Targeted cancer chemotherapy with arterial microcapsule chemoembolization: review of 1013 patients

A novel approach to inoperable or recurrent rectal cancer by chemoembolization: A new arrow in our quiver?

Purpose

Assess the feasibility, safety and efficacy of TACE with irinotecan loaded micro particles (debiri) for the treatment of locally advanced rectal cancer patients.

Results

We assessed the Edmonton Symptom Assessment System (ESAS). The tool is designed to assess nine common symptoms in cancer patients: pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, wellbeing and shortness of breath. The ESAS score was 7 in 10/12 (83%) patients before treatment and 6 in 2/12 (16.5%) patients. After treatment in 6/12 (50%) patients the score dropped to 3; 3/12 (33%) reported 4, 1/12 (8%) reported 2. All patients experienced local control disease with a degree of citoreduction; in 4 cases (33%) we observed outstanding responses with a dramatic reduction in the tumors size which led us to surgical radical resections.

Materials and methods

We run a prospective mono-institutional study where we recruited, 12 non- consecutive patients with histology confirmation of rectal cancer, inoperable and not treatable due to severe comorbidities, or pelvic recurrence/progression after curative treatment, chemotherapy, radiotherapy and/or surgery. Their performance status (PS) ECOG was 2-3. Twelve patients (10 male and 2 female) with a median age 71 (range 56-89) were recruited in the study.

Conclusions

The study has met the primary endpoint and showed encouraging activity. Debiri could be a possible option for locally advanced/inoperable or recurred rectal cancer patients. Further trials are warranted to validate this methodic in early stages.

Inferior mesenteric artery chemoembolization and chemotherapy for advanced rectal cancer: report of a clinical case

Patients with advanced and incurable colorectal cancer have a very poor prognosis. Curative-intent resection was performed in 70%-90% of cases in reported series of colorectal cancer, sometimes after neoadjuvant chemotherapy and radiotherapy. The remaining 10%-30% of patients are treated with palliative intent, where treatment is aimed at relieving disease-related symptoms and improving quality of life. The provision of palliative care for these patients is complicated and outcomes are often disappointing. Although there are many available options including a variety of surgical and nonsurgical interventions, the best management remains controversial. Transarterial chemoembolization with irinotecan-loaded drug-eluting beads (DEBIRI) is an effective, minimally invasive procedure performed by interventional radiologists that allows intra-arterial drug delivery to stop vascular feeding and exert local cytotoxic effects. We here report on a patient treated with DEBIRI followed by systemic chemotherapy with the FOLFOX regimen for locally advanced, inoperable colorectal cancer.

Primary non-Hodgkin's lymphoma of the prostate with intractable hematuria: A case report and review of the literature

Cases of primary non-Hodgkin’s lymphoma of the prostate are globally rare. The present study reports a case of prostatic diffuse large B-cell lymphoma (DLBCL) with intractable hematuria in a 75-year-old male. The patient presented with difficulties in urination and gross hematuria. A prostate biopsy was performed immediately, followed by conservative treatment for bleeding. A bilateral iliac arteriography and chemoembolization were then performed as emergency procedures under local anesthesia due to significant bleeding and a sharply decreased blood pressure, indicating the failure of the conservative treatment. Consequently, the bleeding was effectively controlled. Pathological examination of the prostate biopsy confirmed the presence of a DLBCL of non-germinal center B-cell origin. Immunohistochemical examination demonstrated cluster of differentiation (CD)20(++), CD3(+), leukocyte common antigen(+++), B-cell lymphoma-2(+) and prostate-specific antigen(−) results. Due to the poor general condition and low hemoglobin levels of the patient, a low-dose Rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) chemotherapy regimen was administered. Subsequent to three courses of chemotherapy, the patient achieved complete remission. In conclusion, combining R-CHOP and bilateral selective iliac arterial chemoembolization could be a safe and effective way to treat patients with non-Hodgkin’s lymphoma of the prostate and intractable hematuria.

Effect of alginate-chitosan sustained release microcapsules for transhepatic arterial embolization in VX2 rabbit liver cancer model

Two lipid-solid dispersion loading Norcantharidin sustained-released microspheres of alginate-chitosan (NCTD/LSD-ACMs) were prepared via the emulsification-gelation method. The effects of microspheres for transarterial hepatic chemoembolization were evaluated in VX2 rabbit liver cancer model. The VX2 animal model was established by biopsy needle, divided randomly into four groups, and disposed with three preparations including NCTD/LSD-ACMs (60-120 μm), NCTD/LSD-ACMs(120-200 μm), and NCTD solution through the hepatic arteries compared with the untreated group (control group). The serum of all rabbits before and at 3, 7, and 14 days after embolization was collected to determine the level of aspartate aminotransferase (AST). The AST level increased in the three treated groups on the first day compared with the control group (p < 0.05), and was higher in the two embolization groups (with no significant difference, p >0.05) than that in the NCTD group (p < 0.05). The tumor growth rates, which were significantly decreased in the two embolization groups compared with that in the control group, and the degree of liver cell necrosis assessed by the histopathological specimens, were used to evaluate the embolization effect. Liquefactive necrosis and coagulative necrosis were observed in the two embolization groups. The results showed that NCTD/LSD-ACMs are a potential candidate for embolization of liver cancer.

The antitumor effect of a new docetaxel-loaded microbubble combined with low-frequency ultrasound in vitro: preparation and parameter analysis

PURPOSE

To develop a novel docetaxel (DOC)-loaded lipid microbubbles (MBs) for achieving target therapy and overcoming the poor water-solubility drawback of DOC.

