Lung Shunt Fraction prior to Yttrium-90 Radioembolization Predicts Survival in Patients with Neuroendocrine Liver Metastases: Single-Center Prospective Analysis

Influence of Early Versus Delayed Hepatic Artery Perfusion Scan on 90Y Selective Internal Radiation Therapy Planning

Purpose: This study evaluated the effect of an increase in the time interval between hepatic intra-arterial injection of 99mTc-macroaggregated albumin (MAA) and hepatic artery perfusion scintigraphy (HAPS) on the lung shunt fraction (LSF) and perfused volume (PV) calculations in the treatment planning of selective internal radiation therapy (SIRT). Methods: The authors enrolled 51 HAPS sessions from 40 patients diagnosed with primary or metastatic liver malignancy. All patients underwent scan at the first and fourth hour after hepatic arterial injection of 99mTc-MAA. Based on single-photon emission computed tomography images, LSF values were measured from each patient's first and fourth hour images. PV1 and PV4 were also calculated based on three-dimensional images using 5% and 10% cutoff threshold values and compared with each other. Results: The authors found that the median of LSF4 was statistically significantly higher than LSF1 (3.05 vs. 4.14, p ≤ 0.01). There was no statistically significant difference between PV1 and PV4 on the 10% (p = 0.72) thresholds. Conclusions: LSF values can be overestimated in case of delayed HAPS, potentially leading to treatment cancellation due to incorrectly high results in patients who could benefit from SIRT. Threshold-based PV values do not significantly change over time; nevertheless, keeping the short interval time would be safer.

Non-Invasive Imaging Biomarkers to Predict the Hepatopulmonary Shunt Fraction Before Transarterial Radioembolization in Patients with Hepatocellular Carcinoma

Purpose

To identify disease-specific profiles comprising patient characteristics and imaging biomarkers on contrast-enhanced (CE)-computed tomography (CT) that enable the non-invasive prediction of the hepatopulmonary shunt fraction (HPSF) in patients with hepatocellular carcinoma (HCC) before resin-based transarterial radioembolization (TARE).

Patients and Methods

This institutional review board-approved (EA2/071/19) retrospective study included 56 patients with HCC recommended for TARE. All patients received tri-phasic CE-CT within 6 weeks prior to an angiographic TARE evaluation study using technetium-99m macroaggregated albumin. Imaging biomarkers representative of tumor extent, morphology, and perfusion, as well as disease-specific clinical parameters, were used to perform data-driven variable selection with backward elimination to generate multivariable linear regression models predictive of HPSF. Results were used to create clinically applicable risk scores for patients scheduled for TARE. Additionally, Cox regression was used to identify independent risk factors for poor overall survival (OS).

Results

Mean HPSF was 13.11% ± 7.6% (range: 2.8- 35.97%). Index tumor diameter (p = 0.014) or volume (p = 0.034) in combination with index tumor non-rim arterial phase enhancement (APHE) (p < 0.001) and washout (p < 0.001) were identified as significant non-invasive predictors of HPSF on CE-CT. Specifically, the prediction models revealed that the HPSF increased with index lesion diameter or volume and showed higher HPSF if non-rim APHE was present. In contrast, index tumor washout was associated with decreased HPSF levels. Independent risk factors of poorer OS were radiogenomic venous invasion and ascites at baseline.

Conclusion

The featured prediction models can be used for the initial non-invasive estimation of HPSF in patients with HCC before TARE to assist in clinical treatment evaluation while potentially sparing ineligible patients from the angiographic shunt evaluation study.

