Radiofrequency ablation as first-line treatment in patients with early colorectal liver metastases amenable to surgery. Ann Surg. 2010;251:796-803. [PMID: 19858704 DOI: 10.1097/sla.0b013e3181bc9fae]

Nanomedicine-unlocked radiofrequency dynamic therapy dampens incomplete radiofrequency ablation-arised immunosuppression to suppress cancer relapse

Incomplete radiofrequency ablation (iRFA) not only leaves residual tumor, but also render the residual tumor highly self-adaptable and immunosuppressive, consequently expediting residual tumor progression including relapse. To address it, radiofrequency dynamic therapy (RFDT) with identical trigger (namely radiofrequency) has been established and enabled by polyethylene glycol (PEG)-modified Fe-based single atom nanozyme (P@Fe SAZ). P@Fe SAZ can respond to radiofrequency field to produce reactive oxygen species (ROS), attaining the nanomedicine-unlocked low-temperature RFDT. Systematic experiments reveal that ROS further remodels iRFA-potentiated immunosuppressive microenvironment, e.g., expediting tumor-associated macrophages (TAMs) polarization into TAMs-M1, rejecting the intratumoral infiltrations of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). Coincidently, they have been demonstrated to stimulate dendritic cells (DCs) maturation and encourage the proliferations and infiltrations of effector T cells, consequently boosting anti-tumor immune responses and attenuating iRFA-enhanced plasticity, treatment resistance and self-adaptation of residual hepatocellular carcinoma (HCC) after iRFA. Thanks to them, such a nanomedicine-unlocked low-temperature RFDT exerts powerful actions on residual HCC model after iRFA with rapid expansion inhibition, relapse repression, survival prolongation, apoptosis promotion, etc. This low-temperature RFDT opens a window to address the iRFA-enhanced immunosuppression.

Ablative techniques in colorectal liver metastases: A systematic review, descriptive summary of practice, and recommendations for optimal data reporting

BACKGROUND

Radiofrequency Ablation (RFA) and Microwave Ablation (MWA) are alternative treatments for colorectal liver metastasis (CRLM) patients that are unsuitable for resection. However, consensus is lacking regarding selection criteria, tumour characteristics, ablation technique delivery, and device settings. This study aims to summarise current evidence to inform future prospective studies.

METHODS

A systematic review was conducted following PRISMA guidelines. Studies assessing RFA and MWA treatment of CRLM were identified in Medline, Embase, Web of Science and the Cochrane database of systematic reviews, from inception until 31st August 2024.

RESULTS

Fifty-two studies were included (retrospective cohort n = 45, prospective cohort n = 5, non-randomized comparative studies n = 2). Fifty-four inclusion criteria were used across 45 studies and were not stated in 7 studies. Tumours varied in mean number [1-8] and diameter (1.54-4.35 cm). Neoadjuvant chemotherapy use (10-100 % of patients), ablation delivery approach (open n = 4, laparoscopic n = 11, percutaneous n = 26, mixed n = 5), anaesthetic mode (GA n = 18, LA n = 11, mixed n = 2) and delivering clinician (radiologist n = 11, surgeon n = 16, both n = 1) all varied. Thirty-two studies lacked complete ablation device settings. Six studies followed a standardized ablation algorithm and 14 studies had specific settings. Five-year survival ranged from 0 to 69.7 % for ablation.

CONCLUSIONS

There is significant heterogeneity in the reporting of study design, patient selection, and ablation techniques for CRLM. The lack of standardized approaches and inconsistent reporting of methodology and outcomes make it challenging to determine the optimal ablative treatment for CRLM. We recommend that future research should focus on clearly defining selection and treatment criteria, as well as treatment delivery.

CT versus MR guidance for radiofrequency ablation in patients with colorectal liver metastases: a 10-year follow-up favors MR guidance

OBJECTIVES

To compare the results of CT- vs MR-guided radiofrequency ablation (RFA) of liver metastases (LM) from colorectal cancer after 10 years of follow-up in an observational, retrospective, and multicentric study.

METHODS

A total of 238 patients with 496 LM were treated with RFA either with CT (CT group) or magnetic resonance (MR group) guidance. Every ablated LM was assessed and followed up with diagnostic MRI. Technical success, technique efficacy, predictive factors, recurrence rates, and overall survival were assessed.

RESULTS

The CT group comprised 143 patients and the MR group 77 patients. Eighteen patients underwent ablation with both modalities. Technical success per patient and per lesion was 88% and 93% for CT and 87% and 89.6% for MR, and technique efficacy was 97.1% and 98.6% for CT and 98.7% and 99.3% for MR respectively. Local recurrence following the first ablation (primary patency) occurred in 20.1% (CT) vs 4.6% (MR) (p < 0.001). Residual liver tumor, size of LM, and advanced N and M stage at initial diagnosis were independent predictors for overall survival in both groups. The median overall survival measured from first RFA treatment was 2.6 years. The 1-year, 5-year, and 10-year survival were 85.9%, 25.5%, and 19.1% respectively.

CONCLUSIONS

The MR group had significantly better local control compared to the CT group. There was no significant difference in patient survival between the two groups.

CLINICAL RELEVANCE STATEMENT

MR-guided radiofrequency ablation of colorectal liver metastases is safe and effective, and offers better local control than CT-guided ablation.

KEY POINTS

• Imaging modality for radiofrequency ablation guidance is an independent predictor of local recurrence in colorectal liver metastases. • MR-guided radiofrequency ablation achieved better local control of liver metastases from colorectal cancer than CT-guided. • The number and size of liver metastases are, among others, independent predictors of survival. Radiofrequency ablation with MR guidance improved clinical outcome but does not affect survival.

Determining the Relationship between Delivery Parameters and Ablation Distribution for Novel Gel Ethanol Percutaneous Therapy in Ex Vivo Swine Liver

Ethyl cellulose-ethanol (ECE) is emerging as a promising formulation for ablative injections, with more controllable injection distributions than those from traditional liquid ethanol. This study evaluates the influence of salient injection parameters on forces needed for infusion, depot volume, retention, and shape in a large animal model relevant to human applications. Experiments were conducted to investigate how infusion volume (0.5 mL to 2.5 mL), ECE concentration (6% or 12%), needle gauge (22 G or 27 G), and infusion rate (10 mL/h) impacted the force of infusion into air using a load cell. These parameters, with the addition of manual infusion, were investigated to elucidate their influence on depot volume, retention, and shape (aspect ratio), measured using CT imaging, in an ex vivo swine liver model. Force during injection increased significantly for 12% compared to 6% ECE and for 27 G needles compared to 22 G. Force variability increased with higher ECE concentration and smaller needle diameter. As infusion volume increased, 12% ECE achieved superior depot volume compared to 6% ECE. For all infusion volumes, 12% ECE achieved superior retention compared to 6% ECE. Needle gauge and infusion rate had little influence on the observed depot volume or retention; however, the smaller needles resulted in higher variability in depot shape for 12% ECE. These results help us understand the multivariate nature of injection performance, informing injection protocol designs for ablations using gel ethanol and infusion, with volumes relevant to human applications.

Radiofrequency Ablation Combined with Hepatic Artery Embolization Using a Tris-acryl Gelatin Microsphere for Colorectal Liver Metastases-Initial Experience

Purpose

We aim to evaluate retrospectively the feasibility, safety, and initial therapeutic outcomes of radiofrequency ablation combined with hepatic artery embolization using a tris-acryl gelatin microsphere for colorectal liver metastases.

Material and Methods

Six consecutive patients (4 men and 2 women) with median age of 68 years (range 57-78 years) underwent computed tomography fluoroscopy-guided radiofrequency ablation immediately after hepatic artery embolization using microspheres. This study evaluated tumor visibility on noncontrast-enhanced computed tomography immediately after hepatic artery embolization; analyzed local tumor progression; defined technical success as the coverage of the tumor by the ablative zone; and assessed adverse events based on Common Terminology Criteria for Adverse Events v5.0.

