The local efficacy and influencing factors of ultrasound-guided percutaneous microwave ablation in colorectal liver metastases: a review of a 4-year experience at a single center

Habitat Radiomics Based on MRI for Predicting Metachronous Liver Metastasis in Locally Advanced Rectal Cancer: a Two‑center Study

RATIONALE AND OBJECTIVES

This study aimed to explore the feasibility of using habitat radiomics based on magnetic resonance imaging (MRI) to predict metachronous liver metastasis (MLM) in locally advanced rectal cancer (LARC) patients. A nomogram was developed by integrating multiple factors to enhance predictive accuracy.

METHODS

Retrospective data from 385 LARC patients across two centers were gathered. The data from Center 1 were split into a training set of 203 patients and an internal validation set of 87 patients, while Center 2 provided an external test set of 95 patients. K - means clustering was used on T2 - weighted images, and the region of interest was extended at different thicknesses. After feature extraction and selection, four machine - learning algorithms were utilized to build radiomics models. A nomogram was created by combining habitat radiomics, conventional radiomics, and clinical independent predictors. Model performance was evaluated by the AUC, and clinical utility was assessed through calibration curve and DCA.

RESULTS

Habitat radiomics outperformed other single models in predicting MLM, with AUCs of 0.926, 0.864, and 0.851 in respective sets. The integrated nomogram achieved even higher AUCs of 0.959, 0.925, and 0.889. DCA and calibration curve analysis showed its high net benefit and good calibration.

CONCLUSION

MRI - based habitat radiomics can effectively predict MLM in LARC patients. The integrated nomogram has optimal predictive performance and improves model accuracy significantly.

Lipoic Acid/Choline Ionic Liquid Enhanced Intratumoral Heat/Mass Transfer for Suppressing Thermo-Mediated Tumor Relapse and Metastasis

Thermal ablation (TA) is widely used for clinical treatment of various cancers. However, TA often struggles to efficiently kill tumor cells without injuring adjacent normal tissues/cells, leading to thermo-mediated tumor relapse and metastasis, owing to the immunosuppressive microenvironment surrounding residual tumor cells. In this study, a temperature-sensitive ionic liquid composed of lipoic acid and choline (LACH/PNA) is developed as a multifunctional TA sensitizer to suppress tumor metastasis induced by incomplete microwave ablation. LACH/PNA exhibits a high diffusion coefficient by disrupting the tumor matrix and modulating cancer-associated fibroblasts, thereby facilitating heat and mass transfer in tumors. LACH/PNA demonstrates greater cytotoxicity toward hepatoma cells than on normal hepatocytes with this effect further intensified by thermal treatment. These findings highlight LACH/PNA as a promising multifunctional sensitizer for clinical chemoablation-microwave ablation synergy.

Pathogenetic development, diagnosis and clinical therapeutic approaches for liver metastasis from colorectal cancer (Review)

Colorectal cancer (CRC) is a prevalent malignancy and a significant proportion of patients with CRC develop liver metastasis (CRLM), which is a major contributor to CRC‑related mortality. The present review aimed to comprehensively examine the pathogenetic development and diagnosis of CRLM and the clinical therapeutic approaches for treatment of this disease. The molecular mechanisms underlying CRLM were discussed, including the role of the tumour microenvironment and epithelial‑mesenchymal transition. The present review also highlighted the importance of early detection and the current challenges in predicting the development of CRLM. Various treatment strategies were reviewed, including surgical resection, chemotherapy and immunotherapy, and the potential of novel therapies, such as selective internal radiation therapy and Traditional Chinese Medicine. Despite recent advancements in treatment options, the treatment of CRLM remains a therapeutic challenge due to the complexity of the liver microenvironment and the heterogeneity of CRC. The present review emphasized the need for a multidisciplinary approach and the integration of emerging therapies to improve patient outcomes.

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 for colorectal liver metastases with ultrasound fusion imaging assistance: a stratified analysis study based on tumor size and location

PURPOSE

To investigate the efficacy of ultrasound fusion imaging-assisted microwave ablation (MWA) for patients with colorectal liver metastases (CRLM) based on stratified analysis of tumor size and location.

METHODS

Patients with CRLM who underwent ultrasound fusion imaging-assisted MWA in our hospital between February 2020 and February 2023 were enrolled into this retrospective study. Ultrasound fusion imaging was used for detection, guidance, monitoring and immediate evaluation throughout the MWA procedures. Technical success, technique efficacy, local tumor progression (LTP), intrahepatic progression and overall survival (OS) were recorded and analyzed. The subgroup analysis of intrahepatic progression of MWA for CRLM was performed according to tumor size and location.

RESULTS

A total of 51 patients with 122 nodules were enrolled. Both technical success and technique efficacy were acquired in all nodules. In a median follow-up period of 19 months, 2.5% of the nodules (3/122) were observed LTP. The 1-year and 2-year cumulative intrahepatic progression rates were 38.7% and 52.1% respectively. Patients were divided into subgroups according to tumor size (≥ 30 mm, n = 13; < 30 mm, n = 38) and tumor location (perivascular, n = 20; non-perivascular, n = 31 and subcapsular, n = 36; non-subcapsular, n = 15). The cumulative intrahepatic progression rates were similar between the subgroups regarding tumor size and perivascular location, while significantly higher in the subcapsular group than in the non-subcapsular group (p = 0.021).

CONCLUSION

Ultrasound fusion imaging-assisted MWA exhibited satisfactory local efficacy for CRLM, especially for non-subcapsular tumors.

Prediction of Local Tumor Progression After Thermal Ablation of Colorectal Cancer Liver Metastases Based on Magnetic Resonance Imaging Δ-Radiomics

PURPOSE

This study aimed to enhance the predictability of local tumor progression (LTP) postthermal ablation in patients with colorectal cancer liver metastases (CRLMs). A sophisticated approach integrating magnetic resonance imaging (MRI) Δ-radiomics and clinical feature-based modeling was employed.

MATERIALS AND METHODS

In this retrospective study, 37 patients with CRLM were included, encompassing a total of 57 tumors. Radiomics features were derived by delineating the images of lesions pretreatment and images of the ablation zones posttreatment. The change in these features, termed Δ-radiomics, was calculated by subtracting preprocedure values from postprocedure values. Three models were developed using the least absolute shrinkage and selection operators (LASSO) and logistic regression: the preoperative lesion model, the postoperative ablation area model, and the Δ model. Additionally, a composite model incorporating identified clinical features predictive of early treatment success was created to assess its prognostic utility for LTP.

RESULTS

LTP was observed in 20 out of the 57 lesions (35%). The clinical model identified, tumor size (P = 0.010), and ΔCEA (P = 0.044) as factors significantly associated with increased LTP risk postsurgery. Among the three models, the Δ model demonstrated the highest AUC value (T2WI AUC in training, 0.856; Delay AUC, 0.909; T2WI AUC in testing, 0.812; Delay AUC, 0.875), whereas the combined model yielded optimal performance (T2WI AUC in training, 0.911; Delay AUC, 0.954; T2WI AUC in testing, 0.847; Delay AUC, 0.917). Despite its superior AUC values, no significant difference was noted when comparing the performance of the combined model across the two sequences (P = 0.6087).

CONCLUSIONS

Combined models incorporating clinical data and Δ-radiomics features serve as valuable indicators for predicting LTP following thermal ablation in patients with CRLM.

