Delayed tumour enhancement on gadoxetate-enhanced MRI is associated with overall survival in patients with colorectal liver metastases

Assessment of the response to systemic treatment of colorectal liver metastases on cross-sectional imaging - a systematic review

Colorectal cancer (CRC) is one of the most common malignancies in the world. Nowadays many treatments are available to help control CRC, including surgery, radiation therapy, interventional radiology, and drug treatments. A multidisciplinary approach and the role of radiologists is needed to assist the surgeon in the management thanks to emerging technology and strategies. The Response Evaluation Criteria in Solid Tumours (RECIST) has been created to objectify and standardize cancer response assessment. Thus, in this article specific presumptions and practical aspects of evaluating responses according to the RECIST 1.1 are discussed. Furthermore, examples of possible response to systemic treatment of colorectal liver metastases (CRLM), including tumour necrosis, apparent diffusion coefficient (ADC) values, tumour calcification, tumour fibrosis and intratumoural fat deposition observed on cross-sectional imaging, are described. Disappearing liver metastases (DLM) presents a therapeutic dilemma. The optimal management of DLM remains controversial due to the uncertainty of residual microscopic disease and effective long-term outcomes. The article provides an overview of the CRLM phenomenon and current possible assessment methods of the response to systemic treatment.

A radiomic biomarker for prognosis of resected colorectal cancer liver metastases generalizes across MRI contrast agents

Introduction

Contrast-enhanced MRI is routinely performed as part of preoperative work-up for patients with Colorectal Cancer Liver Metastases (CRLM). Radiomic biomarkers depicting the characteristics of CRLMs in MRI have been associated with overall survival (OS) of patients, but the reproducibility and clinical applicability of these biomarkers are limited due to the variations in MRI protocols between hospitals.

Methods

In this work, we propose a generalizable radiomic model for predicting OS of CRLM patients who received preoperative chemotherapy and delayed-phase contrast enhanced (DPCE) MRIs prior to hepatic resection. This retrospective two-center study included three DPCE MRI cohorts (n=221) collected between January 2006 and December 2012. A 10-minute delayed Gd-DO3A-butrol enhanced MRI discovery cohort was used to select features based on robustness across contrast agents, correlation with OS and pairwise Pearson correlation, and to train a logistic regression model that predicts 3-year OS.

Results

The model was evaluated on a 10-minute delayed Gd-DO3A-butrol enhanced MRI validation cohort (n=121), a 20-minute delayed Gd-EOB-DTPA (n=72) cohort from the same institute, and a 5-minute delayed Gd-DTPA cohort (n=28) from an independent institute. Two features were selected: minor axis length and dependence variance. The radiomic signature model stratified high-risk and low-risk CRLM groups in the Gd-DO3Abutrol (HR = 6.29, p = .007), Gd-EOB-DTPA (HR = 3.54, p = .003) and Gd-DTPA (HR = 3.16, p = .04) validation cohorts.

Discussion

While most existing MRI findings focus on a specific contrast agent, our study shows the potential of MRI features to be generalizable across main-stream contrast agents at delayed phase.

The growth pattern of liver metastases on MRI predicts early recurrence in patients with colorectal cancer: a multicenter study

OBJECTIVES

The multicenter study aimed to explore the relationship between the growth pattern of liver metastases on preoperative MRI and early recurrence in patients with colorectal cancer liver metastases (CRCLM) after surgery.

METHODS

A total of 348 CRCLM patients from 3 independent centers were enrolled, including 130 patients with 339 liver metastases in the primary cohort and 218 patients in validation cohorts. Referring to the gross classification of hepatocellular carcinoma (HCC), the growth pattern of each liver metastasis on MRI was classified into four types: rough, smooth, focal extranodular protuberant (FEP), and nodular confluent (NC). Disease-free survival (DFS) curve was constructed using the Kaplan-Meier method.