Results

Ten tumors with median maximum diameter of 9 mm (range 5-52 mm) were treated in nine sessions. Eight tumors (80%, 8/10 tumors) were detected as high-attenuation nodules. One tumor was treated in two sessions because follow-up computed tomography revealed an insufficient ablative margin. Therefore, the primary and secondary technical success was 90% (9/10 tumors) and 100% (10/10 tumors), respectively. Grade 2 pneumothorax was observed in one session (11%, 1/9 sessions). No grade 3 or higher adverse event was observed. The local tumor progression rate was 20% (2/10 tumors) during the median follow-up of 14 months.

Conclusions

Radiofrequency ablation following microsphere embolization may be a feasible, safe, and useful therapeutic option for controlling small colorectal liver metastases.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Ablative Margins of Colorectal Liver Metastases Using Deformable CT Image Registration and Autosegmentation

Background Confirming ablation completeness with sufficient ablative margin is critical for local tumor control following colorectal liver metastasis (CLM) ablation. An image-based confirmation method considering patient- and ablation-related biomechanical deformation is an unmet need. Purpose To evaluate a biomechanical deformable image registration (DIR) method for three-dimensional (3D) minimal ablative margin (MAM) quantification and the association with local disease progression following CT-guided CLM ablation. Materials and Methods This single-institution retrospective study included patients with CLM treated with CT-guided microwave or radiofrequency ablation from October 2015 to March 2020. A biomechanical DIR method with AI-based autosegmentation of liver, tumors, and ablation zones on CT images was applied for MAM quantification retrospectively. The per-tumor incidence of local disease progression was defined as residual tumor or local tumor progression. Factors associated with local disease progression were evaluated using the multivariable Fine-Gray subdistribution hazard model. Local disease progression sites were spatially localized with the tissue at risk for tumor progression (<5 mm) using a 3D ray-tracing method. Results Overall, 213 ablated CLMs (mean diameter, 1.4 cm) in 124 consecutive patients (mean age, 57 years ± 12 [SD]; 69 women) were evaluated, with a median follow-up interval of 25.8 months. In ablated CLMs, an MAM of 0 mm was depicted in 14.6% (31 of 213), from greater than 0 to less than 5 mm in 40.4% (86 of 213), and greater than or equal to 5 mm in 45.1% (96 of 213). The 2-year cumulative incidence of local disease progression was 72% for 0 mm and 12% for greater than 0 to less than 5 mm. No local disease progression was observed for an MAM greater than or equal to 5 mm. Among 117 tumors with an MAM less than 5 mm, 36 had local disease progression and 30 were spatially localized within the tissue at risk for tumor progression. On multivariable analysis, an MAM of 0 mm (subdistribution hazard ratio, 23.3; 95% CI: 10.8, 50.5; P < .001) was independently associated with local disease progression. Conclusion Biomechanical deformable image registration and autosegmentation on CT images enabled identification and spatial localization of colorectal liver metastases at risk for local disease progression following ablation, with a minimal ablative margin greater than or equal to 5 mm as the optimal end point. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Sofocleous in this issue.

Neoadjuvant chemotherapy does not increase risk for anastomotic leak for simultaneous resection of primary colon cancer with synchronous liver metastasis: A NSQIP-colectomy analysis

BACKGROUND AND OBJECTIVES

In patients with colon cancer with synchronous liver metastasis, treatment algorithms are complex and often require multidisciplinary evaluation. Neoadjuvant therapy is frequently utilized, but there is an unclear relationship with postoperative outcomes in patients with simultaneous resection.

METHODS

This is a retrospective cohort study from the National Surgical Quality Improvement Program and Targeted Colectomy databases. All patients with stage IV colon cancer undergoing simultaneous colectomy with synchronous liver metastasis resection or ablation between 2015 and 2019 were identified and categorized into subgroups based on receipt of neoadjuvant chemotherapy. Multivariable logistic regression was utilized to assess for risk factors of anastomotic leaks and serious postoperative complications.

RESULTS

We identified 1006 patients who underwent simultaneous colectomy and liver operations. Of those, 418 (41.6%) received neoadjuvant chemotherapy within 90 days of surgery, while 588 (58.4%) had simultaneous upfront surgery. On multivariable logistic regression, neoadjuvant therapy was not associated with postoperative anastomotic leaks (odds ratio [OR]: 1.30; p = 0.39) or serious complications (OR: 1.04; p = 0.82).

CONCLUSION

Neoadjuvant therapy does not increase postoperative complications in simultaneous colon and liver resections. These results may alleviate concerns regarding postoperative morbidity in the decision-making process of administering neoadjuvant therapy.

Study Protocol COVER-ALL: Clinical Impact of a Volumetric Image Method for Confirming Tumour Coverage with Ablation on Patients with Malignant Liver Lesions

PURPOSE

This study aims to evaluate the intra-procedural use of a novel ablation confirmation (AC) method, consisting of biomechanical deformable image registration incorporating AI-based auto-segmentation, and its impact on tumor coverage by quantitative three-dimensional minimal ablative margin (MAM) CT-generated assessment.

MATERIALS AND METHODS

This single-center, randomized, phase II, intent-to-treat trial is enrolling 100 subjects with primary and secondary liver tumors (≤ 3 tumors, 1-5 cm in diameter) undergoing microwave or radiofrequency ablation with a goal of achieving ≥ 5 mm MAM. For the experimental arm, the proposed novel AC method is utilized for ablation applicator(s) placement verification and MAM assessment. For the control arm, the same variables are assessed by visual inspection and anatomical landmarks-based quantitative measurements aided by co-registration of pre- and post-ablation contrast-enhanced CT images. The primary objective is to evaluate the impact of the proposed AC method on the MAM. Secondary objectives are 2-year LTP-free survival, complication rates, quality of life, liver function, other oncological outcomes, and impact of AC method on procedure workflow.

DISCUSSION

The COVER-ALL trial will provide information on the role of a biomechanical deformable image registration-based ablation confirmation method incorporating AI-based auto-segmentation for improving MAM, which might translate in improvements of liver ablation efficacy.

CONCLUSION

The COVER-ALL trial aims to provide information on the role of a novel intra-procedural AC method for improving MAM, which might translate in improvements of liver ablation efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04083378.

More Liver Metastases Detected Intraoperatively Indicates Worse Prognosis for Colorectal Liver Metastases Patients after Resection Combined with Microwave Ablation

Background

Whether more tumor numbers detected in surgery compared to preoperative image affecting survival of colorectal liver metastases (CRLM) patients after hepatectomy combined with microwave ablation (MWA) remains unclear.

Methods

From 2013 to 2018, 85 CRLM patients who underwent hepatectomy combined with MWA were retrospectively assessed. Compared to the tumor numbers in preoperative image, patients with equal intraoperative tumor numbers were defined as the equal number group (n = 45); patients detected more tumor numbers in surgery were defined as the more number group (n = 40). Clinicopathological factors and prognosis were compared between two groups.

Results

Compared to the equal number group, the more number group was characterized by more lymphatic metastasis, synchronous metastasis of liver lesion, and tumor numbers over 5 (all P < 0.05). Median survival time was 46.7 months and 26.8 months in the equal and more number group. Significantly worse overall survival (OS) was found in more number group to the equal number group (P = 0.027). In Cox analysis, more tumor number than image and high level of carbohydrate antigen 19-9 (CA19-9) were poor prognostic factors for OS.

Conclusion

In patients receiving hepatectomy combined with MWA, detecting more liver metastases in surgery than preoperative image indicates poor long-term survival. These patients were characterized by more lymphatic metastasis, synchronous metastasis of liver lesion, and tumor numbers over 5. Intensive follow-up to detect early recurrence and potent postoperative therapy to improve survival may be justified in patients detected more tumor numbers in surgery with a high CA19-9 level.

Single-centre survival analysis over 10 years after MR-guided radiofrequency ablation of liver metastases from different tumour entities

Background

Radiofrequency ablation (RFA) is a minimal-invasive, local therapy in patients with circumscribed metastatic disease. Although widely used, long time survival analysis of treated liver metastases is still pending while also analysing the patients’ experience of MR-based radiofrequency.

Methods

Monocentric, retrospective analysis of long-time overall and progression free survival (OS; PFS) of 109 patients, treated with MRI-guided hepatic RFA between 1997 and 2010, focusing on colorectal cancer patients (CRC). Complimentary therapies were evaluated and Kaplan Meier-curves were calculated. Patients’ experience of RFA was retrospectively assessed in 28 patients.

