Standards of practice in transarterial radioembolization

Outcomes in Patients with Macrotrabecular-Massive Subtype Hepatocellular Carcinoma Treated with Yttrium-90 Transarterial Radioembolization

PURPOSE

To compare the outcomes of yttrium-90 transarterial radioembolization (TARE) in patients with hepatocellular carcinoma (HCC) with and without macrotrabecular-massive (MTM) subtypes.

MATERIALS AND METHODS

Forty-one consecutive patients with HCC (male, 90.3%; mean age, 65.3 years [SD ± 10.7]) who underwent yttrium-90 TARE between September 2014 and January 2022 were grouped into the MTM-HCC (n = 17, 41.5%) and non-MTM-HCC (n = 24, 58.5%) groups based on their histopathological subtypes. Demographic, clinical, and radiological characteristics were compared. Survival, univariate, and multivariate analyses were performed, and prognostic factors were evaluated.

RESULTS

In MTM-HCC group, the rates of moderately to poorly differentiated tumors were significantly higher (13/17 vs 8/16, P = .007), and new intrahepatic/extrahepatic metastases were detected more frequently (12/17 vs 15/24, P = .038). Median overall survival (OS) in the cohort was 29 months (range, 17.1-40.9 months), whereas patients with MTM-HCC had a significantly shorter median OS (20 vs 44 months, P = .014). In univariate analysis, MTM-HCC subtype (hazard ratio [HR], 2.690; P = .021), the presence of satellite nodules (HR, 3.810; P = .004), and macrovascular invasion (HR, 3.321; P = .012) were identified as significant prognostic factors. In multivariate analysis, MTM-HCC subtype and macrovascular invasion were determined as independent poor prognostic factors (P = .038 and P = .012, respectively).

CONCLUSIONS

In patients with HCC treated with yttrium-90 TARE, both the rates of moderately to poorly differentiated histopathological classes and the development of intrahepatic or extrahepatic metastases were significantly higher in the MTM-HCC subtype. OS was worse in patients with MTM-HCC, and macrovascular invasion and MTM-HCC subtype were identified as independent poor prognostic factors.

Clinical Application of Radioembolization in Hepatic Malignancies: Protocol for a Prospective Multicenter Observational Study

Background

Radioembolization, also known as transarterial radioembolization or selective internal radiation therapy with yttrium-90 (90Y) resin microspheres, is an established treatment modality for patients with primary and secondary liver tumors. However, large-scale prospective observational data on the application of this treatment in a real-life clinical setting is lacking.

Objective

The main objective is to collect data on the clinical application of radioembolization with 90Y resin microspheres to improve the understanding of the impact of this treatment modality in its routine practice setting.

Methods

Eligible patients are 18 years or older and receiving radioembolization for primary and secondary liver tumors as part of routine practice, as well as have signed informed consent. Data is collected at baseline, directly after treatment, and at every 3-month follow-up until 24 months or study exit. The primary objective of the Cardiovascular and Interventional Radiological Society of Europe Registry for SIR-Spheres Therapy (CIRT) is to observe the clinical application of radioembolization. Secondary objectives include safety, effectiveness in terms of overall survival, progression-free survival (PFS), liver-specific PFS, imaging response, and change in quality of life.

Results

Between January 2015 and December 2017, 1047 patients were included in the study. The 24-month follow-up period ended in December 2019. The first results are expected in the third quarter of 2020.

Conclusions

The CIRT is the largest observational study on radioembolization to date and will provide valuable insights to the clinical application of this treatment modality and its real-life outcomes.

Trial Registration

ClinicalTrials.gov NCT02305459; https://clinicaltrials.gov/ct2/show/NCT02305459

International Registered Report Identifier (IRRID)

DERR1-10.2196/16296

Multi-modal image analysis for semi-automatic segmentation of the total liver and liver arterial perfusion territories for radioembolization

Purpose

We have developed a multi-modal imaging approach for SIRT, combining ^99mTc-MAA SPECT/CT and/or ⁹⁰Y PET, ¹⁸F-FDG PET/CT, and contrast-enhanced CBCT for voxel-based dosimetry, as a tool for treatment planning and verification. For radiation dose prediction calculations, a segmentation of the total liver volume and of the liver perfusion territories is required.

Method

In this paper, we proposed a procedure for multi-modal image analysis to assist SIRT treatment planning. The pre-treatment ¹⁸F-FDG PET/CT, ^99mTc-MAA SPECT/CT, and contrast-enhanced CBCT images were registered to a common space using an initial rigid, followed by a deformable registration. The registration was scored by an expert using Likert scores. The total liver was segmented semi-automatically based on the PET/CT and SPECT/CT images, and the liver perfusion territories were determined based on the CBCT images. The segmentations of the liver and liver lobes were compared to the manual segmentations by an expert on a CT image.

Result

Our methodology showed that multi-modal image analysis can be used for determination of the liver and perfusion territories using CBCT in SIRT using all pre-treatment studies. The results for image registration showed acceptable alignment with limited impact on dosimetry.

