Utility of pre-procedural [99mTc]TcMAA SPECT/CT Multicompartment Dosimetry for Treatment Planning of 90Y Glass microspheres in patients with Hepatocellular Carcinoma: comparison of anatomic versus [99mTc]TcMAA-based Segmentation.

PURPOSE: Pre-treatment [99mTc]TcMAA-based radioembolization treatment planning using multicompartment dosimetry involves the definition of the tumor and normal tissue compartments and calculation of the prescribed absorbed doses. The aim was to compare the real-world utility of anatomic and [99mTc]TcMAA-based segmentation of tumor and normal tissue compartments. MATERIALS AND METHODS: Included patients had HCC treated by glass [90Y]yttrium microspheres, ≥ 1 tumor, ≥ 3 cm diameter and [99mTc]TcMAA SPECT/CT imaging before treatment. Segmentation was performed retrospectively using dedicated dosimetry software: (1) anatomic (diagnostic CT/MRI-based), and (2) [99mTc]TcMAA threshold-based (i.e., using an activity-isocontour threshold). CT/MRI was co-registered with [99mTc]TcMAA SPECT/CT. Logistic regression and Cox regression, respectively, were used to evaluate relationships between total perfused tumor absorbed dose (TAD) and objective response rate (ORR) and overall survival (OS). In a subset-analysis pre- and post-treatment dosimetry were compared using Bland-Altman analysis and Pearson's correlation coefficient. RESULTS: A total of 209 patients were enrolled. Total perfused tumor and normal tissue volumes were larger when using anatomic versus [99mTc]TcMAA threshold segmentation, resulting in lower absorbed doses. mRECIST ORR was higher with increasing total perfused TAD (odds ratio per 100 Gy TAD increase was 1.22 (95% CI: 1.01-1.49; p = 0.044) for anatomic and 1.19 (95% CI: 1.04-1.37; p = 0.012) for [99mTc]TcMAA threshold segmentation. Higher total perfused TAD was associated with improved OS (hazard ratio per 100 Gy TAD increase was 0.826 (95% CI: 0.714-0.954; p = 0.009) and 0.847 (95% CI: 0.765-0.936; p = 0.001) for anatomic and [99mTc]TcMAA threshold segmentation, respectively). For pre- vs. post-treatment dosimetry comparison, the average bias for total perfused TAD was + 11.5 Gy (95% limits of agreement: -227.0 to 250.0) with a strong positive correlation (Pearson's correlation coefficient = 0.80). CONCLUSION: Real-world data support [99mTc]TcMAA imaging to estimate absorbed doses prior to treatment of HCC with glass [90Y]yttrium microspheres. Both anatomic and [99mTc]TcMAA threshold methods were suitable for treatment planning. TRIAL REGISTRATION NUMBER: NCT03295006.

Direct comparison and reproducibility of two segmentation methods for multicompartment dosimetry: round robin study on radioembolization treatment planning in hepatocellular carcinoma.

PURPOSE: Investigate reproducibility of two segmentation methods for multicompartment dosimetry, including normal tissue absorbed dose (NTAD) and tumour absorbed dose (TAD), in hepatocellular carcinoma patients treated with yttrium-90 (90Y) glass microspheres. METHODS: TARGET was a retrospective investigation in 209 patients with < 10 tumours per lobe and at least one tumour ≥ 3 cm ± portal vein thrombosis. Dosimetry was compared using two distinct segmentation methods: anatomic (CT/MRI-based) and count threshold-based on pre-procedural 99mTc-MAA SPECT. In a round robin substudy in 20 patients with ≤ 5 unilobar tumours, the inter-observer reproducibility of eight reviewers was evaluated by computing reproducibility coefficient (RDC) of volume and absorbed dose for whole liver, whole liver normal tissue, perfused normal tissue, perfused liver, total perfused tumour, and target lesion. Intra-observer reproducibility was based on second assessments in 10 patients ≥ 2 weeks later. RESULTS: 99mTc-MAA segmentation calculated higher absorbed doses compared to anatomic segmentation (n = 209), 43.9% higher for TAD (95% limits of agreement [LoA]: - 49.0%, 306.2%) and 21.3% for NTAD (95% LoA: - 67.6%, 354.0%). For the round robin substudy (n = 20), inter-observer reproducibility was better for anatomic (RDC range: 1.17 to 3.53) than 99mTc-MAA SPECT segmentation (1.29 to 7.00) and similar between anatomic imaging modalities (CT: 1.09 to 3.56; MRI: 1.24 to 3.50). Inter-observer reproducibility was better for larger volumes. Perfused normal tissue volume RDC was 1.95 by anatomic and 3.19 by 99mTc-MAA SPECT, with corresponding absorbed dose RDC 1.46 and 1.75. Total perfused tumour volume RDC was higher, 2.92 for anatomic and 7.0 by 99mTc-MAA SPECT with corresponding absorbed dose RDC of 1.84 and 2.78. Intra-observer variability was lower for perfused NTAD (range: 14.3 to 19.7 Gy) than total perfused TAD (range: 42.8 to 121.4 Gy). CONCLUSION: Anatomic segmentation-based dosimetry, versus 99mTc-MAA segmentation, results in lower absorbed doses with superior reproducibility. Higher volume compartments, such as normal tissue versus tumour, exhibit improved reproducibility. TRIAL REGISTRATION: NCT03295006.

