Disappearing liver metastases: A systematic review of the current evidence

Preoperative chemotherapy in upfront resectable colorectal liver metastases: New elements for an old dilemma?

The use of preoperative or "neoadjuvant" chemotherapy (NAC) has long been controversial for resectable colorectal liver metastases (CRLM). The European Society of Medical Oncology (ESMO) 2023 guidelines on metastatic colorectal cancer (CRC) indicate a combination of surgical/technical and oncologic/prognostic criteria as the two determinants for allocating patients to NAC or upfront hepatectomy. However, surgical and technical criteria have evolved, and oncologic prognostic criteria date from the pre-modern chemotherapy era and lack prospective validation. The traditional literature is interpreted as not supporting the use of NAC because several studies fail to demonstrate a benefit in overall survival (OS) compared to upfront surgery; however, OS may not be the most appropriate endpoint to consider. Moreover, the commonly quoted studies against NAC contain many limitations that may explain why NAC failed to demonstrate its value. The query of the recent literature focused primarily on other aspects than OS, such as surgical technique, the impact of side effects of chemotherapy, the histological growth pattern of metastases, or the detection of circulating tumor DNA, shows data that support a more widespread use of NAC. These should prompt a critical reappraisal of the use of NAC, leading to a more precise selection of patients who could benefit from it.

Dynamic surgical anatomy using 3D reconstruction technology in complex hepato-biliary surgery with vascular involvement. Results from an international multicentric survey

INTRODUCTION

Three-dimensional liver modeling can lead to substantial changes in choosing the type and extension of liver resection. This study aimed to explore whether 3D reconstruction helps to better understand the relationship between liver tumors and neighboring vascular structures compared to standard 2D CT scan images.

METHODS

Contrast-enhanced CT scan images of 11 patients suffering from primary and secondary hepatic tumors were selected. Twenty-three experienced HBP surgeons participated to the survey. A standardized questionnaire outlining 16 different vascular structures (items) having a potential relationship with the tumor was provided. Intraoperative and histopathological findings were used as the reference standard. The proper hypothesis was that 3D accuracy is greater than 2D. As a secondary endpoint, inter-raters' agreement was explored.

RESULTS

The mean difference between 3D and 2D, was 2.6 points (SE: 0.40; 95 % CI: 1.7-3.5; p < 0.0001). After sensitivity analysis, the results favored 3D visualization as well (mean difference 1.7 points; SE: 0.32; 95 % CI: 1.0-2.5; p = 0.0004). The inter-raters' agreement was moderate for both methods (2D: W = 0.45; 3D: W = 0.44).

CONCLUSION

3D reconstruction may give a significant contribution to better understanding liver vascular anatomy and the precise relationship between the tumor and the neighboring structures.

Liver Transplantation for Colorectal Liver Metastases: Is It Appropriate?

Colorectal cancer with liver metastases is a condition with significant morbidity and mortality that affects many people around the world. Many treatments exist to target liver metastases, including surgical resection, chemotherapy, nonsurgical liver-directed therapies, and liver transplantation. The field of transplant oncology is emerging as a promising alternative to palliative chemotherapy alone in appropriately selected patients. Though few clinical trials have been completed to evaluate safety of liver transplant for colorectal cancer metastases, there are several ongoing trials to hopefully make transplant a viable option for more patients with limited options.

Optimizing Adjuvant Therapy after Surgery for Colorectal Cancer Liver Metastases: A Systematic Review

The liver is the most common site of colorectal cancer metastatic spread. Although metastasectomy is the gold standard for fit patients with resectable colorectal cancer liver metastases (CRLMs), their management after surgical treatment remains controversial. The objective of this systematic review was to collate the currently available data of the agents used in the adjuvant setting in order to define the most optimal therapeutic strategy. A systematic review of the literature was conducted by searching PubMed/Medline and Cochrane library databases. We included studies that evaluated the efficacy, the tolerability and the safety profile of various chemotherapeutic agents that are used as adjuvant treatment after surgical resection of CRLMs. The outcomes of interest were regression-free survival (RFS), disease-free survival (DFS), overall survival (OS) and severe toxicities. From 543 initial articles, 29 publications with 7028 patients were finally included. In general, the results of the eligible studies indicated that adjuvant therapy after resection of CRLMs led to improved RFS/DFS rates, but this benefit did not contribute to a statistically significant prolongation of OS. Moreover, the choice of the therapeutic strategy, namely systematic or regional chemotherapy or the combination of both, did not seem to have a differential impact on patient outcomes. However, these results should be interpreted with caution since the majority of the chosen studies are of low or moderate quality. In this context, further high-quality clinical trials conducted on patient sub-populations with modern therapies are required in order to reduce in-study and between-study heterogeneity and determine which patients are expected to derive the maximum benefit from adjuvant therapy after surgery for CRLMs.

