Integrating Radioembolization (90Y Microspheres) Into Current Treatment Options for Liver Tumors: Introduction to the International Working Group Report

Temporary Reversal of Hepatoenteric Collaterals during 90Y Radioembolization Planning and Administration

PURPOSE

This paper aims to evaluate the safety and efficacy of the temporary redirection of blood flow of hepatoenteric collaterals using a balloon catheter in the common hepatic artery (CHA) to prevent the nontarget deposition of ⁹⁰Y microspheres.

MATERIALS AND METHODS

In this retrospective single-center study of patients who received ⁹⁰Y radioembolization (RE) from September 2010 to September 2015, diagnostic (67 patients) or treatment (72 patients) angiograms with the attempted use of a balloon catheter in the CHA to temporarily direct blood flow away from the hepatoenteric arteries were analyzed. SPECT/CT nuclear scintigraphy was performed after both diagnosis and treatment.

RESULTS

Overall, only 12 hepatoenteric arteries in 11 patients required embolization due to persistent hepatoenteric flow despite the use of the balloon occlusion technique in a total of 86 patients. Physicians performed the ⁹⁰Y RE using balloon occlusion with glass (n = 22) or resin (n = 50) microspheres. Over 80% administration of the prescribed ⁹⁰Y dose was accomplished in 34 (67%) resin and 20 (95%) glass microsphere patients. Post-treatment ⁹⁰Y RE scintigraphy confirmed the absence of extrahepatic activity in all patients. One grade 2 gastrointestinal ulcer was present after 90 days of follow-up.

CONCLUSION

Temporary CHA occlusion with a balloon catheter is a reliable and reproducible alternative to the conventional coil embolization of hepatoenteric arteries during diagnostic Tc-99m macroaggregated albumin and therapeutic ⁹⁰Y RE delivery.

Efficacy and safety of guidewireless catheterization with a steerable microcatheter in patients scheduled for yttrium-90 radioembolization: a prospective multicenter trial

Introduction

A steerable, guidewireless microcatheter is of interest to interventional radiologists because it can improve effectiveness and reduce procedure timing and cost.

Aim

To assess the feasibility and safety of yttrium 90 radioembolization with a new steerable microcatheter without the need to use a guidewire.

Material and methods

A steerable microcatheter (Direxion; Boston Scientific, Natick, MA, USA) was prospectively used for yttrium-90 microsphere delivery in 50 patients (57 applications). The following factors were documented: vessel anatomy; shape and position of the guiding catheter; anticipated catheter position; technical success of catheterization; degree of difficulty in maneuvering; time to reach the target position; and complications.

Results

The microcatheter target position was in the right hepatic artery (n = 30, 53%), the middle hepatic artery (n = 4, 7%), the left hepatic artery (n = 19, 33%), or in a segmental artery (n = 4, 7%). Vessel catheterization was successful in 53 of 57 hepatic arteries (93%). The mean time to reach the target position was 53.3 ±53.0 s. The mean degree of difficulty in maneuvering the catheter to the target position was 2.3 ±1.3 (easy) on a 6-point scale. The only complication observed was mild vasospasm in 1 patient.

Conclusions

The Direxion steerable microcatheter is characterized by unique steerability, allowing yttrium 90 delivery to be performed safely without use of a guidewire.

Effectiveness of Liver-Directed Therapy for the Management of Intractable Hypoglycemia in Metastatic Insulinoma

OBJECTIVE

The aim of the study was to evaluate efficacy of chemoembolization and radioembolization in treating patients with recurrent hypoglycemia secondary to metastatic insulinoma.

METHODS

A retrospective review was performed of all patients with metastatic insulinoma treated with liver-directed therapy (LDT) at a large academic medical center from January 1998 to August 2017. Primary outcomes included blood glucose levels, occurrence of symptomatic hypoglycemic episodes, and tumor imaging response rates.

