Technical solutions to ensure safe yttrium-90 radioembolization in patients with initial extrahepatic deposition of (99m)technetium-albumin macroaggregates

Angiographic Aspects of Transarterial Radioembolization: A Comparison of Technical Options to Avoid Extrahepatic Microsphere Depositions

The influence of the interventional treatment approach for transarterial radioembolization (TARE) on the incidence of extrahepatic microsphere depositions and to angiographic complications was evaluated. In total, 398 TARE cycles were analyzed. Interventional treatment approaches were classified as single treatment position (TP) with interventional occlusion (IO), multiple TPs without IO, and multiple TPs with IO. Correlations with extrahepatic microsphere depositions, angiographic complications, and periprocedural clinical events were performed. Alternative treatment strategies were evaluated. Applications from multiple TPs could have ensured the safe application of microspheres in 48.2% of cases that were originally performed from a single TP after IO. Extrahepatic microsphere accumulations were detected after 5.2%, 5.3%, and 1.5% of TARE procedures from a single TP without IO, a single TP with IO, and multiple TPs without IO, respectively. Applications from multiple TPs did not increase angiographic complications. During the 30-day follow-up, nausea/vomiting and upper abdominal discomfort were observed more frequently in the group with IO than in the group without IO (7.9%/4.6% and 9.2%/5.9%, respectively). In many TARE procedures, the same target liver can be treated from multiple TPs instead of a single TP, reducing the need for the interventional occlusion of aberrant arteries and potential extrahepatic microsphere depositions.

Enhanced Embolization Efficacy with the Embolic Microspheres Guided by the Aggregate Gradation Theory Through In Vitro and Simulation Evaluation

PURPOSE

Size of the embolic microspheres is of critical importance in the transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) to achieve the optimal embolization therapy. In this regard, to optimize the size distribution of the embolic microspheres and enhance the embolization efficacy, the aggregate gradation theory is used to formulate the microspheres.

METHODS

Finite element analysis (FEA) and in vitro experiments confirmed a better embolic efficacy for the poly(vinyl alcohol) (PVA) microspheres formulated according to the aggregate gradation theory.

RESULTS

The average volume flow of the graded group was 1.31 × 10^-4 mL/s in vitro experiment, which was lowest among all the groups suggesting the graded group had the optimal embolic effect. The graded group has the largest pressure gradient of 314.22 Pa/μm in FEA among all the groups, which can be attributed to the highest packing density of the graded group compared with other groups.

CONCLUSIONS

The graded embolic microspheres have a larger drag coefficient compared with the narrow size distribution groups both in vitro experiment and FEA. These findings can be used to formulate the embolic agents with optimal size distributions and are significant for the improvement of clinical embolization therapy.

Current Status and Future Direction of Hepatic Radioembolisation

Radioembolisation is a locoregional treatment modality for hepatic malignancies. It consists of several stages that are vital to its success, which include a pre-treatment angiographic simulation followed by nuclear medicine imaging, treatment activity choice, treatment procedure and post-treatment imaging. All these stages have seen much advancement over the past decade. Here we aim to provide an overview of the practice of radioembolisation, discuss the limitations of currently applied methods and explore promising developments.

Yttrium-90 hepatic radioembolization: clinical review and current techniques in interventional radiology and personalized dosimetry

In recent years, yttrium-90 ((90)Y) microsphere radioembolization has been establishing itself as a safe and efficacious treatment for both primary and metastatic liver cancers. This extends to both first-line therapies as well as in the salvage setting. In addition, radioembolization appears efficacious for patients with portal vein thrombosis, which is currently a contraindication for surgery, transplantation and transarterial chemoembolization. This article reviews the efficacy and expanding use of (90)Y microsphere radioembolization with an added emphasis on recent advances in personalized dosimetry and interventional radiology techniques. Directions for future research into combination therapies with radioembolization and expansion into sites other than the liver are also explored.

Outcomes and Predictors of Toxicity after Selective Internal Radiation Therapy Using Yttrium-90 Resin Microspheres for Unresectable Hepatocellular Carcinoma

Purpose

We sought to report outcomes and toxicity in patients with hepatocellular carcinoma (HCC) who received resin yttrium-90 selective internal radiation therapy (⁹⁰Y-SIRT) and to identify factors associated with declining liver function.