The impact of the advanced lung cancer inflammation index on the outcomes of patients with metastatic colorectal cancer who receive chemotherapy

BACKGROUND

Advanced lung cancer inflammation index (ALI) is reported to be a prognosticator in various cancer patients with chemotherapy. However, the clinical impact of the ALI on treatment strategies in metastatic colorectal cancer (mCRC) patients remains unclear.

METHODS

A total of 356 patients, who received first-line chemotherapy for mCRC between April 2005 and November 2019 in a single institution, were retrospectively enrolled. The association of pretreatment ALI (calculated as follows: BMI × albumin value/neutrophil-to-lymphocyte ratio) status with clinicopathological factors and patient survival outcome was analyzed, using subgroup analysis.

RESULTS

The ALI-low cases were significantly associated with female sex, more synchronous metastasis, multiple metastatic sites, less primary tumor resection, less liver resection after chemotherapy, and poor overall survival (OS). A multivariate Cox proportional hazards analysis clarified that the ALI-low status was independently associated with poor OS (HR: 1.78, 95% CI 1.27-2.48, P = 0.001), in addition to right side tumor, multiple metastatic sites, and the non-performance of liver resection after chemotherapy. A subgroup analysis revealed that primary tumor resection and the resection of liver metastases after chemotherapy could not improve the prognosis of ALI-low cases in comparison with ALI-high cases, and the type of first-line chemotherapy did not significantly affect the association between the prognosis and the ALI status.

CONCLUSION

ALI comprehensively evaluates the prognostic host status and is a reliable prognosticator for the mCRC patients with chemotherapy. Calculating pretreatment ALI may serve as a cost-effective and easily available tool for constructing treatment strategies.

Current status and novel insights into the role of metastasectomy in the era of immunotherapy

INTRODUCTION

New perspectives on the role of metastasectomy have emerged along with the advances in cancer immunotherapy. Despite accumulating evidence that encourages the use of immunotherapy in the metastatic setting, current data regarding its combination with surgical resection of secondary lesions, as well as the best timeline and sequence of such a therapeutic approach is limited.

AREAS COVERED

We review the currently available literature on the role of metastasectomy in the era of novel immunotherapeutic agents and provide comprehensive evidence from ongoing trials about the available treatment strategies. In metastatic melanoma, immune checkpoint inhibitors (ICIs) play a key role both in the neoadjuvant and adjuvant setting to achieve long-term disease control. In metastatic renal cell carcinoma, investigation is ongoing regarding the emerging role of ICIs before metastasectomy. ICIs have improved outcomes in patients with metastatic colorectal and head and neck cancer.

EXPERT OPINION

In the neoadjuvant setting, the high response rates and the durability of responses to immunotherapy may enable the resectability of metastatic lesions. In the adjuvant setting post metastasectomy, immunotherapy constitutes a safe and efficacious approach to support immune tumor surveillance and delay or even prevent disease relapse. Patient participation in relevant clinical trials should be encouraged.

Disappearing Colorectal Liver Metastases: Do We Really Need a Ghostbuster?

The development of new systemic treatment strategies has resulted in a significant increase in the response rates of colorectal liver metastases (CRLM) in the last few years. Although the radiological response is a favorable prognostic factor, complete shrinkage of CRLM, known as disappearing liver metastases (DLM), presents a therapeutic dilemma, and proper management is still debated in the literature. In fact, DLM is not necessarily equal to cure, and when resected, pathological examination reveals in more than 80% of patients a variable percentage of the tumor as residual disease or early recurrence in situ. Moreover, while a higher incidence of intrahepatic recurrence is documented in small series when surgery is avoided, its clinical significance for long-term OS is still under investigation. In light of this, a multidisciplinary approach and, in particular, radiologists’ role is needed to assist the surgeon in the management of DLM, thanks to emerging technology and strategy. Therefore, the aim of this review is to provide an overview of the DLM phenomenon and current management.