Prediction of Lung Shunt Fraction for Yttrium-90 Treatment of Hepatic Tumors Using Dynamic Contrast Enhanced MRI with Quantitative Perfusion Processing

There is no noninvasive method to estimate lung shunting fraction (LSF) in patients with liver tumors undergoing Yttrium-90 (Y90) therapy. We propose to predict LSF from noninvasive dynamic contrast enhanced (DCE) MRI using perfusion quantification. Two perfusion quantification methods were used to process DCE MRI in 25 liver tumor patients: Kety's tracer kinetic modeling with a delay-fitted global arterial input function (AIF) and quantitative transport mapping (QTM) based on the inversion of transport equation using spatial deconvolution without AIF. LSF was measured on SPECT following Tc-99m macroaggregated albumin (MAA) administration via hepatic arterial catheter. The patient cohort was partitioned into a low-risk group (LSF ≤&amp;nbsp;10%) and a high-risk group (LSF &gt;&amp;nbsp;10%). Results: In this patient cohort, LSF was positively correlated with QTM velocity |u| (r = 0.61, F = 14.0363, p = 0.0021), and no significant correlation was observed with Kety's parameters, tumor volume, patient age and gender. Between the low LSF and high LSF groups, there was a significant difference for QTM |u| (0.0760 ± 0.0440 vs. 0.1822 ± 0.1225 mm/s, p = 0.0011), and Kety's Ktrans (0.0401 ± 0.0360 vs 0.1198 ± 0.3048, p = 0.0471) and Ve&amp;nbsp;(0.0900 ± 0.0307 vs. 0.1495 ± 0.0485, p = 0.0114). The area under the curve (AUC) for distinguishing between low LSF and high LSF was 0.87 for |u|, 0.80 for Ve and 0.74 for Ktrans. Noninvasive prediction of LSF is feasible from DCE MRI with QTM velocity postprocessing.

Using an Assumed Lung Mass Inaccurately Estimates the Lung Absorbed Dose in Patients Undergoing Hepatic 90Yttrium Radioembolization Therapy

RATIONALE

Currently, the estimated absorbed radiation dose to the lung in ⁹⁰Y radioembolization therapy is calculated using an assumed 1 kg lung mass for all patients. The aim of this study was to evaluate whether using a patient-specific lung mass measurement for each patient rather than a generic, assumed 1 kg lung mass would change the estimated lung absorbed dose.

METHODS

A retrospective analysis was performed on 68 patients who had undergone ⁹⁰Y radioembolization therapy at our institution. Individualized lung volumes were measured manually on CT scans for each patient, and these volumes were used to calculate personalized lung masses. The personalized lung masses were used to recalculate the estimated lung absorbed dose from the ⁹⁰Y therapy, and this dose was compared to the estimated lung absorbed dose calculated using an assumed 1 kg lung mass.

RESULTS

Patient-specific lung masses were significantly different from the generic 1 kg when compared individually for each patient (p < 0.0001). Median individualized lung mass was 0.71 (IQR: 0.59, 1.02) kg overall and was significantly different from the generic 1 kg lung mass for female patients [0.59 (0.50, 0.68) kg, (p < 0.0001)] but not for male patients [0.99 (0.71, 1.14) kg, (p = 0.24)]. Median estimated lung absorbed dose was 4.48 (2.38, 11.71) Gy using a patient-specific lung mass and 3.45 (1.81, 6.68) Gy when assuming a 1 kg lung mass for all patients. The estimated lung absorbed dose was significantly different using a patient-specific versus generic 1 kg lung mass when comparing the doses individually for each patient (p < 0.0001). The difference in the estimated lung absorbed dose between the patient-specific and generic 1 kg lung mass method was significant for female patients as a subgroup but not for male patients.

CONCLUSIONS

The current method of assuming a 1 kg lung mass for all patients inaccurately estimates the lung absorbed dose in ⁹⁰Y radioembolization therapy. Using patient-specific lung masses resulted in estimated lung absorbed doses that were significantly different from those calculated using an assumed 1 kg lung mass for all patients. A personalized dosimetry method that includes individualized lung masses is necessary and can warrant a ⁹⁰Y dose reduction in some patients with lung masses smaller than 1 kg.

LEVEL OF EVIDENCE

Level 3, Retrospective Study.