Evolution of Personalized Dosimetry for Radioembolization of Hepatocellular Carcinoma.

Yttrium-90 transarterial radioembolization (TARE) has progressed from a salvage or palliative lobar or sequential bilobar regional liver therapy for patients with advanced disease to a versatile, potentially curative, and often highly selective local treatment for patients across Barcelona Clinic Liver Cancer stages. With this shift, radiation dosimetry has evolved to become more tailored to patients and target lesion(s), with treatment dose and distributions adapted for specific clinical goals (ie, palliation, bridging or downstaging to liver transplantation, converting to surgical resection candidacy, or ablative/curative intent). Data have confirmed that "personalizing" dosimetry yields real-world improvements in tumor response and overall survival while maintaining a favorable adverse event profile. In this review, imaging techniques used before, during, and after TARE have been reviewed. Historical algorithms and contemporary image-based dosimetry methods have been reviewed and compared. Finally, recent and upcoming developments in TARE methodologies and tools have been discussed.

Yttrium-90 Radioembolization in the VX2 Rabbit Model: Radiation Safety and Factors Influencing Delivery Efficiency.

The purpose of this study was to define the optimal infusion parameters and operator radiation exposure for yttrium-90 (90Y) radioembolization in the VX2 rabbit model of liver cancer. Forty-one rabbits with VX2 were treated with glass microspheres with vial sizes of 1, 3, and 5 GBq. The mean administered activity was 51.5 MBq (95% CI, 39.1-63.9). Delivery efficiency improved with 1 GBq versus with 3 GBq (residual 11.0% vs 46.4%, respectively; P = .0013) and improved with 1 GBq versus with 5 GBq (residual 11.0% vs 33.8%, respectively; P = .0060). The mean operator extremity exposure was 41.7 µSv/infusion. The optimal minimum infusion volume and rate was 49 mL and 21 mL/min, respectively. Fecal elimination occurred with microsphere uptake in the gallbladder at 1 and 2 weeks. 90Y radioembolization can be safely and efficiently performed in the VX2 rabbit model. Methodological considerations as a "how-to" for the setup of a preclinical 90Y laboratory are included to support future translational research.

Correlation and Agreement of Yttrium-90 Positron Emission Tomography/Computed Tomography with Ex Vivo Radioembolization Microsphere Deposition in the Rabbit VX2 Liver Tumor Model.

PURPOSE: To demonstrate a stronger correlation and agreement of yttrium-90 (90Y) positron emission tomography (PET)/computed tomography (CT) measurements with explant liver tumor dosing compared with the standard model (SM) for radioembolization. MATERIALS AND METHODS: Hepatic VX2 tumors were implanted into New Zealand white rabbits, with growth confirmed by 7 T magnetic resonance imaging. Seventeen VX2 rabbits provided 33 analyzed tumors. Treatment volumes were calculated from manually drawn volumes of interest (VOI) with three-dimensional surface renderings. Radioembolization was performed with glass 90Y microspheres. PET/CT imaging was completed with scatter and attenuation correction. Three-dimensional ellipsoid VOI were drawn to encompass tumors on fused images. Tumors and livers were then explanted for inductively coupled plasma (ICP)-optical emission spectroscopy (OES) analysis of microsphere content. 90Y PET/CT and SM measurements were compared with reference standard ICP-OES measurements of tumor dosing with Pearson correlation and Bland-Altman analyses for agreement testing with and without adjustment for tumor necrosis. RESULTS: The median infused activity was 33.3 MBq (range, 5.9-152.9). Tumor dose was significantly correlated with 90Y PET/CT measurements (r = 0.903, P < .001) and SM estimates (r = 0.607, P < .001). Bland-Altman analyses showed that the SM tended to underestimate the tumor dosing by a mean of -8.5 Gy (CI, -26.3-9.3), and the degree of underestimation increased to a mean of -18.3 Gy (CI, -38.5-1.9) after the adjustment for tumor necrosis. CONCLUSIONS: 90Y PET/CT estimates were strongly correlated and had better agreement with reference measurements of tumor dosing than SM estimates.

