Hepatopulmonary shunting in patients with primary and secondary liver tumors scheduled for radioembolization

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.

Embolization therapy with microspheres for the treatment of liver cancer: State-of-the-art of clinical translation

Embolization with microspheres is a therapeutic strategy based on the selective occlusion of the blood vessels feeding a tumor. This procedure is intraarterially performed in the clinical setting for the treatment of liver cancer. The practice has evolved over the last decade through the incorporation of drug loading ability, biodegradability and imageability with the subsequent added functionality for the physicians and improved clinical outcomes for the patients. This review highlights the evolution of the embolization systems developed through the analysis of the marketed embolic microspheres for the treatment of malignant hepatocellular carcinoma, namely the most predominant form of liver cancer. Embolic microspheres for the distinct modalities of embolization (i.e., bland embolization, chemoembolization and radioembolization) are here comprehensively compiled with emphasis on material characteristics and their impact on microsphere performance. Moreover, the future application of the embolics under clinical investigation is discussed along with the scientific and regulatory challenges ahead in the field. STATEMENT OF SIGNIFICANCE: Embolization therapy with microspheres is currently used in the clinical setting for the treatment of most liver cancer conditions. The progressive development of added functionalities on embolic microspheres (such as biodegradability, imageability or drug and radiopharmaceutical loading capability) provides further benefit to patients and widens the therapeutic armamentarium for physicians towards truly personalized therapies. Therefore, it is important to analyze the possibilities that advanced biomaterials offer in the field from a clinical translational perspective to outline the future trends in therapeutic embolization.

Yttrium-90 radioembolization for unresectable hepatocellular carcinoma: predictive modeling strategies to anticipate tumor response and improve patient selection

Objectives

This study aims to better characterize potential responders of Y-90-radioembolization at baseline through analysis of clinical variables and contrast enhanced (CE) MRI tumor volumetry in order to adjust therapeutic regimens early on and to improve treatment outcomes.

Methods

Fifty-eight HCC patients who underwent Y-90-radioembolization at our center between 10/2008 and 02/2017 were retrospectively included. Pre- and post-treatment target lesion volumes were measured as total tumor volume (TTV) and enhancing tumor volume (ETV). Survival analysis was performed with Cox regression models to evaluate 65% ETV reduction as surrogate endpoint for treatment efficacy. Univariable and multivariable logistic regression analyses were used to evaluate the combination of baseline clinical variables and tumor volumetry as predictors of ≥ 65% ETV reduction.

Results

Mean patients’ age was 66 (SD 8.7) years, and 12 were female (21%). Sixty-seven percent of patients suffered from liver cirrhosis. Median survival was 11 months. A threshold of ≥ 65% in ETV reduction allowed for a significant (p = 0.04) separation of the survival curves with a median survival of 11 months in non-responders and 17 months in responders. Administered activity per tumor volume did predict neither survival nor ETV reduction. A baseline ETV/TTV ratio greater than 50% was the most important predictor of arterial devascularization (odds ratio 6.3) in a statistically significant (p = 0.001) multivariable logistic regression model. The effect size was strong with a Cohen’s f of 0.89.

Conclusion

We present a novel approach to identify promising candidates for Y-90 radioembolization at pre-treatment baseline MRI using tumor volumetry and clinical baseline variables.

Key Points

• A decrease of 65% enhancing tumor volume (ETV) on follow-up imaging 2–3 months after Y-90 radioembolization of HCC enables the early prediction of significantly improved median overall survival (11 months vs. 17 months, p = 0.04).

• Said decrease in vascularization is predictable at baseline: an ETV greater than 50% is the most important variable in a multivariable logistic regression model that predicts responders at a high level of significance (p = 0.001) with an area under the curve of 87%.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-022-08585-x.

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.

Selective devascularization treatment for large hepatocellular carcinoma: Stage 2A IDEAL prospective case series

BACKGROUND

Rapid growth and invasiveness of hepatocellular carcinoma (HCC) largely depends on its vascularity and active angiogenic capacity. That feature was used to control the tumor in the past with some limitations. These deficiencies were addressed in our new procedure by hepatic artery ligation and extrahepatic collaterals division (HALED) of the liver lobe containing large HCC. This study tried to assess the feasibility, safety and the short term effects of HALED.

MATERIALS AND METHODS

This is a prospective stage 2a development IDEAL (Idea, Development, Exploration, Assessment and Long-term monitoring) case series. It included adult patients with large-sized HCC (diameter > 5 cm) subjected to HALED carried out in our center during five years' trial evaluating one-month postoperative outcomes. Patients will be reported prospectively in a sequential order with explanation of reasons for rejected cases and description of changes to technique or indication as the procedure evolved. This study registry number is NCT03129685 at the ClinicalTrials.gov.

