Superabsorbent Polymer Microspheres Research Articles

In Vitro Characterization of Drug-Loaded Superabsorbent Polymer Microspheres: Absorption and Release Capacity of Contrast Material, Antibiotics and Analgesics.

To examine the characteristics of drug-loaded superabsorbent polymer microspheres (SAP-MS) such as drug absorption, drug release, diameter, and visibility. SAP-MS (HepaSphere150-200µm; Merit Medical, South Jordan, UT, USA) were suspended in drug solutions: (a) cefazolin, (b) lidocaine, (c) iopamidol and cefazolin, (d) iopamidol and lidocaine, and (e) iopamidol, cefazolin, and lidocaine. The concentrations of drugs were measured, and the amount of each drug absorbed was calculated. Filtered drug-loaded SAP-MS were mixed with saline, and the drug release rates were calculated. The diameter changes of SAP-MS during absorption were observed. Radiography of drug-loaded SAP-MS was evaluated as radiopacity by contrast-to-noise ratio (CNR). The drug concentration did not change during absorption. The release rates increased for 10min and then came to an equilibrium. The mean amounts of drug absorbed at 180min and mean release rates at 24h were (a) cefazolin: 265.4mg, 64.2%; (b) lidocaine: 19.6mg, 75.6%; (c) iopamidol: 830.2mg, 22.5%; cefazolin: 137.6mg, 21.2%; (d) iopamidol: 1620.6mg, 78.5%; lidocaine: 13.5mg, 81.4%; and (e) iopamidol: 643.7mg, 52.9%; cefazolin: 194.0mg, 51.6%; lidocaine: 5.3mg, 58.4%. The diameter of SAP-MS increased for approximately 15min. Finally, the diameters of SAP-MS were (a) 3.9 times, (b) 5.0 times, (c) 2.2 times, (d) 5.5 times, and (e) 3.6 times larger than the original size. Drug-loaded SAP-MS containing iopamidol were visible under X-ray imaging, with CNRs of (c) 3.0, (d) 9.0, and (e) 4.5. SAP-MS can absorb and release iopamidol, cefazolin, and lidocaine.

Repeated transarterial chemoembolization with epirubicin-loaded superabsorbent polymer microspheres vs. conventional transarterial chemoembolization for hepatocellular carcinoma.

The aim of the present study was to evaluate the long-term outcomes and the impact of repeated conventional transarterial chemoembolization (C-TACE) and transarterial chemoembolization with epirubicin-loaded superabsorbent polymer embolics (SAP-TACE) on liver function in TACE-naïve patients with unresectable hepatocellular carcinoma (HCC). Overall, 155 consecutive patients with HCC received either C-TACE or SAP-TACE. The first cohort (n=71), treated between 2011 and 2014, received C-TACE; the second cohort (n=84), treated between 2014 and 2016, received SAP-TACE. Overall survival and deterioration of liver function were compared between the two cohorts. The 1-, 2- and 3-year overall survival rates and median survival times were 74, 50, 35% and 26 months in the C-TACE cohort and 75, 60, 39% and 28 months in the SAP-TACE cohort, respectively. There were no significant differences between the two groups (P=0.289). Age <70 years, Child-Pugh class A, alpha-fetoprotein <400 ng/ml and des-gamma-carboxy prothrombin <1,000 mAU/ml were identified as favorable prognostic factors in multivariate analysis. In the subgroup of patients with a Child-Pugh score of 5, survival was 29 months for C-TACE vs. 55 months for SAP-TACE (P<0.05). In the C-TACE cohort, the median Child-Pugh score was 6 after 3 cycles and 7 after 5 cycles of TACE, and the score worsened significantly (before vs. 3 cycles, P<0.05; before vs. 5 cycles, P<0.05). In the SAP-TACE cohort, the median Child-Pugh score was 6 after 3 and 5 cycles of TACE, and the score did not worsen during the treatment cycles. There were no differences in overall survival between repeated C-TACE and SAP-TACE in TACE-naïve patients with HCC. However, liver function deterioration was more evident in patients treated with C-TACE than in those treated with SAP-TACE.

Preparation of Surface-Reinforced Superabsorbent Polymer Hydrogel Microspheres via Incorporation of In Situ Synthesized Silver Nanoparticles.

