Late gadolinium enhancement of colorectal liver metastases post-chemotherapy is associated with tumour fibrosis and overall survival post-hepatectomy

Dual-Time-Point Radiomics for Prognosis Prediction in Colorectal Liver Metastasis Treated with Neoadjuvant Therapy Before Radical Resection: A Two-Center Study

BACKGROUND

Optimal prognostic stratification for colorectal liver metastases (CRLM) patients undergoing surgery with neoadjuvant therapy (NAT) remains elusive. This study aimed to develop and validate dual-time-point radiomic models for CRLM prognosis prediction using pre- and post-NAT imaging features.

METHODS

Radiomic features were extracted from four MRI sequences in 100 cases of CRLM patients who underwent NAT and radical resection. RAD scores were generated, and clinical/pathologic variables were incorporated into uni- and multivariate Cox regression analyses to construct prognosis models. Time-ROC, time-C index, decision curve analysis (DCA), and calibration curves assessed the predictive performance of Fong score and pre- and post-NAT models for overall survival (OS) and disease-free survival (DFS) in a testing set.

RESULTS

The final models included four variables for OS and three variables for DFS. The post-NAT models outperformed the pre-NAT models in time-ROC, time-C index, calibration, and DCA analysis, except for the 1-year DFS area under the curve (AUC). The Fong score models underperformed. The post-NAT OS RAD score effectively stratified patients into prognostic subgroups.

CONCLUSIONS

The radiomic models incorporating pre- and post-NAT MRI features and clinical/pathologic variables effectively stratified CRLM patients prognositically. The post-NAT models demonstrated superior performance.

Enhancement of colorectal cancer liver metastases with gadoxetate-enhanced MRI at multiple time points is associated with disease-free survival following hepatectomy

OBJECTIVES

To investigate signal intensity of colorectal cancer liver metastases (CRLM) at hepatobiliary phase (HBP) gadoxetate-enhanced MRI at 2 time points pre- (TP1) and post- chemotherapy (TP2) and association with disease-free survival (DFS) in patients undergoing curative liver resection.

METHODS

Retrospective study was conducted. Single largest tumours were outlined and HBP T1 signal intensity was measured and normalized to skeletal muscle at TP1 and TP2. Enhancement thresholds were defined and risk groups at each TP and Kaplan-Meier survival curves were compared using the log-rank test. Univariate and multivariate association of enhancement and 8 clinical features with risk of recurrence were calculated using Cox proportional hazards.

RESULTS

82 patients (48 male, mean age 59 years) underwent 135 imaging studies, 58 at TP1, 77 at TP2, and 53 patients at TP1 + 2. Of 82 patients, 58 recurred with a median time to recurrence of 11.7 months. Enhancement of ≥135 and ≥15 at TP1 and TP2, respectively, were predictive of reduced risk of recurrence (P < .05), although not when corrected for multiple testing (P = .33 and .20, respectively). Enhancement was not associated with recurrence in multivariate model including 8 clinical features (P > .05). Change in enhancement between TP was not associated with risk of recurrence; however, tumours that consistently exhibited low enhancement were 9 times more likely to recur.

CONCLUSIONS

Increased CRLM enhancement in the HBP following gadoxetic acid at 2 TPs is associated with improved DFS in patients undergoing liver resection. This initial observation warrants further investigation of serial enhancement measurements as prognostic biomarkers.

ADVANCES IN KNOWLEDGE

Dual-time point signal assessment may be informative for clinical outcomes in CRLM undergoing resection.

ESR Essentials: assessing the radiological response of liver metastases to systemic therapy-practice recommendations by the European Society of Gastrointestinal and Abdominal Radiology