Comparative Evaluation of CEUS and CECT in the Detection of Liver Metastases of Middle and Low Rectal Cancer

Objective

To explore the imaging manifestations and clinical application value of contrast-enhanced ultrasound (CEUS) in liver metastases of middle and low rectal cancer by performing CEUS in patients. Additionally, we compared the results of CEUS with those of abdominal contrast-enhanced computed tomography (CECT) to assess the reliability of diagnosing liver metastases in patients with middle and low rectal cancer.

Methods

Hepatic CEUS was performed in 1095 patients with middle and low rectal cancer, and all patients underwent abdominal CECT examinations to determine the presence or absence of liver metastases. The results of both examinations were compared to evaluate the value of hepatic CEUS for detecting liver metastases in patients with middle and low rectal cancer.

Results

Among 1095 patients with middle and low rectal cancer, 132 were diagnosed with liver metastases of middle and low rectal cancer. 130 cases of liver metastases of rectal cancer were identified using hepatic CEUS, whereas 126 cases were identified using abdominal CECT. The detection rates of hepatic CEUS and abdominal CECT for liver metastases of middle and low rectal cancer showed no statistically significant differences (P > 0.05). The Kappa value for the diagnosis of liver metastases of middle and low rectal cancer between hepatic CEUS and abdominal CECT was 0.974 (P < 0.001), indicating good consistency between the two imaging modalities in detecting liver metastases of middle and low rectal cancer.

Conclusion

Hepatic CEUS can be used to diagnose liver metastases in middle and low rectal cancer, providing crucial imaging evidence for clinical treatment planning. It exhibited higher sensitivity than that of abdominal CECT in diagnosing liver metastases of middle and low rectal cancer, enabling the identification of higher number of liver metastases of middle and low rectal cancer cases.

Thermal-responsive activation of engineered bacteria to trigger antitumor immunity post microwave ablation therapy

Incomplete tumor removal after microwave ablation (MWA), a widely used hyperthermia-based therapy, can result in tumor recurrence. Herein, attenuated Salmonella typhimurium VNP20009 is engineered to release interleukin-15&interleukin-15-receptor-alpha (IL-15&IL-15Rα) in response to mildly elevated temperature. Such 15&15R@VNP colonizes in tumors upon intravenous injection, and the expression of IL-15&IL-15Rα is triggered by MWA. Anti-tumor immune responses are elicited, efficiently suppressing tumor growth even after incomplete microwave ablation. We further design VNP20009 with thermal-responsive co-expression of both IL-15&IL-15Rα and soluble programmed cell death protein (sPD-1). Such sPD-1-15&15R@VNP can also reverse the functional suppression of immune cells driven by PD-1/PD-L1 axis, reinvigorating progenitor exhausted T cells, a critical subset of cytotoxic T lymphocytes responsive to immune checkpoint blockade. Such thermal-responsive engineered bacteria are thus a promising adjuvant therapy to potentiate tumor ablation therapies via effectively activating antitumor immunity.

Comparison of Effectiveness and Safety of Microwave Ablation of Colorectal Liver Metastases Adjacent versus Nonadjacent to the Diaphragm

PURPOSE

To compare the effectiveness and safety of percutaneous microwave ablation (MWA) for colorectal liver metastasis (CLM) adjacent versus nonadjacent to the diaphragm.

MATERIALS AND METHODS

This was a retrospective analysis of a prospectively created MWA database, from 2 prospective clinical trials for patients with CLM treated in a single tertiary center from 2012 to 2023. CLM adjacent to the diaphragm was defined as a tumor located <1 cm from the diaphragm. Minimal ablation margin (MM) was calculated with 3-dimensional software using postablation contrast-enhanced computed tomography (CT). Adverse events were assessed with Common Terminology Criteria for Adverse Events (CTCAE) v5.0 classification for 6 months.

RESULTS

Two hundred nine CLMs underwent 191 MWA sessions in 143 patients. Mean tumor diameter was 1.52 cm (SD ± 0.53). Eighty-three of 209 (39.7%) CLMs were adjacent to the diaphragm. There was no difference in local tumor progression-free survival (LTPFS) between CLMs adjacent and nonadjacent to the diaphragm (hazard ratio [HR], 0.65; 95% CI, 0.37-1.16; P = .15). MMs of 5-10 mm and >10 mm were documented in 49.3% versus 46.8% (P = .83) and 21.6% versus 12.6% (P = .16) for CLMs adjacent versus nonadjacent to the diaphragm, respectively. Twelve-month LTPFS was similar between groups (HR, 0.65; 95% CI, 0.37-1.16; P = .15) without local tumor progression for MM of >10 mm. There were 3 Grade IV adverse events: 1 diaphragmatic perforation, 1 liver abscess, and 1 biloma. Pneumothorax was associated with location adjacent to the diaphragm (P < .001) and transpulmonary approach (P < .001). Median length of hospital stay was 2 days (interquartile range [IQR], 1-3 days) for patients who needed thoracostomy (n = 20, 9.6%) compared with 1 day (IQR, 1-8 days) for those who did not, without long-term sequelae.

CONCLUSIONS

MWA of CLM adjacent to the diaphragm is effective and safe, without difference in success and 12-month LTPFS. Pneumothorax was associated with location adjacent to the diaphragm and thoracostomy that resulted in longer hospitalization without long-term sequelae.

Constructing a prognostic model for colorectal cancer with synchronous liver metastases after preoperative chemotherapy: a study based on SEER and an external validation cohort

BACKGROUND

The combination of preoperative chemotherapy and surgical treatment has been shown to significantly enhance the prognosis of colorectal cancer with liver metastases (CRLM) patients. Nevertheless, as a result of variations in clinicopathological parameters, the prognosis of this particular group of patients differs considerably. This study aimed to develop and evaluate Cox proportional risk regression model and competing risk regression model using two patient cohorts. The goal was to provide a more precise and personalized prognostic evaluation system.

METHODS

We collected information on individuals who had a pathological diagnosis of colorectal cancer between 2000 and 2019 from the Surveillance, Epidemiology, and End Results (SEER) Database. We obtained data from patients who underwent pathological diagnosis of colorectal cancer and got comprehensive therapy at the hospital between January 1, 2010, and June 1, 2022. The SEER data collected after screening according to the inclusion and exclusion criteria were separated into two cohorts: a training cohort (training cohort) and an internal validation cohort (internal validation cohort), using a random 1:1 split. Subgroup Kaplan-Meier (K-M) survival analyses were conducted on each of the three groups. The data that received following screening from the hospital were designated as the external validation cohort. The subsequent variables were chosen for additional examination: age, gender, marital status, race, tumor site, pretreatment carcinoembryonic antigen level, tumor size, T stage, N stage, pathological grade, number of tumor deposits, perineural invasion, number of regional lymph nodes examined, and number of positive regional lymph nodes. The primary endpoint was median overall survival (mOS). In the training cohort, we conducted univariate Cox regression analysis and utilized a stepwise regression approach, employing the Akaike information criterion (AIC) to select variables and create Cox proportional risk regression models. We evaluated the accuracy of the model using calibration curve, receiver operating characteristic curve (ROC), and area under curve (AUC). The effectiveness of the models was assessed using decision curve analysis (DCA). To evaluate the non-cancer-related outcomes, we analyzed variables that had significant impacts using subgroup cumulative incidence function (CIF) and Gray's test. These analyses were used to create competing risk regression models. Nomograms of the two models were constructed separately and prognostic predictions were made for the same patients in SEER database.