Results

1-, 3-, 5-, 10-year OS rates of 109 patients with different tumour entities were 83.4%, 53.4%, 31.0% and 22.9%, median 39.2 months, with decreasing survival rates for larger metastases size. For 72 CRC patients 1-, 3-, 5-, 10-year OS rates of 90.2%, 57.1%, 36.1% and 26.5% were documented (median 39.5 months). Thereof, beneficial outcome was detected for patients with prior surgery of the CRC including chemotherapy (median 53.0 months), and for liver metastases up to 19 mm (28.5% after 145 months). Hepatic PFS was significantly higher in patients with liver lesions up to 29 mm compared to larger ones (p = 0.035). 15/28 patients remembered RFA less incriminatory than other applied therapies.

Conclusions

This is the first single-centre, long-time OS and PFS analysis of MRI-guided hepatic RFA of liver metastases from different tumour entities, serving as basis for further comparison studies. Patients’ experience of MR based RFA should be analysed simultaneously to the performed RFA in the future.

Microwave Ablation for Colorectal Liver Metastases: A Systematic Review and Pooled Oncological Analyses

Simple Summary

Liver resection for colorectal liver metastases (CRLM) represents the best curative option; however, few patients are candidates for surgery. Microwave ablation (MWA) can be a valid alternative in selected patients. This systematic review reports the oncological results of MWA for CRLM. The literature available on the Web was analyzed for reports concerning MWA for resectable CRLM, published before January 2021. Finally, 12 papers concerning MWA complications, recurrence-free (RF) cases, patients free from local recurrence (FFLR), and overall survival rates (OS) were selected. Global RF rates at 1, 3, and 5 years were 65.1%, 44.6%, and 34.3%, respectively. Global FFLR at 3, 6, and 12 months were 96.3%, 89.6%, and 83.7%, respectively. Global OS rates at 1, 3, and 5 years were 86.7%, 59.6%, and 44.8%, respectively. A better FFLR was achieved with an MWA surgical approach at 3, 6, and 12 months, with 97.1%, 92.7%, and 88.6%, respectively. Surgical MWA for CRLM smaller than 3 cm was a safe and valid option. MWA can be entered as part of the flowchart decision of CRLM curative treatment, especially for use in the parenchyma-sparing strategy and as a complement to surgery.

Abstract

(1) Background: colorectal liver metastases (CRLM) are the most common extra-lymphatic metastases in colorectal cancer; however, few patients are fit for curative surgery. Microwave ablation (MWA) showed promising outcomes in this cohort of patients. This systematic review and pooled analysis aimed to analyze the oncological results of MWA for CRLM. (2) Methods: Following PRISMA guidelines, PubMed, Scopus, EMBASE, Google Scholar, Science Direct, and the Wiley Online Library databases were searched for reports published before January 2021. We included papers assessing MWA, treating resectable CRLM with curative intention. We evaluated the reported MWA-related complications and oncological outcomes as being recurrence-free (RF), free from local recurrence (FFLR), and overall survival rates (OS). (3) Results: Twelve out of 4822 papers (395 patients) were finally included. Global RF rates at 1, 3, and 5 years were 65.1%, 44.6%, and 34.3%, respectively. Global FFLR rates at 3, 6, and 12 months were 96.3%, 89.6%, and 83.7%, respectively. Global OS at 1, 3, and 5 years were 86.7%, 59.6%, and 44.8%, respectively. A better FFLR was reached using the MWA surgical approach at 3, 6, and 12 months, with reported rates of 97.1%, 92.7%, and 88.6%, respectively. (4) Conclusions: Surgical MWA treatment for CRLM smaller than 3 cm is a safe and valid option. This approach can be safely included for selected patients in the curative intent approaches to treating CRLM.

Technical efficacy and local recurrence after stereotactic radiofrequency ablation of 2653 liver tumors: a 15-year single-center experience with evaluation of prognostic factors

PURPOSE

To assess the technical outcome and local tumor control of multi-probe stereotactic radiofrequency ablation (SRFA) in a large series of patients. Furthermore, to determine factors accounting for adverse outcomes.

MATERIAL AND METHODS

Between 2003 and 2018, 865 patients were treated by SRFA for 2653 primary and metastatic liver tumors with a median tumor size of 2.0 cm (0.5 - 19 cm). Primary technical efficacy (PTE) and local recurrence (LR) were evaluated, and possible predictors for adverse events analyzed using uni- and multi-variable binary logistic regression.

RESULTS

Overall, 2553 of 2653 tumors were successfully ablated at initial SRFA resulting in a PTE rate of 96.2%. Predictors of lower PTE rates were age > 70 years, tumor size > 5 cm, number of probes, location close to liver capsule/organs and segment II. LR occurred in 220 of 2653 tumors (8.3%) with the following predictors: age, tumor type/size, conglomerates, segments I/IVa/IVb, number of probes and location close to major vessels/bile duct. Multivariable analysis revealed tumor size > 5 cm (odds ratio [OR] 3.153), age > 70 years (OR 1.559), and location in segment II (OR 1.772) as independent prognostic factors for PTE, whereas tumor location close to major vessels (OR 1.653) and in segment IVb (OR 2.656) were identified as independent prognostic factors of LR.

CONCLUSIONS

Stereotactic RFA is an attractive option in the management of primary or metastatic liver tumors with good local tumor control, even in large tumors. The presented prognostic factors for adverse local oncological outcome might help to stratify unfavorable tumors for ablation.

Contemporary evidence on colorectal liver metastases ablation: toward a paradigm shift in locoregional treatment

Image-guided percutaneous ablation techniques represent an attractive local therapy for the treatment of colorectal liver metastases (CLM) given its low risk of severe complications, which allows for early initiation of adjuvant therapies and spare functional liver parenchyma, allowing repeated treatments at the time of recurrence. However, ablation does not consistently achieve similar oncological outcomes to surgery, with the latter being currently considered the first-line local treatment modality in international guidelines. Recent application of computer-assisted ablation planning, guidance, and intra-procedural response assessment has improved percutaneous ablation outcomes. In addition, the evolving understanding of tumor molecular profiling has brought to light several biological factors associated with oncological outcomes following local therapies. The standardization of ablation procedures, the understanding of previously unknown biological factors affecting ablation outcomes, and the evidence by ongoing prospective clinical trials are poised to change the current perspective and indications on the use of ablation for CLM.

CT radiomics models are unable to predict new liver metastasis after successful thermal ablation of colorectal liver metastases

BACKGROUND

Patients with colorectal liver metastases (CRLM) who undergo thermal ablation are at risk of developing new CRLM after ablation. Identification of these patients might enable individualized treatment.

PURPOSE

To investigate whether an existing machine-learning model with radiomics features based on pre-ablation computed tomography (CT) images of patients with colorectal cancer can predict development of new CRLM.

MATERIAL AND METHODS

In total, 94 patients with CRLM who were treated with thermal ablation were analyzed. Radiomics features were extracted from the healthy liver parenchyma of CT images in the portal venous phase, before thermal ablation. First, a previously developed radiomics model (Original model) was applied to the entire cohort to predict new CRLM after 6 and 24 months of follow-up. Next, new machine-learning models were developed (Radiomics, Clinical, and Combined), based on radiomics features, clinical features, or a combination of both.

RESULTS

The external validation of the Original model reached an area under the curve (AUC) of 0.57 (95% confidence interval [CI]=0.56-0.58) and 0.52 (95% CI=0.51-0.53) for 6 and 24 months of follow-up. The new predictive radiomics models yielded a higher performance at 6 months compared to 24 months. For the prediction of CRLM at 6 months, the Combined model had slightly better performance (AUC=0.60; 95% CI=0.59-0.61) compared to the Radiomics and Clinical models (AUC=0.55-0.57), while all three models had a low performance for the prediction at 24 months (AUC=0.52-0.53).

CONCLUSION

Both the Original and newly developed radiomics models were unable to predict new CLRM based on healthy liver parenchyma in patients who will undergo ablation for CRLM.