The liver is a common site for metastatic spread, especially in advanced colorectal, breast, and pancreatic cancers. Imaging evaluation of liver metastases after systemic treatments like chemotherapy, targeted therapy, or immunotherapy is essential to distinguish treatment response from disease progression. The widely used response evaluation criteria in solid tumours (RECIST 1.1) focus on lesion size changes to evaluate treatment response. However, newer therapies, mainly targeted therapy and immunotherapy, often induce changes beyond size reduction, such as tumour necrosis, fibrosis, cystic transformation, calcifications, and modifications at the liver-tumour interface. These morphological and enhancement changes can be evaluated on CT and MRI and may better reflect the biological response in specific clinical settings. Overall, RECIST 1.1 criteria are recommended for assessing the radiological response of liver metastases after systemic treatment. The use of alternative radiological criteria validated on CT (such as Chun or Choi criteria) is recommended in specific clinical settings (e.g. metastatic colorectal cancer or metastatic gastrointestinal stromal tumours). Additionally, CT and MR modifications that reflect fibrosis, necrosis, calcifications, and haemorrhage can serve as ancillary indicators of tumoural response. These alternative criteria and radiological findings should be systematically assessed, particularly in liver metastases with minimal size changes, to better identify responders. KEY POINTS: RECIST 1.1 is the standard for evaluating tumour response in solid tumours and is recommended for the assessment of liver metastases after systemic therapy. CT attenuation, enhancement, and liver/tumour interface may correlate better with tumoural response compared to size reduction. CT and MR changes suggesting necrosis, fibrosis, calcifications, and haemorrhage can be used as additional indicators of tumoural response.

Late/delayed gadolinium enhancement in MRI after intravenous administration of extracellular gadolinium-based contrast agents: is it worth waiting?

The acquisition of images minutes or even hours after intravenous extracellular gadolinium-based contrast agents (GBCA) administration ("Late/Delayed Gadolinium Enhancement" imaging; in this review, further termed LGE) has gained significant prominence in recent years in magnetic resonance imaging. The major limitation of LGE is the long examination time; thus, it becomes necessary to understand when it is worth waiting time after the intravenous injection of GBCA and which additional information comes from LGE. LGE can potentially be applied to various anatomical sites, such as heart, arterial vessels, lung, brain, abdomen, breast, and the musculoskeletal system, with different pathophysiological mechanisms. One of the most popular clinical applications of LGE regards the assessment of myocardial tissue thanks to its ability to highlight areas of acute myocardial damage and fibrotic tissues. Other frequently applied clinical contexts involve the study of the urinary tract with magnetic resonance urography and identifying pathological abdominal processes characterized by high fibrous stroma, such as biliary tract tumors, autoimmune pancreatitis, or intestinal fibrosis in Crohn's disease. One of the current areas of heightened research interest revolves around the possibility of non-invasively studying the dynamics of neurofluids in the brain (the glymphatic system), the disruption of which could underlie many neurological disorders.

A New Automated Prognostic Prediction Method Based on Multi-Sequence Magnetic Resonance Imaging for Hepatic Resection of Colorectal Cancer Liver Metastases

Colorectal cancer is a prevalent and life-threatening disease, where colorectal cancer liver metastasis (CRLM) exhibits the highest mortality rate. Currently, surgery stands as the most effective curative option for eligible patients. However, due to the insufficient performance of traditional methods and the lack of multi-modality MRI feature complementarity in existing deep learning methods, the prognosis of CRLM surgical resection has not been fully explored. This paper proposes a new method, multi-modal guided complementary network (MGCNet), which employs multi-sequence MRI to predict 1-year recurrence and recurrence-free survival in patients after CRLM resection. In light of the complexity and redundancy of features in the liver region, we designed the multi-modal guided local feature fusion module to utilize the tumor features to guide the dynamic fusion of prognostically relevant local features within the liver. On the other hand, to solve the loss of spatial information during multi-sequence MRI fusion, the cross-modal complementary external attention module designed an external mask branch to establish inter-layer correlation. The results show that the model has accuracy (ACC) of 0.79, the area under the curve (AUC) of 0.84, C-Index of 0.73, and hazard ratio (HR) of 4.0, which is a significant improvement over state-of-the-art methods. Additionally, MGCNet exhibits good interpretability.

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.

Contrast-enhanced US of the Liver and Kidney: A Problem-solving Modality

Contrast-enhanced US (CEUS) has an important role as a supplement to CT or MRI in clinical practice. The main established utilizations are in the liver and the kidney. The primary advantages of CEUS compared with contrast-enhanced CT or MRI relate to its superior contrast resolution, real-time continuous scanning, pure intravascular nature, portability, and safety-especially in patients with renal impairment or CT or MRI contrast agent allergy. This article focuses on the use of CEUS in the liver and kidney.

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.

Combination Analysis of a Radiomics-Based Predictive Model With Clinical Indicators for the Preoperative Assessment of Histological Grade in Endometrial Carcinoma

BACKGROUND

Histological grade is one of the most important prognostic factors of endometrial carcinoma (EC) and when selecting preoperative treatment methods, conducting accurate preoperative grading is of great significance.