RESULTS

In primary cohort, 42 (12.4%) of the 339 liver metastases were rough type, 237 (69.9%) were smooth type, 29 (8.6%) were FEP type, and 31 (9.1%) were NC type. Those patients with FEP- and/or NC-type liver metastases had shorter DFS than those without such metastases (p < 0.05). However, there were no significant differences in DFS between patients with rough- and smooth-type liver metastases and those without such metastases. The patients with FEP- and/or NC-type liver metastases also had shorter DFS than those without such metastases in two external validation cohorts. In addition, 40.5% of high-risk-type (FEP and NC) liver metastases converted to low-risk types (rough and smooth) after neoadjuvant chemotherapy.

CONCLUSION

The FEP- and NC-type liver metastases were associated with early recurrence, which may facilitate the clinical treatment of CRCLM patients.

KEY POINTS

• In the primary cohort, patients with FEP- and NC-type metastases had shorter disease-free survival (DFS) and a higher intrahepatic recurrence rate than patients without such metastases in the liver. • In the primary cohort, there were no significant differences in DFS or intrahepatic recurrence rate between patients with rough- and smooth-type metastases and those without such metastases in the liver. • High-risk patients had shorter DFS and a higher intrahepatic recurrence rate than low-risk patients in primary and external validation cohorts.

Comprehensive Imaging Characterization of Colorectal Liver Metastases

Colorectal liver metastases (CRLM) have heterogenous histopathological and immunohistochemical phenotypes, which are associated with variable responses to treatment and outcomes. However, this information is usually only available after resection, and therefore of limited value in treatment planning. Improved techniques for in vivo disease assessment, which can characterise the variable tumour biology, would support further personalization of management strategies. Advanced imaging of CRLM including multiparametric MRI and functional imaging techniques have the potential to provide clinically-actionable phenotypic characterisation. This includes assessment of the tumour-liver interface, internal tumour components and treatment response. Advanced analysis techniques, including radiomics and machine learning now have a growing role in assessment of imaging, providing high-dimensional imaging feature extraction which can be linked to clinical relevant tumour phenotypes, such as a the Consensus Molecular Subtypes (CMS). In this review, we outline how imaging techniques could reproducibly characterize the histopathological features of CRLM, with several matched imaging and histology examples to illustrate these features, and discuss the oncological relevance of these features. Finally, we discuss the future challenges and opportunities of CRLM imaging, with a focus on the potential value of advanced analytics including radiomics and artificial intelligence, to help inform future research in this rapidly moving field.

Delayed MRI Enhancement of Colorectal Cancer Liver Metastases Is Associated With Metastatic Mutational Profile

BACKGROUND/AIM

Individual tumor genomics plays a key role in determining patient prognosis, response to chemotherapy and in guiding therapy. In prior studies, it was shown that the degree of late enhancement of colorectal liver metastases (CRCLM) target tumor enhancement (TTE) as seen on magnetic resonance imaging (MRI) was associated with overall survival. In order to better understand the relationship between MRI enhancement and survival, the aim of this study was to characterize genomic profiles of tumors clustered by MRI TTE, and investigate the association between TTE and genetic mutations.

MATERIALS AND METHODS

Matched tumor and normal tissue samples from patients with weak TTE and strong TTE were analyzed by Next-generation sequencing (NGS) technology using a custom colorectal cancer panel.

RESULTS

We discovered a total of 42 non-synonymous somatic mutations from 10 patients with weak TTE and 26 with 10 patients with strong TTE. Adenomatosis Polyposis Coli (APC) was the most commonly altered gene, 18 of those APC mutations were found in the weak TTE and 9 in the strong TTE group.

CONCLUSION

An association exists between TTE and mutational status of CRCLM, which may offer some explanation as to why TTE is associated with overall survival in patients with CRCLM.

Rim enhancement on hepatobiliary phase of pre-treatment 3.0 T MRI: A potential marker for early chemotherapy response in colorectal liver metastases treated with XELOX

PURPOSE

To assess the value of the enhanced features on the hepatobiliary phase (HBP) of pre-treatment Gd-EOB-DTPA MRI in evaluating response to chemotherapy in colorectal liver metastases (CRLMs).