Local Treatments in the Unresectable Patient with Colorectal Cancer Metastasis: A Review from the Point of View of the Medical Oncologist

For patients with isolated liver metastases from colorectal cancer who are not candidates for potentially curative resections, non-surgical local treatments may be useful. Non-surgical local treatments are classified according to how the treatment is administered. Local treatments are applied directly on hepatic parenchyma, such as radiofrequency, microwave hyperthermia and cryotherapy. Locoregional therapies are delivered through the hepatic artery, such as chemoinfusion, chemoembolization or selective internal radiation with Yttrium 90 radioembolization. The purpose of this review is to describe the different interventional therapies that are available for these patients in routine clinical practice, the most important clinical trials that have tried to demonstrate the effectiveness of each therapy and recommendations from principal medical oncologic societies.

Histotripsy for the Treatment of Cholangiocarcinoma Liver Tumors: In Vivo Feasibility and Ex Vivo Dosimetry Study

Histotripsy is a noninvasive, nonionizing, and nonthermal focused ultrasound ablation method that is currently being developed for the treatment of liver cancer. Promisingly, histotripsy has been shown for ablating primary [hepatocellular carcinoma (HCC)] and metastatic [colorectal liver metastasis (CLM)] liver tumors in preclinical and early clinical studies. The feasibility of treating cholangiocarcinoma (CC), a less common primary liver tumor that arises from the bile ducts, has not been explored previously. Given that prior work has established that histotripsy susceptibility is based on tissue mechanical properties, there is a need to explore histotripsy as a treatment for CC due to its dense fibrotic stromal components. In this work, we first investigated the feasibility of histotripsy for ablating CC tumors in vivo in a patient-derived xenograft mouse model. The results showed that histotripsy could generate CC tumor ablation using a 1-MHz small animal histotripsy system with treatment doses of 250, 500, and 1000 pulses/point. The second set of experiments compared the histotripsy doses required to ablate CC tumors to HCC and CLM tumors ex vivo. For this, human tumor samples were harvested after surgery and treated ex vivo with a 700-kHz clinical histotripsy transducer. Results demonstrated that significantly higher treatment doses were required to ablate CC and CLM tumors compared to HCC, with the highest treatment dose required for CC tumors. Overall, the results of this study suggest that histotripsy has the potential to be used for the ablation of CC tumors while also highlighting the need for tumor-specific treatment strategies.

Image-Guided Ablation for Colorectal Liver Metastasis: Principles, Current Evidence, and the Path Forward

Image-guided ablation can provide effective local tumor control in selected patients with CLM. A randomized controlled trial suggested that radiofrequency ablation combined with systemic chemotherapy resulted in a survival benefit for patients with unresectable CLM, compared to systemic chemotherapy alone. For small tumors, ablation with adequate margins can be considered as an alternative to resection. The improvement of ablation technologies can allow the treatment of tumors close to major vascular structures or bile ducts, on which the applicability of thermal ablation modalities is challenging. Several factors affect the outcomes of ablation, including but not limited to tumor size, number, location, minimal ablation margin, RAS mutation status, prior hepatectomy, and extrahepatic disease. Further understanding of the impact of tumor biology and advanced imaging guidance on overall patient outcomes might help to tailor its application, and improve outcomes of image-guided ablation.

Recurrence and survival following microwave, radiofrequency ablation, and hepatic resection of colorectal liver metastases: A systematic review and network meta-analysis

BACKGROUND

Gold standard for colorectal liver metastases (CRLM) remains hepatic resection (HR). However, patients with severe comorbidities, unresectable or deep-situated resectable CRLM are candidates for ablation. The aim of the study was to compare recurrence rate and survival benefit of the microwave ablation (MWA), radiofrequency ablation (RFA) and HR by conducting the first network meta-analysis.

DATA SOURCES

Systematic search of the literature was conducted in the electronic databases. Both updated traditional and network meta-analyses were conducted and the results were compared between them.

RESULTS

HR cohort demonstrated significantly less local recurrence rate and better 3- and 5-year disease-free (DFS) and overall survival (OS) compared to MWA and RFA cohorts. HR cohort included significantly younger patients and with significantly lower preoperative carcinoembryonic antigen (CEA) by 10.28 ng/mL compared to RFA cohort. Subgroup analysis of local recurrence and OS of solitary and ≤ 3 cm CRLMs did not demonstrate any discrepancies when compared with the whole sample.

CONCLUSIONS

For resectable CRLM the treatment of choice still remains HR. MWA and RFA can be used as a single or adjunct treatment in patients with unresectable CRLM and/or prohibitive comorbidities.

Predicting local tumour progression after ablation for colorectal liver metastases: CT-based radiomics of the ablation zone

PURPOSE

To assess whether CT-based radiomics of the ablation zone (AZ) can predict local tumour progression (LTP) after thermal ablation for colorectal liver metastases (CRLM).

MATERIALS AND METHODS

Eighty-two patients with 127 CRLM were included. Radiomics features (with different filters) were extracted from the AZ and a 10 mm periablational rim (PAR)on portal-venous-phase CT up to 8 weeks after ablation. Multivariable stepwise Cox regression analyses were used to predict LTP based on clinical and radiomics features. Performance (concordance [c]-statistics) of the different models was compared and performance in an 'independent' dataset was approximated with bootstrapped leave-one-out-cross-validation (LOOCV).

RESULTS

Thirty-three lesions (26 %) developed LTP. Median follow-up was 21 months (range 6-115). The combined model, a combination of clinical and radiomics features, included chemotherapy (HR 0.50, p = 0.024), cT-stage (HR 10.13, p = 0.016), lesion size (HR 1.11, p = <0.001), AZ_Skewness (HR 1.58, p = 0.016), AZ_Uniformity (HR 0.45, p = 0.002), PAR_Mean (HR 0.52, p = 0.008), PAR_Skewness (HR 1.67, p = 0.019) and PAR_Uniformity (HR 3.35, p < 0.001) as relevant predictors for LTP. The predictive performance of the combined model (after LOOCV) yielded a c-statistic of 0.78 (95 %CI 0.65-0.87), compared to the clinical or radiomics models only (c-statistic 0.74 (95 %CI 0.58-0.84) and 0.65 (95 %CI 0.52-0.83), respectively).

CONCLUSION

Combining radiomics features with clinical features yielded a better performing prediction of LTP than radiomics only. CT-based radiomics of the AZ and PAR may have potential to aid in the prediction of LTP during follow-up in patients with CRLM.

Liver metastases

Liver metastases are commonly detected in a range of malignancies including colorectal cancer (CRC), pancreatic cancer, melanoma, lung cancer and breast cancer, although CRC is the most common primary cancer that metastasizes to the liver. Interactions between tumour cells and the tumour microenvironment play an important part in the engraftment, survival and progression of the metastases. Various cells including liver sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, parenchymal hepatocytes, dendritic cells, resident natural killer cells as well as other immune cells such as monocytes, macrophages and neutrophils are implicated in promoting and sustaining metastases in the liver. Four key phases (microvascular, pre-angiogenic, angiogenic and growth phases) have been identified in the process of liver metastasis. Imaging modalities such as ultrasonography, CT, MRI and PET scans are typically used for the diagnosis of liver metastases. Surgical resection remains the main potentially curative treatment among patients with resectable liver metastases. The role of liver transplantation in the management of liver metastasis remains controversial. Systemic therapies, newer biologic agents (for example, bevacizumab and cetuximab) and immunotherapeutic agents have revolutionized the treatment options for liver metastases. Moving forward, incorporation of genetic tests can provide more accurate information to guide clinical decision-making and predict prognosis among patients with liver metastases.

Percutaneous ablation of post-surgical solitary early recurrence of colorectal liver metastases is an effective "test-of-time" approach

Standard treatment of early recurrence of colorectal liver metastases (CLM) after liver resection (LR) is chemotherapy followed by loco-regional therapy. We reviewed the outcome of a different strategy ("test-of-time" approach): upfront percutaneous ablation without chemotherapy. Twenty-six consecutive patients with early solitary liver-only recurrence amenable to both resection and ablation (< 30 mm, distant from vessels) undergone "test-of-time" approach were analyzed. Early recurrence had a median size of 17 mm and occurred after a median interval from LR of 4 months. Primary efficacy rate of ablation was 100%. Five patients are alive and disease-free after a mean follow-up of 46 months. Five patients had local-only recurrence; all had repeat treatment (LR = 4; Ablation = 1) without chemotherapy. Local recurrence risk was associated with incomplete ablation of 1-cm thick peritumoral margin. The remaining 16 patients had non-local recurrence, 13 early after ablation. Overall, six (23%) patients had ablation as unique treatment and 13 (50%) avoided or postponed chemotherapy (mean chemotherapy-free interval 33.5 months). Ablation without chemotherapy of early liver-only recurrence is a reliable "test-of-time" approach. It minimized the invasiveness of treatment with good effectiveness and high salvageability in case of local failure, avoided worthless surgery, and saved chemotherapy for further disease progression.