PURPOSE

To develop a magnetic resonance imaging (MRI) radiomics-based nomogram for discriminating histological grades 1 and 2 (G1 and G2) from grade 3 (G3) EC.

METHODS

This was a retrospective study included 358 patients with histologically graded EC, stratified as 250 patients in a training cohort and 108 patients in a test cohort. T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI) and a dynamic contrast-enhanced three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) were performed via 1.5-Tesla MRI. To establish ModelADC, the region of interest was manually outlined on the EC in an apparent diffusion coefficient (ADC) map. To establish the radiomic model (ModelR), EC was manually segmented by two independent radiologists and radiomic features were extracted. The Radscore was calculated based on the least absolute shrinkage and selection operator regression. We combined the Radscore with carbohydrate antigen 125 (CA125) and body mass index (BMI) to construct a mixed model (ModelM) and develop the predictive nomogram. Receiver operator characteristic (ROC) and calibration curves were assessed to verify the prediction ability and the degree of consistency, respectively.

RESULTS

All three models showed some amount of predictive ability. Using ADC alone to predict the histological risk of EC was limited in both the cohort [area under the curve (AUC), 0.715; 95% confidence interval (CI), 0.6509-0.7792] and test cohorts (AUC, 0.621; 95% CI, 0.515-0.726). In comparison with ModelADC, the discrimination ability of ModelR showed improvement (Delong test, P < 0.0001 for both the training and test cohorts). ModelM, established based on the combination of radiomic and clinical indicators, showed the best level of predictive ability in both the training (AUC, 0.925; 95% CI, 0.898-0.951) and test cohorts (AUC, 0.915; 95% CI, 0.863-0.968). Calibration curves suggested a good fit for probability (Hosmer-Lemeshow test, P = 0.673 and P = 0.804 for the training and test cohorts, respectively).

CONCLUSION

The described radiomics-based nomogram can be used to predict EC histological classification preoperatively.

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.

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.

Late Gadolinium Hyperintensity of Suspected Colorectal Liver Metastases on Gadofosveset-Enhanced Magnetic Resonance Imaging: A Predictor of Benignity and a Potential Problem-Solving Tool

PURPOSE

Late gadolinium hyperintensity (LGH) is sometimes seen in colorectal liver metastasis (CRLM) and represents a significant diagnostic pitfall due to overlap with LGH in benign hemangiomas; therefore, the objective of this study was to determine the prevalence of LGH and the ability of LGH to differentiate between CRLM and benign lesions with intravascular (gadofosveset) vs extracellular contrast agents (gadobutrol).

METHODS

Patients with known colorectal cancer and suspected liver lesions were prospectively recruited into this institutional review board-approved, single institution study and received magnetic resonance imaging of the liver with gadofosveset and gadobutrol. The prevalence of LGH for CRLMs and solid benign lesions was determined. Receiver operating characteristics curves were determined for the presence of LGH as a predictor of benignity. The utility of LGH to differentiate between CRLM and solid benign lesions using gadofosveset vs gadobutrol was compared using the generalized estimating equation.

RESULTS

Twenty-five patients with 131 solid focal liver lesions were recruited. The prevalence of LGH of CRLMs was 11.2% (95% confidence interval [CI]: 0.5%-21.8%) with gadofosveset vs 63.7% (95% CI: 45.7%-81.7%) with gadobutrol. The area under the receiver operating characteristic curve for the presence of LGH as a predictor of benignity was 0.86 using gadofosveset vs 0.75 using gadobutrol. Both LGH (P = .003) and the interaction of contrast agent and LGH (P = .003) statistically significantly differentiated CRLM from benign lesions.

CONCLUSION

LGH is more common with extracellular than with intravascular contrast agents and is statistically significantly associated with benign lesions rather than metastases.

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.

Targeted delivery of 20(S)-ginsenoside Rg3-based polypeptide nanoparticles to treat colon cancer