Yttrium-90 Radioembolization to the Prostate Gland: Proof of Concept in a Canine Model and Clinical Translation.

PURPOSE: To investigate the feasibility, safety, and absorbed-dose distribution of prostatic artery radioembolization (RE) in a canine model. MATERIALS AND METHODS: Fourteen male castrated beagles received dihydroandrosterone/estradiol to induce prostatic hyperplasia for the duration of the study. Each dog underwent fluoroscopic prostatic artery catheterization. Yttrium-90 (90Y) microspheres (TheraSphere; Boston Scientific, Marlborough, Massachusetts) were delivered to 1 prostatic hemigland (dose escalation from 60 to 200 Gy), with the contralateral side serving as a control. Assessments for adverse events were performed throughout the follow-up (Common Terminology Criteria for Adverse Events v5.0). Positron emission tomography/magnetic resonance (MR) imaging provided a confirmation after the delivery of absorbed-dose distribution. MR imaging was performed before and 3, 20, and 40 days after RE. Tissue harvest of the prostate, rectum, bladder, urethra, penis, and neurovascular bundles was performed 60 days after RE. RESULTS: All the animals successfully underwent RE. Positron emission tomography/MR imaging demonstrated localization to and good coverage of only the treated hemigland. No adverse events occurred. The MR imaging showed a significant dose-dependent decrease in the treated hemigland size at 40 days (25%-60%, P < .001). No extraprostatic radiographic changes were observed. Necropsy demonstrated no gross rectal, urethral, penile, or bladder changes. Histology revealed RE-induced changes in the treated prostatic tissues of the highest dose group, with gland atrophy and focal necrosis. No extraprostatic RE-related histologic findings were observed. CONCLUSIONS: Prostate 90Y RE is safe and feasible in a canine model and leads to focal dose-dependent changes in the gland without inducing unwanted extraprostatic effects. These results suggest that an investigation of nonoperative prostate cancer is warranted.

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.

Long-Term Hepatotoxicity of Yttrium-90 Radioembolization as Treatment of Metastatic Neuroendocrine Tumor to the Liver.

PURPOSE: To determine long-term hepatotoxicity of yttrium-90 (90Y) radioembolization in patients treated for metastatic neuroendocrine tumor (mNET) and evaluate if imaging and laboratory findings of cirrhosis-like morphology are associated with clinical symptoms. MATERIALS AND METHODS: Retrospective review from 2003 to 2016 was performed for patients with mNET treated with 90Y glass microspheres. Fifty-four patients with > 2 year follow-up were stratified into unilobar (n = 15) vs whole-liver (n = 39) treatment. The most common primary mNET sites were small bowel (19 of 54), pancreas (19 of 54), and unknown (8 of 54). Preradioembolization imaging and laboratory findings were compared with most recent follow-up for indications of worsening portal hypertension and decline in hepatic function. RESULTS: Among patients who underwent unilobar radioembolization, imaging follow-up at a mean of 4.1 years (range, 2.0-15.2 y) revealed cirrhosis-like morphology in 26.7% (4 of 15), ascites in 13.3% (2 of 15), varices in 6.7% (1 of 15), and a 21.9% increase in splenic volume. The respective incidences in patients treated with whole-liver 90Y radioembolization were 56.4% (22 of 39), 41.0% (16 of 39), and 15.4% (6 of 39), with a 64.7% increase in splenic volume. Patients treated with whole-liver radioembolization exhibited significantly decreased platelet counts (P = .023) and lower albumin levels (P = .0002). Eight patients (20.5%) treated with whole-liver radioembolization who exhibited cirrhosis-like morphology showed clinical signs of hepatic decompensation; only 2 of 39 patients (5.1%) had no other causes of hepatotoxicity. CONCLUSIONS: Whole-liver 90Y radioembolization for patients with mNET results in long-term imaging findings of cirrhosis-like morphology and portal hypertension in > 50% of treated patients, but the majority remain clinically asymptomatic. Long-term hepatotoxicity solely attributable to 90Y develops in a small percentage of patients.

Same-day 90Y radioembolization: implementing a new treatment paradigm.