RESULTS

Seven patients were identified (4 male patients). The mean age at the first LDT was 60.9 (standard deviation [SD], 9.2) years. The median follow-up was 1.8 years. Thirty-three sessions of LDT were performed including 30 sessions of chemoembolization and 3 sessions of radioembolization. Technical success rate was 97% (32/33 procedures) with an initial clinical success rate of 100%, defined as absence of recurrent symptomatic hypoglycemia within 1 month after first cycle of LDT and overall clinical success rate of 85%. Random daytime glucose levels increased from 75.0 (SD, 26) mg/dL to 152.8 (SD, 52.4) mg/dL after LDT. The mean time to recurrence of intractable hypoglycemia was 21 (SD, 9) months. No severe complications were reported.

CONCLUSIONS

Liver-directed therapy with chemoembolization or radioembolization is effective for treatment of symptomatic hypoglycemia secondary to malignant insulinoma metastatic to liver.

Evaluation of Early Response to Treatment of Hepatocellular Carcinoma with Yttrium-90 Radioembolization Using Quantitative Computed Tomography Analysis

Objective

To identify an imaging predictor for the assessment of early treatment response to yttrium-90 transarterial radioembolization (TARE) in patients with hepatocellular carcinoma (HCC), using a quantitative assessment of dynamic computed tomography (CT) images.

Materials and Methods

Dynamic contrast-enhanced CT was obtained pre- and 4 weeks post-TARE in 44 patients (34 men, 10 women; mean age, 60 years) with HCC. Computer software was developed for measuring the percentage increase in the combined delayed-enhancing area and necrotic area (pD + N) and the percentage increase in the necrotic area (pNI) in the tumor-containing segments pre- and post-TARE. Local progression-free survival (PFS) was compared between patient groups using Cox regression and Kaplan-Meier analyses.

Results

Post-TARE HCC with pD + N ≥ 35.5% showed significantly longer PFS than those with pD + N < 35.5% (p = 0.001). The local tumor progression hazard ratio was 17.3 (p = 0.009) for pD + N < 35.5% versus pD + N ≥ 35.5% groups. HCCs with a high pNI tended to have longer PFS, although this difference did not reach statistical significance.

Conclusion

HCCs with a larger pD + N are less likely to develop local progression after TARE.

Hepatopulmonary Shunting: A Prognostic Indicator of Survival in Patients with Metastatic Colorectal Adenocarcinoma Treated with 90Y Radioembolization

Purpose To determine if high lung shunt fraction (LSF) is an independent prognostic indicator of poor survival in patients who undergo yttrium 90 radioembolization for unresectable liver-dominant metastatic colorectal cancer. Materials and Methods Retrospective data were analyzed from 606 patients (62% men; mean age, 62 years) who underwent radioembolization to treat liver metastases from colorectal adenocarcinoma between July 2002 and December 2011 at 11 U.S. centers. Institutional review board exemptions were granted prior to the collection of data at each site. Overall survival was estimated by using Kaplan-Meier survival and univariate Cox proportional hazards models to examine the effect of LSF on survival and to compare this to other potential prognostic indicators. Multivariate analysis was also performed to determine whether LSF is an independent risk factor for poor survival. Results LSF higher than 10% was predictive of significantly decreased survival (median, 6.9 months vs 10.0 months; hazard ratio, 1.60; P < .001) and demonstrated a mild but significant correlation to serum carcinoembryonic antigen levels and tumor-to-liver volume ratio (Pearson correlation coefficients, 0.105 and 0.113, respectively; P < .05). A progressive decrease in survival was observed as LSF increased from less than 5% to more than 20% (P < .05). LSF did not correlate with the presence of extrahepatic metastases or prior administration of bevacizumab. Conclusion Increased LSF is an independent prognostic indicator of worse survival in patients undergoing radioembolization for liver-dominant metastatic colorectal adenocarcinoma. High LSF correlates poorly to other potential markers of tumor size, such as tumor-to-liver volume ratio or serum carcinoembryonic antigen level, and does not correlate to the presence of extrahepatic metastases. ^© RSNA, 2016 Online supplemental material is available for this article.