The image registration performs well according to the expert reviewer (scored as perfect or with little misalignment in 94% of the cases). The semi-automatic liver segmentation agreed well with manual liver segmentation (dice coefficient of 0.92 and an average Hausdorff distance of 3.04 mm). The results showed disagreement between lobe segmentation using CBCT images compared to lobe segmentation based on CT images (average Hausdorff distance of 14.18 mm), with a high impact on the dosimetry (differences up to 9 Gy for right and 21 Gy for the left liver lobe).

Conclusion

This methodology can be used for pre-treatment dosimetry and for SIRT planning including the determination of the activity that should be administered to achieve the therapeutical goal. The inclusion of perfusion CBCT enables perfusion-based definition of the liver lobes, which was shown to be markedly different from the anatomical definition in some of the patients.

Holmium-166 Radioembolization in Hepatocellular Carcinoma: Feasibility and Safety of a New Treatment Option in Clinical Practice

PURPOSE

To investigate clinical feasibility, technical success and toxicity of ¹⁶⁶Ho-radioembolization (¹⁶⁶Ho-RE) as new approach for treatment of hepatocellular carcinomas (HCC) and to assess postinterventional calculation of exact dosimetry through quantitative analysis of MR images.

MATERIALS AND METHODS

From March 2017 to April 2018, nine patients suffering from HCC were treated with ¹⁶⁶Ho-RE. To calculate mean doses on healthy liver/tumor tissue, MR was performed within the first day after treatment. For evaluation of hepatotoxicity and to rule out radioembolization-induced liver disease (REILD), the Model for End-Stage Liver Disease (MELD) Score, the Common Terminology Criteria for Adverse Events and specific laboratory parameters were used 1-day pre- and posttreatment and after 60 days. After 6 months, MR/CT follow-up was performed.

RESULTS

In five patients the right liver lobe, in one patient the left liver lobe and in three patients both liver lobes were treated. Median administered activity was 3.7 GBq (range 1.7-5.9 GBq). Median dose on healthy liver tissue was 41 Gy (21-55 Gy) and on tumor tissue 112 Gy (61-172 Gy). Four patients suffered from mild postradioembolization syndrome. No significant differences in median MELD-Score were observed pre-, posttherapeutic and 60 days after ¹⁶⁶Ho-RE. No deterioration of liver function and no indicators of REILD were observed. One patient showed a complete response, four a partial response, three a stable disease and one a progressive disease at the 6 months follow-up.

CONCLUSION

¹⁶⁶Ho-RE seems to be a feasible and safe treatment option with no significant hepatotoxicity for treatment of HCC.

Multimodal image registration for liver radioembolization planning and patient assessment

Purpose

Multimodal imaging plays a key role in patient assessment and treatment planning in liver radioembolization. It will reach its full potential for convenient use in combination with deformable image registration methods. A registration framework is proposed for multimodal liver image registration of multi-phase CT, contrast-enhanced late-phase T1, T2, and DWI MRI sequences.

Methods

A chain of four pair-wise image registrations based on a variational registration framework using normalized gradient fields as distance measure and curvature regularization is introduced. A total of 103 cases of 35 patients was evaluated based on anatomical landmarks and deformation characteristics.

Results

Good anatomical correspondence and physical plausibility of the deformation fields were attained. The global mean landmark errors vary from 3.20 to 5.36 mm, strongly influenced by low resolved images in z-direction. Moderate volume changes are indicated by mean minimum and maximum Jacobian determinants of 0.44 up to 1.88. No deformation foldings were detected. The mean average divergence of the deformation fields range from 0.08 to 0.16 and the mean harmonic energies vary from 0.08 to 0.58.

Conclusion

The proposed registration solutions enable the combined use of information from multimodal imaging and provide an excellent basis for patient assessment and primary planning for liver radioembolization.

Assessment of Therapy Response to Transarterial Radioembolization for Liver Metastases by Means of Post-treatment MRI-Based Texture Analysis

INTRODUCTION

To determine whether post-treatment magnetic resonance imaging (MRI)-based texture analysis of liver metastases (LM) may be suited predicting therapy response to transarterial radioembolization (TARE) during follow-up.

MATERIALS AND METHODS

Thirty-seven patients with LM treated by TARE (mean age 63.4 years) between January 2006 and December 2014 were identified in this retrospective feasibility study. They underwent dynamic contrast-enhanced and hepatocellular phase MRI after TARE (mean 2.2 days). Response was evaluated on follow-up imaging scheduled in intervals of 3 months (median follow-up, 7.3 months) based on response evaluation criteria in solid tumors 1.1 (RECIST 1.1). Results of texture analysis [mean, standard deviation, skewness (s), kurtosis (k), entropy and uniformity] were compared between patients with progressive disease (PD) and patients with stable disease (SD), partial or complete response (PR/CR). Receiver operating characteristics including the area under the curve (AUC) and cutoff values including the sensitivity and specificity were calculated.