METHODS

We retrospectively studied 65 patients with CRLMs who underwent Gd-EOB-DTPA enhanced MRI before chemotherapy from October 2015 to November 2017. The diagnosis of liver metastasis was established on the basis of imaging findings. Two radiologists evaluated the size, contrast-enhanced (CE) patterns of the maximum lesion on the HBP. According to the different CE patterns, we quantified area signal intensity (SI) by applying SI ratio (such as SI_center/outer and SI_rim/center). All of the above parameters were analyzed in terms of chemotherapy response.

RESULTS

Rim enhancement on the HBP was more frequent in the responding group of 28 patients (72%) than in the non-responding group of eight patients (31%). Additionally, there was a significant association between chemotherapy response and quantitative parameters: including diameter (P = 0.04), SI_center/outer (P = 0.047) and SI_rim/center (P = 0.012). The HBP CE pattern (P = 0.007) and SI_center/outer (P = 0.022) were independent factors for chemotherapy response. The areas under the curve (AUCs) of the above-mentioned parameters were significant associated with response to chemotherapy, in which diameter, HBP CE patterns, SI_center/outer, and SI_rim/center were 0.638, 0.706, 0.712, and 0.673, respectively. Moreover, the combination of these parameters obtained the largest AUC of 0.821.

CONCLUSION

The CE patterns, in particular with rim enhancement, and SI ratio parameters on the HBP are useful indicators for early evaluation of therapeutic response after chemotherapy in patients with CRLMs.

Abbreviated MRI protocol for colorectal liver metastases: How the radiologist could work in pre surgical setting

Background

MRI is the most reliable imaging modality that allows to assess liver metastases. Our purpose is to compare the per-lesion and per-patient detection rate of gadoxetic acid-(Gd-EOB) enhanced liver MRI and fast MR protocol including Diffusion Weighted Imaging (DWI) and T2-W Fat Suppression sequence in the detection of liver metastasis in pre surgical setting.

Methods

One hundred and eight patients with pathologically proven liver metastases (756 liver metastases) underwent Gd-EOBMRI were enrolled in this study. Three radiologist independently graded the presence of liver lesions on a five-point confidence scale assessed only abbreviated protocol (DWI and sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) fat suppressed sequence) and after an interval of more than 2 weeks the conventional study (all acquired sequences). Per-lesion and per-patient detection rate of metastases were calculated. Weighted к values were used to evaluate inter-reader agreement of the confidence scale regarding the presence of the lesion.

Results

MRI detected 732 liver metastases. All lesions were identified both by conventional study as by abbreviated protocol. In terms of per-lesion detection rate of liver metastasis, all three readers had higher detection rate both with abbreviated protocol and with standard protocol with Gd-EOB (96.8% [732 of 756] vs. 96.5% [730 of 756] for reader 1; 95.8% [725 of 756] vs. 95.2% [720 of 756] for reader 2; 96.5% [730 of 756] vs. 96.5% [730 of 756] for reader 3). Inter-reader agreement of lesions detection rate between the three radiologists was excellent (k range, 0.86–0.98) both for Gd-EOB MRI and for Fast protocol (k range, 0.89–0.99).

Conclusion

Abbreviated protocol showed the same detection rate than conventional study in detection of liver metastases.

MRI Findings of Liver Parenchyma Peripheral to Colorectal Liver Metastasis: A Potential Predictor of Long-term Prognosis