RESULTS

This study comprised a total of 735 individuals. The mOS of the training cohort, internal validation cohort, and QDU cohort was 55.00 months (95%CI 46.97-63.03), 48.00 months (95%CI 40.65-55.35), and 68.00 months (95%CI 54.91-81.08), respectively. The multivariate Cox regression analysis revealed that age, N stage, presence of perineural infiltration, number of tumor deposits and number of positive regional lymph nodes were identified as independent prognostic risk variables (p < 0.05). In comparison to the conventional TNM staging model, the Cox proportional risk regression model exhibited a higher C-index. After controlling for competing risk events, age, N stage, presence of perineural infiltration, number of tumor deposits, number of regional lymph nodes examined, and number of positive regional lymph nodes were independent predictors of the risk of cancer-specific mortality (p < 0.05).

CONCLUSION

We have developed a prognostic model to predict the survival of patients with synchronous CRLM who undergo preoperative chemotherapy and surgery. This model has been tested internally and externally, confirming its accuracy and reliability.

Multimodal Theranostic Nanoparticles for Necrosis Targeting, Fluorescence/SPECT Imaging, and Radiotherapy of Residual Tumors after Hepatocellular Carcinoma Ablation

Thermal ablation has been commonly used as an effective treatment for hepatocellular carcinoma; however, peri-necrotic tumor residues after ablation play a significant role in tumor recurrence and poor prognosis. Therefore, developing agents that can effectively target and eliminate residual tumors is critically needed. Necrosis targeting strategies have potential implications for evaluating tumor necrosis areas and treating the surrounding residual tumors. To address this issue, we have developed a biodegradable nanoparticle with necrosis avidity that is compatible with fluorescence imaging, single photon emission computed tomography (SPECT) imaging, and necrosis targeted radiotherapy. The nanoparticles were synthesized using iodine-131-labeled hypericin (131I-Hyp) as the core and amphiphilic copolymer poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) as the shell. The developed nanoparticle, PNP@(131I-Hyp), has a uniform spherical morphology with a size of 33.07 ± 3.94 and 45.93 ± 0.58 nm determined by cryogenic transmission electron microscopy (cryo-TEM) and dynamic light-scattering analysis (polydispersity index = 0.19 ± 0.01), respectively, and having a good stability and blood compatibility in vitro. In mouse subcutaneous ablated-residual tumor models, fluorescence and SPECT imaging demonstrated that PNP@(131I-Hyp) prominently accumulated in the tumor and was retained for as long as 168 h following intravenous injection. Moreover, ex vivo analyses showed that PNP@(131I-Hyp) mainly gathered in the necrotic zones of subcutaneous tumors and inhibited residual tumors by radiotherapy. In addition, histological examination of harvested organs and hematological analysis demonstrated that intravenous injection of 5 mCi/kg nanoparticles caused no gross abnormalities. This multifunctional nanoparticle, therefore, has necrosis imaging and targeted therapeutic effects on residual tumors after thermal ablation of hepatocellular carcinoma, showing potential for clinical application.

Case report: hepatic arterial infusion chemotherapy combined with sintilimab and lenvatinib for conversion therapy of colorectal cancer liver metastases

Background

Liver metastasis is one of the most common causes of death in patients with colorectal cancer. Therefore, improving the treatment effect of liver metastatic carcinoma of colorectal cancer is also one of the effective ways to improve the survival time of patients with colorectal cancer. The main treatment method for liver metastasis of colorectal cancer is preoperative neoadjuvant chemotherapy through intravenous administration. However, no one has reported a conversion therapy approach for the treatment of colorectal cancer liver metastases patients through arterial infusion chemotherapy combined with targeted agents and PD-1 monoclonal antibody. This case reports a conversion therapy method of liver metastases of colorectal cancer by hepatic arterial infusion chemotherapy (HAIC), sintilimab injection combined with lenvatinib to achieve radical resection of liver metastatic carcinoma after treatment.

Case presentation

The patient was a 69-year-old man who had previously undergone laparoscopic left hemicolectomy for descending colorectal cancer and multiple interventional and surgical treatments for hepatocellular carcinoma. During this treatment, the patient underwent radiological and serological tests, and primary liver cancer was considered at the initial diagnosis stage. Therefore, this liver malignant tumor lesion was treated according to the primary liver cancer treatment protocol before surgical resection. Therefore, the patient received HAIC combined with sintilimab injection and lenvatinib. After three treatment cycles, radiological examination showed no obvious tumor activity, alpha-fetoprotein (AFP) decreased to normal, protein induced by vitamin K absence or antagonist II (PIVKA II) decreased significantly, and the curative effect was evaluated as complete remission. Subsequently, we performed surgical resection of this liver lesion. The pathological response of left lobe tumor was partial remission (PR). Most of the tumors were necrotic and the necrosis rate was greater than 95%. A small amount of live tumor tissue remains (<5%). The pathological classification of this tumor was confirmed as moderately differentiated adenocarcinoma by immunohistochemical staining of multiple tumor indicators in the pathology department. No significant adverse drug events were observed in this patient during treatment.

Conclusion

Hepatic arterial infusion chemotherapy combined with sintilimab injection and lenvatinib conversion therapy provides the opportunity for radical surgical resection of colorectal cancer liver metastases.

Percutaneous ablation of colorectal liver metastases: a comparison between the outcomes of grayscale US guidance and Sonazoid CEUS Kupffer phase guidance using propensity score matching

PURPOSE

To assess the utility of Sonazoid contrast-enhanced ultrasound (CEUS) for guiding percutaneous microwave ablation (MWA) for colorectal liver metastases (CRLMs).

MATERIALS AND METHODS

The medical records of patients who had undergone ultrasound (US)-guided percutaneous MWA between July 2020 and June 2022, were reviewed. Propensity score matching (PSM) with a ratio of 1:1 was used to balance the potential bias between the grayscale US-guided and Sonazoid CEUS-guided groups. Local tumor progression (LTP), intrahepatic recurrence (IR), and complication rates were compared between the two groups.

RESULTS

Of 252 patients enrolled, 247 achieved complete ablation, and the technical effectiveness was 98.0% (247/252). Of these 247 patients, 158 were in the grayscale US-guided group and 89 in the Sonazoid CEUS-guided group. The median follow-up period was 14.6 months. After PSM, there were no significant differences in LTP, IR, or complication rates between the two groups (p = 0.100, p = 0.511, p > 0.99, respectively). Multivariate analysis identified tumor size ≥ 3 cm (hazard ratio [HR], 7.945; 95% CI, 2.591-24.370; p < 0.001), perivascular (HR, 2.331; 95% CI, 1.068-5.087; p = 0.034), and tumor depth > 8 cm (HR, 3.194; 95% CI, 1.439-7.091; p = 0.004) as significant factors associated with LTP. For tumors with poor vision on grayscale US, Sonazoid CEUS-guided ablation achieved a better LTP rate than grayscale US-guided ablation (3.7% vs.14.8%, p = 0.032).

CONCLUSION

For tumors with poor vision on grayscale US, Sonazoid CEUS guidance is recommended for better local tumor control.

Different power modes of microwave ablation for hepatocellular carcinoma: Evaluation of recurrence rate and factors related to recurrence

PURPOSE

To evaluate the safety and efficacy of different power modes(constant power and variable power) percutaneous microwave ablation (MWA) for treating hepatocellular carcinoma (HCC) and to predict the risk factors of recurrence after MWA.

MATERIALS AND METHODS

In this retrospective study, a total of 112 patients with solitary HCC were included from January 2015 to January 2021. All patients received MWA through a percutaneous approach that was guided by ultrasound, 45 patients received variable power MWA, and the remaining 67 were treated with constant power MWA. The complete ablation rates, local recurrence rates, complications, and short-term survival were analyzed. Possible risk factors for tumor recurrence were analyzed.