Predictive Factors for Resistant Disease with Medical/Radiologic/Liver-Directed Anti-Tumor Treatments in Patients with Advanced Pancreatic Neuroendocrine Neoplasms: Recent Advances and Controversies

Simple Summary

Tumor resistance, both primary and acquired, is leading to increased complexity in the nonsurgical treatment of patients with advanced panNENs, which would be greatly helped by reliable prognostic/predictive factors. The importance in identifying resistance is being contributed to by the increased array of possible treatments available for treating resistant advanced disease; the variable clinical course as well as response to any given treatment approach of patients within one staging or grading system, the advances in imaging which are providing increasing promising results/parameters that correlate with grading/outcome/resistance, the increased understanding of the molecular pathogenesis providing promising prognostic markers, all of which can contribute to selecting the best treatment to overcome resistance disease. Several factors have been identified that have prognostic/predictive value for identifying development resistant disease and affecting overall survival (OS)/PFS with various nonsurgical treatments of patients with advanced panNENs. Prognostic factors identified for patients with advanced panNENs for both OS/PFSs include various clinically-related factors (clinical, laboratory/biological markers, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors. Particularly important prognostic factors for the different treatment modalities studies are the recent grading systems. Most prognostic factors for each treatment modality for OS/PFS are not specific for a given treatment option. These advances have generated several controversies and new unanswered questions, particularly those related to their possible role in predicting the possible sequence of different anti-tumor treatments in patients with different presentations. Each of these areas is reviewed in this paper.

Abstract

Purpose: Recent advances in the diagnosis, management and nonsurgical treatment of patients with advanced pancreatic neuroendocrine neoplasms (panNENs) have led to an emerging need for sensitive and useful prognostic factors for predicting responses/survival. Areas covered: The predictive value of a number of reported prognostic factors including clinically-related factors (clinical/laboratory/imaging/treatment-related factors), pathological factors (histological/classification/grading), and molecular factors, on therapeutic outcomes of anti-tumor medical therapies with molecular targeting agents (everolimus/sunitinib/somatostatin analogues), chemotherapy, radiological therapy with peptide receptor radionuclide therapy, or liver-directed therapies (embolization/chemoembolization/radio-embolization (SIRTs)) are reviewed. Recent findings in each of these areas, as well as remaining controversies and uncertainties, are discussed in detail, particularly from the viewpoint of treatment sequencing. Conclusions: The recent increase in the number of available therapeutic agents for the nonsurgical treatment of patients with advanced panNENs have raised the importance of prognostic factors predictive for therapeutic outcomes of each treatment option. The establishment of sensitive and useful prognostic markers will have a significant impact on optimal treatment selection, as well as in tailoring the therapeutic sequence, and for maximizing the survival benefit of each individual patient. In the paper, the progress in this area, as well as the controversies/uncertainties, are reviewed.

Surgical and survival outcomes after robotic and open pancreaticoduodenectomy with positive margins

BACKGROUND

Though nowadays a palliative pancreaticoduodenectomy (PD) can be performed safely with relatively low mortality and acceptable morbidity rates in experienced centers, there have been no studies on the routine use of a palliative PD or on the advantages of performing surgical resection as a debulking procedure. Furthermore, the impact of resection margins on survival outcomes has been a matter of controversy. Therefore, this study aimed to clarify the role of robotic PD (RPD) in pancreatic and periampullary adenocarcinomas with positive resection margins.

METHODS

Patients undergoing RPDs and open PDs (OPDs) were included in this study. Based on the resection margins, the patients were divided into the R0, R1, and R2 PD groups. Surgical risks and survival outcomes were analyzed.

RESULTS

There were 348 PDs, including 29 (8.3%) palliative and 319 (91.7%) curative. Primary tumor origin, tumor sizes, perineural invasions, and abnormal serum carcinoembryonic antigen (CEA) levels were factors leading to palliative resection. The multivariate analysis showed that only pancreatic head adenocarcinomas and abnormal serum CEA levels (>5 ng/mL) were independent predictors. The surgical risks between curative and palliative PD were similar. There were no significant differences in the surgical risks and other surgical parameters between palliative RPDs and OPDs. For curative resection, RPDs resulted in less blood loss, greater harvested lymph nodes yield, less postoperative complications, less delayed gastric emptying, and shorter hospital stays than OPDs. The survival outcome was significantly better following R0 resection in overall periampullary adenocarcinomas, whereas a significant survival difference was shown only between the R0 and R2 resections for pancreatic head adenocarcinomas.