The prognosis of radiofrequency ablation versus hepatic resection for patients with colorectal liver metastases: A systematic review and meta-analysis based on 22 studies

BACKGROUND

Though hepatic resection (HR) is the standard local therapy for patients with colorectal cancer liver metastases (CRLMs), currently, radiofrequency ablation (RFA) may play an alternative role for elderly and vulnerable patients with various organ dysfunctions. This study aims to compare the prognosis of RFA and HR in treatment of CRLMs.

METHODS

A systematic search of PubMed, Embase, Cochrane Library and Web of Science up to October 1, 2020 was conducted for relevant studies that compared the prognosis of RFA with HR in the treatment of CRLMs. The primary outcomes were 30-day mortality, long-term recurrence, overall survival (OS) and disease-free survival (DFS). The secondary outcomes were various factors of OS, recurrence-free survival (RFS), survival, recurrence and complication.

RESULTS

A total of 22 studies including 4385 CRLM patients were identified. There was no significant difference between RFA and HR in 30-day mortality, with a pooled OR of 0.88 (95% CI 0.34-2.29; P = 0.80). CRLM patients undergoing RFA experienced significantly higher incidences of marginal and intrahepatic recurrence than HR, with pooled ORs of 7.09 (95% CI 4.56-11.2; 1251 pts) and 2.02 (95% CI 1.24-3.28; 1038 pts). In addition, RFA showed lower 1-, 3- and 5-yr OS rate than HR with pooled ORs of 0.39, 0.40 and 0.60 respectively. A lower 5-yr DFS rate was also found in RFA than HR group, with a pooled OR of 0.74 (95% CI 0.56-0.97; P = 0.03; 1231 pts). Multivariable analysis showed that tumor size, multiple tumors, age, primary node positive and metachronous metastasis were independent factors of OS, and multiple tumors was also an independent factor of RFS.

CONCLUSIONS

Though the 30-day mortality of RFA was equal to HR, RFA showed a higher recurrence rate and poor long-term survival outcomes for CRLM patients. Tumor size, multiple tumors, age, primary node positive and metachronous metastasis were independent factors of survival. However, the results were limited because of the inequality baseline characteristics between the comparative groups. Randomized or propensity score matching studies should be performed to clarify the effectiveness of RFA and to determine target populations that benefit most from RFA in the future.

Hepatic thermal injury promotes colorectal cancer engraftment in C57/black 6 mice

Treatment options for liver metastases (primarily colorectal cancer) are limited by high recurrence rates and persistent tumor progression. Surgical approaches to management of these metastases typically use heat energy including electrocautery, argon beam coagulation, thermal ablation of surgical margins for hemostasis, and preemptive thermal ablation to prevent bleeding or to effect tumor destruction. Based on high rates of local recurrence, these studies assess whether local effects of hepatic thermal injury (HTI) might contribute to poor outcomes by promoting a hepatic microenvironment favorable for tumor engraftment or progression due to induction of procancer cytokines and deleterious immune infiltrates at the site of thermal injury. To test this hypothesis, an immunocompetent mouse model was developed wherein HTI was combined with concomitant intrasplenic injection of cells from a well-characterized MC38 colon carcinoma cell line. In this model, HTI resulted in a significant increase in engraftment and progression of MC38 tumors at the site of thermal injury. Furthermore, there were local increases in expression of messenger ribonucleic acid (mRNA) for hypoxia-inducible factor-1α (HIF1α), arginase-1, and vascular endothelial growth factor α and activation changes in recruited macrophages at the HTI site but not in untreated liver tissue. Inhibition of HIF1α following HTI significantly reduced discreet hepatic tumor development (P = 0.03). Taken together, these findings demonstrate that HTI creates a favorable local environment that is associated with protumorigenic activation of macrophages and implantation of circulating tumors. Discrete targeting of HIF1α signaling or inhibiting macrophages offers potential strategies for improving the outcome of surgical management of hepatic metastases where HTI is used.

An Analysis of Free-hand Targeting in Laparoscopic Liver Microwave Ablation

BACKGROUND

Recently, new technologies have been developed for antenna placement in laparoscopic liver tumor ablation (LLTA). At this point, it is important to analyze the efficacy of free-hand targeting to identify deficiencies and opportunities for improvement.

METHODS

This was an institutional review board-approved retrospective study. Video recordings of 30 consecutive patients with 77 lesions who underwent LLTA were reviewed. Tumor-specific anatomic and targeting-related parameters were analyzed using χ2, t test, and regression analyses.

RESULTS

Neuroendocrine metastasis was the dominant tumor type, with median tumor size 1.4 cm (range, 0.5 to 5.2). In total, 41 (53%) tumors were superficial and 36 (47%) deep. In 68 lesions (88%), an optimal targeting was achieved with first attempt, without a need for repositioning; whereas 9 lesions (12%) required repositioning of antenna. For 37% (15/41) of superficial and 56% (20/36) of deep lesions, a straight avascular needle trajectory was not present, requiring steering of the antenna around vascular and biliary structures. All procedures were completed laparoscopically without bleeding or biliary complications. Local treatment recurrence rate in follow-up was 10% (n=8).

CONCLUSIONS

This study shows that in experienced hands, LLTA through free-hand technique is safe and efficacious, providing an accurate targeting with the first pass in 90% of tumors. Although newer technology is being developed to guide less-experienced surgeons in needle targeting, it should be kept in mind that a straight trajectory is not available for 1/3 of superficial and half of deep lesions. Hence, ablation surgeons need to develop free-hand skills to avoid possible hemorrhagic and biliary complications in LLTA.

Oncological outcomes and predictors of radiofrequency ablation of colorectal cancer liver metastases

BACKGROUND

Surgical resection is considered the standard treatment option for long-term survival in colorectal cancer liver metastasis (CRLM) patients, but only a small number of patients are suitable for resection following diagnosis. Radiofrequency ablation (RFA) is an accepted alternative therapy for CRLM patients who are not suitable for resection. However, the relatively high rate of local tumor progression (LTP) is an obstacle to the more widespread use of RFA.

AIM

To determine the oncological outcomes and predictors of RFA in CRLM patients.

METHODS

A retrospective analyze was performed on the clinical data of 85 consecutive CRLM patients with a combined total of 138 liver metastases, who had received percutaneous RFA treatment at our institution from January 2013 to December 2018. Contrast-enhanced computed tomography was performed the first month after RFA to assess the technique effectiveness of the RFA and to serve as a baseline for subsequent evaluations. The Kaplan-Meier method was used to calculate overall survival (OS) and LTP-free survival (LTPFS). The log-rank test and Cox regression model were used for univariate and multivariate analyses to determine the predictors of the oncological outcomes.

RESULTS

There were no RFA procedure-related deaths, and the technique effectiveness of the treatment was 89.1% (123/138). The median follow-up time was 30 mo. The LTP rate was 32.6% (45/138), and the median OS was 36 mo. The 1-, 3-, and 5-year OS rates were 90.6%, 45.6%, and 22.9%, respectively. Univariate analysis revealed that tumor size and ablative margin were the factors influencing LTPFS, while extrahepatic disease (EHD), tumor number, and tumor size were the factors influencing OS. Multivariate analysis showed that tumor size larger than 3 cm and ablative margin of 5 mm or smaller were the independent predictors of shorter LTPFS, while tumor number greater than 1, size larger than 3 cm, and presence of EHD were the independent predictors of shorter OS.

CONCLUSION

RFA is a safe and effective treatment method for CRLM. Tumor size and ablative margin are the important factors affecting LTPFS. Tumor number, tumor size, and EHD are also critical factors for OS.