RESULTS

The complete ablation rates were 95.9% for the first ablation and 100% for the second ablation for ≤3 cm lesions. The complete ablation rates were 84.2%(95.9% versus 84.2%, p = 0.039) for the first ablation and 94.7% (100% versus 94.7%, p = 0.113) for the second ablation for 3-5 cm lesions. Local and distant recurrence rates were 18.7%(21/112) and 14.3%(16/112). The 1-, 2-year survival rates were 86.3 and 66.3%, respectively. Subgroup analysis showed that 1-, 2-year survival rates were 91.1% and 78.5% in ≤3 cm group, and were 74.4% and 40.9% in 3-5 cm group, respectively. Univariate analysis revealed that a positive correlation existed between the HBV DNA replication(p = 0.007), AFP level of pre-MWA(p = 0.001) and post-MWA(p<0.001), tumor diameter(p<0.001), irregular shape(p = 0.014), proximity to the risk location(p = 0.008), poor differentiation(p = 0.003), constant power(p = 0.028), length(p<0.001) and width of ablation zone(p = 0.001), and present complication(p<0.001), and early recurrence. Multivariate analysis identified HBV DNA replication(OR = 0.266, p = 0.036), AFP level of pre-MWA (OR = 4.001, p = 0.036), tumor diameter (OR = 2.153, p = 0.042), tumor location (OR = 0.910, p = 0.046), and width of ablation zone(OR = 2.530, p = 0.044) were independent prognosis factors causing postoperative HCC recurrence.

CONCLUSION

Variable power MWA of HCC appears to be a safe and effective treatment. HBV DNA, AFP level of pre-MWA, tumor diameter, tumor location, and width of ablation range appear to be independent predictors of tumor recurrence.

Unresectable Intermediate-Size (3-5 cm) Colorectal Liver Metastases: Stereotactic Ablative Body Radiotherapy Versus Microwave Ablation (COLLISION-XL): Protocol of a Phase II/III Multicentre Randomized Controlled Trial

BACKGROUND

Although microwave ablation (MWA) has a low complication rate and good efficacy for small-size (≤ 3 cm) colorectal liver metastases (CRLM), local control decreases with increasing size. Stereotactic body radiotherapy (SBRT) is gaining interest as a potential means to treat intermediate-size CRLM and might be less susceptible to increasing volume. The objective of this study is to compare the efficacy of MWA to SBRT in patients with unresectable, intermediate-size (3-5 cm) CRLM.

METHODS

In this two-arm, multicentre phase II/ III randomized controlled trial, 68 patients with 1-3 unresectable, intermediate-size CRLM suitable for both MWA and SBRT, will be included. Patients will be treated with MWA or SBRT as randomised. The Primary endpoint is local tumour progression-free survival (LTPFS) at 1 year (intention-to-treat analysis). Main secondary endpoints are overall survival, overall and distant progression-free survival (DPFS), local control (LC) and procedural morbidity and mortality and assessment of pain and quality of life.

DISCUSSION

Current guidelines lack clear recommendations for the local treatment of liver only intermediate-size, unresectable CRLM and studies comparing curative intent SBRT and thermal ablation are scarce. Although safety and feasibility to eradicate tumours ≤ 5 cm have been established, both techniques suffer from lower LTPFS and LC rates for larger-size tumours. For the treatment of unresectable intermediate-size CRLM clinical equipoise has been reached. We have designed a two-armed phase II/ III randomized controlled trial directly comparing SBRT to MWA for unresectable CRLM 3-5 cm.

LEVEL OF EVIDENCE

Level 1, phase II/ III Randomized controlled trial.

TRIAL REGISTRATION

NCT04081168, September 9th 2019.

Complications and local recurrence of malignant liver tumor after ablation in risk areas: a retrospective analysis

INTRODUCTION

Microwave ablation (MWA) is an effective local treatment for malignant liver tumors; however, its efficacy and safety for liver tumors adjacent to important organs are debatable.

PATIENTS AND METHODS

Forty-three cases with liver tumors adjacent to important organs were the risk group and 66 cases were the control group. The complications between two groups were compared by chi-square test and t-test. Local tumor recurrence (LTR) was analyzed by log-rank test. Factors affecting complications were analyzed by logistic regression and Spearman analyses. Factors affecting LTR were analyzed by Cox regression analysis. A receiver operating characteristic curve predicted pain treated with drugs and LTR.

RESULTS

We found no significant difference in complications and LTR between two groups. The risk group experienced lower ablation energy and more antennas per tumor than control group. Necrosis volume after MWA was positively correlated with pain; necrosis volume and ablation time were positively correlated with recovery duration. Major diameter of tumor >3 cm increased risk of LTR by 3.319-fold, good lipiodol deposition decreased risk of LTR by 73.4%. The area under the curve (AUC) for necrosis volume in predicting pain was 0.74, with a 69.1 cm3 cutoff. AUC for major diameter of tumor in predicting LTR was 0.68, with a 27.02 mm cutoff.

CONCLUSION

MWA on liver tumors in at-risk areas is safe and effective, this is largely affected by proper ablation energy, antennas per tumor, and experienced doctors. LTR is primarily determined by major diameter of tumor and lipiodol deposition status.

Prediction of Local Tumor Progression After Microwave Ablation in Colorectal Carcinoma Liver Metastases Patients by MRI Radiomics and Clinical Characteristics-Based Combined Model: Preliminary Results

PURPOSE

To investigate the predictability of local tumor progression (LTP) after microwave ablation (MWA) in colorectal carcinoma liver metastases (CRLM) patients by magnetic resonance imaging (MRI) radiomics and clinical characteristics-based combined model.

MATERIALS AND METHODS

Forty-two consecutive CRLM patients (67 tumors) with post-MWA complete response at 1st month MRI were included in this retrospective study. One hundred and eleven radiomics features were extracted for each tumor and for each phase by manual segmentation from pre-treatment MRI T2 fat-suppressed (Phase 2) and early arterial phase T1 fat-suppressed sequences (Phase 1). A clinical model was constructed using clinical data, two combined models were created with feature reduction and machine learning by combining clinical data and Phase 2 and Phase 1 radiomics features. The predicting performance for LTP development was investigated.

RESULTS

LTP developed in 7 patients (16.6%) and 11 tumors (16.4%). In the clinical model, the presence of extrahepatic metastases before MWA was associated with a high probability of LTP (p < 0.001). The pre-treatment levels of carbohydrate antigen 19-9 and carcinoembryonic antigen were higher in the LTP group (p = 0.010, p = 0.020, respectively). Patients with LTP had statistically significantly higher radiomics scores in both phases (p < 0.001 for Phase 2 and p = 0.001 for Phase 1). The classification performance of the combined model 2, created by using clinical data and Phase 2-based radiomics features, achieved the highest discriminative performance in predicting LTP (p = 0,014; the area under curve (AUC) value 0.981 (95% CI 0.948-0.990). The combined model 1, created using clinical data and Phase 1-based radiomics features (AUC value 0,927 (95% CI 0.860-0.993, p < 0.001)) and the clinical model alone [AUC value of 0.887 (95% CI 0.807-0.967, p < 0.001)] had similar performance.