PURPOSE: To assess the feasibility of conducting pretreatment mesenteric angiography, coil embolization, 99mTc macroaggregated albumin (99mTc-MAA) scintigraphy, and 90Y radioembolization treatment in a single, same-day, combined outpatient encounter. METHODS: This was a retrospective study of 78 patients treated during the period 2008 - 2015 who were managed in a single outpatient encounter under the guidance of the Interventional Radiology Department and The Nuclear Medicine Department. Pretreatment planning was performed by reviewing baseline imaging and estimated perfused liver volume bearing the tumor. The region of interest was estimated using 3-D software; this value was used for dosimetry planning. Maximum lung shunting fractions of 10 % for hepatocellular carcinoma and 5 % for liver metastases were assumed. Subsequently, hepatic angiography and 99mTc-MAA scintigraphy were performed followed by 90Y treatment in one outpatient encounter. Total in-room procedure time was recorded. RESULTS: All patients underwent same-day angiography, 99mTc-MAA scintigraphy and 90Y radioembolization. Of the 78 patients, 16 received multiple segmental treatments to both lobes, 44 received treatment to the right lobe, and 18 received treatment to the left lobe. The median dose was 106 Gy. The median number of 90Y vials needed was two (range one to six). The median in-room time was 160 min (75 - 250 min). The residential status of the patients was as follows, 18 % (14/78) were local residents, 55 % (43/78) traveled from outside the city limits, 18 % (14/78) were from out-of-state, and 9 % (7/78) were resident abroad. Of the 78 patients, 61 (77 %) had hepatocellular carcinoma, and 17 (22 %) had liver metastases. The median lung dose was 3.5 Gy. CONCLUSION: This study demonstrated the feasibility of same-day 90Y evaluation and treatment while maintaining the principles of safe and effective 90Y infusion including tumoricidal dosimetry (lobar, segmentectomy), minimization of nontarget flow, and minimization of lung dose. This paradigm translates into expeditious cancer care and significant cost savings.

Independent Analysis of Albumin-Bilirubin Grade in a 765-Patient Cohort Treated with Transarterial Locoregional Therapy for Hepatocellular Carcinoma.

PURPOSE: To assess validity of albumin-bilirubin (ALBI) grade as a predictor of survival in patients undergoing transarterial embolization for hepatocellular carcinoma. MATERIALS AND METHODS: Baseline albumin and bilirubin values of 765 consecutive patients treated with conventional transarterial chemoembolization or yttrium-90 ((90)Y) radioembolization at a single institution were used to determine liver function according to ALBI grade. Survival outcomes were stratified by ALBI grade using Kaplan-Meier and stratified by Child-Pugh (C-P) class and Barcelona Clinic Liver Cancer (BCLC) stage. Discriminatory ability was assessed by C-index. RESULTS: For 428 patients receiving (90)Y radioembolization, ALBI grade yielded distinct survival curves (P < .001). When stratified by C-P class and BCLC stage, ALBI grade revealed different survival outcomes for C-P B (P = .001), BCLC A (P < .001), BCLC B (P = .001), and BCLC C (P < .001). When substratified by BCLC stage, ALBI grade was a better discriminator of survival than C-P class (C-index 0.792, 0.763, respectively). For 337 patients receiving transarterial chemoembolization, ALBI grade yielded distinct survival curves (P < .001). When stratified by C-P class and BCLC stage, ALBI grade provided distinct survival curves for C-P B (P = .02), BCLC B (P = .001), and BCLC C (P = .02). When substratified by BCLC stage, ALBI grade was a better discriminator of survival than C-P class (C-index 0.739, 0.735, respectively). CONCLUSIONS: ALBI grade outperforms C-P class at discriminating survival in patients receiving transarterial chemoembolization or (90)Y radioembolization. ALBI grade is also valuable in patients with moderate liver dysfunction and BCLC B disease.

Gastric injury from (90)Y to left hepatic lobe tumors adjacent to the stomach: fact or fiction?