Superabsorbent polymer (SAP) particles are primarily applied for absorbing and storing liquids. Here, poly (acrylic acid) (PAA)-based SAP microspheres incorporated with silver nanoparticles (AgNPs) are prepared as an effort to maintain microsphere shape during swelling and minimize gel blocking. PAA-based SAP spheres are synthesized via inverse suspension polymerization. AgNPs are formed within SAP spheres through in situ reduction of silver nitrate (AgNO3), using polyvinylpyrrolidone as the reducing agent. The formation of AgNPs within SAP was observed via techniques such as scanning electron microscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and transmission electron microscopy. Energy dispersive spectroscopy analyses reveal that thin and dense layers of AgNPs are formed on the outer regions of the SAP spheres at higher concentrations of AgNO3. The water absorbency capacity decreases on increasing the amount of incorporated silver nanoparticles; however, it is comparable with that of commercially available surface-crosslinked SAP particles. Finally, micro-computerized tomography (micro-CT) study revealed that AgNP-incorporated SAP spheres maintained their shapes during swelling and exhibit higher void fractions in the packed gel bed, minimizing gel blocking and improving fluid permeability.

Synthesis and application of superabsorbent polymer microspheres for rapid concentration and quantification of microbial pathogens in ambient water

Even though numerous methods have been developed for the detection and quantification of waterborne pathogens, the application of these methods is often hindered by the very low pathogen concentrations in natural waters. Therefore, rapid and efficient sample concentration methods are urgently needed. Here we present a novel method to pre-concentrate microbial pathogens in water using a portable 3D-printed system with super-absorbent polymer (SAP) microspheres, which can effectively reduce the actual volume of water in a collected sample. The SAP microspheres absorb water while excluding bacteria and viruses by size exclusion and charge repulsion. To improve the water absorption capacity of SAP in varying ionic strength waters (0–100 mM), we optimized the formulation of SAP to 180 g⋅L−1 Acrylamide, 75 g⋅L−1 Itaconic Acid and 4.0 g⋅L−1 Bis-Acrylamide for the highest ionic strength water as a function of the extent of cross-linking and the concentration of counter ions. Fluorescence microscopy and double-layer agar plating respectively showed that the 3D-printed system with optimally-designed SAP microspheres could rapidly achieve a 10-fold increase in the concentration of Escherichia coli (E. coli) and bacteriophage MS2 within 20 min with concentration efficiencies of 87% and 96%, respectively. Fold changes between concentrated and original samples from qPCR and RT-qPCR results were found to be respectively 11.34–22.27 for E. coli with original concentrations from 104 to 106 cell·mL−1, and 8.20–13.81 for MS2 with original concentrations from 104 to 106 PFU·mL−1. Furthermore, SAP microspheres can be reused for 20 times without performance loss, significantly decreasing the cost of our concentration system.

In vitro evaluation of radiopacity of contrast-loaded superabsorbent polymer microspheres (SAP-MS) with static imaging and flow model.

To evaluate the radiopacity of contrast-loaded superabsorbent polymer microspheres (SAP-MS) under X-ray imaging. SAP-MS were suspended in contrast material (iodixanol) and the diameter change was assessed. The diameter of contrast-loaded SAP-MS in saline was measured sequentially. Radiography of the contrast-loaded SAP-MS was evaluated as radiopacity by contrast-to-noise ratio and visibility by multiple reader scoring. Under digital subtraction angiography, contrast-loaded SAP-MS were injected into a flow model. The flow speed was 1-10cm/s, and images were acquired at 1-7.5 frames per second using a pulse width of 10-85ms. Images were assessed by multiple reader scoring. The diameter of SAP-MS increased to 4.0-5.0 times its original size for approximately 15min. The diameter of contrast-loaded SAP-MS in saline further increased by 10-30% within several minutes and returned to the previous size. Radiopacity and visibility of contrast-loaded SAP-MS decreased in 30min after mixing with saline. Visibility was better with slow flow speed and narrow pulse width. For effective observation, contrast-loaded SAP-MS should be kept in non-diluted contrast material until use. The conditions of slower flow and use of a narrow pulse width are recommended.

Superabsorbent Polymer Microspheres Prepared with Hypertonic Saline to Reduce Microsphere Expansion.