CONCLUSION

Combined models based on clinical data and radiomics features obtained from T2 fat-suppressed and early arterial-phase T1 fat-suppressed MRI are valuable markers in predicting LTP after MWA in CRLM patients. Large-scale studies with internal and external validations are needed to come to a firm conclusion on the predictability of radiomics models in CRLM patients.

Rational Design of Biomaterials to Potentiate Cancer Thermal Therapy

Cancer thermal therapy, also known as hyperthermia therapy, has long been exploited to eradicate mass lesions that are now defined as cancer. With the development of corresponding technologies and equipment, local hyperthermia therapies such as radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound, have has been validated to effectively ablate tumors in modern clinical practice. However, they still face many shortcomings, including nonspecific damages to adjacent normal tissues and incomplete ablation particularly for large tumors, restricting their wide clinical usage. Attributed to their versatile physiochemical properties, biomaterials have been specially designed to potentiate local hyperthermia treatments according to their unique working principles. Meanwhile, biomaterial-based delivery systems are able to bridge hyperthermia therapies with other types of treatment strategies such as chemotherapy, radiotherapy and immunotherapy. Therefore, in this review, we discuss recent progress in the development of functional biomaterials to reinforce local hyperthermia by functioning as thermal sensitizers to endow more efficient tumor-localized thermal ablation and/or as delivery vehicles to synergize with other therapeutic modalities for combined cancer treatments. Thereafter, we provide a critical perspective on the further development of biomaterial-assisted local hyperthermia toward clinical applications.

Uncooled TATO microwave system for liver ablation

Aim: To evaluate the safety and efficacy of uncooled TATO microwave ablation (MWA) for primary and metastatic liver cancer. Materials & methods: This was a retrospective study on percutaneous liver ablations performed with TATO MWA. Twenty-five ablations were performed; 11 (44%) were performed for hepatocellular carcinoma, 14 (56%) for colorectal carcinoma, gastric and pancreatic metastases. Results: Adverse events were reported only in one (4%) ablation: an abscess that was observed in the ablated area and was resolved with a percutaneous drainage and antibiotic therapy. Local tumor control rate was 92% at the 3-month follow-up. Conclusion: TATO MWA was safe and effective with high reproducibility in treating primary and secondary liver cancer with satisfactory technical and clinical outcomes.

Deep learning model based on contrast-enhanced ultrasound for predicting early recurrence after thermal ablation of colorectal cancer liver metastasis

OBJECTIVES

To develop and validate a deep learning (DL) model based on quantitative analysis of contrast-enhanced ultrasound (CEUS) images that predicts early recurrence (ER) after thermal ablation (TA) of colorectal cancer liver metastasis (CRLM).

METHODS

Between January 2010 and May 2019, a total of 207 consecutive patients with CRLM with 13,248 slice images at three dynamic phases who received CEUS within 2 weeks before TA were retrospectively enrolled in two centres (153 for the training cohort (TC), 32 for the internal test cohort (ITC), and 22 for the external test cohort (ETC)). Clinical and CEUS data were used to develop and validate the clinical model, DL model, and DL combining with clinical (DL-C) model to predict ER after TA. The performance of these models was compared by the receiver operating characteristic curve (ROC) with the DeLong test.

RESULTS

After a median follow-up of 56 months, 49% (99/207) of patients experienced ER. Three key clinical features (preoperative chemotherapy (PC), lymph node metastasis of the primary colorectal cancer (LMPCC), and T stage) were used to develop the clinical model. The DL model yielded better performance than the clinical model in the ETC (AUC: 0.67 for the clinical model, 0.76 for the DL model). The DL-C model significantly outperformed the clinical model and DL model (AUC: 0.78 for the DL-C model in the ETC; both, p < 0.001).

CONCLUSIONS

The model based on CEUS can achieve satisfactory prediction and assist physicians during the therapeutic decision-making process in clinical practice.

KEY POINTS

• This is an exploratory study in which ablation-related contrast-enhanced ultrasound (CEUS) data from consecutive patients with colorectal cancer liver metastasis (CRLM) were collected simultaneously at multiple institutions. • The deep learning combining with clinical (DL-C) model provided desirable performance for the prediction of early recurrence (ER) after thermal ablation (TA). • The DL-C model based on CEUS provides guidance for TA indication selection and making therapeutic decisions.

Current Strategies for Modulating Tumor-Associated Macrophages with Biomaterials in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth most common cause of cancer-related deaths in the world. However, there are currently few clinical diagnosis and treatment options available, and there is an urgent need for novel effective approaches. More research is being undertaken on immune-associated cells in the microenvironment because they play a critical role in the initiation and development of HCC. Macrophages are specialized phagocytes and antigen-presenting cells (APCs) that not only directly phagocytose and eliminate tumor cells, but also present tumor-specific antigens to T cells and initiate anticancer adaptive immunity. However, the more abundant M2-phenotype tumor-associated macrophages (TAMs) at tumor sites promote tumor evasion of immune surveillance, accelerate tumor progression, and suppress tumor-specific T-cell immune responses. Despite the great success in modulating macrophages, there are still many challenges and obstacles. Biomaterials not only target macrophages, but also modulate macrophages to enhance tumor treatment. This review systematically summarizes the regulation of tumor-associated macrophages by biomaterials, which has implications for the immunotherapy of HCC.

A retrospective case-series of influence of chronic hepatitis B on synchronous liver metastasis of colorectal cancer

Main point

Our retrospective analysis of a large number of cases found in patients with primary colorectal cancer (CRC) carrying positive HBsAg inhibited the occurrence of synchronous liver metastases (SLM). However, liver cirrhosis caused by non-HBV factors promoted the occurrence of SLM.

Objectives

This study aimed to investigate the effect of HBV on the occurrence of synchronous liver metastases (SLM) of colorectal cancer (CRC).

Methods

Univariate and multivariate analyses were used to analyze the influence of clinical parameters on the occurrence of SLM.

Results

A total of 6, 020 patients with primary CRC were included in our study, of which 449 patients carrying HBsAg(+) accounted for 7.46%. 44 cases of SLM occurred in the HBsAg(+) group, accounting for 9.80%, which was much lower than 13.6% (758/5571) in the HBsAg(-) group (X=5.214, P=0.022). Among CRC patients with HBsAg(-), the incidence of SLM was 24.9% and 14.9% in the group with high APRI and FIB-4 levels, respectively, which were significantly higher than that in the compared groups (12.3% and 12.5%, all P<0.05). Compared with the control group, female patients, late-onset patients, and HBV-infective patients had lower risks of SLM (HR=0.737, 95%CI: 0.614-0.883, P<0.001; HR=0.752, 95%CI: 0.603-0.943, P=0.013; HR=0.682, 95%CI: 0.473-0.961, P=0.034).

Conclusions

The carriage of HBsAg(+) status inhibited the occurrence of SLM from CRC. HBV-causing liver cirrhosis did not further influence the occurrence of SLM, whereas non-HBV-factor cirrhosis promoted the occurrence of SLM. Nevertheless, this still required prospective data validation.

Predictive Factors for Local Recurrence after Intraoperative Microwave Ablation for Colorectal Liver Metastases

This study aimed to clarify local recurrence (LR) predictive factors following intraoperative microwave ablation (MWA) for colorectal liver metastases. The data from 195 patients with 1392 CRLM lesions, who were preoperatively diagnosed by gadolinium-enhanced MRI with diffusion-weighted imaging and dynamic CT and treated with intraoperative MWA (2450 MHz) with or without hepatectomy, from January 2005 to December 2019, were retrospectively reviewed and analyzed using logistic regression. In addition, the margins were measured on contrast-enhanced CT 6 weeks post-ablation. Overall, 1066 lesions were ablated. The LRs occurred in 44 lesions (4.1%) among 39 patients (20.0%). The multivariate analysis per patient showed that tumor size > 20 mm and ablation margin < 5 mm were significant predictors for LR. Furthermore, multivariate analysis per lesion revealed that segments 1, 7, and 8 and tumor size > 15 mm, ablation margin < 5 mm, tumor size > 20 mm, and proximity to the Glisson were significant LR predictors. Finally, the outcome of this study may help determine indications for MWA.