CONCLUSION

Compared with R0 PDs, palliative R1 PDs could benefit patients with pancreatic head adenocarcinomas when considering survival outcomes without increasing surgical risks. RPD can be considered for curative purposes and as an alternative for palliative management.

Liver-Directed Therapies for Neuroendocrine Neoplasms

PURPOSE OF REVIEW

To comprehensively synthesise and appraise the available evidence regarding therapies for metastatic neuroendocrine neoplasms that exploit the hepatic vasculature to deliver therapy to liver metastases.

RECENT FINDINGS

Various techniques including transarterial embolisation/chemoembolisation (TAE/TACE) and selective internal radiotherapy (SIRT, also termed radioembolisation [RE]) have been examined in patents with neuroendocrine liver metastases. Variations in the radioactive agents for selective internal radiotherapy (SIRT) have been explored, such as the use of Holmium-166, in addition to more established agents such as Yttrium-90. Recent trials have examined the safety and efficacy of combining liver-targeted therapy with systemic treatments, such as peptide receptor radionuclide therapy. More retrospective case series of liver-directed modalities will not provide additional knowledge. Randomised clinical trials have begun to compare the efficacy of different forms of liver-directed therapies, and also their combination with systemic treatment. Their results are expected to guide optimal treatment sequencing within multimodal concepts.

Association between objective response rate and overall survival in metastatic neuroendocrine tumors treated with radioembolization: a systematic literature review and regression analysis

OBJECTIVES

Neuroendocrine tumors (NETs) are a heterogeneous group of cancers arising from neuroendocrine cells. The aim was to evaluate objective response rate (ORR) as a predictor of overall survival (OS) in patients with metastatic NETs (mNETs) treated with radioembolization (RE).

METHODS

Randomized controlled trials and observational studies of RE treatment of mNETs were identified by systematic literature review (SLR). Pooled ORR and OS estimates were calculated and a weighted generalized linear model (GLM) of ORR as a predictor of OS was derived, stratified by ORR assessment criteria and RE type (Yttrium-90 resin or glass microspheres).

RESULTS

The SLR identified 32 observational studies. Mean ORR was 41% (95% confidence interval 38-45%). The Yttrium-90 resin and glass microsphere GLMs accounted for 59% and 57% of OS deviance, respectively. ORR was a significant predictor of OS in the resin microspheres model (p < 0.001), but not the glass microspheres model (p = 0.11).

CONCLUSIONS

A weighted GLM showed a significant relationship between ORR and OS in patients with mNETs treated with Yttrium-90 resin microspheres. ORR could therefore potentially be an OS surrogate in future trials of Yttrium-90 resin microspheres. Further research is needed to confirm the relationship between ORR and OS and the difference between resin and glass microspheres.

Three-dimensional regions-of-interest-based intra-operative four-dimensional soft tissue perfusion imaging using a standard x-ray system with no gantry rotation: A simulation study for a proof of concept

PURPOSE

Many interventional procedures aim at changing soft tissue perfusion or blood flow. One problem at present is that soft tissue perfusion and its changes cannot be assessed in an interventional suite because cone-beam computed tomography is too slow (it takes 4-10 s per volume scan). In order to address the problem, we propose a novel method called IPEN for Intra-operative four-dimensional soft tissue PErfusion using a standard x-ray system with No gantry rotation.

METHODS

IPEN uses two input datasets: (a) the contours and locations of three-dimensional regions-of-interest (ROIs) such as arteries and sub-sections of cancerous lesions, and (b) a series of x-ray projection data obtained from an intra-arterial contrast injection to contrast enhancement to wash-out. IPEN then estimates a time-enhancement curve (TEC) for each ROI directly from projections without reconstructing cross-sectional images by maximizing the agreement between synthesized and measured projections with a temporal roughness penalty. When path lengths through ROIs are known for each x-ray beam, the ROI-specific enhancement can be accurately estimated from projections. Computer simulations are performed to assess the performance of the IPEN algorithm. Intra-arterial contrast-enhanced liver scans over 25 s were simulated using XCAT phantom version 2.0 with heterogeneous tissue textures and cancerous lesions. The following four sub-studies were performed: (a) The accuracy of the estimated TECs with overlapped lesions was evaluated at various noise (dose) levels with either homogeneous or heterogeneous lesion enhancement patterns; (b) the accuracy of IPEN with inaccurate ROI contours was assessed; (c) we investigated how overlapping ROIs and noise in projections affected the accuracy of the IPEN algorithm; and (d) the accuracy of the perfusion indices was assessed.