Role of stereotactic body radiotherapy in multidisciplinary management of liver metastases in patients with colorectal cancer

In the treatment of colorectal cancer patients with distant metastases, the development of new anticancer agents has considerably prolonged progression-free survival. Such survival benefits attributed to chemotherapy have increased the relative significance of local therapy in patients with limited metastases. The liver is recognized as the most common site of metastasis of colorectal cancer because of the intestinal mesenteric drainage to the portal veins. Hepatic resection of isolated liver metastases of colorectal cancer is the only option for a potential cure. However, hepatic metastases are resectable in only approximately 20% of the patients. For remaining patients with high-risk resectable liver metastases or those who are unfit for surgery, less invasive, local therapies including radiation therapy (stereotactic body radiation therapy, SBRT) may have a potential role in treatment. Although the local control rate of SBRT for colorectal liver metastases has room for improvement, its less-invasive nature and broad indications deserve consideration. Future research should include SBRT dose escalation or the selection of patients who benefit from local ablative therapies. SBRT may offer an alternative, non-invasive approach for the treatment of colorectal liver metastases in a multidisciplinary treatment strategy.

The Influence of Radiological “Disappearing Lesions” on the Efficacy and Prognosis of Patients with Colorectal Liver Metastases Undergoing Conversion Therapy

Purpose

The purpose of the current study was to analyze the influence of radiological “disappearing liver metastasis” (DLM) on the efficacy and prognosis of patients with colorectal liver metastases (CRLM) undergoing conversion therapy.

Methods

Patients with CRLM by the multidisciplinary team (MDT) of the First Affiliated Hospital of Chongqing Medical University were retrospectively enrolled from January 2014 to January 2021. The relationship between the occurrence and recurrence of DLM and different clinical factors was analyzed.

Results

Thirty-five of the 113 patients (31.0%) with initially unresectable CRLM developed DLM, and of the 361 lesions, 177 disappeared (49.0%). Within 6 months, 6-12 months, and 12-24 months groups, the recurrence rate was 3.4%, 16.8%, and 34.8%, but there is no recurrence in after 24 months group. There was a statistical difference between chemotherapy alone and chemotherapy combined with the targeted therapy group on the occurrence of DLM (58.3% vs. 37.1%, P < 0.001). There were significant differences between <5 mm group and >10 mm group on occurrence of DLM（76.7% vs. 30.4%, P < 0.001) and between 5-10 mm group and >10 mm group also (70.0% vs. 30.4%, P < 0.001). Through univariate and multivariate analyses, it was concluded that age (P = 0.026, 95%CI = 3.690) and treatment regimens (P = 0.033, 95%CI = 2.703) had a significant influence on the progression-free survival (PFS) time of DLM.

Conclusion

Younger patients, who use chemotherapy alone to achieve a therapeutic effect, might have better survival benefits when the lesions do not progress within 2 years after the appearance of DLMs.

Development of a Margin Determination Framework for Tumor-Tracking Radiation Therapy With Intraoperatively Implanted Fiducial Markers

PURPOSE

To develop an internal target volume (ITV) margin determination framework (or decision-supporting framework) for treating multiple lung metastases using CyberKnife Synchrony with intraoperatively implanted fiducial markers (IIFMs). The feasibility of using non-ideally implanted fiducial markers (a limited number and/or far from a target) for tracking-based lung stereotactic ablative radiotherapy (SABR) was investigated.

METHODS

In the developed margin determination framework, an optimal set of IIFMs was determined to minimize a tracking uncertainty-specific ITV (ITVtracking) margin (margin required to cover target-to-marker motion discrepancy), i.e., minimize the motion discrepancies between gross tumor volume (GTV) and the selected set of fiducial markers (FMs). The developed margin determination framework was evaluated in 17 patients with lung metastases. To automatically calculate the respiratory motions of the FMs, a template matching-based FM tracking algorithm was developed, and GTV motion was manually measured. Furthermore, during-treatment motions of the selected FMs were analyzed using log files and compared with those calculated using 4D CTs.

RESULTS

For 41 of 42 lesions in 17 patients (97.6%), an optimal set of the IIFMs was successfully determined, requiring an ITVtracking margin less than 5 mm. The template matching-based FM tracking algorithm calculated the FM motions with a sub-millimeter accuracy compared with the manual measurements. The patient respiratory motions during treatment were, on average, significantly smaller than those measured at simulation for the patient cohort considered.