RESULTS

According to RECIST 1.1, 24 patients (64.9%) had PD, 8 SD (21.6%) and 5 PR (13.5%). MRI-based texture analysis showed an earlier differentiation between patients with and without PD when compared with RECIST 1.1. Median k (2.88 vs. 2.35) in arterial phase MRI and median s (0.48 vs. 0.25) and k (2.85 vs. 2.25) in venous phase MRI were significantly different (p < 0.05). The AUC for k derived from arterial phase MRI was 0.73 (cutoff = 2.55, sensitivity = 0.83, specificity = 0.62) (p < 0.05). The AUC for s and k in venous phase MRI was 0.76 (cutoff = 0.35, sensitivity = 0.71, specificity = 0.85) (p > 0.05) and 0.83 (cutoff = 2.50, sensitivity = 0.75, specificity = 0.85) (p < 0.05).

CONCLUSION

This study indicates the potential of MRI-based texture analysis at arterial and venous phase MRI for the early prediction of PD after TARE.

LEVEL OF EVIDENCE

IV.

Image quality of arterial phase and parenchymal blood volume (PBV) maps derived from C-arm computed tomography in the evaluation of transarterial chemoembolization

Background

To evaluate the benefits of arterial phase imaging and parenchymal blood volume (PBV) maps acquired by C-arm computed tomography during TACE procedure in comparison to cross-sectional imaging (CSI) using CT or MRI.

Methods

From January 2014 to December 2016, a total of 29 patients with HCC stage A or B (mean age 65 years; range 47 to 81 years, 86% male) were included in this study. These patients were referred to our department for TACE treatment and received peri-interventional C-arm CT. Dual phase findings of each lesion in terms of overall image quality, conspicuity, tumor size and feeding arteries were compared between arterial phase imaging and PBV using 5-point semi-quantitative Likert-scale, whereby pre-interventional CSI served as reference standard.

Results

A significantly higher overall image quality of the PBV maps compared to arterial phase C-arm CT acquisitions (4.34 (±0.55) vs. 3.93 (±0.59), p = 0.0032) as well as a higher conspicuity of HCC lesions (4.27 ± 0.74 vs. 3.83 ± 1.08, p < 0.0001) was observed. Arterial phase imaging led to an overestimation of tumor size (mean size, 26.5 ± 15.9 mm) compared to PBV (24.9 ± 15.2 mm, p = 0.0004) as well as CSI (25.2 ± 15.1 mm), p = 0.021). Regarding detectability of tumor feeding arterial vessels, significantly more feeding vessels were detected in arterial phase C-arm CT (n = 1.67 ± 0.92 vessels) compared to PBV maps (n = 1.27 ± 0.63 vessels) (p = 0.0001). One lesion was missed in pre-interventional CT imaging, but detected by C-arm CT.

Conclusion

The combination of PBV maps and arterial phase images acquired by C-arm CT during TACE procedure enables precise detection of the majority of HCC lesions and tumor feeding arteries and has therefore the potential to improve patient outcome.

Single-institution experience with selective internal radiation therapy (SIRT) for the treatment of unresectable colorectal liver metastases

BACKGROUND

Liver metastases are the commonest cause of death for patients with colorectal cancer. Growing evidence supports the use of selective internal radiation therapy (SIRT) in combination with conventional chemotherapy regimens for liver-only or liver-dominant unresectable metastatic colorectal cancer.

AIMS

To measure and evaluate outcomes of the first 20 consecutive patients with unresectable colorectal liver metastasis selected for SIRT in addition to their chemotherapy at a single Irish institution.

METHODS

Retrospective case series was performed. Patient charts and medical records were reviewed.

RESULTS

All 20 patients (100%) selected for angiographic workup were subsequently successfully treated with radioembolization. All patients were discharged 1 day post-SIRT. At initial imaging evaluation, 12 (60%) had a partial response in their liver, 2 (10%) had stable disease, and 6 (30%) had liver-specific progressive disease. Median follow up was 10 months (range 6-26). At last follow up, 14 (70%) patients were alive and 6 (30%) deceased. Most recent imaging demonstrated 2 (10%) with a complete response, 7 (35%) had a partial response, 2 (10%) had stable disease, and 9 (45%) had progressive disease within their liver. One patient was downstaged to hepatic resection, and one with a complete hepatic response had his primary sigmoid tumor resected 11 months post-SIRT.

CONCLUSIONS

SIRT is a safe and effective therapy for certain patients with unresectable colorectal liver metastases. This case series supports our opinion that selected patients should be offered SIRT in concert with their medical oncologist, concomitant with their chemotherapy. Larger multi-center studies are required to more clearly define the patient groups that will derive most benefit from SIRT.