RESULTS

The TECs estimated by IPEN were sufficiently accurate at a reference dose level with the root-mean-square deviation (RMSD) of 0.0027 ± 0.0001 cm^-1 or 13 ± 1 Hounsfield unit (mean ± standard deviation) for the homogeneous lesion enhancement and 0.0032 ± 0.0005 cm^-1 for the heterogeneous enhancement (N = 20 each). The accuracy was degraded with decreasing doses: The RMSD with homogeneous enhancement was 0.0220 ± 0.0003 cm^-1 for 20% of the reference dose level. Performing 3 × 3 pixel averaging on projection data improved the RMSDs to 0.0051 ± 0.0002 cm^-1 for 20% dose. When the ROI contours were inaccurate, smaller ROI contours resulted in positive biases in TECs, whereas larger ROI contours produced negative biases. The bias remained small, within ± 0.0070 cm^-1 , when the Sorenson-Dice coefficients (SDCs) were larger than 0.81. The RMSD of the TEC estimation was strongly associated with the condition of the problem, which can be empirically quantified using the condition number of a matrix A z that maps a vector of ROI enhancement values z to projection data and a weighted variance of projection data: a linear correlation coefficient (R) was 0.794 (P < 0.001). The perfusion index values computed from the estimated TECs agreed well with the true values (R ≥ 0.985, P < 0.0001).

CONCLUSION

The IPEN algorithm can estimate ROI-specific TECs with high accuracy especially when 3 × 3 pixel averaging is applied, even when lesion enhancement is heterogeneous, or ROI contours are inaccurate but the SDC is at least 0.81.

Comparison of Tc-99m MAA Planar Versus SPECT/CT Imaging for Lung Shunt Fraction Evaluation Prior to Y-90 Radioembolization: Are We Overestimating Lung Shunt Fraction?

PURPOSE

To compare lung shunt fraction (LSF) prior to Y-90 radioembolization calculated using planar imaging versus SPECT/CT in patients with hepatocellular carcinoma (HCC).

METHODS

A single institution retrospective analysis of technetium-99m macroaggregated albumin (Tc-99m MAA) LSF studies for 293 consecutive patients with HCC between 2013 and 2018 was performed. LSF using planar imaging (PLSF) was compared to retrospectively calculated LSF using SPECT/CT (SLSF) via semiautomated segmentation using MIM v.6.9. Sub-analyses of patients were performed based on PLSF range, tumor size, BCLC stage, and Child-Pugh (C-P) score. Mean LSF absolute discrepancy between sub-groups was analyzed. Comparisons were performed using paired t tests and linear regression analysis.

RESULTS

Mean PLSF, 8.27%, was greater than mean SLSF, 3.27% (p < 0.001). When categorizing patients by PLSF ranges of < 10%, 10-19.9%, and ≥ 20%, PLSF remained greater than SLSF in all subgroups (p's < 0.001). Patients with PLSF ≥ 20% had a greater absolute discrepancy with SLSF (13.31%) compared to patients with PLSF < 20% (4.74%; p < 0.0001). LSF absolute discrepancy was greater for patients with a maximum liver tumor size ≥ 5.0 cm (5.59%) compared to a liver tumor size < 5.0 cm (4.40%; p = 0.0076). For all BCLC grades and C-P scores, PLSF was greater than SLSF. A greater LSF discrepancy existed for patients with a worse C-P score (C-P A: 4.78%, C-P B/C: 6.12%; p = 0.0081), but not BCLC stage (0/A/B: 4.87%, C: 4.56%; p = 0.5993).