Systematic review and meta-analysis of local ablative therapies for resectable colorectal liver metastases

INTRODUCTION

Local ablative therapies (LAT) have shown positive but heterogenous outcomes in the treatment of colorectal liver metastases (CRLM). The aim of this systematic review is to evaluate LAT and compare them with surgical resection.

METHODS

In accordance with PRISMA guidelines, Medline, EMBASE, Cochrane and Web of Science databases were searched for reports published before January 2019. We included papers assessing radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation (CA) and electroporation (IRE) treating resectable CRLM with curative intention. We evaluated LAT related complications and oncological outcomes as tumour progression (LTP), disease-free survival (DFS) and overall survival (OS).

RESULTS

The literature search yielded 6767 records; 20 papers (860 patients) were included. No included studies related mortality with LAT. Median adverse events percentage was 7%: (8% RFA;7% MWA). Median 3y-DFS was 32% (24% RFA; 60% MWA); 5y-DFS was 27%: (18% RFA; 38.5% MWA). Median 3y-OS was 59% (60% RFA; 70% MWA; 34% CA), 5y-OS was 44.5% (43% RFA; 55% MWA; 20% CA). Surgical resection showed decreased LTP, improved DFS and OS than those reported with LAT, with RFA accounting for reduced 1y-DFS (RR 0.83, 95%CI 0.71-0.98), 3y-DFS (RR 0.5, 95%CI 0.33-0.76), 5y-DFS (RR 0.53, 95%CI 0.28-0.98) and 5y-OS (RR 0.76, 95%CI 0.58-0.98) in comparison with surgical resection.

CONCLUSIONS

Low quality evidence suggests that both RFA and MWA seem superior to CA. MWA presents similar adverse events when compared to RFA with a possible increase in DFS and OS. Surgical resection still seems to provide superior DFS and OS in comparison with LAT.

Resection vs. ablation for lesions characterized as resectable-ablative within the colorectal liver oligometastases criteria: a propensity score matching from retrospective study

Background

There has been no prospective or retrospective studies reporting the comparison outcome between surgery and ablation for resectable-ablative (lesions could be treated by resection or complete ablation) colorectal liver oligometastases (CLOM). The purpose of this study was to compare the efficacy and prognostic difference in patients who underwent R0 resection vs. complete ablation within the resectable-ablative CLOM criteria.

Methods

From January 2008 to May 2018, a total of 2,367 patients diagnosed with colorectal liver metastases were included in this observational study. The metastasis was characterized by only limited to liver with number ≤5, size ≤5 cm, and resectable-ablative (lesions could be treated by resection or complete ablation). The evaluated indications, including liver progression-free survival (LPFS), overall survival (OS), survival rates, pattern and number of recurrences, and complications, were compared by using propensity score matching (PSM). The Kaplan-Meier curves were generated, and a log-rank test was performed. The Cox regression model was used for univariate and multivariate analyses to identify predictors of outcomes.

Results

A total of 421 consecutive patients were eligible for this study, with 250 and 171 undergoing R0 resection and complete ablation, respectively. PSM identified 145 patients from each group. The 1-, 3-, 5- and 8-year OS rates in the resection group and the ablation group were 95.8% vs. 95.0%, 69.8% vs. 60.1%, 53.6% vs. 42.5%, and 45.1% vs. 32.9% (p = 0.075), respectively. The median LPFS in the resection group was significantly longer than that in the ablation group (35 months vs. 15 months, p = 0.011). No statistical difference was found in LPFS between the two groups when comparing ≤3 cm liver metastases. For liver metastasis >3 cm, the median LPFS in the resection group and ablation group was 11 months and 5 months, respectively (p = 0.001). In terms of high risk of clinical risk score (CRS), the resection group showed longer LPFS than the ablation group (median 18 months vs. 10 months, p = 0.043).

Conclusion

For patients within the CLOM criteria suggesting that liver metastases were resectable as well as ablative, resection could result in longer liver recurrence-free survival than ablation in cases with size >3 cm or high risk of CRS. But for ≤3 cm liver metastases, their treatment efficacies were comparable.

Management of Liver Oligometastatic Esophageal Cancer: Overview and Critical Analysis of the Different Loco-Regional Treatments

Esophageal cancer (EC) is an aggressive disease that is associated with a poor prognosis. Since metastastic EC is usually considered suitable only for palliative therapy with an estimated 5-year overall survival (OS) less than 5%, the optimal management of patients with liver oligometastatic EC (LOEC) is still undefined. The aim of this review is to provide an overview of the different treatment options for LOEC. A literature search was conducted using PubMed, Embase, and Cochrane to identify articles evaluating different treatment strategies for LOEC. Among 828 records that were identified, 20 articles met the inclusion criteria. These studies included patients who have undergone any type of surgical procedure and/or loco-regional therapy. Liver resection resulted in the best survival for patients with low tumor burden (3 lesions): 5-year OS 30–50% versus 8–12% after only chemotherapy (CHT). The 5-year OS of loco-regional therapies was 23% with a local recurrence risk ranging 0–8% for small lesions (2 to 3 cm). An aggressive multidisciplinary approach for LOEC patients may improve survival. Surgery seems to be the treatment of choice for resectable LOEC. If unfeasible, loco-regional therapies may be considered. In order to better select these patients and offer a chance of cure, prospective trials and a definition of treatment protocols are needed.

Thermal Ablation of Metastatic Colon Cancer to the Liver

Colorectal cancer (CRC) is responsible for approximately 10% of cancer-related deaths in the Western world. Liver metastases are frequently seen at the time of diagnosis and throughout the course of the disease. Surgical resection is often considered as it provides long-term survival; however, few patients are candidates for resection. Percutaneous ablative therapies are also used in the management of this patient population. Different thermal ablation (TA) technologies are available including radiofrequency ablation, microwave ablation (MWA), laser, and cryoablation. There is growing evidence about the role of interventional oncology and image-guided percutaneous ablation in the management of metastatic colorectal liver disease. This article aims to outline the technical considerations, outcomes, and rational of TA in the management of patients with CRC liver metastases, focusing on the emerging role of MWA.

Ablation or Resection for Colorectal Liver Metastases? A Systematic Review of the Literature

Background: Successful use of ablation for small hepatocellular carcinomas (HCC) has led to interest in the role of ablation for colorectal liver metastases (CRLM). However, there remains a lack of clarity about the use of ablation for colorectal liver metastases (CRLM), specifically its efficacy compared with hepatic resection. Methods: A systematic review of the literature on ablation or resection of colorectal liver metastases was performed using MEDLINE, Cochrane Library, and Embase until December 2018. The aim of this study was to summarize the evidence for ablation vs. resection in the treatment of CRLM. Results: This review identified 1,773 studies of which 18 were eligible for inclusion. In the majority of the studies, overall survival (OS) and disease-free survival (DFS) were significantly higher and local recurrence (LR) rates were significantly lower in the resection groups. On subgroup analysis of solitary CRLM, resection was associated with improved OS, DFS, and reduced LR. Three series assessed the outcome of resection vs. ablation for technically resectable CRLM, and showed improved outcome in the resection group. In fact, there were no studies showing a survival advantage of ablation compared to resection in the treatment of CRLM. Conclusions: Resection remains the "gold standard" in the treatment of CRLM and should not be replaced by ablation at present. This review supports the use of ablation only as an adjunct to resection and as a single treatment option when resection is not safely possible.

Local treatment of oligometastatic disease: current role

The presence of distant metastases has long been a predictor of poor outcome in solid cancer. However, in an oncologic situation called oligometastatic disease (OMD), multiple studies have revealed a survival benefit with aggressive treatment of these metastases. Besides surgery and radiation therapy, local thermal therapies have developed into a treatment option for OMD. Most studies concerning local therapy of OMD are available for colorectal cancer, which is therefore the focus of this article. Furthermore, this review gives a basic overview of the most popular ablation techniques for treatment of OMD.

Solitary colorectal liver metastasis after curative intent surgery: prognostic factors affecting outcomes and survival

BACKGROUND

The aim of this study was to identify the prognostic factors affecting recurrence and survival in patients who underwent curative intent surgery for colorectal cancer (CRC) with a single liver metastasis.