CONCLUSION

Use of the developed margin determination framework employing CyberKnife Synchrony with a limited number of IIFMs is feasible for lung SABR.

The liver-first approach for synchronous colorectal liver metastases: A systematic review and meta-analysis of completion rates and effects on survival

BACKGROUND

Patients presenting with synchronous colorectal liver metastases are increasingly being considered for a curative treatment, and the liver-first approach is gaining popularity in this context. However, little is known about the completion rates of the liver-first approach and its effects on survival.

METHODS

A systematic review and meta-analysis of liver-first strategy for colorectal liver metastasis. The primary outcome was an assessment of the completion rates of the liver-first approach. Secondary outcomes included overall survival, causes of non-completion, and clinicopathologic data.

RESULTS

Seventeen articles were amenable for inclusion and the total study population was 1041. The median completion rate for the total population was 80% (range 20-100). The median overall survival for the completion and non-completion groups was 45 (range 12-69) months and 13 (range 10.5-25) months, respectively. Metadata showed a significant survival benefit for the completion group, with a univariate hazard ratio of 12.0 (95% confidence interval, range 5.7-24.4). The major cause of non-completion (76%) was liver disease progression before resection of the primary tumor. Pearson tests showed significant negative correlation between median number of lesions and median size of the largest metastasis and completion rate.

CONCLUSIONS

The liver-first approach offers a complete resection to most patients enrolled, with an overall survival benefit when completion can be assured. One-fifth fails to return to intended oncologic therapy and the major cause is interim metastatic progression, most often in the liver. Risk of non-completion is related to a higher number of lesions and large metastases. The majority of studies stem from primary rectal cancers, which may influence on the return to intended oncologic therapy as well.PROSPERO id no: 170459.

A meta-analysis evaluating contrast-enhanced intraoperative ultrasound (CE-IOUS) in the context of surgery for colorectal liver metastases

BACKGROUND

This study aimed to assess the outcomes of contrast-enhanced intraoperative ultrasound (CE-IOUS) for patients with colorectal liver metastases (CRLMs) undergoing surgery.

METHOD

A thorough literature search was performed in PubMed, Scopus, and Cochrane databases, in accordance with the PRISMA guidelines. The Odds Ratio, Weighted Mean Difference, and 95% Confidence Interval were evaluated, by means of Random-Effects model.

RESULTS

Eleven articles met the inclusion criteria and incorporated 497 patients. The present study shows that CE-IOUS is associated with higher sensitivity and accuracy compared with multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and intraoperative ultrasound (IOUS) in identifying CRLMs (p < 0.05). The positive predictive value was similar among the different modalities. Furthermore, new CRLMs were identified by CE-IOUS, thus affecting the surgical plan in 128 patients (51.8% of the patients with new CRLMs). Moreover, 91 patients (71%) underwent a more extensive hepatectomy and 15 patients (11.7%) were considered non-operable. Two alternative contrast agents, Sonazoid and Sonovue, were employed with similar sensitivity (p > 0.05).

CONCLUSION

These outcomes suggest the superiority of the CE-IOUS over MDCT, MRI, and IOUS for the staging of patients with CRLMs undergoing surgery. However, they should be treated with caution given the small number of the included studies.

Management of disappearing colorectal liver metastases: an international survey

BACKGROUND

Improved chemotherapy response rates have lead to "disappearing" colorectal liver metastases (dCRLM). We aim to assess management patterns of dCRLM from an international body of hepatobiliary surgeons.

METHODS

A survey was designed, tested for item relevance, readability and content validity, and distributed to the AHPBA, IHPBA and ANZHPBA.

RESULTS

The majority of 226 respondents were <15 years from training (69%), practiced in academia (82%) and devoted >50% of their practice to hepatobiliary (75%). Surgeons utilize CT(45%) or MRI(47%) for preoperative planning with a preferred imaging interval of <6 weeks. Nearly all have experienced dCRLM (99%) and 63% of surgeons have waited a few months to assess for durability of response prior to definitive surgical/ablative therapy. Only 24% place fiducial markers for lesions <1-cm prior to neoadjuvant chemotherapy. Intra-operatively, 97% of surgeons perform ultrasound, and 71% ablation. When a tumor has "disappeared," 49% elect for observation and 31% resect if the dCRLM is superficial. Of those electing observation, 87% believe there is effective treatment with progression on surveillance imaging.

CONCLUSIONS

Nearly all surgeons have experienced dCRLM with half choosing observation over intervention due to the belief that these lesions may be re-addressed in the future.

