A prospective multicentre trial on survival after Microwave Ablation VErsus Resection for Resectable Colorectal liver metastases (MAVERRIC)

Safety and Effectiveness of Microwave Ablation of Liver Tumors: Initial Real-World Results from the Multinational NeuWave Observational Liver Ablation (NOLA) Registry

PURPOSE

To investigate the safety and effectiveness of microwave ablation (MWA) for treating liver tumors using real-world data from a multicenter registry (NeuWave Observational Liver Ablation [NOLA]).

MATERIALS AND METHODS

NOLA is approved to enroll up to 1,500 adults treated with MWA and follow them for 5 years. Initial data for 615 patients treated across 24 tertiary healthcare centers in the United States (14), Europe (8), and Asia (2), from January 2020 to October 2022, are summarized herein. Effectiveness and safety endpoints included technical success (TS), technique efficacy (TE), local tumor progression (LTP), adverse events (AEs), and overall survival (OS). AEs were retrospectively graded according to the Society of Interventional Radiology (SIR) classification. A total of 615 patients (male, 72.7%; median age, 66 years; range, 25-89 years) underwent 721 MWA sessions to treat 760 liver tumors, with 95.6% of sessions performed percutaneously.

RESULTS

TS and TE were achieved in 98.1% (730/744) and 95.1% (615/647) of tumors, respectively. The cumulative incidence of LTP at 12 months was 11.9% (95% confidence interval [CI], 8.8%-15.5%) for patients. Within 30 days following the ablation, 408 AEs were reported, with 78.4% (320/408) classified as mild, 3.9% (16/408) as moderate, and 16.9% (69/408) as severe AEs. Procedure-related AEs and serious AEs were reported in 63.7% (392/615) and 11.7% (72/615) of the total patient cohort, respectively. The OS rate at 12 months was 95.5% (95% CI, 92.8%-97.2%).

CONCLUSIONS

MWA is a safe and effective treatment for primary and metastatic liver tumors in a large, real-world patient population.

EORTC consensus recommendations on the optimal management of colorectal cancer liver metastases

Patients with colorectal cancer liver metastases have long represented a unique and thoroughly investigated population. Nevertheless, the optimal management of these is still controversial with a number of open questions which are only partially addressed by available studies and existing guidelines. The European Organisation for Research and Treatment of Cancer (EORTC) Gastrointestinal Tract Cancer Group (GITCG) sought to fill this knowledge gap and promoted the development of a European consensus on this subject. By using the Delphi methodology and leveraging a multidisciplinary team of 43 international experts, including gastrointestinal oncologists, hepatobiliary surgeons, interventional radiologists, radiation oncologists, radiologists, nuclear medicine physicians and pathologists from 12 European countries, 34 practical recommendations and two consensus statements were proposed. These cover varying aspects of the optimal management of colorectal cancer liver metastases such as baseline imaging, selection criteria for liver-directed therapies, treatment strategies, assessment of treatment response, follow-up, care delivery, clinical research and future perspectives. This roadmap document is intended to complement national and international guidelines, and to provide practical guidance for clinicians and multidisciplinary teams, ultimately promoting practice standardisation, optimal management and better patient outcomes across Europe. Also, it provides a unique opportunity to highlight grey areas and unmet needs, and to give a strategic direction to future research in the field by identifying topics where there is no consensus among experts.

Advancements in microwave ablation for tumor treatment and future directions

Microwave ablation (MWA) is a minimally invasive treatment that uses thermal energy to target and destroy tumors. Compared to other ablation methods, such as radiofrequency ablation (RFA), MWA operates at higher frequencies, allowing for faster ablation and larger treatment areas. In addition to its direct tumor-destroying effects, MWA has been shown to activate immune responses, contributing to long-term antitumor effects. MWA can also be combined with surgery, chemotherapy, and immunotherapy to enhance treatment outcomes. This review examines the current research on MWA's technical innovations, clinical applications, and its potential in improving cancer treatment efficacy.

Surgery or Percutaneous Ablation for Liver Tumors? The Key Points Are: When, Where, and How Large

The most recent comparisons between liver resection (LR) and percutaneous thermal ablation (PTA) reported similar efficacy and survival outcomes for primary and secondary liver tumors ≤ 3 cm in size. Nevertheless, LR still remains the most popular treatment strategy worldwide, and percutaneous ablation is usually reserved to patients who are not surgical candidates. However, in our opinion, the debate should no longer be what is the most effective treatment for patients with resectable small liver cancer who are not candidates for liver transplantation, but rather when LR or PTA are best suited to the individual patient. Subcapsular tumors or tumors closely adjacent to critical structures or vulnerable organs should undergo LR because ablation can often not achieve an adequate safety margin. Conversely, PTA should be considered the first choice to treat central tumors because it has lower complication rates, lower costs, and shorter hospital stay. Furthermore, recent technical improvements in tumor targeting and accurate assessment of the extent of the safety margin, such as stereotactic navigation, fusion imaging and software powered by Artificial Intelligence enabling the immediate comparison between the pre-procedure planned margins and the ablation area, are also changing the approach to tumors larger than 3 cm. The next trials should be aimed at investigating up to what tumor size PTA supported by these advanced technologies can achieve outcomes comparable to LR.