Colorectal Liver Metastases: A Literature Review of Viable Surgical Options with a Special Focus on Microwave Liver Thermal Ablation and Mini-Invasive Approach

Colorectal cancer (CRC) is the third most common tumor worldwide and it is characterized in 20-30% of cases by liver involvement, which strongly affects the long-term patient outcome. There are many available therapies for liver colorectal metastases (CRLMs); the current standard of care is represented by liver resection, and when feasible, associated with systemic chemotherapy. Microwave thermal ablation (MWA) is a viable option in unresectable patients or to achieve treatment with a parenchymal spearing approach. A literature review was performed for studies published between January 2000 and July 2022 through a database search using PUBMED/Medline and the Cochrane Collaboration Library with the following MeSH search terms and keywords: microwave, ablation, liver metastases, colorectal neoplasm, and colon liver rectal metastases. The recurrence rate and overall patients' survival were evaluated, showing that laparoscopic MWA is safe and effective to treat CRLMs when resection is not feasible, or a major hepatectomy in fragile patients is necessary. Considering the low morbidity of this procedure, it is a viable option to treat patients with recurrent diseases in the era of effective chemotherapy and multimodal treatments.

Clinical application status and prospect of the combined anti-tumor strategy of ablation and immunotherapy

Image-guided tumor ablation eliminates tumor cells by physical or chemical stimulation, which shows less invasive and more precise in local tumor treatment. Tumor ablation provides a treatment option for medically inoperable patients. Currently, clinical ablation techniques are widely used in clinical practice, including cryoablation, radiofrequency ablation (RFA), and microwave ablation (MWA). Previous clinical studies indicated that ablation treatment activated immune responses besides killing tumor cells directly, such as short-term anti-tumor response, immunosuppression reduction, specific and non-specific immune enhancement, and the reduction or disappearance of distant tumor foci. However, tumor ablation transiently induced immune response. The combination of ablation and immunotherapy is expected to achieve better therapeutic results in clinical application. In this paper, we provided a summary of the principle, clinical application status, and immune effects of tumor ablation technologies for tumor treatment. Moreover, we discussed the clinical application of different combination of ablation techniques with immunotherapy and proposed possible solutions for the challenges encountered by combined therapy. It is hoped to provide a new idea and reference for the clinical application of combinate treatment of tumor ablation and immunotherapy.

Metallo-alginate hydrogel can potentiate microwave tumor ablation for synergistic cancer treatment

Microwave ablation (MWA) as a local tumor ablation strategy suffers from posttreatment tumor recurrence. Development of adjuvant biomaterials to potentiate MWA is therefore of practical significance. Here, the high concentration of Ca²⁺ fixed by alginate as Ca²⁺-surplus alginate hydrogel shows enhanced heating efficiency and restricted heating zone under microwave exposure. The high concentration of extracellular Ca²⁺ synergizes with mild hyperthermia to induce immunogenic cell death by disrupting intracellular Ca²⁺ homeostasis. Resultantly, Ca²⁺-surplus alginate hydrogel plus MWA can ablate different tumors on both mice and rabbits at reduced operation powers. This treatment can also elicit antitumor immunity, especially if synergized with Mn²⁺, an activator of the stimulation of interferon genes pathway, to suppress the growth of both untreated distant tumors and rechallenged tumors. This work highlights that in situ-formed metallo-alginate hydrogel could act as microwave-susceptible and immunostimulatory biomaterial to reinforce the MWA therapy, promising for clinical translation.

Microwave Ablation, Radiofrequency Ablation, Irreversible Electroporation, and Stereotactic Ablative Body Radiotherapy for Intermediate Size (3-5 cm) Unresectable Colorectal Liver Metastases: a Systematic Review and Meta-analysis

Purpose of Review

Based on good local control rates and an excellent safety profile, guidelines consider thermal ablation the gold standard to eliminate small unresectable colorectal liver metastases (CRLM). However, efficacy decreases exponentially with increasing tumour size. The preferred treatment for intermediate-size unresectable CRLM remains uncertain. This systematic review and meta-analysis compare safety and efficacy of local ablative treatments for unresectable intermediate-size CRLM (3–5 cm).

Recent Findings

We systematically searched for publications reporting treatment outcomes of unresectable intermediate-size CRLM treated with thermal ablation, irreversible electroporation (IRE) or stereotactic ablative body-radiotherapy (SABR). No comparative studies or randomized trials were found. Literature to assess effectiveness was limited and there was substantial heterogeneity in outcomes and study populations. Per-patient local control ranged 22–90% for all techniques; 22–89% (8 series) for thermal ablation, 44% (1 series) for IRE, and 67–90% (1 series) for SABR depending on radiation dose.

Summary

Focal ablative therapy is safe and can induce long-term disease control, even for intermediate-size CRLM. Although SABR and tumuor-bracketing techniques such as IRE are suggested to be less susceptible to size, evidence to support any claims of superiority of one technique over the other is unsubstantiated by the available evidence. Future prospective comparative studies should address local-tumour-progression-free-survival, local control rate, overall survival, adverse events, and quality-of-life.

Long-Term Comparative Study on the Local Tumour Control of Different Ablation Technologies in Primary and Secondary Liver Malignancies

Purpose: To evaluate local tumour control (LTC) by local ablation techniques (LAT) in liver malignancies. Materials and methods: In patients treated with LAT between January 2013 and October 2020 target lesions were characterised by histology, dimensions in three spatial axes, volume, vascularisation and challenging (CL) location. LAT used were: Radiofrequency Ablation (RFA), Microwave Ablation (MWA), Cryoablation (CRYO), Electrochemotherapy (ECT), and Interstitial Brachytherapy (IBT). Results: 211 LAT were performed in 155 patients. Mean follow-up including MRI for all patients was 11 months. Lesions treated with ECT and IBT were significantly larger and significantly more often located in CL in comparison to RFA, MWA and CRYO. Best LTC (all data for 12 months are given below) resulted after RFA (93%), followed by ECT (81%), CRYO (70%), IBT (68%) and MWA (61%), and further, entity-related for HCC (93%), followed by CRC (83%) and BrC (72%), without statistically significant differences. LTC in hypovascular lesions was worse (64%), followed by intermediate (82% p = 0.01) and hypervascular lesions (92% p = 0.07). Neither diameter (<3 cm: 81%/3−6 cm: 74%/>6 cm: 70%), nor volume (<10 cm3: 80%/10−20 cm3: 86%/>20 cm3: 67%), nor CL (75% in CL vs. 80% in non CL) had a significant impact on LTC. In CL, best LTC resulted after ECT (76%) and IBT (76%). Conclusion: With suitable LAT, similarly good local tumour control can be achieved regardless of lesion size and location of the target.

