Characteristics of primary and secondary hepatic malignancies associated with hepatopulmonary shunting

Hepatocellular Carcinoma Epigenetic Patterns Correspond to Differences in Ethnoracial Status and Treatment Response in a Single-Center Retrospective Study

PURPOSE

To correlate epigenetic patterns with ethnoracial status and locoregional therapy (LRT) response in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

DNA and RNA were extracted from 47 distinct formalin-fixed paraffin-embedded tumor samples from 42 patients with HCC (n = 14 Black, n = 19 White, n = 9 Hispanic). LRT response was determined using computed tomography (CT) or magnetic resonance (MR) imaging 3 months posttreatment of 35 tumors (n = 22 complete response, n = 13 retreatment candidates). RNA expression and DNA methylation were used to stratify patients by ethnoracial status and treatment response using partial least-squares discriminant analysis (PLS-DA). Results were validated using hierarchical clustering. Ingenuity pathway analysis was performed to identify upstream regulators and pathways.

RESULTS

PLS-DA identified 100 genes and 12 methylated regions that differentiated tumors from Black from White/Hispanic patients. Hierarchical clustering clustered samples with the top 16 genes or the top 5 methylation regions. Dysregulated pathways included adrenomedullin pathway (P = .030), EIF2 signaling (P = .007), and several metabolic pathways. AGTR1 (log2fold = 1.59) and GSTM3 (log2fold = 2.53) represented potential differentially expressed therapeutic targets. PLS-DA identified 100 genes and 150 methylation regions that differentiated between complete responders and retreatment candidates. Hierarchical clustering clustered samples with the top 30 genes or the top 13 methylation regions. Dysregulated pathways included metabolic and DNA repair-related pathways. ASAP2 (log2fold = 0.29) and RAD50 (log2fold = 0.22) represented potential differentially expressed therapeutic targets.

CONCLUSIONS

Variation in gene expression and DNA methylation patterns in patients with HCC corresponded to ethnoracial status and LRT response. These initial results suggest tumor profiling has the potential to close ethnoracial disparities and improve treatment stratification.

Prognostic Value of Preoperative MRI-derived 3D Quantitative Tumor Arterial Burden in Patients with Hepatocellular Carcinoma Receiving Transarterial Chemoembolization

Purpose To investigate the association of tumor arterial burden (TAB) on preoperative MRI with transarterial chemoembolization refractoriness (TACER) and progression-free survival (PFS) in patients with hepatocellular carcinoma (HCC). Materials and Methods This retrospective study included patients with HCC who underwent repeated transarterial chemoembolization (TACE) treatments between January 2013 and December 2020. HCC was confirmed with pathology or imaging, and patients with other tumors, lost follow-up, or with a combination of other treatments were excluded. TACER was defined as viable lesions of more than 50% or increase in tumor number after two or more consecutive TACE treatments, continuous elevation of tumor markers, extrahepatic spread, or vascular invasion. TAB assessed with preoperative MRI was divided into high and low groups according to the median. A Cox proportional hazards model was used to determine the predictors of TACER and PFS. Results A total of 355 patients (median age, 61 years [IQR, 54-67]; 306 [86.2%] men, 49 [13.8%] women) were included. During a median follow-up of 32.7 months, the high TAB group had significantly faster TACER and decreased PFS than the low TAB group (all log-rank P < .001). High TAB was the strongest independent predictor of TACER and PFS in multivariable Cox regression analyses (hazard ratio [HR], 2.23 [95% CI: 1.51, 3.29]; HR, 2.30 [95% CI: 1.61, 3.27], respectively), especially in patients with Barcelona Clinic Liver Cancer stage A or a single tumor. The restricted cubic spline plot demonstrated that the HR of TACER and PFS continuously increased with increasing TAB. Conclusion High preoperative TAB at MRI was a risk factor for faster refractoriness and progression in patients with HCC treated with TACE. Keywords: Interventional-Vascular, MR Angiography, Hepatocellular Carcinoma, Transarterial Chemoembolization, Progression-free Survival, MRI Supplemental material is available for this article. © RSNA, 2024.

Lung Mean Dose Prediction in Transarterial Radioembolization (TARE): Superiority of [166Ho]-Scout Over [99mTc]MAA in a Prospective Cohort Study

PURPOSE

Radiation pneumonitis is a serious complication of radioembolization. In holmium-166 ([166Ho]) radioembolization, the lung mean dose (LMD) can be estimated (eLMD) using a scout dose with either technetium-99 m-macroaggregated albumin ([99mTc]MAA) or [166Ho]-microspheres. The accuracy of eLMD based on [99mTc]MAA (eLMDMAA) was compared to eLMD based on [166Ho]-scout dose (eLMDHo-scout) in two prospective clinical studies.