Radioembolisation of hepatocellular carcinoma: a primer

Transarterial radioembolisation (TARE) has gained increasing acceptance as an additional/alternative locoregional treatment option for hepatocellular carcinoma, and colorectal hepatic metastases that present beyond potentially curative options. This is a catheter-based transarterial selective internal brachytherapy that involves injection of radioactive microspheres (usually Y-90) that are delivered selectively to the liver tumours. Owing to the combined radioactive and microembolic effect, the findings at follow-up imaging are significantly different from that seen with other transarterial treatment options. Considering increasing confidence among clinicians, refinement in techniques and increasing number of ongoing trials, TARE is expected to gain further acceptance and become an important tool in the armamentarium for the treatment of liver malignancies. So it is imperative that all radiologists involved in the management of liver malignancies are well versed with TARE to facilitate appropriate discussion at multidisciplinary meetings to direct further management. In this article, we provide a comprehensive review on various aspects of radioembolisation with Y-90 for hepatocellular carcinoma including the patient selection, treatment planning, radiation dosimetry and treatment, side effects, follow-up imaging and future direction.

Yttrium-90 radioembolization of unresectable hepatocellular carcinoma - a single center experience

PURPOSE

To determine the value of radioembolization (RE) for treatment of unresectable hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Records of patients undergoing RE for unresectable HCC were retrospectively reviewed. Biochemical and clinical toxicities, imaging response (according to modified Response Evaluation Criteria In Solid Tumors), time-to-progression (TTP) and overall survival (OS) were analyzed. Data were stratified according to clinical and procedural parameters. Univariate and multivariate analyses were performed.

RESULTS

One hundred and fifteen patients (89 male, mean age 69.3 years) underwent 158 REs (119 resin-, 39 glass-based) (Barcelona Clinic Liver Cancer [BCLC]-A: 6.1%, B: 33.9%, C: 60.0%). Median clinical follow-up was 5.9 (0.9-83.5) months. No grade 4 or 5 clinical toxicities were noted. Objective response rate was 35.6%; disease control rate was 76.7%. Median TTP of the treated part of the liver was 4 (0.9-45.4) months. 108/115 patients died during follow-up (median OS 8.4 [0.3-82.8] months after first RE [BCLC-A: 52.8 months, BCLC-B: 12.4 months, BCLC-C: 6.1 months]). On multivariate analysis, baseline Eastern Co-operative Oncology Group status <1, ascites prior to RE and best imaging response were predictors of longer OS. In BCLC-C patients, tumor burden, ascites prior to RE, baseline gamma-glutamyltransferase and Child-Pugh score were predictive of OS.

CONCLUSIONS

RE is safe and effective in carefully selected patients suffering from HCC with a low complication rate. Low baseline Eastern Co-operative Oncology Group status and absence of ascites prior to RE are positive prognostic factors.

Connecting cancer biology and clinical outcomes to imaging in KRAS mutant and wild-type colorectal cancer liver tumors following selective internal radiation therapy with yttrium-90

PURPOSE

To determine whether pathologic colorectal tumor KRAS mutation status is correlated with progression-free survival (PFS) by imaging after selective internal radiation therapy with Yttrium-90 (SIRT Y90) for metastatic colorectal cancer in the liver (mCRC).

MATERIALS AND METHODS

This was an IRB approved, HIPAA compliant retrospective cohort study. Consecutive patients with unresectable mCRC with documented KRAS mutation status treated at a single center from 2002 to 2013 with SIRT Y90 were investigated. Treatment response was compared between KRAS wild-type (wt) and mutant (mut) using an anatomic tumor response criteria based on RECIST 1.0. Kaplan-Meier estimation and Cox regression analysis were used to measure progression-free survival (PFS) and to assess independent prognostic factors for PFS.

RESULTS

82 of 186 patients met review criteria. 33 (40.2%) patients were identified as KRAS mut. PFS was longer in KRAS wt (median 166 days [95% CI 96-258 days]) vs. mut (median 91 days [95% CI 79-104 days], p = 0.002). KRAS mut patients were 1.48 times more likely to progress at first follow-up imaging than wt (95% CI 1.06-2.08, p = 0.024). Univariate analysis identified high pre-SIRT Y90 INR, KRAS wt, any use of anti-EGFR therapy, and post-SIRT Y90 chemotherapy as prognostic factors for longer PFS. In multivariate analysis, only KRAS wt was an independent prognostic factor for longer PFS (RR: 1.80 [95% CI 1.08-2.99], p = 0.024).

CONCLUSION

Longer PFS is associated with KRAS wt vs. mut following SIRT Y90.

Liver CT for vascular mapping during radioembolisation workup: comparison of an early and late arterial phase protocol

OBJECTIVES

To compare right gastric (RGA) and segment 4 artery (A4) origin detection rates during radioembolisation workup between early and late arterial phase liver CT protocols.

METHODS

100 consecutive patients who underwent liver CT between May 2012-January 2015 with early or late arterial phase protocol (n = 50 each, 10- vs. 20-s post-threshold delay) were included. RGA/A4 origin detection rates, assessed by two raters, and contrast-to-noise ratio (CNR) of the hepatic artery relative to the portal vein were compared between the protocols.