Background Gadoxetic acid (Gd-EOB-DTPA)-enhanced MRI is superior to CT in the detection of colorectal liver metastases (CRLMs) smaller than 10 mm. However, few studies have used MRI findings to predict patients' long-term prognosis. Purpose To investigate the relationship between Gd-EOB-DTPA-enhanced MRI findings in the liver parenchyma peripheral to CRLM and both pathologic vessel invasion and long-term prognosis. Materials and Methods This retrospective study included patients who underwent Gd-EOB-DTPA-enhanced MRI before curative surgery for CRLM, without neoadjuvant chemotherapy, between July 2008 and June 2015. Early enhancement, reduced Gd-EOB-DTPA uptake, and bile duct dilatation peripheral to the CRLM at MRI were evaluated by three abdominal radiologists. All tumor specimens were reevaluated for the presence or absence of portal vein, hepatic vein, and bile duct invasion. Predictors of recurrence-free survival (RFS) and overall survival (OS) after surgery were identified with Cox proportional hazard model with the Bayesian information criterion. Previously reported prognosticators were selected for multivariable analyses. The median follow-up period was 60 months (range, 9-127 months). Results Overall, 106 patients (mean age, 65 years ± 12 [standard deviation]; 68 men) with 148 CRLMs were evaluated. Bile duct dilatation peripheral to the tumor was associated with pathologic portal vein invasion (sensitivity, 12 of 50 [24%]; specificity, 89 of 98 [91%]; P = .02), bile duct invasion (sensitivity, eight of 19 [42%]; specificity, 116 of 129 [90%]; P = .001), poor RFS (P = .03; hazard ratio [HR] = 2.4 [95% confidence interval {CI}: 1.3, 4.2]), and poor OS (P = .01; HR = 2.4 [95% CI: 1.2, 4.9]). For RFS and OS, early enhancement and reduced Gd-EOB-DTPA uptake peripheral to the CRLM were eliminated by means of variable selection in the multivariable analysis, but the combination of these findings with bile duct dilatation provided a predictor of poor OS (P = .001; HR = 3.3 [95% CI: 1.6, 6.8]). Conclusion MRI signal intensity changes peripheral to the colorectal liver metastasis were predictors of long-term prognosis after curative surgery without neoadjuvant chemotherapy. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Bashir in this issue.

Hepatobiliary phase enhancement of liver metastases on gadoxetic acid MRI: assessment of frequency and patterns

OBJECTIVES

To assess for and characterize patterns of hepatobiliary phase (HBP) enhancement in hepatic metastases of various malignancies on gadoxetic acid-enhanced MRI.

METHODS

Eighty gadoxetic acid-enhanced MRI studies performed between July 2012 and November 2019 in patients with hepatic metastases from 13 different primary malignancies were assessed. Most (n = 60) were from colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), or neuroendocrine tumor (NET) primaries. Two radiologists quantitatively evaluated the dominant lesion on each MRI. A lesion was considered enhancing when HBP enhancement relative to muscle exceeded 20%. Lesions were classified by pattern of enhancement. Quantitative enhancement metrics and patterns of enhancement were compared between CRC, PDAC, and NET using non-parametric statistical tests.

RESULTS

Most dominant metastatic lesions > 1 cm (77%, 54/70) demonstrated HBP enhancement. HBP enhancement was identified in hepatic metastases from 10 different primary malignancies, including CRC, PDAC, and NET. PDAC metastases demonstrated a lower degree of HBP enhancement (26%) than CRC (44%, p_adj = 0.04) and NET (51%, p_adj = 0.01) metastases. Three discrete enhancement patterns were identified: peripheral, central (target), and diffuse heterogeneous. Patterns of HBP enhancement varied between CRC, PDAC, and NET, with secondary analysis demonstrating that PDAC had the highest proportion of peripheral pattern (73%, p_adj < 0.001), CRC the highest proportion of diffuse heterogeneous pattern (32%, p_adj < 0.01), and NET the highest proportion of central pattern (89%, p_adj < 0.001).

CONCLUSION

Liver metastases from several primary malignancies, including PDAC, demonstrate mild HBP enhancement in variable patterns. Correlation with OATP1B3 expression and prognosis is required.

KEY POINTS

• Hepatobiliary phase (HBP) enhancement was identified in 77% of hepatic metastases in several different primary malignancies. • Discrete patterns of HBP enhancement exist (peripheral, central, diffuse heterogeneous) and varied between CRC, PDAC, and NET. CRC and PDAC metastases demonstrated mostly non-central patterns (diffuse and peripheral), and NET mostly a central pattern. • Relationship between HBP enhancement, enhancement pattern, OATP1B3 expression, and prognosis requires further dedicated exploration for each malignancy.