MATERIALS AND METHODS

Patients were included if they received both scout doses ([99mTc]MAA and [166Ho]-scout), had a posttreatment [166Ho]-SPECT/CT (gold standard) and were scanned on the same hybrid SPECT/CT system. The correlation between eLMDMAA/eLMDHo-scout and LMDHo-treatment was assessed by Spearman's rank correlation coefficient (r). Wilcoxon signed rank test was used to analyze paired data.

RESULTS

Thirty-seven patients with unresectable liver metastases were included. During follow-up, none developed symptoms of radiation pneumonitis. Median eLMDMAA (1.53 Gy, range 0.09-21.33 Gy) was significantly higher than median LMDHo-treatment (0.00 Gy, range 0.00-1.20 Gy; p < 0.01). Median eLMDHo-scout (median 0.00 Gy, range 0.00-1.21 Gy) was not significantly different compared to LMDHo-treatment (p > 0.05). In all cases, eLMDMAA was higher than LMDHo-treatment (p < 0.01). While a significant correlation was found between eLMDHo-scout and LMDHo-treatment (r = 0.43, p < 0.01), there was no correlation between eLMDMAA and LMDHo-treatment (r = 0.02, p = 0.90).

CONCLUSION

[166Ho]-scout dose is superior in predicting LMD over [99mTc]MAA, in [166Ho]-radioembolization. Consequently, [166Ho]-scout may limit unnecessary patient exclusions and avoid unnecessary therapeutic activity reductions in patients eligible for radioembolization.

TRAIL REGISTRATION

NCT01031784, registered December 2009. NCT01612325, registered June 2012.

CT texture features and lung shunt fraction measured using 99mTc-macroaggregated albumin SPECT/CT before trans-arterial radioembolization for hepatocellular carcinoma patients

The aim of this study is to determine whether contrast-enhanced computed tomography (CECT)-based texture parameters can predict high (> 30 Gy) expected lung dose (ELD) calculated using 99mTc macroaggregated albumin single-photon emission computed tomography/computed tomography (SPECT/CT) for pre-trans-arterial radioembolization (TARE) dosimetry. 35 patients were analyzed, with a treatable planned dose of ≥ 200 Gy for unresectable hepatocellular carcinoma (HCC). Lung shunt fraction (LSF) was obtained from planar and SPECT/CT scans. Texture features of the tumor lesion on CECT before TARE were analyzed. Univariate and multivariate linear regression analyses were performed to determine potential ELD > 30 Gy predictors. Among the 35 patients, nine (25.7%) had ELD > 30 Gy, and had a higher LSF than the ELD ≤ 30 Gy group using the planar (20.7 ± 8.0% vs. 6.3 ± 3.3%; P < 0.001) and SPECT/CT (12.4 ± 5.1% vs. 3.5 ± 2.0%; P < 0.001) scans. The tumor integral total (HU × L) value was a predictor for high LSF using SPECT/CT, with an area under the curve, sensitivity, and specificity of 0.983 (95% confidence interval: 0.869-1.000, P < 0.001), 100%, and 88.5%, respectively. The tumor integral total value is an imaging marker for predicting ELD > 30 Gy. Applying CECT texture analysis may assist in reducing time and cost in patient selection and modifying TARE treatment plans.

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.

Reduction of Hepatopulmonary and Intrahepatic Shunts after Treatment with Sorafenib in Hepatocellular Carcinoma Patients

PURPOSE

To investigate the reduction of elevated shunts after treatment with sorafenib in hepatocellular carcinoma (HCC) patients planned for transarterial radioembolization (TARE).

MATERIALS AND METHODS

Sixteen HCC patients treated with sorafenib were investigated. Shunts were evaluated by SPECT/CT after Technetium-99 m Tc-macroaggregated albumin injection.

RESULTS

All patients had high LSF (median 43.5%, range 28-86), and two (12.5%) of them had widespread intrahepatic shunts with concomitants elevated (36%) and acceptable (18%) lung shunt fraction (LSF). The mean duration of the sorafenib use was 134.4 ± 59.2 days. While one patient (6.25%) developed hand-foot syndrome, minor side effects were seen in all patients. After sorafenib use, LSF fell below 20% in eight patients, and TARE was applied to all of them. There was strong negative correlation between the failure of shunt reduction and presence of macrovascular invasion (ρ = - 0.775) and infiltrative tumour type (ρ = - 0.775).

CONCLUSION

Sorafenib use may be beneficial in some selected HCC patients with elevated shunts. Expected results may not be obtained in patients with infiltrative tumour type or macrovascular invasion, but patients with nodular tumour type with the absence of macrovascular invasion may be appropriate candidates for shunt reduction with ensuring subsequent TARE. Further investigations with sufficient patient population and standardized protocols of follow-up periods are needed to clarify the values for sorafenib use in HCC patients with evaluated shunts.