Histotripsy of Liver Tumors: Patient Selection, Ethical Discussions, and How We Do It

Liver malignancies, both primary and metastatic tumors, are a major cause of cancer-related mortality. Colorectal cancer alone results in liver metastases in nearly 50% of patients, with approximately 85% presenting with unresectable disease. Similarly, hepatocellular carcinoma and intrahepatic cholangiocarcinoma frequently present at advanced stages, limiting curative options. Systemic therapies provide modest survival benefits, underscoring the need for alternative treatments. Locoregional approaches, such as thermal ablation and chemoembolization, while effective, have notable limitations, including invasiveness, peri-procedural risks, and the requirement to interrupt systemic treatments. Histotripsy is a novel, non-invasive method that uses focused ultrasound-induced cavitation to enable precise tumor ablation without heat or radiation. Our institution utilizes a multidisciplinary tumor board approach to evaluate patients for histotripsy, particularly in cases involving unresectable disease, complex surgical candidacy, palliative intent related to disease control and symptom management, or as bridging therapy for transplantation. Early results, including preclinical data and the THERESA and #HOPE4LIVER trials, highlight its efficacy in treating liver tumors with minimal complications. This review outlines institutional protocols for histotripsy, covering pre- and post-procedural management, along with ethical considerations of current treatment paradigms. As a patient-centered approach, histotripsy offers a novel treatment option with a favorable safety profile and compatibility with systemic therapies.

Comprehensive cohort study: computer tomography-guided high-dose rate brachytherapy as metastasis-directed therapy for liver metastases from colorectal cancer in repeat oligoprogression

PURPOSE

The standard treatment for oligometastatic colorectal cancer includes systemic therapy, with surgery and metastasis-directed therapy as options. The optimal strategy, especially for repeat oligoprogression (rOP), remains unclear. We report outcomes of liver computer tomography-guided high-dose rate brachytherapy (CT-BRT) in this setting.

METHODS

This retrospective cohort study included colorectal cancer patients with liver-only oligoprogression during systemic therapy, meeting criteria of up to 5 liver metastases, CT-BRT eligibility, and ECOG status ≤ 2. Patients were followed for local response, progression-free survival (PFS), overall survival (OS), and toxicity. Response, according to RECIST 1.1, was initiated 6 months post-CT-BRT.

RESULTS

A total of 262 metastases were treated in 127 patients, with 67.7% receiving third-line or later systemic therapies. One to four liver metastases were found in 29.1%, 42.5%, 21.2%, and 7.1% of patients, respectively, with a median volume of 128 cm3. A median of 3 applicators was used, with CT-BRT doses of 15 Gy, 20 Gy, and 25 Gy given to 29.9%, 41.7%, and 28.3% of patients. At 6 months complete response occurred in 3.1%, progressive disease in 23.6%, partial response in 19.7%, and stable disease in 53.5%. Median PFS was 9 months, median OS was 16 months, with 1-year and 2-year OS rates of 65% and 16%, respectively. Liver-only metastases and objective response were associated with longer PFS. The G3 toxicity was 4.0%; no events > G3 were reported.

CONCLUSIONS

This largest study documents favorable outcomes of liver CT-BRT for rOP, establishing this method as a viable option in this indication.

Thermal ablation versus surgical resection of small-size colorectal liver metastases (COLLISION): an international, randomised, controlled, phase 3 non-inferiority trial

BACKGROUND

For patients with small-size colorectal liver metastases, growing evidence suggests thermal ablation to be associated with fewer adverse events and faster recovery than resection while also challenging resection in terms of local control and overall survival. This study assessed the potential non-inferiority of thermal ablation compared with surgical resection in patients with small-size resectable colorectal liver metastases.

METHODS

Adult patients (aged ≥18 years) from 14 centres in the Netherlands, Belgium, and Italy with ten or fewer small-size (≤3 cm) colorectal liver metastases, no extrahepatic metastases, and an Eastern Cooperative Oncology Group performance status of 0-2, were stratified per centre, and according to their disease burden, into low, intermediate, and high disease burden subgroups and randomly assigned 1:1 to receive either thermal ablation (experimental group) or surgical resection (control group) of all target colorectal liver metastases using the web-based module Castor electronic data capture with variable block sizes of 4, 6, and 8. Although at the operator's discretion, a minimally invasive approach in both treatment groups was recommended. The primary endpoint was overall survival, assessed in the intention-to-treat population. A hazard ratio (HR) of 1·30 was considered the upper limit of non-inferiority for the primary endpoint. A preplanned interim analysis with predefined stopping rules for futility (conditional power to prove the null hypothesis <20%) and early benefit (conditional power >90%, superior safety outcomes for the experimental group, and no difference or superiority regarding local control for the experimental group) was done 12 months after enrolment of 50% of the planned sample size. Safety was assessed per treatment group. This trial is registered with ClinicalTrials.gov, NCT03088150.

FINDINGS

Between Aug 7, 2017, and Feb 14, 2024, 300 patients were randomly assigned to the experimental group (n=148, 100 male [68%] and 48 female [32%]; median age 67·9 years [IQR 29·2-85·7]) or to the control group (n=148, 107 male [72%] and 41 female [28%]; median age 65·1 [IQR 31·4-87·4]); four patients (two in each treatment group) were excluded after randomisation because they were found to have other disease pathology. Median follow-up at the prespecified interim analysis was 28·9 months (IQR 0·3-77·8). The trial was stopped early for meeting the predefined stopping rules: (1) a conditional likelihood to prove non-inferiority for overall survival of 90·5% (median overall survival not reached in both groups; HR 1·05; 95% CI 0·69-1·58; p=0·83), (2) a non-inferior local control (median local control not reached in both groups; HR 0·13, 95% CI 0·02-1·06; p=0·057), and (3) a superior safety profile for the experimental group. Patients in the experimental group had fewer adverse events than those in the control group (28 [19%] vs 67 [46%]; p<0·0001). Serious adverse events occurred in 11 (7%) of 148 patients in the experimental group and 29 (20%) of 146 in the control group, mostly periprocedural haemorrhage requiring intervention (one [1%] vs eight [5%]), and infectious complications requiring intervention (six [4%] vs 11 [8%]). There were no treatment-related deaths in the experimental group and three treatment-related deaths (2%) in the control group (two due to postoperative cardiac complications and one due to sepsis and liver failure).

