein thrombosis. Overall morbidity was 3%. There were no treatment-associated mortalities. At median follow-up of 6 months, there was 1 tumor with persistent disease (1.9%) and 3 tumors recurred locally (5.7%).

CONCLUSIONS

This early analysis of IRE treatment of perivascular malignant hepatic tumors demonstrates safety for treating liver malignancies. Larger studies and longer follow-up are necessary to determine long-term efficacy.

Does Radiofrequency Ablation Add to Chemotherapy for Unresectable Liver Metastases?

In patients with unresectable colorectal liver metastases (CRLM), radiofrequency ablation (RFA) might be a good alternative, whenever possible. In contrast to systemic therapy, the aim of RFA is to achieve complete local tumor control in an attempt to provide long-term survival. In this article we discuss the available evidence regarding the treatment of patients with unresectable CRLM, focusing on RFA in conjunction with modern systemic therapies. We observed that the available evidence in the existing literature is limited, and often consists of level 2 and 3 evidence, thereby hampering any firm conclusions. Nonetheless, RFA seems superior to chemotherapy alone in patients with liver-only disease amenable for RFA. However, the combination of RFA and chemotherapy has been demonstrated to be feasible and safe, lending support to the concept of RFA followed by chemotherapy, in order to reduce local recurrence rates and prolong survival.