To analyze size changes of superabsorbent polymer (SAP) microspheres with the reduced expansion technique, and to evaluate pharmacological advantages of transarterial chemoembolization using cisplatin-loaded SAP microspheres with the reduced expansion technique. In an in vitro study, diluted contrast materials containing different concentrations of sodium ions were examined to expand SAP microspheres and determined the reduced expansion technique. Size distributions of cisplatin-loaded SAP microspheres were analyzed. In an in vivo study, TACE was performed using cisplatin-loaded SAP microspheres with the reduced expansion and control techniques in 18 VX2 rabbits. The degree of expansion was reduced to the greatest extent by using a mixture of non-ionic contrast material and 10% NaCl at a 4:1 ratio. The mean diameter of the reduced expansion of cisplatin-loaded SAP microspheres was 188.4μm, while that of the control expansion was 404.9μm. The plasma platinum concentrations of the reduced expansion group at 5min after TACE were significantly higher than those of the control expansion group (2.19 ± 0.77 vs. 0.75 ± 0.08μg/mL, P = .01). The tumor platinum concentrations of the reduced expansion group at 1h were significantly higher than those of the control expansion group (10.76 ± 2.57 vs. 1.57 ± 0.14μg/g, P = .044). The expanding level of SAP microspheres can be reduced by using hypertonic saline. Cisplatin-loaded SAP microspheres with the reduced expansion technique have the advantages of achieving higher cisplatin tissue concentration in TACE for liver tumors.

Transcatheter Arterial Chemoembolization with Spherical Embolic Agent in Patients with Pulmonary or Mediastinal Metastases from Breast Cancer

PurposeTo evaluate safety and feasibility of transcatheter arterial chemoembolization with superabsorbent polymer microspheres (SAP-MS) for patients with pulmonary or mediastinal metastasis from breast cancer. MethodsBetween November 2002 and January 2015, 14 patients with 29 unresectable pulmonary or mediastinal breast cancer metastases underwent transcatheter arterial chemoembolization using SAP-MS (50–100 μm) after injection of a combination of 2–4 types of anticancer drugs (eg, cisplatin [30 mg] + fluorouracil [500 mg], or epirubicin [40 mg] + mitomycin C [4 mg] + fluorouracil [500 mg]). As a primary endpoint, local tumor response and adverse events were evaluated 1 month after the first transcatheter arterial chemoembolization, according to Response Evaluation Criteria In Solid Tumors Version 1.1 and Common Terminology Criteria for Adverse Events Version 4 criteria. Transcatheter arterial chemoembolization was repeated as needed. Overall survival was analyzed as a secondary endpoint. ResultsResponse rate was 28.6% (partial response, 4 patients; stable disease, 10 patients). Median progression rate was −12.7%. No cases of hematologic toxicity of grade 3 or higher were observed. A grade 3 maculopapular rash was observed in 1 patient. After the first transcatheter arterial chemoembolization sessions, 63 additional transcatheter arterial chemoembolization sessions were performed (average, 5.5 sessions per patient; range, 2–10 sessions). The median overall survival time after the first session was 29 months, and the 5-year survival rate was 49.5%. ConclusionsTranscatheter arterial chemoembolization with SAP-MS is a well-tolerated and feasible palliative treatment option for patients with pulmonary or mediastinal metastasis from breast cancer.

Safety and efficacy of doxorubicin-eluting superabsorbent polymer microspheres for the treatment of liver metastases from neuroendocrine tumours: preliminary results

BackgroundThe aim of the study was to retrospectively evaluate the symptom control, tumour response, and complication rate in patients with liver-predominant metastatic neuroendocrine tumours treated with transarterial chemoembolization using doxorubicin-eluting superabsorbent polymer (SAP) microspheres.Patients and methodsPatients with neuroendocrine liver metastases who underwent hepatic transarterial chemoembolization using doxorubicin-eluting SAP-microspheres (50–100 μm Hepasphere/Quadrasphere Microsphere® particles, Merit Medical, South Jordan, Utah, USA) were included in this study. Pre-and post-procedure imaging studies were evaluated to assess short and intermediate-term tumour response using modified RECIST criteria. Symptom relief and procedure-related complications were evaluated.ResultsA total of 27 embolization procedures were performed on 17 patients. Twelve of 17 patients (70%) were symptomatic, including carcinoid syndrome (n = 8) and severe, uncontrollable hypoglycemia (n = 4). Eight of 12 patients (67%) had complete symptom relief, and the remaining 4 (33%) had partial relief. One patient developed ischemic cholecystitis (6%). No other hepatobiliary complications occurred. Short-term and intermediate-term imaging follow-up was available for 15/17 patients (88%) and 12/14 patients (86%) respectively. At short-term follow-up (< 3 months), 14 patients (93%) showed partial response and the remaining patient had progressive disease (7%). At intermediate-term imaging follow-up (> 3 months), partial response, stable disease and progressive disease were found respectively in 7 (58%), 3 (25%) and 2 (17%) patients.ConclusionsChemoembolization with doxorubicin-eluting SAP-microspheres is a safe and effective treatment option for neuroendocrine liver metastases and is associated with a low complication rate. In particular, no clinically evident liver necrosis or bile duct complications were encountered.