RESULTS

The first-second rater scored the RGA origin as visible in 58-65 % (specific proportion of agreement 82 %, κ = 0.62); A4 origin in 96-89 % (94 %, κ = 0.54). Thirty-six percent of RGA origins not detectable by DSA were identified on CT. Origin detection rates were not significantly different for early/late arterial phases. Mean CNR was higher in the early arterial phase protocol (1.7 vs. 1.2, p < 0.001).

CONCLUSION

A 10-s delay arterial phase CT protocol does not significantly improve detection of small intra- and extrahepatic branches. RGA origin detection requires further optimization, whereas A4/MHA origin detection is adequate, with good inter-rater reproducibility. CT remains important for preprocedural planning, because it may reveal arterial anatomy not discernible on DSA.

KEY POINTS

• An early arterial phase does not significantly improve RGA and A4/MHA origin detection. • RGA origin detection (58-65 %) on CT is still suboptimal. • 36 % of RGA origins undetectable on DSA can be identified on CT. • A4/MHA origin detection (89-96 %) on CT is excellent. • Inter-rater reproducibility is good for RGA and A4/MHA origin detection on CT.

Surefire infusion system versus standard microcatheter use during holmium-166 radioembolization: study protocol for a randomized controlled trial

Background

An anti-reflux catheter (ARC) may increase the tumor absorbed dose during radioembolization (RE) by elimination of particle reflux and its effects on hemodynamics. Since the catheter is fixed in a centro-luminal position, it may also increase the predictive accuracy of a scout dose administration before treatment. The purpose of the SIM trial is to compare the effects of ARC use during RE with holmium-166 (¹⁶⁶Ho) microspheres in patients with colorectal liver metastases (CRLM), with the use of a standard end-hole microcatheter.

Methods/Design

A within-patient randomized controlled trial (RCT) will be conducted in 25 patients with unresectable chemorefractory liver-dominant CRLM. Study participants will undergo a ¹⁶⁶Ho scout dose procedure in the morning and a therapeutic procedure in the afternoon. The ARC will be randomly allocated to the left/right hepatic artery, and a standard microcatheter will be used in the contralateral artery. SPECT/CT imaging will be performed for quantitative analyses of the microsphere distribution directly after the scout and treatment procedure. Baseline and follow-up investigations include ¹⁸F-FDG-PET + liver CT, clinical and laboratory examinations. The primary endpoint is the comparison of tumor to non-tumor (T/N) activity ratio in both groups. Secondary endpoints include comparisons of mean absorbed dose in tumors and healthy liver tissue, infusion efficiency, the predictive value of ¹⁶⁶Ho scout dose for tumor response. In the entire cohort, a dose-response relationship, clinical toxicity, and overall survival will be assessed. The sample was determined for the expectation that the ARC will increase the T/N ratio by 25 % (mean T/N ratio 2.0 vs. 1.6).

Discussion

The SIM trial is a within-patient RCT that will assess whether ¹⁶⁶Ho RE treatment can be optimized by using an ARC.

Trial registration

The SIM trial is registered at clinicaltrials.gov (NCT02208804). Registered on 31 July 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1643-3) contains supplementary material, which is available to authorized users.

The development, commercialization, and clinical context of yttrium-90 radiolabeled resin and glass microspheres

Selective internal radiation therapy has emerged as a well-accepted therapeutic for primary and metastatic hepatic malignancies. This therapeutic modality requires the combined efforts of multiple medical disciplines to ensure the safe delivery of yttrium-90 (90Y)-labeled microspheres. The development of this therapy followed decades of clinical research involving tumor vascularity and microsphere development. Today, it is essential that treating physicians have a thorough understanding of hepatic tumor vascularity and 90Y microsphere characteristics before undertaking this complex intervention. This review explores the contributions of early investigators of this therapy, as well as the development, US Food and Drug Administration approval, manufacturing process, and attributes of the 2 commercially available 90Y radiolabeled microsphere device to clarify the key physical differences between the products.

Yttrium-90 Radioembolization of Advanced, Unresectable Breast Cancer Liver Metastases-A Single-Center Experience

PURPOSE

To determine value of transarterial radioembolization (TARE) for palliative treatment of unresectable liver-dominant breast metastases (LdBM) and to determine prognostic parameters.

MATERIALS AND METHODS

Records of patients undergoing TARE for progressing LdBM between June 2006 and March 2015 were retrospectively reviewed; 44 female patients (mean age 56.1 y; range, 34.9-85.3 y) underwent 69 TAREs (56 resin-based, 13 glass-based). Of 44 patients, 42 had bilobar disease. Mean administered activity was 1.35 GBq ± 0.71. Median clinical and imaging follow-up times were 121 days (range, 26-870 d; n = 42 patients) and 93 days (range, 26-2,037 d; n = 38 patients). Clinical and biochemical toxicities, imaging response (according to Response Evaluation Criteria In Solid Tumors), time to progression, and overall survival (OS) were evaluated. Data were analyzed with stratification according to clinical and procedural parameters.