Colorectal cancer (CRC) is a major malignancy characterized by a high metastasis rate. Systematic chemotherapy is important for patients with advanced CRC. However, many limitations (e.g., side effects to normal organs, shorter circulation time, and unsatisfactory tumor inhibition results) of traditional chemotherapy restrict its further application. Thus, it is necessary to find a method to overcome these challenges and improve the efficacy of CRC treatment. In this study, 20(S)-ginsenoside (Rg3) co-loaded poly(ethylene glycol)-block-poly(L-glutamic acid-co-L-phenylalanine) (mPEG-b-P(Glu-co-Phe)) nanoparticles (Rg3-NPs) were prepared. mPEG-b-P(Glu-co-Phe)-based drug delivery systems are pH sensitive that can target cancer cells and circulate for longer in blood. Rg3 could be released rapidly from the nanoparticles within tumor cells. A subcutaneous colon cancer mouse model was developed to evaluate the anticancer efficiency of the Rg3-NPs. The in vivo study indicated that the Rg3-NPs could significantly inhibit tumor proliferation by decreasing the expressions of proliferating cell nuclear antigen, resulting in tumor apoptosis through the increased expressions of caspase-3. Our study demonstrated the marked potential of the Rg3-NPs to treat CRC.

Tumor enhancement of colorectal liver metastases on preoperative gadobutrol-enhanced MRI at 5 minutes post-contrast injection is associated with overall survival post-hepatectomy

Previous studies have demonstrated that target tumor enhancement (TTE) of colorectal cancer liver metastases (CRCLM) on 10-minute delayed phase gadobutrol-enhanced MRI is associated with overall survival post-hepatectomy. The purpose of this study was to determine whether TTE of CRCLM on preoperative gadobutrol-enhanced MRI measured at 5-minute delayed phase is also associated with overall survival. We performed a single-institution, REB-approved, retrospective study of 121 patients with CRCLM who had received a clinical gadobutrol-enhanced MRI after treatment with chemotherapy and prior to liver surgery between January 1, 2006 and December 31, 2012. The TTE of the colorectal liver metastases (CRLM) on 5-minute delayed phase was determined. Kaplan-Meier and Cox-regression survival analyses were used in order to determine the association between TTE on 5-minute delayed phase and overall survival, after adjusting for known prognostic variables. TTE of chemotherapy-treated CRLM on gadobutrol-enhanced MRI at 5-minute post-contrast injection is associated with overall survival post-hepatectomy. On Kaplan-Meier survival analysis, there was a significant difference in overall survival between strong and weak TTE groups (log-rank P=0.009) with 74.4% survival at 36 months in the strong TTE group compared to only 44.6% in the weak TTE group. On Cox-regression analysis, the adjusted hazard ratio of death for patients with low TTE was 0.40 (95% CI: 0.18-0.90, P=0.026), after adjusting for known prognostic variables. This study provides preliminary evidence that tumor enhancement of CRLM at 5 minutes post-contrast injection on gadobutrol-enhanced MRI may provide preoperative prognostic information. This may be helpful for risk stratification of patients for surgery.

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

OBJECTIVES

To determine whether tumour enhancement on preoperative delayed-phase gadoxetate-enhanced MRI can predict long-term survival in patients with colorectal liver metastases (CRCLM) post-hepatectomy.

MATERIALS AND METHODS

Sixty-five patients who received a preoperative gadoxetate-enhanced MRI prior to liver resection for CRCLM from January 1, 2010, to December 31, 2012, were included in this retrospective study. Target tumour enhancement (TuEn) was calculated as the mean percentage increase in SNR from precontrast to 10-min or 20-min delayed phase for up to two target lesions. Per-patient TuEn was stratified into weak and strong enhancement based on the cut-off determined by the Youden Index for 3-year survival. Kaplan-Meier and Cox regression analyses were used to determine whether tumour enhancement could predict overall survival independent of potential confounders (clinical risk score).

RESULTS

The proportion surviving at 3 years was 85.1% in patients with strong TuEn at 10 min vs. 56.5% in those with weak TuEn at 10 min (p = 0.001). The proportion surviving at 3 years was 79.4% in patients with strong TuEn at 20 min vs. 58.7% in those with weak TuEn at 20 min (p = 0.011). After adjusting for potential confounders, the hazard ratio of death was 0.24 (p = 0.009) in patients who had weak TuEn at 10 min and 0.32 (p = 0.018) in patients who had weak TuEn at 20 min.

CONCLUSIONS

Strong delayed tumour enhancement seen on gadoxetate-enhanced MRI is associated with overall survival in patients with CRCLM post-hepatectomy and may be useful for preoperative risk stratification.

KEY POINTS

• Delayed tumour enhancement of colorectal liver metastases on gadoxetate-enhanced MRI is associated with survival post-hepatectomy • Delayed tumour enhancement of colorectal liver metastases on gadoxetate-enhanced MRI can be measured at both 10 min and 20 min post-contrast injection.