Erratum To: Short-term efficacy of transarterial chemoembolization with epirubicin-loaded superabsorbent polymer microspheres for hepatocellular carcinoma: comparison with conventional transarterial chemoembolization.

This study aimed to compare the short-term efficacy of transarterial chemoembolization (TACE) with epirubicin-loaded superabsorbent polymer embolics (SAP) and conventional TACE in TACE-naive patients with unresectable hepatocellular carcinoma (HCC). Fifty consecutive patients (mean age, 72.8 years; hepatitis C, 46%; BCLC-A or B, 52% or 48%) treated with TACE with SAP during 2013–2015 and 55 consecutive patients (mean age, 71.8 years; hepatitis C, 40%; BCLC-A or B, 51% or 49%) treated with conventional TACE during 2011–2013 were evaluated. Safety evaluations were based on CTCAE ver. 4.0. Short-term efficacies, i.e., at 1 month after TACE, were assessed using the European Association for the Study of the Liver criteria. Overall survival rates were calculated using the Kaplan–Meier method. Short-term response markers were analyzed by univariate and multivariate analyses. There was no significant difference in the incidence of any grade of adverse events. The objective response rates were 50% and 62% in patients treated with TACE with SAP and with conventional TACE, respectively (P = 0.358). The overall survival rates were not significantly different (P = 0.810); the 1-year survival rates and the median survival time of the patients treated with TACE with SAP and with conventional TACE were 76% and 74%, and 18 months and 21 months, respectively. Overall survival was related to the short-term response. An alpha-fetoprotein level <1,000 ng/mL was a significant short-term response marker on multivariate analysis. For TACE-naive patients, TACE with SAP and conventional TACE had comparable safety and short-term efficacies.

肝細胞癌に対するエピルビシン含浸superabsorbent polymer microsphereを使用したDEB−TACEの局所奏功因子

肝細胞癌に対するエピルビシン含浸superabsorbent polymer microsphereを使用したDEB−TACEの局所奏功因子

The application of coated superabsorbent polymer in well cement for plugging the microcrack

The research objectives are designed to realize the application of superabsorbent polymer (SAP) in well cement to plug microcrack. Gypsum–chitosan–gypsum coated SAP is proposed. Percolation theory is used to research plugging microcrack mechanism. According to the exact analytical solution of square plane percolation threshold, dosage threshold of coated SAP microspheres is calculated as 28.40%, which can deliver the plugging of microcrack. The method of manufacturing quantitative microcrack is established, and self-designed instrument is employed to test plugging performance. The results show the ability of plugging microcrack when the dosage of coated SAP microsphere is higher than the threshold.

Management of vascular lake phenomenon on angiography during chemoembolization with superabsorbent polymer microspheres.

Contrast material pooling on angiography within a tumor bed during embolization for hepatocellular carcinoma (HCC) presents as the vascular lake (VL) phenomenon. This retrospective study aimed to evaluate the frequency and management of VLs during chemoembolization with drug-eluting beads (DEBs) and the relationship between the VL and local response. A total of 123 HCC patients without vascular invasion or intrahepatic metastases who underwent chemoembolization with DEBs (50-100 µm superabsorbent polymer microspheres loaded with epirubicin) were enrolled. Gelatin sponge particles (GS) were injected for additional embolization in limited patients with steadily increasing size of VLs during DEB injection. Overall, 338 nodules were divided into three groups: lesions without a VL (non-VL; n = 250); lesions with a VL but without additional GS embolization [VL-GS (-), n = 58]; and lesions with both VL and additional GS embolization [VL-GS (+); n = 30]. The local responses were statistically compared by Fisher's exact test with the Bonferroni correction. The frequency of VLs was 26.0% (88/338). The response rate in the non-VL group (54.0%) was significantly lower than those in the VL-GS (-) (91.4%; P < 0.0001) and VL-GS (+) (96.7%; P < 0.0001) groups. VL is a common angiographic finding and might be associated with the local response.