Association of dysmorphic intratumoral vessel with high lung shunt fraction in patients with hepatocellular carcinoma

To evaluate the role of dysmorphic intratumoral vessels as imaging marker for the prediction of high lung shunt fraction (LSF) in patients with hepatocellular carcinoma (HCC). This retrospective study included 403 patients with HCC who underwent a planning arteriography for transarterial radioembolization with administration of 99mTc-macroaggregated albumin to calculate LSF. The LSF was measured by using planar body scans. Two radiologists evaluated the pre-treatment contrast-enhanced CT findings, including tumor number, size, margin, distribution, tumor burden, portal and hepatic vein invasion, early hepatic vein enhancement, and dysmorphic intratumoral vessels. The logistic regression analysis was performed to determine significant predictors for high LSF > 20%. Using the identified predictors, diagnostic criteria for high LSF were proposed. Among 403 patients, 52 (13%) patients had high LSF > 20%, and dysmorphic tumor vessels were present in 115 (28.5%) patients. Predictors for LSF > 20% were tumor size > 11 cm, hepatic vein invasion, early hepatic vein enhancement, and dysmorphic intratumoral vessel. If the patient had three or more of the four predictors for LSF > 20% on imaging, the accuracy and specificity for diagnosing LSF > 20% were 88.8% and 96.3% respectively. Dysmorphic intratumoral vessel in HCC is an imaging marker suggesting a high LSF, which may be applicable to treatment modification or patient exclusion for radioembolization with combined interpretation of tumor size and hepatic vein abnormality.

An Analysis of Microwave Ablation Parameters for Treatment of Liver Tumors from the 3D-IRCADb-01 Database

Simulation techniques are powerful tools for determining the optimal conditions necessary for microwave ablation to be efficient and safe for treating liver tumors. Owing to the complexity and computational resource consumption, most of the existing numerical models are two-dimensional axisymmetric models that emulate actual three-dimensional cancers and the surrounding tissue, which is often far from reality. Different tumor shapes and sizes require different input powers and ablation times to ensure the preservation of healthy tissues that can be determined only by the full three-dimensional simulations. This study aimed to tailor microwave ablation therapeutic conditions for complete tumor ablation with an adequate safety margin, while avoiding injury to the surrounding healthy tissue. Three-dimensional simulations were performed for a multi-slot microwave antenna immersed in two tumors obtained from the 3D-IRCADb-01 liver tumors database. The temperature dependence of the dielectric and thermal properties of healthy and tumoral liver tissues, blood perfusion, and water content are crucial for calculating the correct ablation time and, thereby, the correct ablation process. The developed three-dimensional simulation model may help practitioners in planning patient-individual procedures by determining the optimal input power and duration of the ablation process for the actual shape of the tumor. With proper input power, necrotic tissue is placed mainly in the tumor, and only a small amount of surrounding tissue is damaged.

Hepatopulmonary syndrome delays postoperative recovery and increases pulmonary complications after hepatectomy

BACKGROUND

This study attempted to investigate the impact of hepatopulmonary syndrome (HPS) on postoperative outcomes in hepatitis B virus-induced hepatocellular carcinoma (HBV-HCC) patients.

METHODS

HBV-HCC patients undergoing primary curative hepatectomy for HCC in our hospital were diagnosed with HPS by contrast-enhanced echocardiography (CEE) and arterial blood gas analysis. Patients were divided into HPS, intrapulmonary vascular dilation (IPVD) (patients with positive CEE results and normal oxygenation) and control (patients with negative CEE results) groups. Baseline information, perioperative clinical data and postoperative pulmonary complications (PPCs) were compared among all groups. Cytokines in patient serums from each group (n = 8) were also assessed.

RESULTS

Eighty-seven patients undergoing hepatectomy from October 2019 to January 2020 were analyzed. The average time in the postanaesthesia care unit (112.10 ± 38.57 min) and oxygen absorption after extubation [34.0 (14.5-54.5) min] in the HPS group was longer than in IPVD [81.81 ± 26.18 min and 16.0 (12.3-24.0) min] and control [93.70 ± 34.06 min and 20.5 (13.8-37.0) min] groups. There were no significant differences in oxygen absorption time after extubation between HPS and control groups. The incidence of PPCs, especially bi-lateral pleural effusions in the HPS group (61.9%), was higher than in IPVD (12.5%) and control (30.0%) groups. Increased serum levels of the growth-regulated oncogene, monocyte chemoattractant protein, soluble CD40 ligand and interleukin 8 might be related to delayed recovery in HPS patients.

CONCLUSIONS

HPS patients with HBV-HCC suffer delayed postoperative recovery and are at higher risk for PPCs, especially bi-lateral pleural effusions, which might be associated with changes in certain cytokines.