Evolution of Surgical Treatment of Colorectal Liver Metastases in the Real World: Single Center Experience in 1212 Cases

BACKGROUND

In recent years, the treatment of colorectal liver metastases (CRLM) has undergone significant evolution thanks to technical improvements as well as oncological advances, which have been the subject of targeted studies aimed at understanding the details of this heterogeneous disease. The purpose of this study is to put together pieces of this complex scenario by providing an overview of the evolution that has occurred in the context of a single center within a multidisciplinary management approach.

METHODS

Between 2005 and 2020, 1212 resections for CRLM were performed at the Hepatobiliary Surgery Division of San Raffaele Hospital, Milan. The series was divided into three historical periods, which were compared in terms of disease characteristics and short- and long-term outcomes: Period 1, 2005-2009 (293 cases); Period 2, 2010-2014 (353 cases); Period 3, 2015-2020 (566 cases). The trends for surgical technical complexity, oncological burden of the disease, use of the laparoscopic approach and use of techniques for hepatic hypertrophy were analyzed year by year. Uni- and multivariate analyses were performed to identify factors associated with inclusion to a laparoscopic approach and with long-term prognosis.

RESULTS

The number of resections performed over the years progressively increased, with an increase in the number of cases with a high Clinical Risk Score and a high profile of technical complexity. The proportion of cases performed laparoscopically increased, but less rapidly compared to other malignant tumors. The risk of postoperative morbidity and mortality was similar in the three analyzed periods. Long-term survival, stratified by Clinical Risk Score, improved in Period 3, while overall survival remained unchanged.

CONCLUSION

The cultural background, the maturation of technical expertise and the consolidation of the multidisciplinary team have resulted in safe expansion of the possibility to offer a curative opportunity to patients, while continuously implementing into clinical practice evidence provided by the literature.

MicroRNAs differential expression profile in metastatic colorectal cancer: A pilot study with literature review

BACKGROUND AND OBJECTIVES

Colorectal cancer is still one of the leading causes of cancer-related deaths worldwide and specific tools to improve disease assessment and treatment response are advocated. The aim of this study was to analyze miRNAs expression in metastatic and non-metastatic colorectal cancer, in order to identify reliable biomarkers suitable for prognosis, treatment and patient's monitoring.

MATERIAL AND METHODS

Among 25 patients (mean age 71 ± 12 years; Female/Male: 12/13) submitted to laparoscopic colorectal resection between August 2017 and February 2019, miRNAs were extracted from fresh frozen tissues of solid tumors. Gene expression's analysis arising from microarray technology was performed.

RESULTS

Pathological evaluation identified 15 metastatic patients (8 presenting with stage III and 7 with stage IV cancers) and 10 non-metastatic patients (4 presenting with stage I and 6 stage II cancers). Bioinformatic analysis of solid biopsies revealed 16 miRNAs (11 upregulated and 5 downregulated) differently expressed between metastatic and non-metastatic groups, with three miRNAs (miR-7515, miR-7109-5p and miR-6831-5p) never linked to colorectal cancer before.

CONCLUSIONS

Our study showed an association between miRNAs and metastatic colorectal cancer, suggesting their potential role as biomarkers for tumor management, if confirmed by further studies.

Consensus report from the 9th International Forum for Liver Magnetic Resonance Imaging: applications of gadoxetic acid-enhanced imaging

Objectives

The 9th International Forum for Liver Magnetic Resonance Imaging (MRI) was held in Singapore in September 2019, bringing together radiologists and allied specialists to discuss the latest developments in and formulate consensus statements for liver MRI, including the applications of gadoxetic acid–enhanced imaging.

Methods

As at previous Liver Forums, the meeting was held over 2 days. Presentations by the faculty on days 1 and 2 and breakout group discussions on day 1 were followed by delegate voting on consensus statements presented on day 2. Presentations and discussions centered on two main meeting themes relating to the use of gadoxetic acid–enhanced MRI in primary liver cancer and metastatic liver disease.

Results and conclusions

Gadoxetic acid–enhanced MRI offers the ability to monitor response to systemic therapy and to assist in pre-surgical/pre-interventional planning in liver metastases. In hepatocellular carcinoma, gadoxetic acid–enhanced MRI provides precise staging information for accurate treatment decision-making and follow-up post therapy. Gadoxetic acid–enhanced MRI also has potential, currently investigational, indications for the functional assessment of the liver and the biliary system. Additional voting sessions at the Liver Forum debated the role of multidisciplinary care in the management of patients with liver disease, evidence to support the use of abbreviated imaging protocols, and the importance of standardizing nomenclature in international guidelines in order to increase the sharing of scientific data and improve the communication between centers.