Methods

Patients treated with ⁹⁰Y-SIRT were retrospectively evaluated. Radiographic response was assessed using RECIST 1.1. Median liver progression-free survival (LPFS) and overall survival (OS) were calculated using the Kaplan–Meier method. Bivariate analysis was used to examine associations between change in Child-Pugh (CP) score/class and patient characteristics and treatment parameters.

Results

Twenty-seven patients with unresectable HCC underwent SIRT, 52% were CP Class A, 48% were Class B, 11% were BCLC stage B, and 89% were stage C. Forty-four percent of patients had portal vein thrombus at baseline. One-third of patients received bilobar treatment. Median activity was 32.1 mCi (range 9.18–43.25) and median-­absorbed dose to the liver was 39.6 Gy (range 13.54–67.70). Median LPFS and OS were 2.5 and 11.7 months, respectively. Three-month disease control rate was 63 and 52% in the target lesions and whole liver, respectively. New onset or worsened from baseline clinical toxicities were confined to Grade 1–2 events. However, new or worsened Grade 3–4 laboratory toxicities occurred in 38% of patients at 3 months and 43% of patients at 6 months following SIRT (six had lymphocytopenia, three had hypoalbuminemia, and two had transaminasemia). After 3 months, six patients had worsened in CP score and five had worsened in class from baseline. After 6 months, four patients had worsened in CP score and one had worsened in class from baseline. Pretreatment bilirubinemia was associated with a 2+ increase in CP score within 3 months (P = 0.001) and 6 months (P = 0.039) of ⁹⁰Y-SIRT. Pretreatment transaminasemia and bilirubinemia were associated with increased CP class within 3 months of SIRT (P = 0.021 and 0.009, respectively).

Conclusion

⁹⁰Y-SIRT was well-tolerated in patients with unresectable HCC, with no Grade 3–4 clinical toxicities. However, Grade 3–4 laboratory toxicities and worsened CP scores were more frequent. HCC patients with pretreatment bilirubinemia or transaminasemia may be at higher risk of experiencing a decline in liver function following ⁹⁰Y-SIRT.

Radioembolization with Y-90 Glass Microspheres: Do We Really Need SPECT-CT to Identify Extrahepatic Shunts?

Purpose

Selective Internal Radiation Therapy (SIRT) with ⁹⁰yttrium (Y-90) is an increasingly used therapeutic option for unresectable liver malignancies. Nontarget embolization of extrahepatic tissue secondary to vascular shunting can lead to SIRT associated complications. Our aim was to assess whether extrahepatic shunts can reliably be diagnosed based on hepatic digital subtraction angiography (DSA) or whether subsequent SPECT/CT data can provide additional information.

Materials and Methods

825 patients with hepatocellular carcinoma (n = 636), hepatic metastases (n = 158) or cholangiocellular carcinoma (n = 31) were retrospectively analyzed. During hepatic DSA 128 arteries causing shunt flow to gastrointestinal tissue were coilembolized (right gastric artery n = 63, gastroduodenal artery n = 29; branches to duodenum / pancreas n = 36). Technectium-99m-labeled human serum albumin (HSA) was injected in all 825 patients. SPECT/CT data was used to identify additional or remaining shunts to extrahepatic tissue.

Results

An unexpected uptake of HSA in extrahepatic tissue was found by SPECT/CT in 54/825 (6.5%) patients (located in stomach n = 13, duodenum n = 26, distal bowel segments n = 12, kidney n = 1, diaphragm n = 2). These patients underwent repeated DSA and newly identified shunt vessels were coilembolized in 22/54 patients, while in 12/54 patients a more distal catheter position for repeat injection of HSA was chosen. In 20/54 patients the repeated SPECT/CT data still revealed an extrahepatic HSA uptake. These patients did not receive SIRT.

Conclusion

Most extrahepatic shunts can be identified on DSA prior to Y-90 therapy. However, SPECT-CT data helps to identify additional shunts that were initially not seen on DSA.