Lung Shunt Reduction for Yttrium-90 Radioembolization: Chemoembolization Versus Radioembolization

AIM

To evaluate the efficacy of chemoembolization versus radioembolization in reducing lung shunt fraction (LSF) in patients with hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

In this retrospective study, from March 2012 to January 2021, 457 patients with HCC underwent planning angiography and ^99mTc-macroaggregated albumin imaging for possible yttrium-90 radioembolization. Ten patients underwent radioembolization, and seven patients underwent conventional chemoembolization for LSF reduction, and a second ^99mTc-macroaggregated albumin imaging was obtained approximately 1 month later. LSF under both procedures was compared with the Mann-Whitney U-test and the Wilcoxon signed-rank test.

RESULTS

In the radioembolization group, the mean first and second LSF were 13.0±6.9% and 20.9±9.6%, respectively (p=0.059); after radioembolization, LSF was lower in three patients but higher in seven patients. In the chemoembolization group, the mean first and second LSF were 26.1±17.3% and 8.7±5.5%, respectively (p=0.018); after chemoembolization, LSF was reduced in all seven patients.

CONCLUSION

Chemoembolization appears to be more effective in reducing LSF within 1 month compared with radioembolization.

Same day yttrium-90 radioembolization with single photon emission computed tomography/computed tomography: An opportunity to improve care during the COVID-19 pandemic and beyond

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has made it more challenging for patients to undergo yttrium-90 (Y-90) radioembolization (RE). Same day Y-90 RE provides an opportunity to minimize logistical challenges and infection risk associated with COVID-19, thus improving patient access.

AIM

To describe the use of same day Y-90 RE with routine single photon emission computed tomography/computed tomography (SPECT/CT) in order to optimize therapy.

METHODS

All patients were selected for Y-90 RE through a multidisciplinary tumor board, and were screened and tested for COVID-19 infection per institutional protocol. A same day procedure was developed, consisting of angiography, imaging, and Y-90 resin particle delivery. Routine SPECT/CT after technetium-99m macroaggregated albumin (Tc-99m MAA) administration was performed for assessment of arterial supply, personalized dosimetry, and extrahepatic activity. Post-treatment Y-90 bremsstrahlung SPECT/CT was performed for confirmation of particle delivery, by utilization of energy windowing to limit signal from previously administered Tc-99m MAA particles.

RESULTS

A total of 14 patients underwent same day Y-90 RE between March and June 2020. Mean lung shunt fraction was 6.13% (range 3.5%-13.1%). Y-90 RE was performed for a single lesion in 7 patients, while the remaining 7 patients had treatment of multifocal lesions. The largest lesion measured 8.3 cm. All patients tolerated the procedure well and were discharged the same day.

CONCLUSION

Same day Y-90 RE with resin-based microspheres is feasible, and provides an opportunity to mitigate infection risk and logistical challenges associated with the COVID-19 pandemic and beyond. We recommend consideration of SPECT/CT, especially among patients with complex malignancies, for the potential to improve outcomes and eligibility of patients to undergo same day Y-90 RE.

Does significantly elevated lung shunt fraction (LSF >20%) promote extrahepatic progression in patients with hepatocellular carcinoma treated with radioembolization?

PURPOSE

Radioembolization with yttrium-90 (Y-90) is an effective locoregional therapy for primary and metastatic liver tumors, but its use is restricted or contraindicated for patients with elevated lung shunt fraction (LSF) because of an increased risk of developing pulmonary adverse events, including but not limited to radiation pneumonitis. Elevated LSF is also thought to be correlated with liver tumor progression and metastases.

METHODS

In this retrospective cohort study, we examine rates of metastasis development, rates of adverse events and overall survival (OS) in 23 patients with hepatocellular carcinoma (HCC) and elevated LSF >20% on Tc-99 m macroaggregated albumin scan treated with Y-90 radioembolization at our institution from 2005 to 2016. To minimize confounding variables, patients with baseline extrahepatic metastases or portal vein tumor thrombosis were excluded. Kaplan-Meier estimates were performed for OS and time to development of metastases.

RESULTS

No patient developed clinical and imaging signs of radiation pneumonitis. Median intention to treat OS from day of radioembolization was 21.3 months; median censored OS was 14.7 months. Five out of 23 patients (22%) developed at least one metastasis during follow-up, for an incidence of 20 per 1000 patient-years (compared to the historical rate of 6 per 1000 patient-years for HCC patients in general).

CONCLUSION

HCC patients with LSF >20% treated with Y-90 radioembolization have acceptable toxicities and appear to have a rate of extrahepatic tumor development (22%) higher than expected for patients with HCC.

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.

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.