Key Points

• Gadoxetic acid–enhanced MRI is the preferred imaging method for pre-surgical or pre-interventional planning for liver metastases after systemic therapy.

• Gadoxetic acid–enhanced MRI provides accurate staging of HCC before and after treatment with locoregional/biologic therapies.

• Abbreviated protocols for gadoxetic acid–enhanced MRI offer potential time and cost savings, but more evidence is necessary. The use of gadoxetic acid–enhanced MRI for the assessment of liver and biliary function is under active investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-020-07637-4.

What is the optimal number of neoadjuvant chemotherapy cycles for resectable colorectal liver oligometastases?

Background

The optimal number of neoadjuvant chemotherapy (NAC) cycles for resectable colorectal liver oligometastases (CLOM) remains unclear. The aim of this study was to investigate the optimal number of NAC cycles.

Methods

One hundred twenty-nine consecutive patients were included in this study. X-tile analysis was implemented to investigate the optimal cut-off point for NAC cycles. Propensity score matching was performed to reduce selection bias. Kaplan-Meier curves and Cox risk regression models were used to analyse progression-free survival (PFS) and overall survival (OS).

Results

The optimal cut-off point for NAC cycles was 5. There were no significant differences in R0 resection, pathological response or postoperative complications between the groups with a low number of NAC cycles group (≤5 cycles, n=80) and high number of NAC cycles (>5 cycles, n=49). Patients with a high number of NAC cycles were more likely to have NAC toxicity than those with a low number of cycles (87.8% vs. 65.0%, P=0.004). Multivariate analysis revealed that >5 NAC cycles was an independent predictor of reduced PFS (HR =1.808, 95% CI: 1.205–2.712, P=0.004) and reduced OS (HR =1.723, 95% CI: 1.041–2.851, P=0.034). In the oxaliplatin-based regimen group, patients with a low number of NAC cycles had a better PFS (P<0.001, mPFS: 14.7 vs. 5.4 months) and better OS (P=0.018, mOS: 57.7 months vs. 41.0 months) than those with a high number of cycles. After 1:1 propensity matching (34 cases vs. 34 cases), multivariate analysis revealed that >5 NAC cycles was an independent predictor of reduced PFS (HR =2.265, 95% CI: 1.281–4.007, P=0.005) and reduced OS (HR =2.813, 95% CI: 1.359–5.822, P=0.005). In the oxaliplatin-based regimen group, patients with a low number of NAC cycles had better PFS (P<0.001, mPFS: 17.5 vs. 5.6 months) and better OS (P=0.008, mOS: 59.0 vs. 31.8 months) than those with a high number of cycles.

Conclusions

Fewer than 5 NAC cycles was optimal for biologically resectable CLOM patients. Giving more than 5 NAC cycles was unnecessary because a higher number of NAC cycles has more unfavourable survival and higher NAC toxicities, while leading to similar R0 resection rates and pathological responses.

Contrast-Enhanced Intraoperative Ultrasound Improved Sensitivity and Positive Predictive Value in Colorectal Liver Metastasis: a Systematic Review and Meta-Analysis

BACKGROUND

The diagnostic accuracy of imaging modalities in colorectal cancer liver metastases (CRLM) has improved in recent years, therefore the role of current imaging techniques needs to be defined.

OBJECTIVE

The aim of this study was to assess the diagnostic performance of magnetic resonance imaging, preoperative imaging (magnetic resonance imaging or computed tomography), intraoperative ultrasound, and contrast-enhanced intraoperative ultrasound in the detection of CRLM.

MATERIALS AND METHODS

Eligible trials published before 30 March 2020 were identified from the EMBASE, PubMed, Web of Science, and Cochrane Library databases, and descriptive and quantitative data were extracted. Study quality was evaluated for the identified studies and a random-effects model was used to determine the integrated diagnosis estimation. Meta-regression was implemented to explore the possible contributors to heterogeneity.