Colorectal liver metastases: radiopathological correlation

With the development of chemotherapy regimens, targeted therapies, and hepatic surgery, the survival of patients with colorectal liver metastases (CRLM) has dramatically improved. Imaging plays a central role for the diagnosis, staging, and treatment allocation in these patients. To interpret CRLM on imaging, radiologists must be familiar with the main imaging features of untreated tumors as well as the modifications induced by systemic therapies, and their meaning in relation to pathological tumor response and tumor biology. CRLM have the same histological features as the primary tumor. Most are “non-otherwise specified” (NOS) adenocarcinomas. The mucinous tumor is the most common of the rare subtypes. In NOS tumors, imaging usually differentiates central areas of necrosis from peripheral proliferating tumors and desmoplastic reaction. Areas of mucin mixed with fibrosis are seen in mucinous subtypes to help differentiate the metastases from other tumors cysts or hemangiomas. After treatment, the viable tumor is gradually replaced by ischemic-like necrosis and fibrosis, and remnants cells are mainly located on the periphery of tumors. Imaging can help predict the degree of tumor response, but changes can be difficult to differentiate from the pretherapeutic appearance. When chemotherapy is interrupted or in case of resistance to treatment, a peripheral infiltrating halo of tumor growth may appear. The purpose of the article is to illustrate the significance of the imaging features of colorectal liver metastases during systemic therapy, using radiopathological correlations.

Current state of the art imaging approaches for colorectal liver metastasis

One of the most common cancers worldwide, colorectal cancer (CRC) has been associated with significant morbidity and mortality and therefore represents an enormous burden to the health care system. Recent advances in CRC treatments have provided patients with primary and metastatic CRC a better long-term prognosis. The presence of synchronous or metachronous metastasis has been associated, however, with worse survival. The most common site of metastatic disease is the liver. A variety of treatment modalities aimed at targeting colorectal liver metastases (CRLM) has been demonstrated to improve the prognosis of these patients. Loco-regional approaches such as surgical resection and tumor ablation (operative and percutaneous) can provide patients with a chance at long-term disease control and even cure in select populations. Patient selection is important in defining the most suitable treatment option for CRLM in order to provide the best possible survival benefit while avoiding unnecessary interventions and adverse events. Medical imaging plays a crucial role in evaluating the characteristics of CRLMs and disease resectability. Size of tumors, proximity to adjacent anatomical structures, and volume of the unaffected liver are among the most important imaging parameters to determine the suitability of patients for surgical management or other appropriate treatment approaches. We herein provide a comprehensive overview of current-state-of-the-art imaging in the management of CRLM, including staging, treatment planning, response and survival assessment, and post-treatment surveillance. Computed tomography (CT) scan and magnetic resonance imaging (MRI) are two most commonly used techniques, which can be used solely or in combination with functional imaging modalities such as positron emission tomography (PET) and diffusion weighted imaging (DWI). Providing up-to-date evidence on advantages and disadvantages of imaging modalities and tumor assessment criteria, the current review offers a practice guide to assist providers in choosing the most suitable imaging approach for patients with CRLM.

A clinical-radiomic model for improved prognostication of surgical candidates with colorectal liver metastases

BACKGROUND AND OBJECTIVES

Colorectal cancer with liver metastases is potentially curable with surgical resection however clinical prognostic factors can insufficiently stratify patients. This study aims to assess whether radiomic features are prognostic and can inform clinical decision making.

METHODS

This single-site retrospective study included 102 patients who underwent colorectal liver metastases resection with preoperative computed tomography (CT), magnetic resonance imaging (MRI) with gadoxetic acid (EOB) and clinical covariates. A lasso-regularized multivariate Cox proportional hazards model was applied to 114 features (10 clinical, 104 radiomic) to determine association with disease-free survival (DFS). A prognostic index was derived using the significant Cox regression coefficients and their corresponding input features and a threshold was determined to classify patients into high- and low-risk groups, and DFS compared using log-rank tests.