Efficacy of Near-Infrared Fluorescence-Guided Hepatectomy for the Detection of Colorectal Liver Metastases: A Randomized Controlled Trial

BACKGROUND

The application of indocyanine green fluorescence-guided hepatectomy for liver metastases from colorectal cancer is in the preliminary stage of clinical practice; thus, its efficacy needs to be determined. This study compared the number of intrahepatic colorectal liver metastases detected intraoperatively and postoperative recovery data between patients who underwent traditional hepatectomy (nonindocyanine green group) and traditional hepatectomy plus intraoperative indocyanine green fluorescence imaging (indocyanine green group).

STUDY DESIGN

Between January 2018 and March 2020, patients with potentially resectable colorectal liver metastases were randomly assigned to the nonindocyanine green or indocyanine green group. The number of intrahepatic colorectal liver metastases identified intraoperatively and based on postoperative recovery data were compared between both groups.

RESULTS

Overall, we recruited 80 patients, among whom 72 eligible patients were randomly assigned. After allocation, 64 patients, comprising 32 in each group, underwent the allocated intervention and follow-up. Compared with the nonindocyanine green group, the mean number of intrahepatic colorectal liver metastases identified intraoperatively in the indocyanine green group was significantly greater (mean [standard deviation], 3.03 [1.58] vs 2.28 [1.35]; p = 0.045), the postoperative hospital stay was shorter (p = 0.012) and the 1-year recurrence rate was also lower (p = 0.017). Postoperative complications and 90-day mortality were comparable, with no statistical differences.

CONCLUSIONS

Indocyanine green fluorescence imaging significantly increases the number of intrahepatic colorectal liver metastases identified and reduces postoperative hospital stay and 1-year recurrence rate without increasing hepatectomy-related complications and mortality rates.

Addition of thermal ablation to systemic chemotherapy for the treatment of unresectable intrahepatic cholangiocarcinoma: a propensity score matching analysis

OBJECTIVES

To retrospectively compare the survival outcomes of thermal ablation plus chemotherapy to those of chemotherapy alone in patients with unresectable intrahepatic cholangiocarcinoma (ICC).

METHODS

189 patients with unresectable ICC who received thermal ablation plus chemotherapy or chemotherapy alone as the initial treatment were identified . To avoid potential bias, 1:1 matching between groups was performed through propensity score matching. Overall survival (OS) was the primary endpoint. Clinical and tumor factors related to OS were analyzed through univariate and multivariate analyses.

RESULTS

Of the enrolled patients, 55 received ablation plus chemotherapy, and 134 received chemotherapy alone. The median OS was 16.267 months for patients treated with combined therapy and 6.067 months for patients treated with chemotherapy alone (p = 0.000). The benefit of ablation plus chemotherapy was also preserved in the matched cohort, with a median OS of 15.233 months in the combined treatment group and 7.967 months in the chemotherapy group (p = 0.009). Univariate and multivariate analyses indicated that the type of treatment was an independent factor of OS (p < 0.05).

CONCLUSIONS

The combination of thermal ablation and systemic chemotherapy provides an opportunity to improve the prognosis of patients with unresectable ICC.

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.

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.

Radiofrequency versus microwave ablation for intraoperative treatment of colorectal liver metastases

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Computed tomography-guided microwave ablation of perivascular liver metastases from colorectal cancer: a study of the ablation zone, feasibility, and safety

OBJECTIVES

To compare the ablation margins and safety of microwave ablation (MWA) of perivascular versus non-perivascular liver metastases from colorectal cancer (CRC) and to determine the risk factors for local tumor progression (LTP) after perivascular MWA.

METHODS

Between June 2017 and June 2019, 84 metastases were treated: 39 perivascular (<5 mm from a vessel >3 mm), and 46 non-perivascular. Perivascular metastases were treated with either conventional or optimized protocols (maximum power and/or several heating cycles after repositioning the needle regardless of the initial tumor dimensions). The mean diameter of metastases was 15.4 mm (SD: 7.56).

RESULTS

Vascular proximity did not result in a significant difference in ablation margins. The technical success rate, primary efficacy, and secondary efficacy were 90%, 66%, and 83%, respectively. Perivascular location was not a risk factor for time to LTP (p = 0.49), RFS (p = 0.52), or OS (p = 0.54). LTP was statistically related to the presence of a colonic obstruction (p < 0.05), number of metastases at the time of diagnosis (p < 0.05), type of protocol (p < 0.05), ablation margins (p < 0.001) and LTP was proportional to the number of liver resections before MWA (p < 0.05). There was no LTP in tumors ablated with margins over 10 mm. Two grade 4 complications occurred.

CONCLUSION

MWA is an effective and safe treatment for perivascular liver metastases from CRC, provided that satisfactory margins are achieved. A maximalist attitude could be related to better local control.

Percutaneous Microwave Ablation Versus Open Surgical Resection for Colorectal Cancer Liver Metastasis

Purpose

To compare the therapeutic outcomes between open surgical resection (OSR) and percutaneous microwave ablation (PMWA) for colorectal liver metastasis (CRLM) ≤3 cm.

Methods

In this retrospective study, 200 consecutive patients with 306 CRLMs were reviewed. Overall survival (OS), disease-free survival (DFS), local tumour progression (LTP), intrahepatic distant recurrence, and extrahepatic metastasis were analysed to compare the therapeutic efficacy. Cox proportional hazards regression analysis was used to identify the prognostic factors for OS and DFS. Major complications and postoperative hospital stay were also assessed.

Result

The 1-, 3-, and 5-year OS rates were 91.6%, 64.1%, and 46.3%, respectively, in the PMWA group and 89.7%, 62.4% and 44.7%, respectively, in the OSR group (P=0.839). The 1-, 3-, and 5-year DFS rates were 61.9%, 44.8%, and 41.3%, respectively, in the PMWA group and 58.1%, 24.4%, and 18.3%, respectively, in the OSR group (P =0.066). The two groups had comparable 5-year cumulative rates of intrahepatic distant recurrence (P=0.627) and extrahepatic metastasis (P=0.884). The 5-year cumulative LTP rate was lower in the OSR group than in the PMWA group (P=0.023). The rate of major complications was higher in the OSR group than in the PMWA group (P =0.025), and the length of hospital stay after treatment was shorter in the PMWA group (P<0.001).

Conclusion

There were no significant differences in OS or DFS between the two groups. PMWA was associated with increased LTP, fewer postoperative days and fewer major complications.

Evaluation of the efficacy and postoperative outcomes of hydrodissection-assisted microwave ablation for subcapsular hepatocellular carcinoma and colorectal liver metastases

PURPOSE

To explore the effect of hydrodissection assisted percutaneous microwave ablation (MWA) on the primary technique efficacy (PTE) and local tumor progression (LTP) of subcapsular hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM).

METHODS

A retrospective review of 135 patients with 181 hepatic subcapsular HCC and CRLM that underwent MWA with (hydrodissection group) and without the use of hydrodissection (control group). The PTE, cumulative LTP rate, and postoperative complications were compared between the two groups.

RESULTS

Amongst the 135 patients with 181 tumors, 60 patients with 72 tumors were in the hydrodissection group and 75 patients with 109 tumors were in the control group. The PTEs were 97.2% and 85.3% in hydrodissection and control groups, respectively (P = 0.019). Multivariate analysis showed that hydrodissection significantly improved the PTE of MWA [odds ratio (OR) 0.147; 95% confidence interval (CI) 0.031-0.703; P = 0.016). Among the tumors which achieved complete response at the first (1 month) follow-up, the overall LTP rates were 8.6% (6/70) and 11.8% (11/93) in the hydrodissection and control groups, respectively. The 1- and 2-year cumulative LTP rates were 3.0% and 5.0% for the hydrodissection group and 6.8% and 13.5% in the control group, respectively (P = 0.391). No significant differences were observed in major postoperative complications between the two groups.