Effects of Yttrium-90 selective internal radiation therapy on non-conventional liver tumors

The liver is a common site of metastasis, with essentially all metastatic malignancies having been known to spread to the liver. Nearly half of all patients with extrahepatic primary cancer have hepatic metastases. The severe prognostic implications of hepatic metastases have made surgical resection an important first line treatment in management. However, limitations such as the presence of extrahepatic spread or poor functional hepatic reserve exclude the majority of patients as surgical candidates, leaving chemotherapy and locoregional therapies as next best options. Selective internal radiation therapy (SIRT) is a form of catheter-based locoregional cancer treatment modality for unresectable tumors, involving trans-arterial injection of microspheres embedded with a radio-isotope Yttrium-90. The therapeutic radiation dose is selectively delivered as the microspheres permanently embed themselves within the tumor vascular bed. Use of SIRT has been conventionally aimed at treating primary hepatic tumors (hepatocellular carcinoma) or colorectal and neuroendocrine metastases. Numerous reviews are available for these tumor types. However, little is known or reviewed on non-colorectal or non-neuroendocrine primaries. Therefore, the aim of this paper is to systematically review the current literature to evaluate the effects of Yttrium-90 radioembolization on non-conventional liver tumors including those secondary to breast cancer, cholangiocarcinoma, ocular and percutaneous melanoma, pancreatic cancer, renal cell carcinoma, and lung cancer.

68Gallium- and 90Yttrium-/ 177Lutetium: "theranostic twins" for diagnosis and treatment of NETs

Abundant expression of somatostatin receptors (SSTR) is frequently identified in differentiated neuroendocrine tumors and may serve as potential target for diagnostic imaging and treatment. This article discusses the “theranostic approach” of SSTR-targeting compounds including an overview of its role for diagnosis, staging and restaging, discussing its way to being established in clinical routine, and giving an outlook about further potentially relevant developments.

Radioembolization of hepatic tumors

Unresectable primary and metastatic liver tumors are a leading cause of cancer mortality and morbidity. This remains a challenging and key task for every oncologist despite significant advances that have been made with selective targeted systemic agents and in technology advances with radiotherapy delivery. Radioembolization (RE) is a technique of permanently implanting microspheres containing Yttrium-90 ((90)Y), a beta-emitting isotope with a treatment range of 2 mm, into hepatic tumors. This form of brachytherapy utilizes the unique dual vascular anatomy of the liver to preferentially deliver radioactive particles via the hepatic artery to tumor, sparing normal liver parenchyma. The main treatment inclusion criteria are patients with solid tumors, compensated liver functions, life expectancy of at least three months, and ECOG performance status 0-2. Benefit of RE has been proven in patients that have low-to-moderate extrahepatic disease burden, prior liver radiotherapy, heavy prior chemotherapy and biologic agent exposure, and history of hepatic surgery or ablation. Most of the clinical evidence is reported in metastatic colorectal, and neuroendocrine tumors (NET), and primary hepatocellular cancer. A growing body of data supports the use of RE in hepatic metastatic breast cancer, intrahepatic cholangiocarinoma, and many other metastatic tumor types. Side effects are typically mild constitutional and GI issues limited to the first 7-14 days post treatment, with only 6% grade 3 toxicity reported in large series. Potentially serious or fatal radiation induced liver disease is extremely rare, reported in only 1% or fewer in major series of both metastatic and primary tumors treated with RE. Currently, high priority prospective clinical trials are testing RE combined with chemotherapy in first line therapy for colorectal hepatic metastases, and combined with sorafenib for hepatocellular carcinomas (HCCs). Fortunately, this beneficial and now widely available therapy is being increasingly incorporated into the standard therapy algorithms of multidisciplinary GI cancer teams worldwide. This form of radiotherapy differs significantly from daily external beam radiotherapy in many ways, particularly in dose rate, dosimetric coverage and duration of radiation delivery, side effects, and patient selection factors. A wealth of experience using RE in solid tumors exists and ongoing major prospective clinical trials will soon clarify the role of RE in the management of metastatic colorectal liver metastases.

Safety and efficacy of target vessel catheterization with the new steerable microcatheter Direxion compared with a standard microcatheter: a prospective, preclinical trial

PURPOSE

To assess the potential of a steerable microcatheter in a comparative preclinical trial.

METHODS

A total of 100 small target vessels of the lower limbs with a maximum diameter of 3 mm were prospectively randomized to catheterize with either the preshaped torqueable Direxion™ (J tip shape; Boston Scientific, Natick, MA) or a similarly steam-shaped Renegade™ microcatheter (Boston Scientific) in a porcine model. Catheterization was first performed in combination with a microguidewire and afterwards without.