Efficient Loading of cisplatin into Superabsorbent Polymer Microsphere in the treatment of hepatocellular carcinoma.

Background: Although Superabsorbent Polymer (SAP) microsphere has been useful in treatment of multiple and large hepatocellular carcinoma, efficient loading procedure of cisplatin onto SAP was not established. Loading efficiency of cisplatin was evaluated from the viewpoint of passive concentration gradient and ionic strength. Methods: To load cisplatin into SAP particle, 50mg of cisplatin powder was dissolved in three manners of aqueous solutions: (a) 50mg of cisplatin powder plus 35ml of warmed physiological saline solution (0.9%), (b) 5ml of physiological saline solution (0.9%) plus a half of solution (5ml) of the product made from 50mg of cisplatin powder in 10ml of iohexol 350mgI/ml, and (c) 10ml of iohexol 350mgI/ml plus 0.25ml of 10% NaCl solution Results: Cisplatin dissolved sufficiently in all the three methods. Average amounts of loaded cisplatin into SAP particles were 1.7mg in solution (a), 6.6mg in solution (b), and 11.8mg in solution (c). Since alteration of ionic strength in the method (c) significantly affect the extent of SAP swelling, addition of 0.25ml of 10% NaCl was unquestionably necessary. Release of cisplatin from SAP was evidently gradual, showing 83.1% after 6 hours in static elution experiment and 68.6% after 1 hour in dynamic elution experiment. Conclusions: Cisplatin-loaded SAP may act as a drug delivery system for treatment of liver cancer, and loading of cisplatin should be consciously performed considering cisplatin concentration and ionic strength. (225words)

Local control and prognostic significance of transarterial treatment for limited recurrence of ovarian cancer as third-line and beyond therapy

We aimed to retrospectively evaluate the safety and efficacy of transarterial treatment for the recurrence of ovarian cancer, limited to one or two gross regions, in a palliative setting as third-line and beyond therapy. Twenty-six consecutive patients were enrolled to undergo transarterial treatment of target lesions that were life-threatening or influenced their quality of life. Transarterial infusion via each feeding artery using 20-40 mg cisplatin and 20-40 mg docetaxel per patient was repeated every 4-6 weeks. Superabsorbent polymer microspheres were added for embolization after drug infusion, especially in hepatic or pelvic treatments. Univariate and multivariate Cox's proportional hazards models were used to assess the correlations between overall survival and individual parameters. A total of 63 feeding arteries (median 2 per patient; range 1-5) were treated for 36 target sites (liver, 12; pelvis, 8; abdominal cavity, 7; lymph node, 3; other, 6) at the initial treatment. Of the 128 total sessions, the only grade 3/4 toxicity was neutropenia (3.8 %). The target lesion response rate by RECIST ver.1.1 was 50.0 % (11.5 % complete response; 38.5 % partial response). After a median follow-up of 30 months, the median overall survival was 16 months. Among 10 tumor-associated symptomatic patients, 7 showed symptom improvement. Multivariate analyses shows that the only independent prognostic factor was target lesion response (hazard ratio 18.7; 95 % CI 1.9-183.4; p = 0.01). Transarterial treatment for ovarian cancer achieves a high local response and good symptom control, and significantly contributes to survival for patients with local control after multiple relapses.

Transcatheter Arterial Chemoembolization with Doxorubicin-Eluting Superabsorbent Polymer Microspheres in the Treatment of Hepatocellular Carcinoma: Midterm Follow-up