CONCLUSION

In patients with HCC, SLSF is significantly lower compared to PLSF, with a greater discrepancy among patients with a PLSF ≥ 20%, tumor size ≥ 5 cm, and worse C-P score.

LEVEL OF EVIDENCE

Level 3, Retrospective Study.

Phase Ib trial of gemcitabine with yttrium-90 in patients with hepatic metastasis of pancreatobiliary origin

Background

Gemcitabine, a chemotherapy for hepatic metastasis with pancreatic cancer (PC) or intrahepatic cholangiocarcinoma (ICC) origin, may radiosensitize the targeted tumor cells for yttrium-90 radioembolization (90Y-RE). This clinical trial was designed to investigate the effects of a combination of 90Y-RE and gemcitabine in hepatic metastasis of PC or ICC origin.

Methods

Fourteen patients who had histopathologic diagnosis of unresectable hepatic metastasis of PC or ICC origin were enrolled into the open-label phase Ib clinical trial. Induction dose of gemcitabine on day 1 was followed by 90Y-RE on day 2 with predetermined doses of gemcitabine to follow till week 12. Maximal tolerated dose (MTD) of gemcitabine in combination with 90Y-RE, associated toxicities and hepatic progression free survival (HPFS) were assessed. The tumor response rate was evaluated using both RECIST and PERCIST criteria.

Results

Eight patients met the study criteria; three with PC and five with ICC. The mean age of the patients was 69.4 years. Seven out of 8 patients tolerated predetermined gemcitabine regime (dose level 1 at 400 mg/m² and dose level 2 at 600 mg/m²). All of the patients developed grade 1 toxicities. Three patients (37.5%) had grade 2 hepatobiliary toxicity and one patient (12.5%) had grade 3 hepatobiliary toxicity, who was hospitalized for a short-term. The median HPFS was 8.7 months for all patients. The objective response rate was 62%.

Conclusions

A combination of 90Y-RE and gemcitabine at 600 mg/m² is a safe and potential treatment option for hepatic metastasis of pancreaticobiliary origin.

Safety and efficacy of radioembolization with glass microspheres in hepatocellular carcinoma patients with elevated lung shunt fraction: analysis of a 103-patient cohort

BACKGROUND

Technetium-99m macroaggregated albumin is used to estimate lung shunt fraction (LSF) prior to yttrium-90 (Y90). Studies have debated the safety and efficacy of Y90 in patients with LSF > 15%. We aimed to assess the role of Y90 in hepatocellular carcinoma (HCC) with LSF > 15%.

METHODS

With IRB approval, we searched our prospectively acquired database of HCC patients with Y90 treated with LSF > 15%. Median LSF and liver and lung doses were calculated. The response was assessed using RECIST. Overall survival (OS) was calculated from date of first Y90.

RESULTS

A total of 103 HCC patients underwent Y90. The median baseline LSF was 24.4% (IQR 18.1-28.8). Patients exhibited multifocal disease (59/103, 60%) and median tumor size of 7.85 cm (IQR 5.2, 10.57). BCLC class was A, B, C, and D in 7 (7%), 5 (5%), 85 (83%), and 6 (6%) patients, respectively. The median liver dose was 84.6 Gy (IQR 57.4, 107.55). The median lung dose per session and cumulatively was 22.9 Gy (IQR 15-28) and 29.5 Gy (IQR 20.5-44.3). Thirty-three patients (32%) demonstrated partial response, 57 stable disease, and 13 (13%) had progressive disease. The median OS was 7.3 months (95% CI 5.3, 11.47). Twenty patients (19%) had non-specific pulmonary symptoms (cough, shortness of breath, wheezing) in the 1-year post-Y90. The median time to the appearance of non-specific pulmonary symptoms was 63 days (range 7-224). Thoracic imaging demonstrated no pulmonary fibrosis/injury following treatment in any patient.

CONCLUSION

Y90 can be performed in patients with LSF > 15%. The RECIST response was identified in 32% of the patients. In isolation, LSF > 15% should not deter from treatment with Y90.