⁹⁰Y Hepatic Radioembolization: An Update on Current Practice and Recent Developments

Radioembolization is an established treatment modality that has been subjected to many improvements over the last decade. Developments are occurring at a high pace, affecting patient selection and treatment. The aim of this review is therefore to provide an overview of current practice, with a focus on recent developments in the field of radioembolization. Several practical issues and recommendations in the application of radioembolization will be discussed, ranging from patient selection to treatment response and future applications.

Why Bundled Payments Could Drive Innovation: An Example From Interventional Oncology

This case study illustrates that in a fee-for-service payment environment, innovation that results in more efficient care may also result in lost revenue.

Radioembolization with yttrium-90 microspheres work up: Practical approach and literature review

Radioembolization (RE) is a selective internal radiotherapy technique in which yttrium-90 blended microspheres are infused through the hepatic arteries. It is based on the fact that primary and secondary hepatic tumors are vascularized mostly by arterial blood flow whereas healthy hepatocytes obtain their blood supply mostly from the portal network. This enables high radiation doses to be delivered, sparing the surrounding non-malignant liver parenchyma. Most of the complications are caused by unexpected particles passing into the gastrointestinal tract through branches originating from the main hepatic arterial supply. Knowledge of this hepatic arterial network and of its variations and the technical considerations this raises are required in preparation for treatment. This work describes the specific anatomical features and techniques for this anatomy through recent literature illustrated by cases from our own experience.

The role of SPECT/CT in radioembolization of liver tumours

Radioembolization (RE) with (90)Y microspheres is a promising catheter-based therapeutic option for patients with unresectable primary and metastatic liver tumours. Its rationale arises from the dual blood supply of liver tissue through the hepatic artery and the portal vein. Metastatic hepatic tumours measuring >3 mm derive 80 - 100 % of their blood supply from the arterial rather than the portal hepatic circulation. Typically, an angiographic evaluation combined with (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) scan precedes therapy to map the tumour feeding vessels as well as to avoid the inadvertent deposition of microspheres in organs other than the liver. Prior to administration of (99m)Tc-MAA, prophylactic coil embolization of the gastroduodenal artery is recommended to avoid extrahepatic deposition of the microspheres. SPECT/CT allows direct correlation of anatomic and functional information in patients with unresectable liver disease. SPECT/CT is recommended to assess intrahepatic distribution as well as extrahepatic gastrointestinal uptake in these patients. Pretherapeutic SPECT/CT is an important component of treatment planning including catheter positioning and dose finding. A post-therapy bremsstrahlung (BS) scan should follow RE to verify the distribution of the administered tracer. BS SPECT/CT imaging enables better localization and definition of intrahepatic and possible extrahepatic sphere distribution and to a certain degree allows posttreatment dosimetry. In this paper we address the usefulness and significance of SPECT/CT in therapy planning and therapy monitoring of RE.

Clinical and laboratory toxicity after intra-arterial radioembolization with (90)y-microspheres for unresectable liver metastases

OBJECTIVE

To investigate clinical and laboratory toxicity in patients with unresectable liver metastases, treated with yttrium-90 radioembolization ((90)Y-RE).

METHODS

Patients with liver metastases treated with (90)Y-RE, between February 1(st) 2009 and March 31(st) 2012, were included in this study. Clinical toxicity assessment was based on the reporting in patient's charts. Laboratory investigations at baseline and during a four-month follow-up were used to assess laboratory toxicity according to the Common Terminology Criteria for Adverse Events version 4.02. The occurrence of grade 3-4 laboratory toxicity was stratified according to treatment strategy (whole liver treatment in one session versus sequential sessions). Response assessment was performed at the level of target lesions, whole liver and overall response in accordance with RECIST 1.1 at 3- and 6 months post-treatment. Median time to progression (TTP) and overall survival were calculated by Kaplan-Meier analysis.