RESULTS

No significant differences were found for the mean vessel diameter in the Direxion (1.53 ± 0.44 mm; n = 50) or Renegade (1.62 ± 0.43 mm; n = 50; p = 0.35) group. Guidewire-assisted catheterization was successful in all target vessels, whereas access was achieved in most cases with the guidewire alone. However, when it became necessary to steer the Direxion actively, this was regarded as key to obtain vessel access in three of four target vessels (75 %). Vessel catheterization without guidewire was significantly more successful with the Direxion (88 %; n = 44) compared with the Renegade (32 %; n = 16; p < 0.0001). In addition, this catheterization technique was also significantly faster with the Direxion compared with guidewire-assisted vessel catheterization with the Renegade (16.1 ± 14.4 sec compared with 27.1 ± 24.7 sec; p = 0.011).

CONCLUSIONS

The Direxion microcatheter demonstrated unique steerability characteristics, which makes it a promising new tool especially for complex coaxial endovascular procedures.

Current role of transarterial chemoembolization and radioembolization in the treatment of metastatic colorectal cancer

In this article, we review two liver-directed therapies that are currently used for the palliative treatment of primary and secondary hepatic malignancies, transcatheter arterial chemoembolization (TACE), including a new type of TACE with drug-eluting beads, and radioembolization. Important developments and administration techniques for all therapies are discussed, as well as their integration into the current routine clinical care for management of metastatic colorectal cancer. According to published data from clinical trials, as presented in this review, both radioembolization and TACE/TACE with drug-eluting beads have been proven to be safe and effective in selected patients with chemorefractory liver metastases from colorectal cancer. For patients with unresectable liver-only or liver-dominant disease who have failed standard chemotherapy options or for whom chemotherapy is contraindicated, new modalities, such as those discussed, are particularly valid and promising if clinical guidelines for patient selection and treatment administration are followed.

A new model to estimate prognosis in patients with hepatocellular carcinoma after Yttrium-90 radioembolization

Aims

The current prognostic model to estimate the survival in hepatocellular carcinoma (HCC) patients treated with transarterial hepatic selective internal radiotherapy (SIRT) is not fully characterized. The aim of this study was to establish a new scoring model including assessment of both tumor responses and therapy-induced systemic changes in HCC patients to predict survival at an early time point post-SIRT.

Methods and materials

Between 2008 and 2012, 149 HCC patients treated with SIRT were included into this study. CT images and biomarkers in blood tested at one month post-SIRT were analyzed and correlated with clinical outcome. Tumor responses were assessed by RECIST 1.1, mRECIST, and Choi criteria. Kaplan-Meier methods were used to estimate survival curves. Cox regression was used in uni- and multivariable survival analyses and in the establishment of a prognostic model.

Results

A multivariate proportional hazards model was created based on the tumor response, the number of tumor nodules, the score of the model for end stage liver disease (MELD), and the serum C-reactive protein levels which were independent predictors of survival in HCC patients at one month post-SIRT. This prognostic model accurately differentiated the outcome of patients with different risk scores in this cohort (P<0.001). The model also had the ability to assign a predicted survival probability for individual patients.

Conclusions

A new model to predict survival of HCC patients mainly based on tumor responses and therapy-induced systemic changes provides reliable prognosis and accurately discriminates the survival at an early time point after SIRT in these patients.

Choi criteria are superior in evaluating tumor response in patients treated with transarterial radioembolization for hepatocellular carcinoma

In this study, Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST (mRECIST), Choi and modified Choi criteria were compared to determine which method is optimal for response evaluation in hepatocellular carcinoma (HCC) patients treated with transarterial radioembolization (TARE) with yttrium-90 microspheres. Responses were evaluated by RECIST, mRECIST, Choi and modified Choi criteria in 113 patients with HCC undergoing TARE. Results were compared at 12 weeks after therapy. Kaplan-Meier survival analyses and Cox regression were used to assess differences in time to progression (TTP) and overall survival (OS) between the responders and non-responders defined by each method. The results demonstrated that the responders and non-responders defined by mRECIST and Choi criteria successfully identified patients with a long TTP (400 and 280 days) or short TTP (188 and 166 days) (P=0.004 and 0.002, respectively). Neither RECIST nor modified Choi criteria discriminated between patients who had a short or long clinical benefit. Cox regression analysis revealed that Choi response was a prognostic factor of OS (P=0.004) and was associated with a 53% risk reduction. There was no significant association between survival and RECIST, mRECIST and modified Choi responses. In conclusion, tumor response according to Choi criteria may be helpful to define early HCC patients who benefit from TARE. RECIST, mRECIST and modified Choi appeared inferior.