Streamlining radioembolization in UNOS T1/T2 hepatocellular carcinoma by eliminating lung shunt estimation

BACKGROUND & AIMS

Pre-treatment Tc-99m macroaggregated albumin (MAA) scans are routinely performed prior to transarterial radioembolization (TARE) to estimate lung shunt fraction (LSF) and lung dose. In this study, we investigate LSF observed in early hepatocellular carcinoma (HCC) and provide the scientific rationale for eliminating this step from routine practice.

METHODS

Patients with HCC who underwent Y90 from 2004 to 2018 were reviewed. Inclusion criteria were early stage HCC (UNOS T1/T2/Milan criteria: solitary ≤5 cm, 3 nodules ≤3 cm). LSF was determined using MAA in all patients. Associations between LSF and baseline characteristics were investigated. A "no-MAA" paradigm was then proposed based on a homogenous group that expressed very low LSF.

RESULTS

Of 1,175 patients with HCC treated with TARE, 448 patients met inclusion criteria. Mean age was 65.6 years and 303 (68%) were males. A total of 352 (79%) had solitary lesions and 406 (91%) unilobar disease. Two-hundred and forty-three (54%), 178 (40%) and 27 (6%) patients were Child-Pugh class A, B and C, respectively. Median LSF was 3.9% (IQR 2.4-6%). Median administered activity was 0.9 GBq (IQR 0.6-1.4), for a median segmental volume of 170 cm³ (range: 60-530). Median lung dose was 1.9 Gy (IQR: 1.0-3.3). The presence of a transjugular intrahepatic portosystemic shunt (TIPS; n = 38) was associated with LSF >10% (odds ratio 12.2; 95% CI 5.2-28.6; p <0.001). Median LSF was 3.8% (IQR: 2.4-5.7%) and 6% (IQR: 3.8-15.3%) in no-TIPS vs. TIPS patients (p <0.001).

CONCLUSION

LSF is clinically negligible in patients with UNOS T1/T2 HCC without TIPS. When segmental injections are planned, this step can be eliminated, thereby reducing time-to-treatment, number of procedures, and improving convenience for patients traveling from faraway.

LAY SUMMARY

Transarterial radioembolization is a microembolic transarterial treatment for hepatocellular carcinoma. In our study, we found that early stage patients, where segmental injections are planned, exhibited low lung shunting, effectively eliminating the risk of radiation pneumonitis. We propose that the lung shunt study be eliminated in this subgroup, thus leading to fewer procedures, a cost reduction and improved convenience for patients.

Technical Aspects and Practical Approach Toward Same-Day Y90 Radioembolization in the Management of Hepatocellular Carcinoma

Radioembolization with Yttrium-90 (Y90) has been proven safe and effective for the treatment of primary and secondary hepatic malignancies. Standard protocols have necessitated planning angiography with Technetium-99m macroaggregated albumin (Tc99m MAA) administration/scan typically 1-2 weeks prior to the radioembolization therapy. The intent of this practice is to ensure appropriate patient selection and treatment candidacy while also confirming best dosimetry approaches. At our center, we started performing "same-day Y90" in 2008; in a subset of international patients with travel hardship, we performed the planning and treatment procedures consecutively on the same day. In this article, we reveal our practical approach to treating patients on the same day as planning angiography. With more than 160 same-day procedures completed between 2008 and 2017, the safety and efficacy of such a paradigm has been established at our center. This approach is appealing to patients, their families, and referring physicians. Appropriate patient selection and proper preprocedure planning based on baseline imaging are key elements in successful same-day radioembolization treatments.

Hepatopulmonary shunting on Tc99m-MAA liver mapping: correlation with dynamic cross-sectional imaging and description of different shunting patterns

PURPOSE

The purpose of the study was to correlate lung shunt fraction (LSF) calculated by intra-arterial injection of Technetium-99m (Tc-99m)-labeled macroaggregated albumin (MAA) in a hepatic artery branch with the presence of certain patterns of vascular shunts on dynamic CT or MRI of the liver.

METHODS

This retrospective study was approved by the institutional review board and informed consent was waived. We reviewed 523 MAA scans in 453 patients (301 men, 152 women) performed from July 2007 to June 2015 and their correlative cross-sectional imaging. Patterns of vascular shunts on dynamic CT or MRI performed within 3 months of the MAA study and that potentially divert hepatic arterial inflow to the systemic venous return were defined as "target shunts." Dynamic CT or MRI was classified into three groups with target shunt present, absent, or indeterminate. The mean LSF was compared across the first and second groups using paired t test.

RESULTS

342 CT and MRI studies met inclusion criteria: target shunts were present in 63 studies, absent in 271 studies, and 8 studies were indeterminate. When target shunts were visualized, the mean LSF on corresponding MAA scans was 12.9 ± 10.36% (95% CI 10.29-15.15%) compared to 4.3 ± 3.17% (95% CI 3.93-4.68%) when no target shunt was visualized. The difference was statistically significant (p value < 0.001). Identified target shunts were either direct (arteriohepatic venous shunt) or indirect (arterioportal shunt combined with a portosystemic shunt).