PURPOSE: Radioembolization with (90)Y microspheres is a locoregional radiation therapy for unresectable hepatic neoplasm. Non-target delivery of (90)Y microspheres resulting in gastrointestinal (GI) symptoms is a recognized complication; there is minimal knowledge regarding the radiation effect to the gastric wall from left hepatic lobe (90)Y treatments. Our aim was to study the incidence of GI complications when the target tissue (hepatic parenchyma ± tumor) is in close proximity to the gastric wall. We hypothesized that liver (tumor) to stomach proximity does not correlate with increased toxicity. METHODS: Between November 2011 and September 2013, we studied all patients who underwent left lobe radioembolization with (90)Y glass microspheres. With Institutional Review Board (IRB) approval, we retrospectively reviewed MRI/CT images of these patients, identifying a subset of patients with the left hepatic lobe <1 cm from the gastric wall. Patients were seen in clinic 1 month posttreatment and subsequently at 3-month intervals. Short- and long-term gastric adverse events were tabulated. RESULTS: Ninety-seven patients successfully underwent left hepatic lobe (90)Y microsphere radioembolization in which the average distance from the liver to the stomach wall was 1.0 ± 2.8 mm. The average dose for patients who received radioembolization to the left hepatic lobe was 109 ± 57 Gy. Fifty patients had tumor within 1 cm of the gastric wall. The average dose for patients who received radioembolization to the left hepatic lobe with tumor within 1 cm of the gastric wall was 121 ± 41 Gy. There were no reportable or recordable medical events. Of the patients, 34% reported abdominal pain that was grade 1-2; 65% of the patients reported no abdominal pain. None of the 97 patients developed a clinically evident GI ulcer. CONCLUSION: Patients with left lobe tumors adjacent to or abutting the stomach do not exhibit acute or chronic radiation effects following radioembolization with glass microspheres.

Sustained safety and efficacy of extended-shelf-life (90)Y glass microspheres: long-term follow-up in a 134-patient cohort.

PURPOSE: To validate our initial pilot study and confirm sustained safety and tumor response of extended-shelf-life (90)Y glass microspheres. We hypothesized that for the same planned tissue dose, the increase in number of glass microspheres (decayed to the second week of their allowable shelf-life) administered for the same absorbed dose would result in better tumor distribution of the microspheres without causing additional adverse events. METHODS: Between June 2007 and January 2010, 134 patients underwent radioembolization with extended-shelf-life (90)Y glass microspheres; data from 84 new patients were combined with data from our 50-patient pilot study cohort. Baseline and follow-up imaging and laboratory data were obtained 1 and 3 months after therapy and every 3 months thereafter. Clinical and biochemical toxicities were prospectively captured and categorized according to the Common Terminology Criteria. Response in the index lesion was assessed using WHO and EASL guidelines. RESULTS: The mean delivered radiation dose was 123 Gy to the target liver tissue. The mean increase in number of microspheres with this approach compared to standard (90)Y glass microsphere dosimetry was 103%, corresponding to an increase from 3.84 to 7.78 million microspheres. Clinical toxicities included fatigue (89 patients, 66%), abdominal pain (49 patients, 36.6%), and nausea/vomiting (25 patients, 18.7%). Grade 3/4 bilirubin toxicity was seen in three patients (2%). Two (1%) of the initial 50-patient cohort showed gastroduodenal ulcers; gastroduodenal ulcers were not seen in any of the subsequent 84 patients. According to WHO and EASL guidelines, response rates were 48% and 57%, respectively, and 21% demonstrated a complete EASL response. CONCLUSION: This study showed sustained safety and efficacy of extended-shelf-life (90)Y glass microspheres in a larger, 134-patient cohort. The increase in number of microspheres administered theoretically resulted in better tumor distribution of the microspheres without an increase in adverse events.

Twelve-year experience of radioembolization for colorectal hepatic metastases in 214 patients: survival by era and chemotherapy.

PURPOSE: The aim of this study was to analyze the safety, treatment characteristics and survival outcomes of Yttrium-90 (Y90) radioembolization for unresectable colorectal carcinoma (CRC) liver metastases refractory to standard of care therapy. METHODS: A total of 214 patients with CRC metastases were treated with Y90 radioembolization over 12 years. Toxicity was assessed using National Cancer Institute common terminology criteria. Overall survival was analyzed from date of diagnosis of primary cancer, hepatic metastases and from the first Y90. Uni/multivariate analyses were performed. Substratification by era of chemotherapeutics was performed. RESULTS: Most patients were male (60 %) and <65 years old (61 %). Of them, 98 % had been exposed to chemotherapy. Grade 3 lymphocyte, bilirubin, albumin, ALP and AST toxicities were observed in 39 %, 11 %, 10 %, 8 % and 4 % of patients, respectively. Grade 4 lymphocyte and ALP toxicities were observed in 5 % and 3 % of patients, respectively. Median overall survival was 43.0, 34.6, and 10.6 months from date of diagnosis of primary cancer, hepatic metastases and first Y90, respectively. Survival was significantly longer in patients: (1) who received ≤2 cytotoxic drugs (n = 104) than those who received 3 (n = 110) (15.2 vs. 7.5 months, p = 0.0001); and (2) who received no biologic agents (n = 52) compared with those that did (n = 162) (18.6 vs. 9.4 months, p = 0.0001). Multivariate analyses identified ≤2 cytotoxic agents, no exposure to biologics, ECOG 0, tumor burden <25 %, lack of extrahepatic disease and albumin >3 g/dL as independent predictors of survival. CONCLUSION: In this largest metastatic CRC series published to date, Y90 radioembolization was found to be safe; survival varied by prior therapy. Further studies are required to further refine the role of Y90 in metastatic CRC.