METHODS

Between January 2006 and August 2012, we retrospectively evaluated 141 patients for CRC with single liver metastasis underwent curative intent surgery for colon and liver simultaneously. Some patients (11.3%) had radiofrequency ablation as an option.

RESULTS

The 5-year disease-free and overall survival (OS) rates were 38.9% and 59.6%, respectively. Recurrence occurred in 77 (54.6%) patients after surgery. Multivariate analysis identified node positivity and no adjuvant chemotherapy as independent risk factors for OS. We analyzed the OS risk factors in 76 recurred patients from the time of recurrence. Multivariate analysis revealed the following significant risk factors for OS after recurrence: a high serum carcinoembryonic antigen concentration at the time of recurrence, the treatment type after recurrence (chemotherapy or no treatment) and a left hepatic metastasis.

CONCLUSION

Patients who underwent a curative resection for CRC with a single liver metastasis had a relatively favourable prognosis; in these patients, node positivity and no adjuvant chemotherapy were independent prognostic factors for OS. Furthermore, a high serum carcinoembryonic antigen concentration at the time of recurrence, the treatment type after recurrence (chemotherapy or no treatment) and a left hepatic metastasis may be independent prognostic factors for OS in patients with recurrence. The left hepatic metastasis group tended to have a multiple hepatic relapse more frequently than the right hepatic metastasis group in cases of isolated hepatic relapse.

The role of interventional oncology in the treatment of colorectal cancer liver metastases

Colorectal cancer is a leading cause of death both in Europe and worldwide. Unfortunately, 20-25% of patients with colorectal cancer already have metastases at the time of diagnosis, while 50-60% of the remainder will develop metastases later during the course of the disease. Although hepatic excision is the first-line treatment for patients with liver-limited colorectal metastases and is reported to prolong the survival of these patients, few patients are candidates. Locoregional therapy encompasses minimally invasive techniques practiced by interventional radiology. Most widely used locoregional therapies include ablative treatments (radiofrequency ablation, microwave ablation) and transcatheter intra-arterial therapies (transarterial chemoembolization, and radioembolization with yttrium-90).

The role of interventional oncology in the treatment of colorectal cancer liver metastases

Colorectal cancer is a leading cause of death both in Europe and worldwide. Unfortunately, 20-25% of patients with colorectal cancer already have metastases at the time of diagnosis, while 50-60% of the remainder will develop metastases later during the course of the disease. Although hepatic excision is the first-line treatment for patients with liver-limited colorectal metastases and is reported to prolong the survival of these patients, few patients are candidates. Locoregional therapy encompasses minimally invasive techniques practiced by interventional radiology. Most widely used locoregional therapies include ablative treatments (radiofrequency ablation, microwave ablation) and transcatheter intra-arterial therapies (transarterial chemoembolization, and radioembolization with yttrium-90).

Repeating of local therapy of distant metastases increases overall survival in patients with synchronous metastasized rectal cancer-a monocentric analysis

PURPOSE

The aim was to evaluate the outcome of treatment-naive patients with synchronous metastatic rectal cancer after chemotherapy with FOLFOXIRI followed by local therapeutic procedures of all tumor lesions as complete as possible.

METHODS

We reviewed data of 30 patients with synchronous distant metastatic rectal cancer who underwent chemotherapy with FOLFOXIRI and subsequent local therapy in our institution.

RESULTS

Median follow-up was 28 months (range: 8; 74). Cumulative overall survival (OS) and progression-free survival (PFS) was 93.3, 76.9, 55.6% and 46.2, 29.7, 29.7% after 1, 2, 4 years. Non-response to chemotherapy with FOLFOXIRI was associated with a highly significant decreased OS (p < 0.0001). The consistent use of local ablative procedures led to a statistically significant increase in OS (p < 0.0001), but not in PFS (p = 0.635). Patients with ≤ 4 distant metastases showed a better OS (p = 0.033).

CONCLUSIONS

Response to intensified first-line chemotherapy with FOLFOXIRI, treatment of the primary rectal tumor, and repeated thorough local ablative procedures in patients with synchronous metastasized rectal cancer may lead to long-term survival, even in a subset of patients with unresectable disease at initial diagnosis.

Radiofrequency ablation versus resection for technically resectable colorectal liver metastasis: a propensity score analysis

BACKGROUND

Liver resection is the first-line treatment for patients with resectable colorectal liver metastasis (CRLM), while radiofrequency ablation (RFA) can be used for small unresectable CRLM because of disease extent, poor anatomical location, or comorbidities. However, the long-term outcomes are unclear for RFA treatment in resectable CRLM. This study aimed to compare the recurrence rates and prognosis between resectable CRLM patients receiving either liver resection or RFA.

METHODS

Consecutive patients who underwent RFA or hepatic resection from November 2010 to December 2015 were assigned in this retrospective study. Propensity score analysis was used to eliminate baseline differences between groups. Survival and recurrence rates were compared between patients receiving liver resection and RFA.

RESULTS

With 1:2 ratio of propensity scoring, 46 patients in the RFA group and 92 in the resection group were successfully matched. Overall survival was similar between the two groups, but the resection group had a higher disease-free survival (median, 22 months vs. 14 months). Whereas among patients with a tumor size of ≤ 3 cm, disease-free survival was similar in the two groups (median, 24 months vs. 21 months). Compared to the resection group, the RFA group had a higher rate of intrahepatic recurrence (34.8% vs. 12.0%) and a shorter recurrence free period. The local and systemic recurrence rate and recurrence-free period for the same were insignificant in the two groups. Poor disease-free survival was associated with RFA, T4, tumor diameter > 3 cm, and lymph node positivity.

CONCLUSION

Among patients with technically resectable CRLM, resection provided greater disease-free survival, although both treatment modalities provided similar overall survival.

Colorectal liver metastases: surgery versus thermal ablation (COLLISION) - a phase III single-blind prospective randomized controlled trial

Background

Radiofrequency ablation (RFA) and microwave ablation (MWA) are widely accepted techniques to eliminate small unresectable colorectal liver metastases (CRLM). Although previous studies labelled thermal ablation inferior to surgical resection, the apparent selection bias when comparing patients with unresectable disease to surgical candidates, the superior safety profile, and the competitive overall survival results for the more recent reports mandate the setup of a randomized controlled trial. The objective of the COLLISION trial is to prove non-inferiority of thermal ablation compared to hepatic resection in patients with at least one resectable and ablatable CRLM and no extrahepatic disease.

Methods

In this two-arm, single-blind multi-center phase-III clinical trial, six hundred and eighteen patients with at least one CRLM (≤3 cm) will be included to undergo either surgical resection or thermal ablation of appointed target lesion(s) (≤3 cm). Primary endpoint is OS (overall survival, intention-to-treat analysis). Main secondary endpoints are overall disease-free survival (DFS), time to progression (TTP), time to local progression (TTLP), primary and assisted technique efficacy (PTE, ATE), procedural morbidity and mortality, length of hospital stay, assessment of pain and quality of life (QoL), cost-effectiveness ratio (ICER) and quality-adjusted life years (QALY).

Discussion

If thermal ablation proves to be non-inferior in treating lesions ≤3 cm, a switch in treatment-method may lead to a reduction of the post-procedural morbidity and mortality, length of hospital stay and incremental costs without compromising oncological outcome for patients with CRLM.

Trial registration

NCT03088150, January 11th 2017.

Radiofrequency and Microwave Ablation Compared to Systemic Chemotherapy and to Partial Hepatectomy in the Treatment of Colorectal Liver Metastases: A Systematic Review and Meta-Analysis

Purpose

To assess safety and outcome of radiofrequency ablation (RFA) and microwave ablation (MWA) as compared to systemic chemotherapy and partial hepatectomy (PH) in the treatment of colorectal liver metastases (CRLM).

Methods

MEDLINE, Embase and the Cochrane Library were searched. Randomized trials and comparative observational studies with multivariate analysis and/or matching were included. Guidelines from National Guideline Clearinghouse and Guidelines International Network were assessed using the AGREE II instrument.