INTERPRETATION

The assumption that thermal ablation should be reserved for unresectable colorectal liver metastases requires re-evaluation and the preferred treatment should be individualised and based on clinical characteristics and available expertise.

FUNDING

Medtronic-Covidien.

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.

Microwave Ablation of Refractory Oligometastatic Non-Small Cell Lung Cancer in the Liver

PURPOSE

To evaluate safety and effectiveness of microwave ablation (MWA) in the treatment of liver metastases (LMs) secondary to non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

This retrospective study included patients with NSCLC who underwent MWA of LM from March 2015 to July 2022. Local tumor progression-free survival (LTPFS) and overall survival (OS) were estimated using competing risk analysis and the Kaplan-Meier method. Postprocedural adverse events were recorded according to the Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

RESULTS

Twenty-three patients with 32 LMs were treated in 27 MWA sessions. The mean dimension of the largest index tumor was 1.96 cm (SD ± 0.75). Technical success was 100%. Technical effectiveness was achieved in 26 (81.3%) of 32 tumors. The median length of follow-up was 37.7 months (interquartile range, 20.5-54.5 months). The median LTPFS was 16.3 months (95% confidence interval [CI], 7.87-44.10 months). The median OS was 31.7 months (95% CI, 11.1-65.8 months). Ablation margin was a significant factor for LTPFS, with tumors ablated without a measurable margin being more likely to progress than those with measurable margins (subdistribution hazard ratios [HRs], 0.008-0.024; P < .001). Older age (HR, 1.18; 95% CI, 1.09-1.28; P < .001) and presence of synchronous lung metastases (HR, 14.73; 95% CI, 1.86-116.95; P = .011) were significant predictors of OS. Serious adverse events (CTCAE Grade ≥3) within 30 days occurred in 2 (7.4%) of 27 sessions, including pulmonary embolus and severe abdominal pain.

CONCLUSIONS

Percutaneous MWA was a safe treatment for NSCLC LM, with longer survival noted in younger patients and those without synchronous lung tumors.

Microwave ablation for liver metastases from colorectal cancer: A comprehensive review of clinical efficacy and safety

Microwave ablation (MWA) is emerging as a highly effective treatment for colorectal liver metastases (CRLMs). This review explores the advantages of MWA compared to other ablative techniques such as radiofrequency ablation and cryoablation and highlights its clinical efficacy, safety, and technical considerations. MWA offers significant benefits, including higher intratumoral temperatures, larger ablation zones, and reduced susceptibility to the heat-sink effect, which make it particularly suitable for tumors near large blood vessels. This review details the patient selection criteria, procedural approaches, and the use of advanced imaging techniques to improve the precision and effectiveness of MWA. Clinical outcomes indicate that MWA achieves high rates of complete tumor ablation and long-term survival with a favorable safety profile. This review is significant because it provides updated insights into the expanding role of MWA in treating unresectable CRLM and its potential as an alternative to surgical resection for resectable tumors. By summarizing recent studies and clinical trials, this review highlights the comparative effectiveness, safety, and integration with systemic therapies of MWA. In conclusion, MWA is a promising treatment option for CRLM and offers outcomes comparable to or better than those of other ablative techniques. Future research should focus on optimizing technical parameters, integrating MWA with systemic therapies, and conducting large-scale randomized controlled trials to establish standardized treatment protocols. Advancing our understanding of MWA will enhance its application and improve long-term survival and quality of life for patients with CRLM.

How Can We Improve the Survival of Patients with Colorectal Liver Metastases Using Thermal Ablation?

Thermal ablation has been widely used for patients with small colorectal liver metastases (CRLMs), even for resectable cases; however, solid evidence has been scarce. (1) Thermal ablation versus liver resection. Some propensity-score matching studies using patients with balanced baseline characteristics have confirmed less invasiveness and the comparable survival benefits of thermal ablation to liver resection. A more recent pivotal randomized controlled trial comparing thermal ablation and liver resection was presented during the American Society of Clinical Oncology 2024 meeting. Diameter ≤ 3 cm, ten or fewer resectable and ablatable CRLMs were assigned to thermal ablation or liver resection. No differences were observed in the overall survival and local and distant progression-free survival with less morbidity. (2) Combination of thermal ablation and liver resection. Four matching studies demonstrated comparable data between the combination and liver resection alone groups in the long-term survival and recurrence rates without increasing the postoperative complication rates. The selection of the two approaches depends primarily on the number, size, and location of the CRLMs. (3) Chemotherapy in combination with thermal ablation. A propensity-score matching study comparing thermal ablation ± neoadjuvant chemotherapy was conducted. The addition of neoadjuvant chemotherapy was an independent predictive factor for good progression-free survival without increasing morbidity. Two randomized controlled trials demonstrated that additional thermal ablation to systemic chemotherapy can improve the overall survival for initially unresectable CRLMs. (4) Conclusions. Thermal ablation can provide survival benefits for patients with CRLMs in various situations, keeping adequate indications.