PurposeTo investigate prospectively the safety, tolerability, and efficacy of transarterial chemoembolization using superabsorbent polymer (SAP) microspheres loaded with doxorubicin for the treatment of hepatocellular carcinoma (HCC). Materials and MethodsDuring the years 2006–2011, 64 patients underwent 144 transarterial chemoembolization with SAP microspheres procedures. Most of the patients were staged as Barcelona Clinic Liver Cancer class B (65%). The most frequent underlying liver diseases were hepatitis C (35%) and alcoholic liver disease (28%) resulting in Child-Pugh A (73.4%) or Child-Pugh B (17%) liver cirrhosis. Tumor response was assessed using modified Response Evaluation Criteria in Solid Tumors with magnetic resonance (MR) imaging performed 4–6 weeks after each procedure. ResultsSerious adverse events (n = 9) were ischemic or infectious in nature. Transarterial chemoembolization with SAP microspheres resulted in objective response rates of 67.5%, 44.5%, and 25% after first, second, and third sessions. There were 16 patients (25%) who underwent orthotopic liver transplantation after transarterial chemoembolization with SAP microspheres, of whom 2 experienced recurrent disease. During a median follow-up time of 14 months (range, 2–55 mo), 26 patients (40.5%) died. Median overall and transplant-free survivals were 20.5 months (95% confidence interval, 13.2–27.7) and 18 months (95% confidence interval, 14.2–21.8), respectively. ConclusionsTransarterial chemoembolization with SAP microspheres has an excellent safety profile in cirrhotic patients, even in the presence of advanced liver disease (Child-Pugh B) or advanced stages of HCC. This treatment produced meaningful tumor response rates as assessed by MR imaging.

Chemoembolization with super absorbent polymer microspheres (SAP-MS) loaded with doxorubicin (D) using escalating doses and adverse events (AE) in resectable hepatocellular carcinoma.

e15084 Background: SAP-MS have demonstrated utility in the treatment of hepatocellular carcinoma (HCC) as a bland embolic and have demonstrated the ability to load and release D in vivo. Little is known about its toxicity profile. We aimed to determine if the dose and maximum plasma concentration (Cmax) of D were correlated with occurrence of AE. Methods: A phase II dose-escalation study was performed to systematically evaluate AEs relating to outpatient-based D/ SAP-MS embolization in HCC using a D dose of 0-75 mg. D plasma levels were assessed at multiple time points (0.5, 2, 24 and 675h), in addition to standard analyses of liver and hematologic function. All AEs were reported following the Common Toxicity Criteria Version 3.0. A Pearson product-moment correlation was run to determine the relationship between Cmax and AE. Results: Of 25 patients enrolled, 24 were evaluable (6 = 0mg, 6 = 25mg, 6 = 50mg, 6 = 75mg). The side-effect profile was similar to other abdominal embolization procedures, with abdominal pain (62.5%), fatigue-like symptoms (41.7%), and nausea (41.7%) being the most common AE. There were no correlation between the administered doses of D and all grade AE (r = .209, p .328) or between Cmax's of D and all grade AE (r = .321, p .127). All patients were discharged on the same day. There were no grade 4 or 5 AE and no hepatic decompensation. One patient required hospitalization 7 days post-procedure for groin puncture related complication. Conclusions: In our phase II dose-escalation study, patients experienced minimal post-embolization syndrome, which was not correlated with the amount of doxorubicin administered. The toxicities relating to SAP-MS delivery likely result from the embolic effect as opposed to dose response relating to the use of doxorubicin and can be managed on an outpatient basis. Clinical trial information: NCT01116635.

Transcatheter Arterial Chemoembolization (TACE) of Colorectal Cancer Liver Metastases by Irinotecan-Eluting Microspheres in a Salvage Patient Population

This prospective study evaluated the effectiveness and safety of TACE using irinotecan loaded superabsorbent polymer (SAP) microspheres for treatment of colorectal cancer liver metastases (CCLM) in a salvage setting of patients. A total of 71 TACE procedures were performed in 29 patients with liver only or liver-dominant CCLM. In all patients, systemic chemotherapy before TACE had failed. Two hundred milligrams of irinotecan were loaded into 50-100 mg of SAP microspheres (HepaSphere™ Microspheres) considering tumor size and vascularization. TACE was performed selectively with respect to tumor distribution. Response was evaluated following RECIST and EASL criteria, respectively. Median follow-up after last TACE was 8 (range 1-54) months. All patients had died at time of analysis. All TACE procedures were performed successfully; 35-400 mg (mean 168.3 mg) of irinotecan loaded in 13-100 mg (mean 48.3 mg) SAP microspheres were injected during individual sessions. No major complications occurred. Three, 6, and 12 months after first TACE complete and partial response was present in 72, 32 %, 0 of patients by EASL criteria and stable disease was seen in 86, 48, and 8 % with no complete and no partial response by RECIST criteria. Median overall survival after first TACE was 8 months, and median time to progression was 5 months. Median overall survival was longer in patients with limited (<25 %) compared with extensive (>50 %) intrahepatic disease (21 vs. 5 months, p < 0.005). TACE using irinotecan loaded SAP microspheres is safe and effective in terms of tumor necrosis. Survival benefit in a salvage setting seems to be limited in patients with advanced intrahepatic tumor load.