CONCLUSIONS

Visualizing certain patterns of vascular shunting on a dynamic CT or MRI scan is associated with high LSF.

Hepatic selective internal radiation therapy: how well does pretreatment 99mTc-macroaggregated albumin activity distribution and quantification agree with post-therapy bremsstrahlung imaging?

AIM

The aim of this study was to examine the agreement of pretreatment Tc-macroaggregated albumin imaging performed for selective internal radiation therapy (SIRT) workup with Y percentage lung shunt (PLS) and regional hepatic distribution in subsequent post-therapy bremsstrahlung imaging.

PATIENTS AND METHODS

Planar images were used to calculate PLS. The significant Y bremsstrahlung scatter required background correction. Results using both Y lung background regions of interest (ROI) reported in previous studies and extended ROIs (reflecting lung background variation) were compared with Tc-MAA PLS. Lesion and healthy liver volumes were outlined on diagnostic computed tomography scans and registered to Tc-MAA and Y single-photon emission computed tomography/computed tomographydata. Single-photon emission computed tomography voxel values were normalized to injected Y activity. Volume mean activities were calculated, and converted into the mean absorbed dose. Agreement was quantified using Bland-Altman analysis.

RESULTS

PLS: The bias using previous studies' lung background ROIs was -10.71%, with a 95% confidence interval (CI) of -18.79 to -2.64%. The extended ROI yielded a bias of 0.77% (95% CI: -2.23 to 3.70%). Liver: The healthy liver bias was 0.01 MBq/ml (0.17 Gy), with a -0.05 to 0.06 MBq/ml (95% CI:0.80 -1.93 Gy). The lesion mean activity/ml bias was -0.02 MBq/ml (3.71 Gy), with a -0.81 to 0.76 MBq/ml (95% CI: -35.49 to 28.07 Gy).

CONCLUSIONS

The PLS agreement was sensitive to the Y lung background correction ROI, potentially explaining a previously published controversy. The mean activity and absorbed dose agreement for the metastatic lesions was poorer than the healthy liver volumes studied here.

Efficacy of Radioembolization with 166Ho-Microspheres in Salvage Patients with Liver Metastases: A Phase 2 Study

Radioembolization of liver malignancies with ¹⁶⁶Ho-microspheres has been shown to be safe in a phase 1 dose-escalation study. The purpose of this study was to investigate the efficacy of ¹⁶⁶Ho radioembolization. Methods: In this prospective single-arm study, 56 patients were enrolled, all with liver metastases refractory to systemic therapy and ineligible for surgical resection. The primary outcome was a response by 2 target lesions on triphasic liver CT scans 3 mo after therapy, as assessed using RECIST, version 1.1. Secondary outcomes included overall tumor response, time to imaging progression, overall survival, toxicity, quality of life, and quantification of the microspheres on SPECT and MRI. Results: Between May 2012 and March 2015, 38 eligible patients were treated, one of whom was not evaluable. In 27 (73%) of 37 patients, the target lesions showed complete response, partial response, or stable disease (disease control) at 3 mo (95% confidence interval [CI], 57%-85%). The median overall survival was 14.5 mo (95% CI, 8.6-22.8 mo). For colorectal cancer patients (n = 23), the median overall survival was 13.4 mo (95% CI, 8.2-15.7 mo). Grade 3 or 4 toxic events after treatment (according to the Common Terminology Criteria for Adverse Events, version 4.03) included abdominal pain (in 18% of patients), nausea (8%), ascites (3%), fatigue (3%), gastric stenosis (3%), hepatic failure (3%), liver abscesses (3%), paroxysmal atrial tachycardia (3%), thoracic pain (3%), upper gastrointestinal hemorrhage (3%), and vomiting (3%). On SPECT, ¹⁶⁶Ho could be quantified with high accuracy and precision, with a mean overestimation of 9.3% ± 7.1% in the liver. Conclusion: Radioembolization with ¹⁶⁶Ho-microspheres induced a tumor response with an acceptable toxicity profile in salvage patients with liver metastases.