RESULTS

A total of 59 patients, with liver metastases from colorectal cancer (n = 30), neuroendocrine tumors (NET) (n = 6) and other primary tumors (n = 23) were included. Clinical toxicity after (90)Y-RE treatment was confined to grade 1-2 events, predominantly post-embolization symptoms. No grade 3-4 clinical toxicity was observed, whereas laboratory toxicity grade 3-4 was observed in 38% of patients. Whole liver treatment in one session was not associated with increased laboratory toxicity. Three-months disease control rates for target lesions, whole liver and overall response were 35%, 21% and 19% respectively. Median TTP was 6.2 months for target lesions, 3.3 months for the whole liver and 3.0 months for overall response. Median overall survival was 8.9 months.

CONCLUSION

The risk of severe complications or grade 3-4 clinical toxicity in patients with liver metastases of various primary tumors undergoing (90)Y-RE is low. In contrast, laboratory toxicity grade 3-4 can be expected to occur in more than one-third of patients without any clinical signs of radiation induced liver disease.

99mTc-macroaggregated albumin poorly predicts the intrahepatic distribution of 90Y resin microspheres in hepatic radioembolization

In hepatic (90)Y radioembolization, pretreatment (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) nuclear imaging is used for lung shunt analysis, evaluation of extrahepatic deposition, and sometimes for treatment planning, using a partition model. A high level of agreement between pretreatment (99m)Tc-MAA distribution and final (90)Y-microsphere distribution is assumed. The aim of this study was to investigate the value of pretreatment (99m)Tc-MAA SPECT to predict intrahepatic posttreatment (90)Y-microsphere distribution.

METHODS

Volumes of interest (VOIs) were delineated on pretreatment contrast-enhanced CT or MR images according to Couinaud liver segmentation. All VOIs were registered to the (99m)Tc-MAA SPECT and (90)Y SPECT images. The (99m)Tc-MAA SPECT and (90)Y SPECT activity counts were normalized to the total administered activity of (90)Y. For each VOI, this practice resulted in a predictive amount of (90)Y (MBq/cm(3)) based on (99m)Tc-MAA SPECT in comparison with an actual amount of (90)Y based on (90)Y SPECT. Bland-Altman analysis was used to investigate the agreement of the activity distribution between (99m)Tc-MAA SPECT and (90)Y SPECT.

RESULTS

A total of 39 procedures (225 VOIs) in 31 patients were included for analysis. The overall mean difference between pretreatment and posttreatment distribution of activity concentration for all segments was -0.022 MBq/cm(3) with 95% limits of agreement of -0.581 to 0.537 MBq/cm(3) (-28.9 to 26.7 Gy absorbed dose). A difference of >10%, >20%, and >30% of the mean activity per milliliter was found in, respectively, 153 (68%), 97 (43%), and 72 (32%) of the 225 segments. In every (99m)Tc-MAA procedure, at least 1 segment showed an under- or overestimation of >10%. The position of the catheter tip during administrations, as well as the tumor load of the liver segments, significantly influenced the disagreement.

CONCLUSION

In current clinical practice, (99m)Tc-MAA distribution does not accurately predict final (90)Y activity distribution. Awareness of the importance of catheter positioning and adherence to specific recommendations may lead to optimization of individualized treatment planning based on pretreatment imaging.

Root cause analysis of gastroduodenal ulceration after yttrium-90 radioembolization

INTRODUCTION

A root cause analysis was performed on the occurrence of gastroduodenal ulceration after hepatic radioembolization (RE). We aimed to identify the risk factors in the treated population and to determine the specific mechanism of nontarget RE in individual cases.

METHODS

The records of 247 consecutive patients treated with yttrium-90 RE for primary (n = 90) or metastatic (n = 157) liver cancer using either resin (n = 181) or glass (n = 66) microspheres were reviewed. All patients who developed a biopsy-proven microsphere-induced gastroduodenal ulcer were identified. Univariate and multivariate analyses were performed on baseline parameters and procedural data to determine possible risk factors in the total population. Individual cases were analyzed to ascertain the specific cause, including identification of the culprit vessel(s) leading to extrahepatic deposition of the microspheres.