Results

The search revealed 3530 records; 328 were selected for full-text review; 48 were included: 8 systematic reviews, 2 randomized studies, 26 comparative observational studies, 2 guideline-articles and 10 case series; in addition 13 guidelines were evaluated. Literature to assess the effectiveness of ablation was limited. RFA + systemic chemotherapy was superior to chemotherapy alone. PH was superior to RFA alone but not to RFA + PH or to MWA. Compared to PH, RFA showed fewer complications, MWA did not. Outcomes were subject to residual confounding since ablation was only employed for unresectable disease.

Conclusion

The results from the EORTC-CLOCC trial, the comparable survival for ablation + PH versus PH alone, the potential to induce long-term disease control and the low complication rate argue in favour of ablation over chemotherapy alone. Further randomized comparisons of ablation to current-day chemotherapy alone should therefore be considered unethical. Hence, the highest achievable level of evidence for unresectable CRLM seems reached. The apparent selection bias from previous studies and the superior safety profile mandate the setup of randomized controlled trials comparing ablation to surgery.

Electronic supplementary material

The online version of this article (10.1007/s00270-018-1959-3) contains supplementary material, which is available to authorized users.

RFA Guardian: Comprehensive Simulation of Radiofrequency Ablation Treatment of Liver Tumors

The RFA Guardian is a comprehensive application for high-performance patient-specific simulation of radiofrequency ablation of liver tumors. We address a wide range of usage scenarios. These include pre-interventional planning, sampling of the parameter space for uncertainty estimation, treatment evaluation and, in the worst case, failure analysis. The RFA Guardian is the first of its kind that exhibits sufficient performance for simulating treatment outcomes during the intervention. We achieve this by combining a large number of high-performance image processing, biomechanical simulation and visualization techniques into a generalized technical workflow. Further, we wrap the feature set into a single, integrated application, which exploits all available resources of standard consumer hardware, including massively parallel computing on graphics processing units. This allows us to predict or reproduce treatment outcomes on a single personal computer with high computational performance and high accuracy. The resulting low demand for infrastructure enables easy and cost-efficient integration into the clinical routine. We present a number of evaluation cases from the clinical practice where users performed the whole technical workflow from patient-specific modeling to final validation and highlight the opportunities arising from our fast, accurate prediction techniques.

Early recurrence in patients undergoing curative resection of colorectal liver oligometastases: identification of its clinical characteristics, risk factors, and prognosis

PURPOSE

Oligometastatic disease can potentially be cured when an optimal approach is performed. Early recurrence after liver resection is an intractable problem, and the clinical implications remain unknown in colorectal liver oligometastases (CLOM) patients. This study aimed to investigate the clinical characteristics, risk factors, and prognosis related to early recurrence in these patients.

METHODS

A total of 307 consecutive patients with CLOM undergoing curative liver resection were retrospectively reviewed between September 1999 and June 2016. Early recurrence was defined as any recurrence or death from CLOM that occurred within 6 months of liver resection.

RESULTS

With a median follow-up time of 31.7 months, the 3-year overall survival (OS) and recurrence-free survival rates were 68.7 and 42.5%, respectively. Forty-nine (16.0%) patients developed early recurrence and showed a poorer 3-year OS than those with non-early recurrence (22.3 vs. 75.8%, P < 0.001) or later recurrence (22.3 vs. 52.8 vs. 63.2%, P < 0.001). Moreover, early recurrence was identified as an independent predictor of 3-year OS [hazard ratio (HR) 6.282; 95% confidence interval (CI) 3.980-9.915, P < 0.001]. In multivariate analysis, a node-positive primary tumor [odds ratio (OR) 2.316; 95% CI 1.097-4.892, P = 0.028) and metastatic diameter > 3 cm (OR 2.560; 95% CI 1.290-5.078; P = 0.007) were shown to be risk factors for early recurrence. The salvage liver resection rate for patients with early recurrence was significantly lower than that for patients with later recurrence (4.1 vs. 19.7%, P = 0.010).

CONCLUSIONS

Early recurrence should be investigated in routine clinical practice, even in patients with CLOM after curative liver resection. Detailed preoperative comprehensive measurements might help stratify high-risk patients, and a non-surgical treatment for early recurrence might represent an effective alternative.

Radiofrequency ablation compared to surgical resection for curative treatment of patients with colorectal liver metastases - a meta-analysis

BACKGROUND

Hepatic resection and ablative treatments, such as RFA are available treatment options for liver tumors. Advantages and disadvantages of these treatment options in patients with colorectal liver metastases need further evaluation. The purpose of this study was to systematically evaluate the role of radiofrequency ablation (RFA) compared to surgery in the curative treatment of patients with colorectal liver metastases (CRLM).

METHODS

A systematic search was performed from MEDLINE, EMBASE and the Cochrane Library for studies directly comparing RFA with resection for CRLM, after which variables were evaluated.

RESULTS

RFA had significantly lower complication rates (OR = 0.44, 95% CI = 0.26-0.75, P = 0.002) compared to resection. However, RFA showed a higher rate of any recurrence (OR = 1.66, 95% CI = 1.15-2.40, P = 0.007), local recurrence (OR = 9.56, 95% CI = 6.85-13.35, P = 0.001), intrahepatic recurrence (OR = 1.96, 95% CI = 1.34-2.87, P = 0.001) and extrahepatic recurrence (OR = 1.21, 95% CI = 0.90-1.63, P = 0.22). Also, 5-year disease-free survival (OR = 2.20, 95% CI = 1.28-3.79, P = 0.005) and overall survival (OR = 2.35, 95% CI = 1.49-3.69, P = 0.001) were significantly lower in patients treated with RFA.

CONCLUSIONS

RFA showed a significantly lower rate of complications, but also a lower survival and a higher rate of recurrence as compared to surgical resection. All the included studies were subject to possible patient selection bias and therefore randomized clinical trials are needed to accurately evaluate these treatment modalities.

Predictive factors of long-term colorectal cancer survival after ultrasound-controlled ablation of hepatic metastases

BACKGROUND AND OBJECTIVE

The risk factors associated to long-term survival were assessed in patients with liver metastases of colorectal carcinoma undergoing ablative therapies.

PATIENTS AND METHODS

Single-centre cohort study, retrospectively analysed and prospectively collected consecutive patients with unresectable metastatic liver disease of colorectal carcinoma treated with ablative therapies between 1996 and 2013. Factors associated with survival time were identified using Cox's proportional hazard model with time-dependent covariates. A forward variable selection based on Akaike information criterion was performed. Relative risk and 95% confidence intervals for each factor were calculated. Statistical significance was set as P<.05.

RESULTS

Seventy-five patients with liver metastases of colorectal cancer, with a mean age of 65.6 (10.3) underwent 106 treatments. Variables selected were good quality of life (RR 0.308, 95% CI 0.150-0.632) and tumour extension (RR 3.070, 95% CI 1.776-5.308). The median overall survival was 18.5 months (95% CI 17.4-24.4). The survival prognosis in median was 13.5 vs. 23.4 months for patients with and without tumour extension, and 23.0 vs. 12.8 months for patients with good and fair or poor quality of life, respectively.

CONCLUSIONS

Good quality of life and tumour extension were the only statistically significant predictors of long-term survival in patients of colorectal carcinoma with liver metastatic disease undergoing ablative treatment with ultrasound.

Radiofrequency Ablation versus Liver Resection for Colorectal Cancer Liver Metastasis: An Updated Systematic Review and Meta-analysis

Background:

Controversial results about the therapeutic value of radiofrequency ablation (RFA) and liver resection (LR) in the treatment of colorectal cancer liver metastasis (CRCLM) have been reported. Thus, we performed the present meta-analysis to summarize the related clinical evidences.

Methods:

A systematic literature search was conducted using PubMed (Medline), EMBASE, Cochrane Library, and Web of Science, for all years up to April 2016. Pooled analyses of the overall survival (OS), progression-free survival (PFS), and morbidity rates were performed.

Results:

A total of 14 studies were finally enrolled in the meta-analysis. Patients treated by LR gained a longer OS and PFS than those of patients treated by RFA. Patients in the RFA group had lower morbidity rates than those of patients in the LR group. Publication bias analysis revealed that there was no significant publication bias in the meta-analysis.

Conclusions:

Patients with CRCLM gained much more survival benefits from LR than that from RFA. RFA rendered lower rates of morbidities. More well-designed randomized controlled trails comparing the therapeutic value of LR and RFA are warranted.