Transcatheter Arterial Embolization With Spherical Embolic Agent for Pulmonary Metastases From Renal Cell Carcinoma

This retrospective study aimed to evaluate the safety and local efficacy of transcatheter arterial embolization (TAE) with superabsorbent polymer microspheres (SAP-MS) in patients with pulmonary metastases from renal cell carcinoma (RCC). Sixteen patients with unresectable pulmonary metastases from RCC refractory to standard therapy were enrolled to undergo TAE with the purpose of mass reduction and/or palliation. The prepared SAP-MS swell to approximately two times larger than their dry-state size (100-150 μm [n = 14], 50-100 μm [n = 2]). Forty-nine pulmonary nodules (lung n = 22, mediastinal lymph node n = 17, and hilar lymph node n = 10) were selected as target lesions for evaluation. Local tumor response was evaluated 3 months after TAE according to Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1). The relationship between tumor enhancement ratio by CT during selective angiography and local tumor response was evaluated. The number of TAE sessions per patient ranged from 1 to 5 (median 2.9). Embolized arteries at initial TAE were bronchial arteries in 14 patients (87.5 %) and nonbronchial systemic arteries in 11 patients (68.8 %). Nodule-based evaluation showed that 5 (10.2 %) nodules had complete response, 17 (34.7 %) had partial response, 15 (30.6 %) had stable disease, and 12 (24.5 %) had progressive disease. The response rate was significantly greater in 22 lesions that had a high tumor enhancement ratio than in 27 lesions that had a slight or moderate ratio (90.9 vs. 7.4 %, p = 0.01). Severe TAE-related adverse events did not occur. TAE with SAP-MS might be a well-tolerated and locally efficacious palliative option for patients with pulmonary metastases from RCC.

Chemoembolization and Radioembolization for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) continues to represent a major worldwide problem. Although treatments such as resection, transplantation, and ablation may provide a chance for a cure, these options are often precluded because of advanced disease presentation. Palliative treatments include transarterial embolization and systemic therapies. This review will summarize the state of the science for embolic therapies in HCC (conventional and drug-eluting chemoembolization, radioembolization) as well as discuss related topics including HCC staging, assessment of response, and ongoing clinical trials.

A Randomized Phase II Study of Drug-Eluting Beads versus Transarterial Chemoembolization for Unresectable Hepatocellular Carcinoma

Background: Transcatheter arterial chemoembolization (TACE) is the standard treatment in selected patients with unresectable hepatocellular carcinoma (HCC). Drug-eluting particles are developed to reduce side effects and improve efficacy. We present safety data of a prospective randomized phase II study with doxorubicin-eluting superabsorbent polymer (SAP) microspheres. Material and Methods: We prospectively included 30 HCC patients with different Barcelona Clinic Liver Cancer (BCLC) stages (A = 3, B = 19, C = 8) and randomly assigned them to receive conventional TACE (n = 14) (control group) or doxorubicin-eluting SAP microspheres (n = 16). The doxorubicin plasma level was assessed at different time points, biochemical analysis was performed, and side effects were reported following the Common Toxicity Criteria. Tumor response was assessed at 6 weeks according to the modified Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Results: There was a significantly lower plasma peak concentration (Cmax) of doxorubicin and smaller area under the curve (AUC) with SAP microspheres (mean Cmax 495 ± 293.9 ng/ml, mean AUC 69.7 ± 26.9 ng/ml min) compared to controls (mean Cmax 1,928 ± 560.8 ng/ml, mean AUC 165 ± 32.3 ng/ml/min; both p < 0.001). Furthermore, there were less grade 3 and no grade 4 adverse events in the SAP microsphere group. Tumor response was comparable between the groups. Conclusions: TACE with SAP microspheres leads to low plasma levels of the cytotoxic drug and therefore minimizes toxicity compared to conventional TACE.