Metastatic Insulinoma Following Resection of Nonsecreting Pancreatic Islet Cell Tumor: A Case Report and Review of the Literature

A 56-year-old woman presented to our clinic for recurrent hypoglycemia after undergoing resection of an incidentally discovered nonfunctional pancreatic endocrine tumor 6 years ago. She underwent a distal pancreatectomy and splenectomy, after which she developed diabetes and was placed on an insulin pump. Pathology showed a pancreatic endocrine neoplasm with negative islet hormone immunostains. Two years later, computed tomography scan of the abdomen showed multiple liver lesions. Biopsy of a liver lesion showed a well-differentiated neuroendocrine neoplasm, consistent with pancreatic origin. Six years later, she presented to clinic with 1.5 years of recurrent hypoglycemia. Laboratory results showed elevated proinsulin, insulin levels, and c-peptide levels during a hypoglycemic episode. Computed tomography scan of the abdomen redemonstrated multiple liver lesions. Repeated transarterial catheter chemoembolization and microwave thermal ablation controlled hypoglycemia. The unusual features of interest of this case include the transformation of nonfunctioning pancreatic endocrine tumor to a metastatic insulinoma and the occurrence of atrial flutter after octreotide for treatment.

Protective embolization of the gastroduodenal artery with a one-HydroCoil technique in radioembolization procedures

PURPOSE

Protective occlusion of the gastroduodenal artery (GDA) is required to avoid severe adverse effects and complications in radioembolization procedures. Because of the expandable features of HydroCoils, our goal was to occlude the GDA with only one HydroCoil to provide particle reflux protection.

METHODS

Twenty-three subjects with unresectable liver tumors, who were scheduled for protective occlusion of the GDA before radioembolization therapy, were included. The primary end point was to achieve a proximal occlusion of the GDA with only one detachable HydroCoil. Evaluated parameters were duration of deployment, and early (during the intervention) and late (7-21 days) occlusion rates of GDA. Secondary end points included complete duration of the intervention, amount of contrast medium used, fluoroscopy rates, and adverse effects.

RESULTS

In all cases, the GDA was successfully occluded with only one HydroCoil. The selected diameter/length range was 4/10 mm in 2 patients, 4/15 mm in 6 patients, and 4/20 mm in 15 patients. HydroCoils were implanted, on average, 3.75 mm from the origin of the GDA (range 1.5-6.8 mm), with an average deployment time of 2:47 (median 2:42, range 2:30-3:07) min. In 21 (91%) of 23 patients, a complete occlusion of the GDA was achieved during the first 30 min after the coil implantation; however, in all patients, a late occlusion of the GDA was present after 6 to 29 days. No clinical or technical complications were reported.

CONCLUSION

We demonstrated that occlusion of the GDA with a single HydroCoil is a safe procedure and successfully prevents extrahepatic embolization before radioembolization.

Celiac Artery Stenting to Facilitate Hepatic Yttrium-90 Radioembolization Therapy

Radioembolization offers a novel way to treat the nonresectable, liver predominant hepatic malignancies with better tumor response and overall progression-free survival rates. Transarterial catheter-based radioembolization procedure involves the hepatic arterial administration of glass- or resin-based beta emitting Yttirum-90 microspheres. Safe delivery of the tumoricidal radiation dose requires careful angiogram planning and coil embolization to quantify lung shunting and prevent systemic toxicity, respectively. Diagnostic pretreatment angiogram also serves to identify the hepatic arterial variant anatomy and other coexisting pathologies that might require a different or alternative approach. We describe a complex case of celiac artery stenosis with tortuous pancreaticoduodenal arterial arcade precluding access to the right hepatic artery for performing radioembolization. Celiac artery stenting of the stenosis was performed to facilitate subsequent safe and successful Yttrium-90 microsphere radioembolization.