Outpatient single-session yttrium-90 glass microsphere radioembolization.

PURPOSE: To investigate the feasibility of yttrium-90 ((90)Y) glass microsphere radioembolization (including angiography, lung shunt assessment, and treatment) as a single-session, outpatient procedure. MATERIALS AND METHODS: Between January 2008 and June 2013, 14 patients underwent outpatient, single-session radioembolization with (90)Y glass microspheres. As part of the routine diagnostic work-up, all patients underwent either computed tomography (CT) or magnetic resonance imaging of the liver with three-dimensional analysis and had laboratory results forwarded to our center for confirmation of candidacy before treatment. On treatment day, all patients underwent planning mesenteric angiography with flat panel cone-beam CT imaging. Patients were administered 33-85 MBq of technetium-99m macroaggregated albumin ((99m)Tc-MAA) via a microcatheter positioned in a hepatic artery supplying the tumor of interest. Planar scintigraphy was initiated within 2 hours after the administration of (99m)Tc-MAA and lung shunt fraction was determined. Final dosimetry calculations were performed while the patient was being transferred back from nuclear medicine to interventional radiology. RESULTS: All patients successfully underwent planning angiography with administration of (99m)Tc-MAA and (90)Y radioembolization as a single-session treatment. There were no reportable or recordable medical events; treatment was carried out to the desired dose in all cases. The mean total procedure time was 2.70 hours ± 0.72 (range, 1.63-3.97 h). CONCLUSIONS: This study reports a novel proof of concept for performing radioembolization in a single-session setting. By using the described method, time between initial clinical assessments and radioembolization treatment is decreased, and costs are minimized.

Yttrium-90 radioembolization stops progression of targeted breast cancer liver metastases after failed chemotherapy.

PURPOSE: To determine, in an open-label, retrospective report, the safety and effectiveness of locoregional therapy with yttrium-90 ((90)Y) radioembolization for patients with progressing breast cancer liver metastases (BCLMs) despite multi-agent chemotherapy. MATERIALS AND METHODS: Seventy-five patients with progressing BCLMs and stable extrahepatic disease were treated with radioembolization at a single institution. Retrospective review of a prospectively collected database was performed to evaluate clinical and biochemical toxicities, tumor response, overall survival (OS), and time to progression. Radiologic response assessments included Response Evaluation Criteria In Solid Tumors in primary index lesions and metabolic activity on positron emission tomography (PET). Univariate and multivariate analyses were performed. RESULTS: The mortality rate at 30 days was 4% (n = 3). Clinical toxicity and hyperbilirubinemia of grade 3 or worse occurred in 7.6% (n = 5) and 5.9% of patients (n = 4), respectively. Partial response (PR) was seen in 35.3% of patients (n = 24), stable disease (SD) in 63.2% (n = 43), and progressive disease in 1.5% (n = 1). PET imaging was available in 25 patients, and 21 (84%) had a complete response, PR, or SD. The median OS was 6.6 months (95% confidence interval [CI], 5.0-9.2 mo). The hazard ratio (HR) for OS on multivariate analysis was 0.39 (95% CI, 0.23-0.66) for tumor burden less than 25% compared with greater burden. Elevated bilirubin levels were shown to reduce OS. The HR for hepatic progression was 0.22 (95% CI, 0.05-0.98) for solitary versus multifocal disease. CONCLUSIONS: Locoregional therapy with (90)Y radioembolization is safe and stops or delays the progression of targeted chemorefractory BCLMs. Adverse prognosticators were identified.

Comparative study of staging systems for hepatocellular carcinoma in 428 patients treated with radioembolization.