Pushing boundaries: simultaneous minimal-invasive resection of complex colorectal liver metastases and its primary tumor

INTRODUCTION

Synchronous liver metastases occur in approximately 15-20% of patients with colorectal cancer. Optimal oncological treatment of oligometastatic disease combines surgical resection and systemic therapy. Open simultaneous resection of the primary and liver metastases is well described, but there is not much evidence for the increasing use of the minimally invasive approach. We here report the results of our experience of simultaneous minimally invasive resections.

METHODS

A prospective database of patients with resection of colorectal liver metastases (CRLM) at the Charité - Universitätsmedizin Berlin was used for retrospective data analysis. We report all patients undergoing simultaneous minimal invasive resection of colorectal cancer and its synchronous liver metastases between May 2015 and December 2021.

RESULTS

Out of 281 patients undergoing resection of CRLM, 33 (11.7%) patients had simultaneous minimal invasive resection of the colorectal primary. The primary tumor was located mostly within the rectum (n = 17; 48.6%), followed by the descending colon (n = 6; 17.1%). CRLM were localized in both liver lobes in 69.7% (n = 23) of cases. Following resection of the colorectal tumor, an anastomosis was performed in 31 of 33 patients (93.9%), with no anastomotic leakage observed in the follow up. Simultaneous liver resections were performed mostly as subsegment (n = 20) or bisegment resections (n = 11). Mean IWATE-Score of all hepatic resections was 5.5 (± 2.4). Complication rates (Clavien-Dindo ≥ 3) were similar compared between low/intermediate and advanced/expert difficulty for liver resection (n = 4, 17.4% vs. n = 2, 20.0%; p = 1.0). In one case conversion to open resection was required.

CONCLUSION

Our data indicate that simultaneous minimal invasive resection of CRLM and the primary tumor is a safe and feasible procedure. Complication rates were consistent across different levels of difficulty (low to expert) in liver resections. Therefore, indications for simultaneous resection may be expanded.

The Efficacy and Safety of a Microwave Ablation System with a Dipole Antenna Design Featuring Floating Sleeves and Anti-Phase Technology in Stereotactic Percutaneous Liver Tumor Ablation: Results from a Prospective Study

Purpose: To evaluate the efficacy and safety of the Surgnova Dophi™ M150E microwave ablation system in a prospective single-center observational study. Methods: A cohort of 50 patients with 77 primary or secondary liver tumors underwent CT-navigated stereotactic percutaneous microwave ablation with curative intention using the Surgnova Dophi™ M150E system. The endpoints were primary technique efficacy (PTE), number of complications, ablation defect dimensions, and sphericity index compared to previously reported findings. Results: The PTE was 97.4%, with complete ablation in 75 out of 77 tumors. Complications occurred in 10% of patients, with 4% classified as major. A comparison with previous in vivo data confirmed the reliability of the system in achieving reproducible and predictable ablation results. Conclusions: Stereotactic percutaneous microwave ablation with the Surgnova Dophi™ M150E system is safe and effective for liver tumor treatment.

Change in tissue resistance after irreversible electroporation in liver tumors as an indicator of treatment success - A multi-center analysis with long term follow-up

INTRODUCTION

A nationwide multicenter study was performed to examine whether there is a correlation between decrease in tissue resistance and time to local tumor recurrence after irreversible electroporation (IRE) in patients with hepatocellular carcinoma (HCC) and colorectal cancer liver metastases (CRCLM).

METHODS

All patients treated with IRE for liver tumors in Sweden from 2011 until 2018 were included. Patient characteristics and recurrence patterns were obtained from medical records and radiological imaging. All procedural data from the IRE hardware at the three hospitals performing IRE were retrieved. The resistance during each pulse and the change during each treatment were calculated. The electrode pair with the smallest decrease in tissue resistance was used and compared with the time to LTP.

RESULTS

149 patients with 206 tumors were treated. Exclusion due to missing and inaccurate data resulted in 124 patients with 170 tumors for the analyses. In a multivariable Cox regression model, a smaller decrease in tissue resistance and larger tumor size were associated with shorter time to local tumor recurrence for CRCLM, but not for HCC.

CONCLUSION

There was an association between a decrease in tissue resistance and time to local tumor recurrence for CRCLM. The decrease in resistance, in combination with a rise in current, may be the parameters the interventionist should use during IRE to decide if the treatment is successful.

Ablative margin quantification using deformable versus rigid image registration in colorectal liver metastasis thermal ablation: a retrospective single-center study

PURPOSE

To investigate the correlation of minimal ablative margin (MAM) quantification using biomechanical deformable (DIR) versus intensity-based rigid image registration (RIR) with local outcomes following colorectal liver metastasis (CLM) thermal ablation.

METHODS

This retrospective single-institution study included consecutive patients undergoing thermal ablation between May 2016 and October 2021. Patients who did not have intraprocedural pre- and post-ablation contrast-enhanced CT images for MAM quantification or follow-up period less than 1 year without residual tumor or local tumor progression (LTP) were excluded. DIR and RIR methods were used to quantify the MAM. The registration accuracy was compared using Dice similarity coefficient (DSC). Area under the receiver operating characteristic curve (AUC) was used to test MAM in predicting local tumor outcomes.