RESULTS

Four covariates were significantly associated with DFS; bilobar disease (hazard ratio [HR]= 1.56; P = .0043), complete pathological response (HR= 0.67; P = .025), minimum pixel value (HR= 1.66; P = .00016), and small area emphasis (HR= 0.62; P = .0013) from the EOB-MRI data. Radiomic CT features were not prognostic. The prognostic index strongly stratified high- and low-risk prognostic groups (HR = 0.31; P = .00068).

CONCLUSION

Radiomic MRI features provided meaningful prognostic information above clinical covariates alone. This merits further validation for potential clinical implementation to inform management.

[Computed tomography and/or magnetic resonance imaging of the liver : How, why, what for?]

CLINICAL PROBLEM

Colorectal metastases are the most common malignant liver lesions. Imaging of the liver in patients with colorectal carcinoma is performed for early detection of liver metastases (CRLM) at the time of initial tumor diagnosis, for monitoring and follow-up in order to exclude or diagnose metachronous metastases.

STANDARD RADIOLOGICAL METHODS

Radiological imaging includes primarily multislice computed tomography (CT) and magnetic resonance imaging (MRI), which play an important role regarding therapeutic management and assessment of prognosis.

PERFORMANCE, ACHIEVEMENTS

Contrast-enhanced CT is broadly available and allows for rapid image acquisition including the possibility for complete tumor staging. MRI, on the other hand, is characterized by very good soft tissue contrast and has-especially with the use of diffusion-weighted imaging and administration of liver-specific contrast agents-the highest sensitivity for detection of metastases smaller than 1 cm.

PRACTICAL RECOMMENDATIONS

The choice of imaging in daily routine is often dependent on availability and clinical question. Frequently, e.g. for assessment of resectability (extent of metastases, anatomic relation of lesions to critical structures), both modalities may be implemented in combination.

Late gadolinium MRI enhancement of colorectal liver metastases is associated with overall survival among nonsurgical patients

PURPOSE

To determine if late gadolinium MRI enhancement of colorectal liver metastases (CRCLM) is associated with overall survival among nonsurgical patients.

MATERIALS AND METHODS

This retrospective study was approved by the institutional research ethics board. Late gadolinium enhancement was measured using target tumour enhancement (TTE) in all nonsurgical patients with CRCLM who received a 10-min delayed phase gadobutrol-enhanced liver MRI between March 1, 2006, and August 31, 2014. A total of 122 patients met inclusion/exclusion criteria. Patients were dichotomized into strong and weak TTE. Kaplan-Meier and Cox regression statistics were used to determine whether TTE was associated with overall survival. Noncontributory potential confounding variables (age, sex, number and size of metastases, carcinoembryonic (CEA) level, and presence of extrahepatic disease) were excluded from the final Cox regression model using the backward Wald elimination. Subgroup Kaplan-Meier survival analyses were performed on patients who were chemotherapy-naïve and chemotherapy-treated at the time of MRI.

RESULTS

Strong TTE had increased survival compared with those with weak TTE on Kaplan-Meier analysis (2-year survival: 69.8% vs. 43.5%, p = 0.002). Among 96 patients where data was available for multivariable analysis, weak TTE was associated with death (adjusted hazard ratio 0.25, 95% CI 0.11-0.59, p = 0.002), after adjusting for CEA level. Other potential confounders were noncontributory. Subgroup analyses demonstrated that strong TTE had increased survival compared with those with weak TTE in both the chemotherapy-naïve (p = 0.047) and chemotherapy-treated (p = 0.008) groups.

CONCLUSION

Strong late gadolinium MRI enhancement of CRCLM is associated with overall survival among nonsurgical patients.

KEY POINTS

• MRI enhancement of colorectal liver metastases is associated with overall survival in nonsurgical patients. • MRI enhancement of colorectal liver metastases is associated with overall survival in both chemotherapy-naïve and chemotherapy-treated subgroups.