RESULTS

The first HALED operation was carried out safely on 2013, followed by nineteen patients by 2018. Patients' mean age (±standard deviation) was 62·45 (±9·27), range 38-76 years. Eleven (55%) patients had tumors diameter > 10 cm 13 (65%) patients were advanced BCLC stage. Seven modifications were made on the technique and indications of the procedure towards stability. According to the modified response evaluation criteria in solid tumors, 13 patients (65%) attained complete response. Operative mortality was 5% (one patient) and major morbidity was 10% (two patients). Liver infarction and abscess formation were not noticed in this study.

CONCLUSION

Our forerunner study showed that HALED for large HCC is safe and induces tumor necrosis. Further long-term studies are suggested before starting the 2b stage.

Blood and urine analyses after radioembolization of liver malignancies with [166Ho]Ho-acetylacetonate-poly(l-lactic acid) microspheres

BACKGROUND

[¹⁶⁶Ho]Ho-acetylacetonate-poly(L-lactic acid) microspheres were used in radioembolization of liver malignancies by intra-arterial administration. The primary aim of this study was to assess the stability and biodistribution of these microspheres.

MATERIALS AND METHODS

Peripheral blood and urine samples were obtained from two clinical studies. Patient and in vitro experiment samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS), gamma-ray spectroscopy, light microscopy, Coulter particle counting, and high performance liquid chromatography (HPLC).

RESULTS

The median percentage holmium compared to the total amount injected into the hepatic artery was 0.19% (range 0.08-2.8%) and 0.32% (range 0.03-1.8%) in the 1 h blood plasma and 24 h urine, respectively. Both the blood plasma and urine were correlated with the neutron irradiation exposure required for [¹⁶⁶Ho]Ho-AcAc-PLLA microsphere production (ρ = 0.616, p = 0.002). After a temporary interruption of the phase 2 clinical study, the resuspension medium was replaced to precipitate [¹⁶⁶Ho]Ho³⁺ pre-administration using phosphate. The in vitro near-maximum neutron irradiation experiments showed significant [¹⁶⁶Ho]Ho-AcAc-PLLA microsphere damage.

CONCLUSION

The amount of holmium in the peripheral blood and urine samples after [¹⁶⁶Ho]Ho-AcAc-PLLA microsphere intrahepatic infusion was low. A further decrease was observed after reformulation of the resuspension solution but minimization of production damage is necessary.

Safety of selective internal radiation therapy (SIRT) with yttrium-90 microspheres combined with systemic anticancer agents: expert consensus

Selective internal radiation therapy (SIRT) with microspheres labelled with the β-emitter yttrium-90 (Y-90) enables targeted delivery of radiation to hepatic tumors. SIRT is primarily used to treat inoperable primary or metastatic liver tumors. Eligible patients have usually been exposed to a variety of systemic anticancer therapies, including cytotoxic agents, targeted biologics, immunotherapy and peptide receptor radionuclide therapy (PRRT). All these treatments have potential interactions with SIRT; however, robust evidence on the safety of these potential combinations is lacking. This paper provides current clinical experiences and expert consensus guidelines for the use of SIRT in combination with the anticancer treatment agents likely to be encountered in clinical practice. It was agreed by the expert panel that precautions need to be taken with certain drugs, but that, in general, systemic therapies do not necessarily have to be stopped to perform SIRT. The authors recommend stopping vascular endothelial growth factor inhibitors 4-6 weeks before SIRT, and restart after the patient has recovered from the procedure. It may also be prudent to stop potent radiosensitizers such as gemcitabine therapy 4 weeks before SIRT, and restart treatment at least 2‒4 weeks later. Data from phase III studies combining SIRT with fluorouracil (5FU) or folinic acid/5FU/oxaliplatin (FOLFOX) suggest that hematological toxicity is more common from the combination than it is from chemotherapy without SIRT. There is no evidence to suggest that chemotherapy increases SIRT-specific gastro-intestinal or liver toxicities.

Hepatopulmonary Shunt Reduction With 177Lu-DOTATATE Therapy

A 72-year-old man was diagnosed with well-differentiated neuroendocrine tumor of unknown primary with liver metastasis. All liver lesions were detectable only on Ga-DOTATATE PET/CT and were negative on F-FDG PET/CT. Intrahepatic Y radioembolization therapy was planned, but the hepatopulmonary shunt fraction was found to be 31.6%. Because the hepatopulmonary shunt fraction greater than 20% is an absolute contraindication to radioembolization, we decided to give him Lu-DOTATATE therapy. He received 4 courses of Lu-DOTATATE and showed regression in posttherapy Ga-DOTATATE PET/CT imaging. The hepatopulmonary shunt fraction was reduced to 8% after Lu-DOTATATE therapy.

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.

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.

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.