PURPOSE: To compare the utility of different staging systems and analyze independent predictors of survival in patients with hepatocellular carcinoma (HCC) treated with yttrium-90 ((90)Y) radioembolization. MATERIALS AND METHODS: During the period 2004-2011, 428 patients with HCC were treated with (90)Y radioembolization. All patients were staged prospectively by the following staging systems: Child-Turcotte-Pugh (CTP), United Network for Organ Sharing, Barcelona Clinic Liver Cancer (BCLC), Okuda classification, Cancer of the Liver Italian Program (CLIP), Groupe d'Etude et de Traitement du Carcinome Hepatocellulaire, Chinese University Prognostic Index, and Japan Integrated Staging. The ability of the staging systems to predict survival was assessed. The staging systems were compared using Cox proportional hazards regression model, linear regression, Akaike information criterion (AIC), and concordance index (C-index). Univariate and multivariate analyses were employed to assess independent predictors of survival. RESULTS: When tested independently, all staging systems exhibited significant ability to discriminate early (long survival) from advanced (worse survival) disease. CLIP provided the most accurate information in predicting survival outcomes (AIC = 2,993, C-index = 0.8503); CTP was least informative (AIC = 3,074, C-index = 0.6445). Independent predictors of survival included Eastern Cooperative Oncology Group performance status grade 0 (hazard ration [HR], 0.56; confidence interval [CI], 0.34-0.93), noninfiltrative tumors (HR, 0.62; CI, 0.44-0.89), absence of portal venous thrombosis (HR, 0.60; CI, 0.40-0.89), absence of ascites (HR, 0.56; CI, 0.40-0.76), albumin ≥ 2.8 g/dL (HR, 0.72; CI, 0.55-0.94), alkaline phosphatase ≤ 200 U/L (HR, 0.68; CI, 0.50-0.92), and α-fetoprotein ≤ 200 ng/mL (HR, 0.67; CI, 0.51-0.86). CONCLUSIONS: CLIP was most accurate in predicting survival in patients with HCC. Given that not all patients receive the recommended BCLC treatment strategy, this information is relevant for clinical trial design and predicting long-term outcomes after (90)Y radioembolization.

Radioembolization for hepatocellular carcinoma with portal vein thrombosis: impact of liver function on systemic treatment options at disease progression.

BACKGROUND & AIMS: Yttrium-90 ((90)Y) radioembolization is a microembolic procedure. Hence, it is commonly used in hepatocellular carcinoma (HCC) patients with portal venous thrombosis (PVT). We analyzed liver function, imaging findings, and treatment options (local/systemic) at disease progression following (90)Y treatment in HCC patients with PVT. METHODS: We treated 291 HCC patients with (90)Y radioembolization. From this cohort, we included patients with liver-only disease, PVT and Child-Pugh (CP) score ≤ 7; this identified 63 patients with HCC and PVT (CP-A:35, CP-B7:27). Liver function, CP status, and imaging findings at progression were determined in order to assess potential candidacy for systemic treatment/clinical trials. Survival, time-to-progression (TTP), and time-to-hepatic decompensation analyses were performed using Kaplan-Meier methodology. RESULTS: Of 35 CP-A and 28 CP-B7 patients, 29 and 15 progressed, respectively. Median survival and TTP were 13.8 and 5.6 months in CP-A and 6.5 and 4.9 months in CP-B7 patients, respectively. Of the 29 CP-A patients who progressed, 45% maintained their CP status at progression (55% decompensated to CP-B). Of the 15 CP-B7 patients who progressed, 20% improved to CP-A, 20% maintained their CP score and 60% decompensated. CONCLUSIONS: Knowledge of liver function and CP score of HCC with PVT progressing after (90)Y is critically relevant information, as these patients may be considered for systemic therapy/clinical trials. If a strict CP-A status is mandated, our study demonstrated that 64% of cases exhibited inadequate liver function and were ineligible for systemic therapy/clinical trials. An adjuvant approach using local therapy and systemic agents prior to progression should be investigated.

Radiation lobectomy: time-dependent analysis of future liver remnant volume in unresectable liver cancer as a bridge to resection.