RESULTS

Toxicities included 1 cholecystitis (grade 2) and 1 duodenal ulceration (grade 3); no grade ≥ 4 clinical toxicities were noted. Objective response rate (complete + partial response) was 28.9% (11/38); disease control rate (response + stable disease) was 71.1% (27/38). Median time to progression of treated liver lobe was 101 days (range, 30-2,037 d). During follow-up, 34/42 patients died (median OS after first TARE: 184 d [range 29-2,331 d]). On multivariate analysis, baseline Eastern Cooperative Oncology Group (ECOG) status of 0 (P < .0001, hazard ratio [HR] = 0.146) and low baseline γ-glutamyltransferase (GGT) levels (P = .0146, HR = 0.999) were predictors of longer OS.

CONCLUSIONS

TARE can successfully delay progression of therapy-refractory LdBM with low complication rate. Nonelevated baseline ECOG status and low GGT levels were identified as prognostic factors.

Intravoxel Incoherent Motion Diffusion-Weighted MR Imaging for Prediction of Early Arterial Blood Flow Stasis in Radioembolization of Breast Cancer Liver Metastases

PURPOSE

To retrospectively evaluate predictive value of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) for early arterial blood flow stasis during transarterial radioembolization (TARE) of liver dominant breast metastases (LdBM).

MATERIALS AND METHODS

Preinterventional 1.5T DWI (b0, b1, b2 = 0, 50, 800 s/mm(2)) data for 28 liver lobes of 18 female patients treated by resin-based radioembolization (10 bilobar and 8 unilobar treatments) were analyzed. Apparent diffusion coefficient (ADC) (0, 800) and an estimation of the true diffusion coefficient D' and of the perfusion fraction f' were calculated for the 2 largest metastases. Response rate at 3 months and survival were analyzed. Procedures without full dose application because of early stasis were assigned to group A (n = 15), and procedures with full dose application were assigned to group B (n = 13).

RESULTS

Metastases in group A showed significantly lower f' (0.035 ± 0.018 vs 0.076 ± 0.015, P < .0001) and a trend toward lower ADC(0, 800) with values given in 10(-6) mm(2)/s (1,066 ± 141 vs 1,189 ± 176, P = .051); no group difference was shown for D'. Groups were best discriminated by weighted mean f' values of the 2 largest metastases with accuracy of 100%. Mean tumor diameter before and after TARE was 51 mm ± 18 and 50 mm ± 24 in group A and 47 mm ± 27 and 48 mm ± 32 for group B. Imaging response did not differ between groups (P = .545). Overall survival did not differ significantly between group A (230 d) and B (155 d) (P = .124).

CONCLUSIONS

Perfusion-sensitive IVIM parameter f' may predict early blood flow stasis in patients undergoing TARE for LdBM. Determination of this parameter before intervention may increase awareness of the interventionalist and increase safety of microsphere administration.

The value of intravoxel incoherent motion model-based diffusion-weighted imaging for outcome prediction in resin-based radioembolization of breast cancer liver metastases

Purpose

To evaluate prognostic values of clinical and diffusion-weighted magnetic resonance imaging-derived intravoxel incoherent motion (IVIM) parameters in patients undergoing primary radioembolization for metastatic breast cancer liver metastases.

Subjects and methods

A total of 21 females (mean age 54 years, range 43–72 years) with liver-dominant metastatic breast cancer underwent standard liver magnetic resonance imaging (1.5 T, diffusion-weighted imaging with b-values of 0, 50, and 800 s/mm²) before and 4–6 weeks after radioembolization. The IVIM model-derived estimated diffusion coefficient D’ and the perfusion fraction f’ were evaluated by averaging the values of the two largest treated metastases in each patient. Kaplan–Meier and Cox regression analyses for overall survival (OS) were performed. Investigated parameters were changes in f’- and D’-values after therapy, age, sex, Eastern Cooperative Oncology Group (ECOG) status, grading of primary tumor, hepatic tumor burden, presence of extrahepatic disease, baseline bilirubin, previous bevacizumab therapy, early stasis during radioembolization, chemotherapy after radioembolization, repeated radioembolization and Response Evaluation Criteria in Solid Tumors (RECIST) response at 6-week follow-up.

Results

Median OS after radioembolization was 6 (range 1.5–54.9) months. In patients with therapy-induced decreasing or stable f’-values, median OS was significantly longer than in those with increased f’-values (7.6 [range 2.6–54.9] vs 2.6 [range 1.5–17.4] months, P<0.0001). Longer median OS was also seen in patients with increased D’-values (6 [range 1.6–54.9] vs 2.8 [range 1.5–17.4] months, P=0.008). Patients with remission or stable disease (responders) according to RECIST survived longer than nonresponders (7.2 [range 2.6–54.9] vs 2.6 [range 1.5–17.4] months, P<0.0001). An ECOG status ≤1 resulted in longer median OS than >1 (7.6 [range 2.6–54.9] vs 1.7 [range 1.5–4.5] months, P<0.0001). Pretreatment IVIM parameters and the other clinical characteristics were not associated with OS. Classification by f’-value changes and ECOG status remained as independent predictors of OS on multivariate analysis, while RECIST response and D’-value changes did not predict survival.