RESULTS

A total of 72 patients (mean age 57; 44 men) with 139 tumors (mean diameter 1.5 cm ± 0.8 (SD)) were included. During a median follow-up of 29.4 months, there was one residual unablated tumor and the LTP rate was 17% (24/138). The ranges of DSC were 0.96-0.98 and 0.67-0.98 for DIR and RIR, respectively (p < 0.001). When using DIR, 27 (19%) tumors were partially or totally registered outside the liver, compared to 46 (33%) with RIR. Using DIR versus RIR, the corresponding median MAM was 4.7 mm versus 4.0 mm, respectively (p = 0.5). The AUC in predicting residual tumor and 1-year LTP for DIR versus RIR was 0.89 versus 0.72, respectively (p < 0.001).

CONCLUSION

Ablative margin quantified on intra-procedural CT imaging using DIR method outperformed RIR for predicting local outcomes of CLM thermal ablation.

CLINICAL RELEVANCE STATEMENT

The study supports the role of biomechanical deformable image registration as the preferred image registration method over rigid image registration for quantifying minimal ablative margins using intraprocedural contrast-enhanced CT images.

KEY POINTS

• Accurate and reproducible image registration is a prerequisite for clinical application of image-based ablation confirmation methods. • When compared to intensity-based rigid image registration, biomechanical deformable image registration for minimal ablative margin quantification was more accurate for liver registration using intraprocedural contrast-enhanced CT images. • Biomechanical deformable image registration outperformed intensity-based rigid image registration for predicting local tumor outcomes following colorectal liver metastasis thermal ablation.

Outcomes after Surgical Microwave Ablation for the Treatment of Colorectal Liver Metastasis

BACKGROUND

Colorectal cancer (CRC) is the third most common cause of cancer mortality worldwide. Of these, approximately 25% will have liver metastasis. We performed 394 microwave ablations (MWAs) and analyzed outcomes for survival and ablation failure.

STUDY DESIGN

We conducted a retrospective review of patients who underwent a surgical MWA at a single-center high-volume institution from October 2006 to September 2022 using a prospectively maintained database. The primary outcome was overall survival.

RESULTS

A total of 394 operations were performed on 328 patients with 842 tumors undergoing MWA. Median tumor size was 1.5 cm (range 0.4 to 7.0 cm), with the median number of tumors ablated per operation being 1 (range 1 to 11). A laparoscopic approach was used 77.9% of the time. Concomitant procedures were performed 63% of the time, most commonly hepatectomy (22.3%), cholecystectomy (17.5%), and colectomy (6.6%). Clavien-Dindo grade III or IV complication occurred in 12 patients (3.6%), and all of these patients had undergone concomitant procedures. Mortality within 30 days occurred in 4 patients (1.2%). The rate of incomplete ablation was 1.5% per tumor. Local recurrence occurred at a rate of 6.3% per tumor. Black patients were found to have a higher incidence of incomplete ablation and local recurrence. One-year survival probability was 91% (95% CI 87.9 to 94.3), with a mean overall survival of 57.6 months (95% CI 49.9 to 65.4 months).

CONCLUSIONS

Surgical MWA offers a low-morbidity approach to treatment of colorectal liver metastasis, with low rate of failure. This large series reviews the outcomes of MWA as definitive treatment for colorectal liver metastasis.

Emerging role of local treatment in the era of advanced systemic treatment in pancreatic cancer with liver metastasis: A systematic review and meta-analysis

BACKGROUND

Approximately 50% of pancreatic cancer cases are diagnosed with distant metastases, commonly in the liver, leading to poor prognosis. With modern chemotherapy regimens extending patient survival and stabilizing metastasis, there has been a rise in the use of local treatments. However, the effectiveness for local treatment remains unclear.

METHODS

PubMed, Embase, and Cochrane databases were searched for studies reporting the survival outcomes of pancreatic cancer cases with isolated synchronous or metachronous liver metastases who underwent curative-intent local treatment. Hazard ratios were combined using a random-effects model.

RESULTS

The full texts of 102 studies were screened, and 14 retrospective studies were included in the meta-analysis. Among patients with synchronous liver metastases, overall survival was significantly better in those who underwent curative-intent local treatment than in those who did not (hazard ratio [HR]: 0.35, 95% confidence interval [CI]: 0.24-0.52). Among patients with metachronous liver metastases, overall survival was also significantly better in those who underwent curative-intent local treatment than in those who did not (HR 0.37, 95% CI: 0.19-0.73).

CONCLUSIONS

Curative-intent local treatment may be a feasible option for highly selected pancreatic cancer cases with liver metastases. However, the optimal strategy for local treatments should be explored in future studies.

New trends in surgery for colorectal liver metastasis

By presenting the most up-to-date findings and incorporating the latest evidence, this article seeks to present a comprehensive guide for navigating the complexities inherent in the management of colorectal liver metastasis. It aims to serve as a valuable resource offering clinicians and healthcare professionals an understanding of the diverse modalities and approaches available for treating this challenging and multifaceted disease. In an era of rapidly evolving medical knowledge, this article examines the latest insights to make informed decisions in the realm of colorectal liver metastasis management. The article does not only highlight the up-to-date knowledge but also provides the evidence for existing therapeutic strategies. This practical tool provides evidence-based recommendations to clinicians, thereby contributing to the ongoing advancement of effective treatment strategies for this challenging disease.

Local-Regional Therapy for Oligometastatic Colorectal Cancer

ABSTRACT

Colorectal cancer is one of the most common malignancies in the United States as well as a leading cause of cancer-related death. Upward of 30% of patients ultimately develop metastatic disease, most commonly to the liver and lung. Untreated, patients have poor survival. Historically, patients with oligometastatic disease were treated with resection leading to long-term survival; however, there are many patients who are not surgical candidates. Innovations in thermal ablation, hepatic artery infusions, chemoembolization and radioembolization, and stereotactic ablative radiation have led to an expansion of patients eligible for local therapy. This review examines the evidence behind each modality for the most common locations of oligometastatic colorectal cancer.