CONCLUSION

Hydrodissection-assisted MWA had a significantly higher PTE than MWA alone in hepatic subcapsular HCC and CRLM. Hydrodissection did not significantly impact the cumulative LTP rate or the incidence of postoperative complications.

Oligometastatic Disease and Interventional Oncology: Rationale and Research Directions

Oligometastatic disease (OMD) is generally defined as a stage of clinically or radiographically demonstrated metastatic disease limited in total disease burden and without rapid spread. Interventional oncology performs local therapies for primary and metastatic cancers, including OMD. Interventional oncology treatments can be pursued both as definitive therapy and for palliative purposes. Applied to OMD, these interventions can offer patients a decreasing overall tumor burden, minimizing cancer morbidity, and early evidence suggests a survival benefit. Here, we discuss the range of interventional oncology treatments, including ablation, chemoembolization, radioembolization, and irreversible electroporation. We describe the rationale for their application to OMD and discuss future directions for research.

Thoracoscopic Ablation of Critically Located Liver Tumors: A Safety and Efficacy Cohort Study

Background: Liver resection represents the first curative treatment to treat primary and secondary hepatic tumors. Thoracoscopic liver ablation is a viable and minimally invasive alternative treatment, especially for patients with previous multiple abdominal surgeries. The aim of the study was to evaluate the safety and efficacy of thoracoscopic ablation for liver tumors. Methods: Retrospective analysis of a prospective database of patients with liver tumors, treated with thoracoscopic trans-diagrammatic ablation (MWA or RFA) at our institution from 2012 to 2018. The primary endpoint was post-operative mortality at 30 days, while secondary endpoints were morbidity and efficacy of ablation (i.e., response rate evaluated according to mRECIST criteria, and overall patient survival). Patient demographics, operational characteristics, and complications were recorded. Results: A total of 13 nodules were treated in 10 patients with a median age of 65.5 years. Post-operative mortality was 0%, and overall morbidity was 40% (Clavien-Dindo I complications 30%, II 0%, III 10%, IV 0%). Complete radiological response was obtained in 83.3% of nodules at 3 months. After a median follow-up of 20.95 months, the local tumor progression rate was 30%, with an intra-segmental-recurrence of 30%, and an intra-hepatic-recurrence of 30%. The overall 1-, 2-, and 3-years survival rates were 80%, 58%, and 58%. Conclusion: Thoracoscopic trans-diaphragmatic ablation proved to be a safe and effective way to treat liver tumors when abdominal approach is not feasible. Considering the low morbidity, it is a viable option to treat patients with recurrent disease and/or previous multiple abdominal surgeries.

Monitoring microwave ablation using ultrasound homodyned K imaging based on the noise-assisted correlation algorithm: An ex vivo study

In this paper, we proposed ultrasound homodyned K (HK) imaging based on the noise-assisted correlation algorithm (NCA) for monitoring microwave ablation of porcine liver ex vivo. The NCA-based HK (α_NCA and k_NCA) imaging was compared with NCA-based Nakagami (m_NCA) imaging and NCA-based cumulative echo decorrelation (CED_NCA) imaging. Backscattered ultrasound radiofrequency signals of porcine liver ex vivo during and after the heating of microwave ablation were collected (n = 15), which were processed for constructing B-mode imaging, NCA-based HK imaging, NCA-based Nakagami imaging, and NCA-based CED imaging. To quantitatively evaluate the final coagulation zone, the polynomial approximation (PAX) technique was applied. The accuracy of detecting coagulation area with α_NCA, k_NCA, m_NCA, and CED_NCA parametric imaging was evaluated by comparing the PAX imaging with the gross pathology. The receiver operating characteristic (ROC) curve was used to further evaluate the performance of the three quantitative ultrasound imaging methods for detecting the coagulation zone. Experimental results showed that the average accuracies of α_NCA, k_NCA, m_NCA, and CED_NCA parametric imaging combined with PAX imaging were 89.6%, 83.25%, 89.23%, and 91.6%, respectively. The average areas under the ROC curve (AUROCs) of α_NCA, k_NCA, m_NCA, and CED_NCA parametric imaging were 0.83, 0.77, 0.83, and 0.86, respectively. The proposed NCA-based HK imaging may be used as a new method for monitoring microwave ablation.

Liver tumor ablation in difficult locations: Microwave ablation of perivascular and subdiaphragmatic hepatocellular carcinoma

AIM

To assess the safety and efficacy of CT-guided microwave ablation (MWA) of hepatocellular carcinoma (HCC) near large blood vessels and the diaphragm by analyzing procedural complications and local tumor progression (LTP).

METHODS

From October 2013 through January 2019, 80 patients (54 males and 26 females) with 136 tumors who underwent CT-guided MWA of HCC were included in this retrospective analysis. MWA was performed on 43 perivascular HCC (≤5 mm from a vessel measuring ≥5 mm in diameter), 38 subdiaphragmatic HCC (≤5 mm from diaphragm), and 64 control HCC. Risk factors for local tumor progression (LTP), overall survival, and complications were analyzed using the Chi-square and Cox proportional hazards model methods.

RESULTS

The technical success rate of MWA was 100%. Complication incidence was not significantly different between perivascular and control tumors (20.9% vs 10.9%; p = 0.155) or between subdiaphragmatic and control tumors (21.1% vs 10.9%; p = 0.163). The effect of lesion location on LTP disappeared while controlling for age and lesion size. There was no significant difference in median survival time between patients who had only control tumors (38.8 months) compared to patients with at least one perivascular or subdiaphragmatic tumor (42.5 months; p = 0.098).

CONCLUSION

CT-guided percutaneous MWA of perivascular and subdiaphragmatic HCC tumors is safe and effective. The local tumor recurrence and survival was not significantly different compared to control tumors.

Primary tumour location is an important prognostic factor in colorectal cancer liver metastases following radiofrequency ablation

AIM

To examine the outcomes and different prognoses for colorectal cancer patients with liver metastases (CRCLM) treated with radiofrequency ablation (RFA) based on the origin of the primary tumour (rectum versus colon).

MATERIALS AND METHODS

Patients diagnosed with CRCLM from July 2011 to June 2018 were assessed in the study. The study included 114 patients with 176 lesions. All of the patients underwent RFA of their CRCLM. The overall survival (OS) and progression-free survival (PFS) were assessed with Kaplan-Meier survival function estimate curves and Cox regression analysis between the group of patients with rectal cancer liver metastases (RCLM) and colon cancer liver metastases (CCLM).

RESULTS

Patients with RCLM exhibited worse OS and PFS than those with CCLM. The 1-, 2-, and 3-year OS rates were 87.5%, 75%, and 54.2% in the RCLM group and 93.9%, 87.8%, and 81.8% in the CCLM group (p=0.001), respectively. The 1-, 2-, and 3-year PFS rates were 43.7%, 22.9%, and 20.8% in the RCLM group and 57.6%, 45.4%, and 36.5% in the CCLM group (p=0.001), respectively. Multivariate analysis showed that primary tumour location, carcinoembryonic antigen (CEA), and response to pre-ablation chemotherapy were independent variables for OS and PFS. The N state of the primary tumour also had a significant impact on OS.

CONCLUSION

This study showed that patients with CCLM had better prognoses than those with RCLM following RFA treatment. If patients intend to undergo RFA for CRCLM, the location of the primary tumour should be considered in the assessment of long-term therapeutic effects.

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.