Conclusion

Following radioembolization of breast cancer liver metastases, early changes in the IVIM model-derived perfusion fraction f’ and baseline ECOG score were predictive of patient outcome, and may thus help to guide treatment strategy.

Current status of transarterial radioembolization

Unresectable primary and secondary liver malignancies present a major problem in the treatment of solid tumors. Transarterial radioembolization (TARE) is an increasingly used technique for treating various types of malignant liver tumors. This approach is appealing, as the mechanism of action is independent from other loco-regional treatments and potentially complementary to systemic therapies. There are two commercially available products in use for TARE: ⁹⁰Y-resin and ⁹⁰Y-glass microspheres. Currently available data indicates TARE so be safe and effective in hepatocellular carcinoma (HCC) and metastatic liver disease. In HCC the results compare well with chemoembolization, while the role of TARE in combination with kinase inhibitors has yet to be established. Current data on TARE in metastatic liver disease is promising, but there is a strong need for prospective randomized trials comparing TARE and modern chemotherapeutic regimen to support the growing role of TARE in metastatic liver disease.

Evaluation of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis of Diffusion-Weighted Imaging for Prediction of Tumor Size Changes and Imaging Response in Breast Cancer Liver Metastases Undergoing Radioembolization: A Retrospective Single Center Analysis

To investigate the value of a simplified intravoxel incoherent motion (IVIM) analysis for evaluation of therapy-induced tumor changes and response of breast cancer liver metastases (mBRC) undergoing radioembolization.In 21 females (mean age 54 years, range 43-72) with mBRC tumor size changes and response evaluation criteria in solid tumors (RECIST) response to 26 primary radioembolization procedures were analyzed. Standard 1.5-T liver magnetic resonance imaging including respiratory-gated diffusion-weighted imaging (DWI) with b0 = 0 s/mm, b1 = 50 s/mm, b2 = 800 s/mm before and 6 weeks after each treatment was performed. In addition to the apparent diffusion coefficient (ADC)(0,800), the estimated diffusion coefficient D' and the perfusion fraction f' were determined using a simplified IVIM approach. For each radioembolization, the 2 largest treated metastases (if available) were analyzed. Lesions were categorized according to size changes into group A (reduction of longest diameter [LD]) and group B (LD increase) after 3 months. Radioembolization procedures were further categorized into "response" (partial response and stable disease) and "nonresponse" (progressive disease) according to RECIST after 3 months. ADC and D' are given in 10 mm/s.Forty-five metastases were analyzed. Thirty-two lesions were categorized as A; 13 as B. Before therapy, group A lesions showed significantly larger f'-values than B (P = 0.001), but ADC(0,800) and D' did not differ. After therapy, in group A lesions the ADC(0,800)- and D'-values increased and f' decreased (P < 0.0001); in contrast in group B lesions f' increased (P = 0.001). Groups could be differentiated by preinterventional f' and by changes of D' and f' between pre and postinterventional imaging (area under the curve [AUC] of 0.903, 0.747 and 1.0, respectively).Preinterventional parameters did not differ between responders and nonresponders according to RECIST. ADC(0,800)- and D'-values showed a larger increase in responders compared with nonresponders (P = 0.013 and P = 0.001, respectively). After therapy f'-values decreased significantly in responders (P = 0.001). Good to excellent prediction of long-term RECIST response was possible by therapy-induced changes in LD, D', and f' (AUC 0.903, 0.879, and 0.867, respectively).A simplified IVIM model-based analysis of early post-treatment DWI can deliver additional information on tumor size changes and long-term RECIST response after radioembolization of mBRC. The estimated perfusion fraction f' is better suited for response assessment than the conventional ADC(0,800) or D'. This can be useful to guide further treatment strategy.

Use of C-Arm Cone Beam CT During Hepatic Radioembolization: Protocol Optimization for Extrahepatic Shunting and Parenchymal Enhancement

PURPOSE

To optimize a C-arm computed tomography (CT) protocol for radioembolization (RE), specifically for extrahepatic shunting and parenchymal enhancement.

MATERIALS AND METHODS

A prospective development study was performed per IDEAL recommendations. A literature-based protocol was applied in patients with unresectable and chemorefractory liver malignancies undergoing an angiography before radioembolization. Contrast and scan settings were adjusted stepwise and repeatedly reviewed in a consensus meeting. Afterwards, two independent raters analyzed all scans. A third rater evaluated the SPECT/CT scans as a reference standard for extrahepatic shunting and lack of target segment perfusion.