RESULTS

Eight patients (3.2 %) developed a gastroduodenal ulcer. Stasis during injection was the strongest independent risk factor (p = 0.004), followed by distal origin of the gastroduodenal artery (p = 0.004), young age (p = 0.040), and proximal injection of the microspheres (p = 0.043). Prolonged administrations, pain during administration, whole liver treatment, and use of resin microspheres also showed interrelated trends in multivariate analysis. Retrospective review of intraprocedural and postprocedural imaging showed a probable or possible culprit vessel, each a tiny complex collateral vessel, in seven patients.

CONCLUSION

Proximal administrations and those resulting in stasis of flow presented increased risk for gastroduodenal ulceration. Patients who had undergone bevacizumab therapy were at high risk for developing stasis.

Transarterial radioembolization versus chemoembolization for the treatment of hepatocellular carcinoma (TRACE): study protocol for a randomized controlled trial

Background

Hepatocellular carcinoma is a primary malignant tumor of the liver that accounts for an important health problem worldwide. Only 10 to 15% of hepatocellular carcinoma patients are suitable candidates for treatment with curative intent, such as hepatic resection and liver transplantation. A majority of patients have locally advanced, liver restricted disease (Barcelona Clinic Liver Cancer (BCLC) staging system intermediate stage). Transarterial loco regional treatment modalities offer palliative treatment options for these patients; transarterial chemoembolization (TACE) is the current standard treatment. During TACE, a catheter is advanced into the branches of the hepatic artery supplying the tumor, and a combination of embolic material and chemotherapeutics is delivered through the catheter directly into the tumor. Yttrium-90 radioembolization (⁹⁰Y-RE) involves the transarterial administration of minimally embolic microspheres loaded with Yttrium-90, a β-emitting isotope, delivering selective internal radiation to the tumor. ⁹⁰Y-RE is increasingly used in clinical practice for treatment of intermediate stage hepatocellular carcinoma, but its efficacy has never been prospectively compared to that of the standard treatment (TACE). In this study, we describe the protocol of a multicenter randomized controlled trial aimed at comparing the effectiveness of TACE and ⁹⁰Y-RE for treatment of patients with unresectable (BCLC intermediate stage) hepatocellular carcinoma.

Methods/design

In this pragmatic randomized controlled trial, 140 patients with unresectable (BCLC intermediate stage) hepatocellular carcinoma, with Eastern Cooperative Oncology Group performance status 0 to 1 and Child-Pugh A to B will be randomly assigned to either ⁹⁰Y-RE or TACE with drug eluting beads. Patients assigned to ⁹⁰Y-RE will first receive a diagnostic angiography, followed by the actual transarterial treatment, which can be divided into two sessions in case of bilobar disease. Patients assigned to TACE will receive a maximum of three consecutive transarterial treatment sessions. Patients will undergo structural follow-up for a timeframe of two years post treatment. Post procedural magnetic resonance imaging (MRI) will be performed at one and three months post trial entry and at three-monthly intervals thereafter for two years to assess tumor response. Primary outcome will be time to progression. Secondary outcomes will be overall survival, tumor response according to the modified RECIST criteria, toxicities/adverse events, treatment related effect on total liver function, quality of life, treatment-related costs and cost-effectiveness.

Trial registration

NCT01381211

Experimental microsphere targeting in a representative hepatic artery system

Recent work employing the computational fluid-particle modeling of the hepatic arteries has identified a correlation between particle release position and downstream branch distribution for direct tumor-targeting in radioembolization procedures. An experimental model has been constructed to evaluate the underlying simulation theory and determine its feasibility for future clinical use. A scaled model of a generalized hepatic system with a single inlet and five outlet branches was fabricated to replicate the fluid dynamics in the hepatic arteries of diseased livers. Assuming steady flow, neutrally buoyant microspheres were released from controlled locations within the inlet of the model and the resulting output distributions were recorded. Fluid and particle transport simulations were conducted with identical parameters. The resulting experimentally and simulation-derived microsphere distributions were compared. The experimental microsphere distribution exhibited a clear dependence on injection location that correlated very strongly with the computationally predicted results. Individual branch targeting was possible for each of the five outputs. The experimental results validate the simulation methodology for achieving targeted microsphere distributions in a known geometry under constant flow conditions.