Albumin-Bilirubin and Platelet-Albumin-Bilirubin Grades Accurately Predict Overall Survival in High-Risk Patients Undergoing Conventional Transarterial Chemoembolization for Hepatocellular Carcinoma

PURPOSE

To evaluate albumin-bilirubin (ALBI) and platelet-albumin-bilirubin (PALBI) grades in predicting overall survival in high-risk patients undergoing conventional transarterial chemoembolization for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This single-center retrospective study included 180 high-risk patients (142 men, 59 y ± 9) between April 2007 and January 2015. Patients were considered high-risk based on laboratory abnormalities before the procedure (bilirubin > 2.0 mg/dL, albumin < 3.5 mg/dL, platelet count < 60,000/mL, creatinine > 1.2 mg/dL); presence of ascites, encephalopathy, portal vein thrombus, or transjugular intrahepatic portosystemic shunt; or Model for End-Stage Liver Disease score > 15. Serum albumin, bilirubin, and platelet values were used to determine ALBI and PALBI grades. Overall survival was stratified by ALBI and PALBI grades with substratification by Child-Pugh class (CPC) and Barcelona Liver Clinic Cancer (BCLC) stage using Kaplan-Meier analysis. C-index was used to determine discriminatory ability and survival prediction accuracy.

RESULTS

Median survival for 79 ALBI grade 2 patients and 101 ALBI grade 3 patients was 20.3 and 10.7 months, respectively (P < .0001). Median survival for 30 PALBI grade 2 and 144 PALBI grade 3 patients was 20.3 and 12.9 months, respectively (P = .0667). Substratification yielded distinct ALBI grade survival curves for CPC B (P = .0022, C-index 0.892), BCLC A (P = .0308, C-index 0.887), and BCLC C (P = .0287, C-index 0.839). PALBI grade demonstrated distinct survival curves for BCLC A (P = 0.0229, C-index 0.869). CPC yielded distinct survival curves for the entire cohort (P = .0019) but not when substratified by BCLC stage (all P > .05).

CONCLUSIONS

ALBI and PALBI grades are accurate survival metrics in high-risk patients undergoing conventional transarterial chemoembolization for HCC. Use of these scores allows for more refined survival stratification within CPC and BCLC stage.

Locoregional and systemic therapy for hepatocellular carcinoma

The management of hepatocellular carcinoma (HCC) remains challenging due to late presentation and the presence of accompanying liver dysfunction. As such, most patients are not eligible for curative resection and liver transplant. Management in this scenario depends on a number of factors including hepatic function, tumor burden, patency of hepatic vasculature and patients' functional status. Based on these, patients can be offered catheter based intra-arterial therapy for intermediate stage disease and in more advanced disease, sorafenib. Given recent data, regorafenib is now an option following failure of sorafenib. Catheter directed intra-arterial therapy takes advantage of tumor hypervascularity and the unique dual blood supply of the liver, as hepatic tumors receive arterial perfusion via the hepatic artery while the rest of the liver is supplied by the portal vein. This allows selective embolization and delivery of chemotherapeutic agents to the tumor. Compared to best supportive care, intra-arterial therapy offers a survival benefit in intermediate stage HCC and is the recommended approach for treatment. None of the catheter based approaches; including bland embolization, conventional trans-arterial chemoembolization (cTACE), drug eluting bead trans-arterial chemoembolization (DEB-TACE) or trans-arterial radioembolization (TARE) offers a clear advantage over the other, although DEB-TACE may be characterized by less systemic toxicity. All of these approaches are contraindicated in patients with portal vein thrombosis (PVT). On the other hand, intra-arterial, radio embolization, with Yttrium-90 (Y90) can be offered to patients with PVT. The place of this modality in management of HCC is still being investigated. The role of sorafenib in advanced HCC is not in doubt, as until recently, it was the only systemic therapy approved for the management in this setting. This is despite multiple trials evaluating other agents. The addition of sorafenib to catheter-based therapy in intermediate stage disease has also failed to show any benefit. The modest survival benefit with sorafenib and the failure of other targeted agents suggest that it is important to look beyond inhibition of angiogenesis in advanced HCC. Identification of key drivers and mediators of HCC remains paramount for successful drug development. In line with this, it is refreshing that the excitement that has followed developments in cancer immunotherapy is finding its way to HCC with early trials of anti-PD1 monoclonal antibodies showing sufficient activity that phase III trials are now ongoing for Pembrolizumab and Nivolumab in advanced HCC. Future drug development efforts will focus on defining the feasibility of combining different treatment approaches targeting multiple important modulators of HCC.

Hepatopulmonary shunting after surgical, interventional and systemic therapy in patients with liver malignancies scheduled for radioembolization

BACKGROUND

Hepatopulmonary shunts (HPS) lead to radiation exposure of the lungs in patients undergoing radioembolization (RE) of malignant liver tumors.

PURPOSE

To retrospectively analyze how HPS is affected by prior systemic or local therapy of the liver.

MATERIAL AND METHODS

The percentage HPS was calculated from SPECT/CT scans obtained after technetium-99 m macroaggregated albumin administration into hepatic arteries in 316 patients evaluated for RE.