Radioembolisation with 90Y microspheres for neuroendocrine liver metastases: an institutional case series, systematic review and meta-analysis

BACKGROUND

Neuroendocrine liver metastases are clinically challenging due to their frequent disseminated distribution. This study aims to present a British experience with an emerging modality, radioembolisation with yttrium-90 labelled microspheres, and embed this within a meta-analysis of response and survival outcomes.

METHODS

A retrospective case series of patients treated with SIR-Spheres (radiolabelled resin microspheres) was performed. Results were included in a systematic review and meta-analysis of published results with glass or resin microspheres. Objective response rate (ORR) was defined as complete or partial response. Disease control rate (DCR) was defined as complete/partial response or stable disease.

RESULTS

Twenty-four patients were identified. ORR and DCR in the institutional series was 14/24 and 21/24 at 3 months. Overall survival and progression-free survival at 3-years was 77.6% and 50.4%, respectively. There were no grade 3/4 toxicities post-procedure. A fixed-effects pooled estimate of ORR of 51% (95% CI: 47%-54%) was identified from meta-analysis of 27 studies. The fixed-effects weighted average DCR was 88% (95% CI: 85%-90%, 27 studies).

CONCLUSION

Current data demonstrate evidence of the clinical effectiveness and safety of radioembolisation for neuroendocrine liver metastases. Prospective randomised studies to compare radioembolisation with other liver directed treatment modalities are needed.

90Y radioembolization dosimetry using a simple semi-quantitative method in intrahepatic cholangiocarcinoma: Glass versus resin microspheres

INTRODUCTION

There are two different types of ⁹⁰Y Microspheres, glass and resin, in the market for ⁹⁰Y radioembolization (⁹⁰Y-RE). This study aimed to investigate the dose of radiation delivered through glass vs. resin-based ⁹⁰Y-RE to intrahepatic cholangiocarcinoma (ICC).

METHODS

In this retrospective study, 10 patients with ICC underwent ⁹⁰Y-RE, five underwent glass (Glass group) and other 5 resin (Resin group) microspheres. Technetium-99m macro-aggregated albumin (Tc-99m MAA) shunt study was performed two weeks before ⁹⁰Y-RE. Within 2 h from ⁹⁰Y-RE, Bremsstrahlung SPECT/CT was obtained. Regions of interest (ROIs) were segmented around the targeted tumor and the liver. Tumor and liver volumes, corresponding radioactive counts, and tumor to liver count ratio were calculated using MIM software and compared between Glass and Resin groups.

RESULTS

Mean hepatopulmonary shunt fraction was 7.1 vs. 6.2% for the Glass and Resin groups (p = 0.83), with no extrahepatic activity. There was no difference in the activity and tumor uptake of administered Tc-99m MAA between both groups (p = 0.71 and p = 0.63). Mean administered activity of ⁹⁰Y in the Glass group was higher than the Resin group (73.2 ± 24.3 vs. 44.5 ± 18.2 mCi, p < 0.001). The tumor ⁹⁰Y uptake was significantly higher in the Glass group compared to the Resin group (41.3% vs. 33.5%, p < 0.001), corresponding to the mean tumor dose of 205.7 ± 19.7 vs. 128.9 ± 10.6 Gy, respectively (p < 0.001). The tumor to normal liver parenchyma ⁹⁰Y dose ratio was significantly higher in the Glass group compared to the Resin group, 4.9 ± 0.7 versus 2.4 ± 0.3 respectably (p < 0.001).

CONCLUSIONS

Both ⁹⁰Y glass and resin-based microsphere ⁹⁰Y-RE are feasible and safe in patients with ICC, while ⁹⁰Y glass microsphere delivers higher dose of ⁹⁰Y to the targeted tumors.

ADVANCES IN KNOWLEDGE

While both ⁹⁰Y glass and resin-based microsphere yttrium-90 radioembolization are feasible and safe treatment options for in patients with intrahepatic cholangiocarcinoma, ⁹⁰Y glass microsphere delivers higher dose of ⁹⁰Y to the targeted tumors.

IMPLICATIONS FOR PATIENT CARE

Both of ⁹⁰Y glass and resin-based microsphere can be safely and feasibly used for treatment of intrahepatic cholangiocarcinoma, difference in dose of ⁹⁰Y delivered to the targeted tumors should be clinically considered while choosing the microsphere type.