RESULTS

Overall, 13 studies were included for analysis, comprising 682 patients with a total of 2303 liver lesions. The pooled sensitivity, specificity, and diagnostic odds ratio of contrast-enhanced intraoperative ultrasound were 0.94 (95% confidence interval [CI] 0.89-0.97), 0.83 (95% CI 0.67-0.92), and 79 (95% CI 32-196), respectively. The overall weighted area under the curve was 0.96 (95% CI 0.94-0.97). In univariate meta-regression analysis, disappearing liver metastasis, contrast agent, and Kupffer phase were the potent sources of heterogeneity; however, in multivariate meta-regression, no definite variable was the source of the study heterogeneity.

CONCLUSION

Contrast-enhanced intraoperative ultrasound demonstrated a high sensitivity and specificity for screening CRLM.

Colorectal liver metastases: Current management and future perspectives

The liver is the commonest site of metastatic disease for patients with colorectal cancer, with at least 25% developing colorectal liver metastases (CRLM) during the course of their illness. The management of CRLM has evolved into a complex field requiring input from experienced members of a multi-disciplinary team involving radiology (cross sectional, nuclear medicine and interventional), Oncology, Liver surgery, Colorectal surgery, and Histopathology. Patient management is based on assessment of sophisticated clinical, radiological and biomarker information. Despite incomplete evidence in this very heterogeneous patient group, maximising resection of CRLM using all available techniques remains a key objective and provides the best chance of long-term survival and cure. To this end, liver resection is maximised by the use of downsizing chemotherapy, optimisation of liver remnant by portal vein embolization, associating liver partition and portal vein ligation for staged hepatectomy, and combining resection with ablation, in the context of improvements in the functional assessment of the future remnant liver. Liver resection may safely be carried out laparoscopically or open, and synchronously with, or before, colorectal surgery in selected patients. For unresectable patients, treatment options including systemic chemotherapy, targeted biological agents, intra-arterial infusion or bead delivered chemotherapy, tumour ablation, stereotactic radiotherapy, and selective internal radiotherapy contribute to improve survival and may convert initially unresectable patients to operability. Currently evolving areas include biomarker characterisation of tumours, the development of novel systemic agents targeting specific oncogenic pathways, and the potential re-emergence of radical surgical options such as liver transplantation.

Liver Tumor Microenvironment

The tumor microenvironment (TME) has recently been recognized as an important part of tumor development and growth. TME is a dynamic system orchestrated by immune, cancer and inflammatory cells, as well as the stromal tissue and surrounding extracellular matrix. While TME of primary hepatic tumors is usually characterized by a strong inflammatory background, the TME of liver metastases typically consists of otherwise healthy liver tissue. Chronic inflammation and hypoxia are key to the development and progression of primary liver cancer. The injury caused by chronic inflammation creates a condition of immune evasion that initiates a cascade of events that eventually leads to liver carcinogenesis.With liver metastases, primary tumors "prime" the target organs via secreting factors that induce expansion of myeloid cell populations and create a solid ground for successful cancer settlement. Once in the liver, metastatic cells begin a neovascularization process that is driven mainly by VEGF and FGF. Due to high mortality rates associated with liver cancer, as well as the limited effective treatment options for advanced disease, new therapies are urgently needed. Targeting a single molecule in a number of interactions between the tumor and the TME is highly unlikely to reduce tumor growth. Future trials should focus on combination therapies (i.e. targeted therapies combined with immunotherapy) to treat liver malignancies efficiently.

The Role and Therapeutic Potential of miRNAs in Colorectal Liver Metastasis

Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths worldwide. Liver metastasis is the major cause of CRC patient mortality, occurring in 60% patients with no effective therapies. Although studies have indicated the role of miRNAs in CRC, an in-depth miRNA expression analysis is essential to identify clinically relevant miRNAs and understand their potential in targeting liver metastasis. Here we analyzed miRNA expressions in 405 patient tumors from publicly available colorectal cancer genome sequencing project database. Our analyses showed miR-132, miR-378f, miR-605 and miR-1976 to be the most significantly downregulated miRNAs in primary and CRC liver metastatic tissues, and CRC cell lines. Observations in CRC cell lines indicated that ectopic expressions of miR-378f, -605 and -1976 suppress CRC cell proliferation, anchorage independent growth, metastatic potential, and enhance apoptosis. Consistently, CRC patients with higher miR-378f and miR-1976 levels exhibited better survival. Together, our data suggests an anti-tumorigenic role of these miRNAs in CRC and warrant future in vivo evaluation of the molecules for developing biomarkers or novel therapeutic strategies.