Challenges and Opportunities for Precision Surgery for Colorectal Liver Metastases

The incidence of colorectal cancer and colorectal liver metastases (CRLM) is increasing globally due to an interaction of environmental and genetic factors. A minority of patients with CRLM have surgically resectable disease, but for those who have resection as part of multimodal therapy for their disease, long-term survival has been shown. Precision surgery-the idea of careful patient selection and targeting of surgical intervention, such that treatments shown to be proven to benefit on a population level are the optimal treatment for each individual patient-is the new paradigm of care. Key to this is the understanding of tumour molecular biology and clinically relevant mutations, such as KRAS, BRAF, and microsatellite instability (MSI), which can predict poorer overall outcomes and a poorer response to systemic therapy. The emergence of immunotherapy and hepatic artery infusion (HAI) pumps show potential to convert previously unresectable disease to resectable disease, in addition to established systemic and locoregional therapies, but the surgeon must be wary of poor-quality livers and the spectre of post-hepatectomy liver failure (PHLF). Volume modulation, a cornerstone of hepatic surgery for a generation, has been given a shot in the arm with the advent of liver venous depletion (LVD) ensuring significantly more hypertrophy of the future liver remnant (FLR). The optimal timing of liver resection for those patients with synchronous disease is yet to be truly established, but evidence would suggest that those patients requiring complex colorectal surgery and major liver resection are best served with a staged approach. In the operating room, parenchyma-preserving minimally invasive surgery (MIS) can dramatically reduce the surgical insult to the patient and lead to better perioperative outcomes, with quicker return to function.

Imaging Guidelines during Percutaneous Liver Ablation to Optimize Outcomes and Patient Safety

Image-guided ablation procedures have become a mainstay in cancer therapy. Typically performed from a percutaneous approach, thermal-based ablation procedures rely heavily on imaging guidance both prior to and during the procedure itself. Advances in imaging as they relate to ablation procedures are as important to successful treatments as advancements in the ablation technology itself. Imaging as it relates to procedural planning, targeting and monitoring, and assessment of procedural endpoint is the focus of this article.

Achievement of textbook outcome after hepatectomy combined with thermal ablation for colorectal liver metastases

BACKGROUND

Hepatic resection combined with intraoperative ablation has been described as a technical solution potentially widening the resectability rate of patients with colorectal liver metastases (CRLM). Nevertheless, the perioperative and oncological benefit provided by this combined approach remains unclear. We hypothesized that textbook outcome (TO), which is a composite measure achieved for patients for whom some desired health indicators are met, may help to refine the indications of this approach.

METHODS

Patients submitted to hepatectomy with curative intent in combination with radiofrequency ablation or microwave ablation for CRLM ≤ 3 cm in two tertiary referral centers were included. TO was defined according to a recent definition for liver surgery based on a Delphi process including also the achievement of complete radiological response of the ablated lesion/s at 4 weeks.

RESULTS

Between 2015 and 2022, 112 patients were enrolled. Among them, 63 (56.2%) achieved a TO. According to multivariate analysis, minimally invasive (MI) approach (OR 2.72, 95% CI 0.99-7.48, p = 0.050), simultaneous CR resection (OR 0.28, 95% CI 0.11-0.70, p = 0.007), tumor burden score (OR 0.89, 95% CI 0.82-0.96, p = 0.004), and major hepatectomy (OR 0.12, 95% CI 0.03-0.52, p = 0.004) were significantly associated with the achievement of TO. Median overall survival was longer in those patients who were able to achieve a TO compared to those who did not.

CONCLUSIONS

The combination of hepatectomy and ablation constitutes a valuable solution in patients affected by multiple CRLM and it may provide, also using a MI approach, adequate perioperative and oncological outcomes, allowing to achieve TO, however, in a selected number of patients and depending on several factors including the burden of disease.

Three-Dimensional Margin as a Predictor of Local Tumor Progression after Microwave Ablation: Intraprocedural versus 4-8-Week Postablation Assessment

PURPOSE

To evaluate the prognostic accuracy of intraprocedural and 4-8-week (current standard) post-microwave ablation zone (AZ) and margin assessments for prediction of local tumor progression (LTP) using 3-dimensional (3D) software.

MATERIALS AND METHODS

Data regarding 100 colorectal liver metastases (CLMs) in 75 patients were collected from 2 prospective fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT)-guided microwave ablation (MWA) trials. The target CLMs and theoretical 5- and 10-mm margins were segmented and registered intraprocedurally and at 4-8 weeks after MWA contrast-enhanced CT (or magnetic resonance [MR] imaging) using the same methodology and 3D software. Tumor and 5- and 10-mm minimal margin (MM) volumes not covered by the AZ were defined as volumes of insufficient coverage (VICs). The intraprocedural and 4-8-week post-MWA VICs were compared as predictors of LTP using receiver operating characteristic curve analysis.

RESULTS

The median follow-up time was 19.6 months (interquartile range, 7.97-36.5 months). VICs for 5- and 10-mm MMs were predictive of LTP at both time assessments. The highest accuracy for the prediction of LTP was documented with the intra-ablation 5-mm VIC (area under the curve [AUC], 0.78; 95% confidence interval, 0.66-0.89). LTP for a VIC of 6-10-mm margin category was 11.4% compared with 4.3% for >10-mm margin category (P < .001).