Liver transarterial embolizations in metastatic neuroendocrine tumors

The management of patients with well-differentiated neuroendocrine tumors (NET) and non-resectable liver metastases is challenging. Liver-directed transarterial embolization (TAE), transarterial chemo-embolization (TACE) and selective internal radiation therapy (SIRT) have a place of choice among other treatment modalities. However, their utilization relies on a low level of proof, due to the lack of prospective data, the absence of comparative studies and considerable heterogeneity between local practices. TAE and TACE generally achieve average symptomatic, biological and radiological responses of 75%, 56% and 50%, with progression-free survival of 12-18 months, with acceptable tolerance. Although not clearly demonstrated, TACE may be more effective than TAE in pancreatic NET, but not in small-intestine NET. SIRT has been developed more recently and may achieve similar results, with improved tolerance, but decreased cost-effectiveness, although no prospective comparison has been published to date. There is currently no strong argument to choose between TAE, TACE and SIRT, and they have not been compared to other treatment modalities. The evaluation of their efficacy has mostly relied on criteria based on size variations, which do not take into account tumor viability and metabolism, and thus may not be relevant. These techniques may be especially effective when performed as first-line therapies, in patients with non-major liver involvement (<75%) and with hypervascular metastases. Finally, studies exploring their combination with systemic therapies are ongoing.

Metastatic Liver Disease: Indications for Locoregional Therapy and Supporting Data

Metastatic liver disease is a major cause of cancer-related morbidity and mortality. Surgical resection is considered the only curative treatment, yet only a minority is eligible. Patients who present with unresectable disease are treated with systemic agents and/or locoregional therapies. The latter include thermal ablation and catheter-based transarterial interventions. Thermal ablation is reserved for those with limited tumor burden. It is used to downstage the disease to enable curative surgical resection, as an adjunct to surgery, or in select patients it is potentially curative. Transarterial therapies are indicated in those with more diffuse disease. The goals of care are to palliate symptoms and prolong survival. The indications and supporting data for thermal ablation and transarterial interventions are reviewed, technical and tumor factors that need to be considered prior to intervention are outlined, and finally several cases are presented.

Neuroendocrine tumor liver metastases treated with yttrium-90 radioembolization

OBJECTIVE

Yttrium-90 (Y-90) radioembolization is an emerging treatment option for unresectable neuroendocrine liver metastases (NELM). However, the data regarding this treatment are currently limited. This study evaluates the efficacy and tolerability of Y-90 radioembolization and identifies prognostic factors for radiographic response and survival.

METHODS AND MATERIALS

Thirty-eight patients underwent Y-90 radioembolization for NELM at our institution between April 2004 and February 2012. Patients were assessed radiographically (RECIST criteria, enhancement), serologically, and clinically at 1month, and then at every 3months after treatment for tumor response, toxicity, and survival outcomes.

RESULTS

Median length of follow-up was 17.0months (IQR, 9.0-37.0). Median survival was 29.2months. Three patients (9%) had a radiographic complete response to treatment, 6 (17%) had a partial response, 21 (60%) had stable disease, and 5 (14%) developed progressive disease. Two factors were significantly associated with a good radiographic response (complete/partial response): islet cell histological subtype (p=0.043) and hepatic tumor burden ≥33% (p=0.031). Multivariate analysis revealed that patients requiring multiple Y-90 treatments (HR 2.9, p=0.035) and patients who had previously failed systemic therapy with octreotide/chemotherapy (HR 4.4, p=0.012) had worse survival. Grade 3 serologic toxicity was observed in 2 patients (5%; hyperbilirubinemia, elevated alkaline phosphatase) after treatment. Grade 3 non-serologic toxicities included abdominal pain (11%), fatigue (11%), nausea/vomiting (5%), ascites (5%), dyspnea (3%), diarrhea (3%), and peripheral edema (3%). No grade 4 or 5 toxicity was reported.

CONCLUSIONS

Y-90 radioembolization is a promising treatment option for inoperable NELM and is associated with low rates of grade≥3 toxicity.