RESULTS

Fifty scans were obtained in 29 procedures. The first protocol, using a 6 s delay and 10 s scan, showed insufficient parenchymal enhancement. In the second protocol, the delay was determined by timing parenchymal enhancement on DSA power injection (median 8 s, range 4-10 s): enhancement improved, but breathing artifacts increased (from 0 to 27 %). Since the third protocol with a 5 s scan decremented subjective image quality, the second protocol was deemed optimal. Median CNR (range) was 1.7 (0.6-3.2), 2.2 (-1.4-4.0), and 2.1 (-0.3-3.0) for protocol 1, 2, and 3 (p = 0.80). Delineation of perfused segments was possible in 57, 73, and 44 % of scans (p = 0.13). In all C-arm CTs combined, the negative predictive value was 95 % for extrahepatic shunting and 83 % for lack of target segment perfusion.

CONCLUSION

An optimized C-arm CT protocol was developed that can be used to detect extrahepatic shunts and non-perfusion of target segments during RE.

(90)Y-glass microspheres for hepatic neoplasia

Unresectable liver cancer presents a major problem in the treatment of solid tumors. Transarterial radioembolization is a modern approach toward primary and secondary liver malignancies. The mechanism of action is independent from other therapies that are based on ischemia or chemotoxicity. (90)Y-resin and (90)Y-glass microspheres are commercially available for transarterial radioembolization. Available data on the use of (90)Y-glass microspheres in hepatocellular carcinoma and metastatic disease indicate that this treatment is safe and effective. In hepatocellular carcinoma the results compare well with chemoembolization and might be considered more often. Current data in metastatic disease are promising, but there is a strong need for prospective randomized trials to identify the role of transarterial radioembolization with (90)Y-glass microspheres in metastatic liver disease.

[Transarterial ablative therapy of hepatocellular carcinoma]

CLINICAL/METHODICAL ISSUE

Due to late diagnosis and a lack of organs only about 30 % of patients suffering from hepatocellular carcinoma (HCC) undergo curative treatment.

STANDARD RADIOLOGICAL METHODS

Transarterial chemoembolization (TACE) is a routine procedure in intermediate stage HCC. In addition transarterial embolization (TAE) and transarterial radioembolization (TARE) are available for these patients.

PERFORMANCE

For inoperable patients with HCC, TACE is superior to best supportive care in terms of survival. Combined with percutaneous ablation TACE achieves results similar to resection.

ACHIEVEMENTS

Current developments, such as drug-eluting beads, TARE and multimodal treatment are well suited to further improve outcome in patients with intermediate stage HCC.

PRACTICAL RECOMMENDATIONS

Transarterial therapies in HCC should be applied in accordance with the Barcelona Clinic Liver Cancer (BCLC) criteria. Due to a better safety profile and potentially improved disease-free survival the use of drug-eluting beads should be liberally considered.

Impact of 3D Rotational Angiography on Liver Embolization Procedures: Review of Technique and Applications

In the last years, the interest into interventional applications of C-arm cone-beam CT (CBCT) progressively raised, widening its clinical application from the original field of interventional neuroradiology to the field of peripheral procedures. Liver embolization procedures, due to their complexity and potential treatment-related life-threatening complications, represent one of the main clinical applications of this novel angiographic technique. CBCT has been demonstrated to render procedures safer and technically easier, and to predict outcome as well as to avoid major complications in different treatment scenarios (trans-arterial embolization, trans-arterial chemoembolization, selective internal radiation therapy, percutaneous portal vein embolization). This review summarizes all technical, dosimetric and procedural aspects of CBCT techniques, underlying all its potential clinical advantages in the field of liver embolization procedures. Moreover, the paper provides all the instructions to obtain the best diagnostic performance out of this novel angiographic technique.

Radioembolization with Yttrium-90 microspheres (SIRT) in pancreatic cancer patients with liver metastases: efficacy, safety and prognostic factors

OBJECTIVE

To analyze the clinical efficacy of (90)Y radioembolization in liver metastases from pancreatic cancer, to describe treatment toxicities and to identify biomarkers as predictors of outcome.

METHODS

Data from 19 pancreatic cancer patients (9 females/10 males) who had received (90)Y radioembolization for metastatic liver disease between 06/2004 and 01/2011 were analyzed retrospectively.

RESULTS

The median age at (90)Y radioembolization was 63 years (range 43-77). In 16 patients, previous palliative gemcitabine-based chemotherapy was given for metastatic disease. Objective response in the liver after (90)Y radioembolization was 47%. Median local progression-free survival in the liver was 3.4 months (range 0.9-45.0). Median overall survival (OS) was 9.0 months (range 0.9-53.0) and 1-year survival was 24%. Cox regression models for baseline biomarkers at (90)Y radioembolization revealed correlations of increased carbohydrate antigen 19-9 (p = 0.02) and C-reactive protein (p = 0.03) with shorter OS. Short-term adverse events (nausea, vomiting, fatigue, fever and abdominal pain) did not exceed grade 3. As long-term adverse events, liver abscesses, gastroduodenal ulceration, cholestasis and cholangitis, ascites and spleen infarction were observed.

CONCLUSION

(90)Y radioembolization is able to induce an encouraging local response rate of liver metastases of pancreatic cancer patients. Most short-term toxicities are manageable; however, patients should be followed up carefully for severe long-term toxicities.