CONCLUSIONS

A 3D 5-mm MM is a critical endpoint of thermal ablation, whereas optimal local tumor control is noted with a 10-mm MM. Higher AUCs for prediction of LTP were achieved for intraprocedural evaluation than for the 4-8-week postablation 3D evaluation of the AZ.

Machine learning-based radiomic analysis and growth visualization for ablation site recurrence diagnosis in follow-up CT

OBJECTIVES

Detecting ablation site recurrence (ASR) after thermal ablation remains a challenge for radiologists due to the similarity between tumor recurrence and post-ablative changes. Radiomic analysis and machine learning methods may show additional value in addressing this challenge. The present study primarily sought to determine the efficacy of radiomic analysis in detecting ASR on follow-up computed tomography (CT) scans. The second aim was to develop a visualization tool capable of emphasizing regions of ASR between follow-up scans in individual patients.

MATERIALS AND METHODS

Lasso regression and Extreme Gradient Boosting (XGBoost) classifiers were employed for modeling radiomic features extracted from regions of interest delineated by two radiologists. A leave-one-out test (LOOT) was utilized for performance evaluation. A visualization method, creating difference heatmaps (diff-maps) between two follow-up scans, was developed to emphasize regions of growth and thereby highlighting potential ASR.

RESULTS

A total of 55 patients, including 20 with and 35 without ASR, were included in the radiomic analysis. The best performing model was achieved by Lasso regression tested with the LOOT approach, reaching an area under the curve (AUC) of 0.97 and an accuracy of 92.73%. The XGBoost classifier demonstrated better performance when trained with all extracted radiomic features than without feature selection, achieving an AUC of 0.93 and an accuracy of 89.09%. The diff-maps correctly highlighted post-ablative liver tumor recurrence in all patients.

CONCLUSIONS

Machine learning-based radiomic analysis and growth visualization proved effective in detecting ablation site recurrence on follow-up CT scans.

Trends and overall survival after combined liver resection and thermal ablation of colorectal liver metastases: a nationwide population-based propensity score-matched study

BACKGROUND

In colorectal liver metastases (CRLM) patients, combination of liver resection and ablation permit a more parenchymal-sparing approach. This study assessed trends in use of combined resection and ablation, outcomes, and overall survival (OS).

METHODS

This population-based study included all CRLM patients who underwent liver resection between 2014 and 2022. To assess OS, data was linked to two databases containing date of death for patients treated between 2014 and 2018. Hospital variation in the use of combined minor liver resection and ablation versus major liver resection alone in patients with 2-3 CRLM and ≤3 cm was assessed. Propensity score matching (PSM) was applied to evaluate outcomes.

RESULTS

This study included 3593 patients, of whom 1336 (37.2%) underwent combined resection and ablation. Combined resection increased from 31.7% in 2014 to 47.9% in 2022. Significant hospital variation (range 5.9-53.8%) was observed in the use of combined minor liver resection and ablation. PSM resulted in 1005 patients in each group. Major morbidity was not different (11.6% vs. 5%, P = 1.00). Liver failure occurred less often after combined resection and ablation (1.9% vs. 0.6%, P = 0.017). Five-year OS rates were not different (39.3% vs. 33.9%, P = 0.145).

CONCLUSION

Combined resection and ablation should be available and considered as an alternative to resection alone in any patient with multiple metastases.

Treatment of Oligometastatic GI Cancers

Oligometastatic state is believed to potentially represent a transitional stage between early, locoregional state disease and widely metastatic disease. Historically, locoregional approaches, particularly in advanced colorectal cancers, have demonstrated efficacy in select patients with limited burden of metastatic disease. Recent strides in systemic therapies, including biomarker-based treatments and immunotherapy, alongside innovations in surgical techniques and novel locoregional approaches such as stereotactic radiotherapy and ablation, have ushered in a new era of therapeutic possibilities across all oligometastatic GI cancers. Despite these advancements, there remains a significant gap in high-quality prospective evidence guiding patient selection and treatment decisions across various disease types. Ongoing clinical trials are anticipated to provide crucial insights into oligometastatic states, fostering the refinement of disease-specific oligometastatic state definitions and treatment algorithms. This article reviews existing data on the management of oligometastatic GI cancer, summarizes current state of knowledge for each disease state, and provides updates on ongoing studies in this space.

Tata Memorial Centre Evidence Based Management of Colorectal cancer

This review article examines the evidence-based management of colorectal cancers, focusing on topics characterized by ongoing debates and evolving evidence. To contribute to the scientific discourse, we intentionally exclude subjects with established guidelines, concentrating instead on areas where the current understanding is dynamic. Our analysis encompasses a thorough exploration of critical themes, including the evidence surrounding complete mesocolic excision and D3 lymphadenectomy in colon cancers. Additionally, we delve into the evolving landscape of perioperative chemotherapy in both colon and rectal cancers, considering its nuanced role in the context of contemporary treatment strategies. Advancements in surgical techniques are a pivotal aspect of our discussion, with an emphasis on the utilization of minimally invasive approaches such as laparoscopy and robotic surgery in both colon and rectal cancers, including advanced rectal cases. Moving beyond conventional radical procedures, we scrutinize the feasibility and implications of endoscopic resections for small tumors, explore the paradigm of organ preservation in locally advanced rectal cancers, and assess the utility of total neoadjuvant therapy in the current treatment landscape. Our final segment reviews pivotal trials that have significantly influenced the management of colorectal liver and peritoneal metastasis.