RESULTS

Patients with partial liver resection (n = 80) did not differ in HPS from the remaining patient population (n = 236) (HPS (median [range]) = 10.2 [2.1-48.3]resection% vs. 8.9 [2.3-32.9]no resection%; P = 0.527). In patients undergoing sequential RE, HPS was significantly higher in the liver lobe treated second (n = 10; HPS = 6.4 [2.1-10.2]firstlobe/session% vs. 12.0 [2.0-24.6]second lobe/session%; P = 0.019). (Chemo-)embolization (n = 19; HPS = 11.0 [2.8-48.3]%) or transcutaneous ablation (n = 63; HPS = 8.8 [3.0-32.9]%) had no effect on HPS compared to patients without prior interventions (no (chemo-)embolization: n = 297; HPS = 9.3 [2.1-47.3]%; P = 0.489; no ablation: n = 253; HPS = 9.5 [2.1-48.3]%; P = 0.382). Pretreatment with sorafenib (HPS = 9.5 [2.3-35.9]yes% vs. 10.2 [2.8-42.0]no%; P = 0.777) orbevacizumab (HPS = 10.7 [2.1-30.6]yes% vs. 9.0 [3.9-23.3]no%; P = 0.870) had no effect on HPS.

CONCLUSION

Sequential RE results in an increase in the HPS in the contralateral liver lobe at the time of the second RE session. Other investigated therapy do not affect HPS.

Yttrium-90 Radioembolization of Hepatocellular Carcinoma-Performance, Technical Advances, and Future Concepts

Hepatocellular carcinoma (HCC) is a lethal tumor, claiming over half a million lives per year. Treatment of HCC is commonly performed without curative intent, and palliative options dominate, including catheter-based therapies, namely, transarterial chemoembolization and yttrium-90 ((90)Y) radioembolization. This review will showcase the performance of (90)Y radioembolization for the treatment of HCC, focusing on recent seminal data and technical advances. In particular, novel radioembolization treatment concepts are discussed and compared with conventional HCC therapy.

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.

Safety of a Scout Dose Preceding Hepatic Radioembolization with 166Ho Microspheres

Before (166)Ho radioembolization, a small batch of the same type of microspheres is administered as a scout dose instead of the conventional (99m)Tc-macroaggregated albumin ((99m)Tc-MAA). The (166)Ho scout dose provides a more accurate and precise lung shunt assessment. However, in contrast to (99m)Tc-MAA, an unintended extrahepatic deposition of this β-emitting scout dose could inflict radiation damage, the extent of which we aimed to quantify in this study.

METHODS

All patients eligible for radioembolization in our institute between January 2011 and March 2014 were reviewed. Of the extrahepatic depositions of (99m)Tc-MAA on SPECT, the amount and volume were measured. These were used to calculate the theoretic absorbed dose in the case a (166)Ho scout dose had been used. The extrahepatic activity was measured as the sum of all voxels of the deposition. Volumes were measured using a threshold technique including all voxels from the maximum voxel intensity up to a certain percentage. The threshold needed to obtain the true volume was studied in a phantom study.

RESULTS

In the phantom study, a threshold of 40% was found to overestimate the volume, with the consequence of underestimating the absorbed dose. Of 160 patients, 32 patients (34 cases) of extrahepatic deposition were identified. The depositions contained a median of 1.3% (range, 0.1%-19.5%) of the administered activity in a median volume of 6.8 mL (range, 1.1-42 mL). The use of a scout dose of 250 MBq of (166)Ho microspheres in these cases would theoretically have resulted in a median absorbed dose of 6.0 Gy (range, 0.9-374 Gy). The dose exceeded a limit of 49 Gy (reported in 2013) in 2 of 34 cases (5.9%; 95% confidence interval, 0.7%-20.1%) or 2 of 160 (1.3%; 95% confidence interval, 0.1%-4.7%) of all patients. In these 2 patients with a large absorbed dose (112 and 374 Gy), the culprit vessel was identified in 1 case.

CONCLUSION

Extrahepatic deposition of a (166)Ho scout dose seems to be theoretically safe in most patients. Its safety in clinical practice is being evaluated in ongoing clinical trials.

Yttrium-90 microsphere radioembolization for hepatocellular carcinoma

Yttrium-90 (Y90) radioembolization is an emerging strategy to treat liver malignancies, and clinical data supporting its use have accumulated in recent years. Y90-radioembolization has shown clinical effectiveness in intermediate and advanced hepatocellular carcinoma, with a favorable safety profile. Retrospective data show similar levels of effectiveness to transarterial chemoembolization in intermediate hepatocellular carcinoma, with some evidence of better tolerance. While phase 3 studies comparing Y90-radioembolization to chemoembolization in intermediate hepatocellular carcinoma would be difficult to conduct, studies comparing or combining Y90-radioembolization with sorafenib are under way. Questions also remain about the most suitable modalities for defining the dose to administer. Phase 3 studies are under way to clarify the place of Y90-radioembolization in the algorithm of HCC treatment.