BACKGROUND & AIMS: Portal vein embolization (PVE) is a standard technique for patients not amenable to liver resection due to small future liver remnant ratio (FLR). Radiation lobectomy (RL) with (90)Y-loaded microspheres (Y90) is hypothesized to induce comparable volumetric changes in liver lobes, while potentially controlling the liver tumor and limiting tumor progression in the untreated lobe. We aimed at testing this concept by performing a comprehensive time-dependent analysis of liver volumes following radioembolization. METHODS: 83 patients with right unilobar disease with hepatocellular carcinoma (HCC; N=67), cholangiocarcinoma (CC; N=8) or colorectal cancer (CRC; N=8) were treated by Y90 RL. The total liver volume, lobar (parenchymal) and tumor volumes, FLR and percentage of FLR hypertrophy from baseline (%FLR hypertrophy) were assessed on pre- and post-Y90 CT/MRI scans in a dynamic fashion. RESULTS: Right lobe atrophy (p=0.003), left lobe hypertrophy (p<0.001), and FLR hypertrophy (p<0.001) were observed 1 month after Y90 and this was consistent at all follow-up time points. Median %FLR hypertrophy reached 45% (5-186) after 9 months (p<0.001). The median maximal %FLR hypertrophy was 26% (-14 → 86). Portal vein thrombosis was correlated to %FLR hypertrophy (p=0.02). Median Child-Pugh score worsening (6 → 7) was seen at 1 to 3 months (p=0.03) and 3 to 6 months (p=0.05) after treatment. Five patients underwent successful right lobectomy (HCC N=3, CRC N=1, CC N=1) and 6 HCCs were transplanted. CONCLUSIONS: Radiation lobectomy by Y90 is a safe and effective technique to hypertrophy the FLR. Volumetric changes are comparable (albeit slightly slower) to PVE while the right lobe tumor is treated synchronously. This novel technique is of particular interest in the bridge-to-resection setting.

Radiographic response to locoregional therapy in hepatocellular carcinoma predicts patient survival times.

BACKGROUND & AIMS: It is not clear whether survival times of patients with hepatocellular carcinoma (HCC) are associated with their response to therapy. We analyzed the association between tumor response and survival times of patients with HCC who were treated with locoregional therapies (LRTs) (chemoembolization and radioembolization). METHODS: Patients received LRTs over a 9-year period (n = 463). Patients with metastases, portal venous thrombosis, or who had received transplants were excluded; 159 patients with Child-Pugh B7 or lower were analyzed. Response (based on European Association for the Study of the Liver [EASL] and World Health Organization [WHO] criteria) was associated with survival times using the landmark, risk-of-death, and Mantel-Byar methodologies. In a subanalysis, survival times of responders were compared with those of patients with stable disease and progressive disease. RESULTS: Based on 6-month data, in landmark analysis, responders survived longer than nonresponders (based on EASL but not WHO criteria: P = .002 and .0694). The risk of death was also lower for responders (based on EASL but not WHO criteria: P = .0463 and .707). Landmark analysis of 12-month data showed that responders survived longer than nonresponders (P < .0001 and .004, based on EASL and WHO criteria, respectively). The risk of death was lower for responders (P = .0132 and .010, based on EASL and WHO criteria, respectively). By the Mantel-Byar method, responders had longer survival than nonresponders, based on EASL criteria (P < .0001; P = .596 with WHO criteria). In the subanalysis, responders lived longer than patients with stable disease or progressive disease. CONCLUSIONS: Radiographic response to LRTs predicts survival time. EASL criteria for response more consistently predicted survival times than WHO criteria. The goal of LRT should be to achieve a radiologic response, rather than to stabilize disease.

Radioembolization results in longer time-to-progression and reduced toxicity compared with chemoembolization in patients with hepatocellular carcinoma.

BACKGROUND & AIMS: Chemoembolization is one of several standards of care treatment for hepatocellular carcinoma (HCC). Radioembolization with Yttrium-90 microspheres is a novel, transarterial approach to radiation therapy. We performed a comparative effectiveness analysis of these therapies in patients with HCC. METHODS: We collected data from 463 patients who were treated with transarterial locoregional therapies (chemoembolization or radioembolization) over a 9-year period. We excluded patients who were not appropriate for comparison and analyzed data from 245 (122 who received chemoembolization and 123 who received radioembolization). Patients were followed for signs of toxicity; all underwent imaging analysis at baseline and follow-up time points. Overall survival was the primary outcome measure. Secondary outcomes included safety, response rate, and time-to-progression. Uni- and multivariate analyses were performed. RESULTS: Abdominal pain and increased transaminase activity were more frequent following chemoembolization (P < .05). There was a trend that patients treated with radioembolization had a higher response rate than with chemoembolization (49% vs 36%, respectively, P = .104). Although time-to-progression was longer following radioembolization than chemoembolization (13.3 months vs 8.4 months, respectively, P = .046), median survival times were not statistically different (20.5 months vs 17.4 months, respectively, P = .232). Among patients with intermediate-stage disease, survival was similar between groups that received chemoembolization (17.5 months) and radioembolization (17.2 months, P = .42). CONCLUSIONS: Patients with HCC treated by chemoembolization or radioembolization with Yttrium-90 microspheres had similar survival times. Radioembolization resulted in longer time-to-progression and less toxicity than chemoembolization. Post hoc analyses of sample size indicated that a randomized study with > 1000 patients would be required to establish equivalence of survival times between patients treated with these two therapies.