The Importance of Optimal Thermal Ablation Margins in Colorectal Liver Metastases: A Systematic Review and Meta-Analysis of 21 Studies

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer-related deaths in the US. Thermal ablation (TA) can be a comparable alternative to partial hepatectomy for selected cases when eradication of all visible tumor with an ablative margin of greater than 5 mm is achieved. This systematic review and meta-analysis aimed to encapsulate the current clinical evidence concerning the optimal TA margin for local cure in patients with colorectal liver metastases (CLM).

METHODS

MEDLINE, EMBASE, and the CENTRAL databases were systematically searched from inception until 1 May 2023, in accordance with the PRISMA Guidelines. Measure of effect included the risk ratio (RR) with 95% confidence interval (CI) using the random-effects model.

RESULTS

Overall, 21 studies were included, comprising 2005 participants and 2873 ablated CLMs. TA with margins less than 5 mm were associated with a 3.6 times higher risk for LTP (n = 21 studies, RR: 3.60; 95% CI: 2.58-5.03; p-value < 0.001). When margins less than 5 mm were additionally confirmed by using 3D software, a 5.1 times higher risk for LTP (n = 4 studies, RR: 5.10; 95% CI: 1.45-17.90; p-value < 0.001) was recorded. Moreover, a thermal ablation margin of less than 10 mm but over 5 mm remained significantly associated with 3.64 times higher risk for LTP vs. minimal margin larger than 10 mm (n = 7 studies, RR: 3.64; 95% CI: 1.31-10.10; p-value < 0.001).

CONCLUSIONS

This meta-analysis solidifies that a minimal ablation margin over 5 mm is the minimum critical endpoint required, whereas a minimal margin of at least 10 mm yields optimal local tumor control after TA of CLMs.

Stereotactic ablation: A game changer?

For both primary and metastatic liver cancer, thermal ablation represents an interesting alternative to surgery. However, except for a small fraction of patients, conventional ultrasound- and CT-guided single-probe approaches have not achieved oncologic outcomes comparable with surgery. In this overview, we describe our stereotactic ablation workflow and discuss the short- and long-term results of stereotactic radiofrequency ablation (SRFA) and stereotactic microwave ablation (SMWA) for the treatment of primary and secondary liver tumours. The advantages of this method are discussed together with a summary of the existing stereotactic techniques for thermal ablation and the clinical data that support them. Stereotactic ablation is based on an optical navigation system and a specialized aiming tool. The workflow includes advanced three-dimensional planning, precise needle/probe placements according to the plan and intraoperative image fusion to check the needle positions and the ablation margins. Stereotactic ablation offers all the advantages of a minimally invasive procedure while producing oncological results comparable with surgery. The number of locally treatable liver cancers may be significantly expanded with these cutting-edge instruments and methods. We firmly believe that it can become a cornerstone in the treatment of liver cancers.

A Review of Resection and Surgical Ablation for Primary and Secondary Liver Cancers

The surgical management of primary and secondary liver tumors is constantly evolving. Patient selection, particularly with regard to determining resectability, is vital to the success of programs directed toward invasive treatments of liver tumors. Particular attention should be paid toward determining whether patients are best served with surgical resection or ablative therapies. A multidisciplinary approach is necessary to provide optimal care to patients with liver malignancy.

Percutaneous image-guided ablation for hepatic metastases

The presence of hepatic metastases indicates advanced disease and is associated with significant morbidity and mortality, especially when the hepatic disease is not amenable to locoregional treatments. The primary tumour of origin, the distribution and extent of metastatic disease, the underlying liver reserve, the patient performance status and the presence of comorbidities are factors that determine whether a patient will benefit from hepatectomy or local curative-intent treatments. For patients with metastatic colorectal cancer, the most common primary cancer that spreads to the liver, several studies have demonstrated a survival benefit for patients who can be treated with hepatectomy and/or percutaneous ablation, compared to those treated with chemotherapy alone. Despite advances in surgical techniques increasing the percentage of patients eligible for surgery, most patients have unresectable disease or are poor surgical candidates. Percutaneous ablation can be used to provide local disease control and prolong survival for both surgical and non-surgical candidates. This is typically offered to patients with small hepatic metastases that can be ablated with optimal (≥10 mm) or at least adequate minimum ablation margins (≥5 mm), as high local tumour control rates can be achieved for these patients which are comparable to surgical resection. This review summarizes available evidence and outcomes following percutaneous ablation of the most frequently encountered types of hepatic metastases in the clinical practice of interventional oncology. Patient selection, technical considerations, follow-up protocols and oncologic outcomes are presented and discussed.

Liver-Directed Therapy Combined with Systemic Therapy: Current Status and Future Directions

In the past several decades, major advances in both systemic and locoregional therapies have been made for many cancer patients. This has led to modern cancer treatment algorithms frequently calling for active interventions by multiple subspecialists at the same time. One of the areas where this can be clearly seen is the concomitant use of locoregional and systemic therapies in patients with primary or secondary cancers of the liver. These combined algorithms have gained favor over the last decade and are largely focused on the allure of the combined ability to control systemic disease while at the same time addressing refractory/resistant clonal populations. While the general concept has gained favor and is likely to only increase in popularity with the continued establishment of viable immunotherapy treatments, for many patients questions remain. Lingering concerns over the increase in toxicity when combining treatment methods, patient selection, and sequencing remain for multiple cancer patient populations. While further work remains, some of these questions have been addressed in the literature. This article reviews the available data on three commonly treated primary and secondary cancers of the liver, namely, hepatocellular carcinoma, cholangiocarcinoma, and metastatic colorectal cancer. Furthermore, strengths and weaknesses are reviewed and future directions are discussed.