METHODS

A novel DOC-loaded microbubble (DOC + MB) was prepared by lyophilization and the physicochemical properties including ultrasound contrast imaging of the liver were measured. The anti-tumor effect of the DOC + MBs combined with low-frequency ultrasound (LFUS; 0.8 Hz, 2.56 W/cm², 50% cycle duty) on the DLD-1 cancer cell line was examined using an MTT assay.

RESULTS

The physicochemical properties of the two tested formats of DOC + MBs (1.0 mg and 1.6 mg) was shown: concentration, (6.74 ± 0.02) × 10⁸ bubbles/mL and (8.27 ± 0.15) × 10⁸ bubbles/mL; mean size, 3.296 ± 0.004 μm and 3.387 ± 0.005 μm; pH value, 6.67 ± 0.11 and 6.56 ± 0.05; release rate, 3.41% and 12.50%; Zeta potential, -37.95 ± 7.84 mV and -44.35 ± 8.70 mV; and encapsulation efficiency, 54.9 ± 6.21% and 46.3 ± 5.69%, respectively. Compared with SonoVue, the DOC + MBs similarly enhanced the echo signal of the liver imaging. The anti-tumor effect of the DOC + MBs/LFUS group was significantly better than that of DOC alone and that of the normal MBs/LFUS groups.

CONCLUSIONS

The self-made DOC + MBs have potential as a new ultrasound contrast agent and drug-loaded microbubble, and can obviously enhance the antitumor effect of DOC under LFUS exposure.

Therapeutic ultrasonic microbubbles carrying paclitaxel and LyP-1 peptide: preparation, characterization and application to ultrasound-assisted chemotherapy in breast cancer cells

The aim of this work was to develop a novel targeted drug-loaded microbubble (MB) and to investigate its chemotherapy effect in vitro. Paclitaxel (PTX)-loaded lipid MBs were prepared by a mechanical vibration technique. The LyP-1, a breast tumor homing peptide, was coated onto the surface of PTX-loaded MBs through biotin-avidin linkage. The resulting targeted drug-loaded MBs were characterized and applied to ultrasound-assisted chemotherapy in breast cancer cells. Our results showed the ultrasonic MBs were able to achieve 43%-63% of drug encapsulation efficiency, depending on drug loading amount. The binding affinity assay indicated the attachment of targeted MBs to human MDA-MB-231 breast cancer cells was highly efficient and stable even with ultrasonic irradiation on. The cellular uptake efficiency of payload in targeted MBs was 3.71-, 4.95-, 7.43- and 7.66-fold higher than that of non-targeted MBs at the applied ultrasound time of 30, 60, 90 and 120 s, respectively. In addition, the cell proliferation inhibition assay showed the cell viability of targeted PTX-loaded MBs was significantly lower than that of non-targeted PTX-loaded MBs and non-targeted unloaded MBs when ultrasound was utilized. In conclusion, the study indicated the LyP-1-coated PTX-loaded MBs significantly increased the antitumor efficacy and can be used as a potential chemotherapy approach for ultrasound-assisted breast cancer treatment.

Comparative study of chemoembolization loadable beads: in vitro drug release and physical properties of DC bead and hepasphere loaded with doxorubicin and irinotecan

PURPOSE

To characterize in vitro the loadability, physical properties, and release of irinotecan and doxorubicin from two commercially available embolization microspheres.

MATERIALS AND METHODS

DC Bead (500-700 microm) and Hepasphere (400-600 microm) microspheres were loaded with either doxorubicin or irinotecan solutions. Drug amount was quantified with spectrophotometry, bead elasticity was measured under compression, and bead size and loading homogeneity were assessed with microscopy image analysis. Drug release was measured over 1-week periods in saline by using a pharmacopeia flow-through method.

RESULTS

Almost complete drug loading was obtained for both microsphere types and drugs. Doxorubicin-loaded DC Beads maintained their spherical shape throughout the release. In contrast, Hepaspheres showed less homogeneous doxorubicin loading and, after release, some fractured microspheres. Incomplete doxorubicin release was observed in saline over 1 week (27% +/- 2 for DC beads and 18% +/- 7 for Hepaspheres; P = .013). About 75% of this amount was released within 2.2 hours for both beads. For irinotecan, complete release was obtained for both types of beads, in a sustained manner over 2-3 hours for DC Beads, and in a significantly faster manner as a 7-minute burst for Hepaspheres.

CONCLUSIONS

The two drug-eluting microspheres could be efficiently loaded with both drugs. Incomplete doxorubicin release was attributed to strong drug-bead ionic interactions. Weaker interactions were observed with irinotecan, which led to faster drug release.

Self assembled magnetic PVP/PVA hydrogel microspheres; magnetic drug targeting of VX2 auricular tumours using pingyangmycin

Chemotherapy in cancer treatment is associated with serious side effects and as a result there is great interest in research aimed at bringing down the level of systemic cytotoxicity. With advances in material science, magnetic drug targeting has emerged as one of the viable ways of attaining this. In this study, we used self assembled PVP/PVA magnetic hydrogel microspheres to deliver pingyangmycin (Bleomycin A5) to rabbit auricular VX2 tumours in the presence of a 0.5 T permanent magnet both during and 24 h after perfusion. A total of 22 New Zealand white rabbits ranging from 13 to 16 weeks and weighing 2.5-3.0 kg (2.46 +/- 0.2) successfully implanted with tumours 200-300 mm2 in size were used. In group D (1 mg pingyangmycin in 50 mg ferrofluid without a magnet) 2 weeks post treatment, there was statistically significant difference compared to the control (p = 0.05) in favor of group D. However, when compared to the group with 1 mg pingyangmycin(BLM) in 50 mg of ferrofluid and 0.5 mg (BLM) in 50 mg ferrofluid both with a permanent magnet in place for 24 h, the statistically significant difference was in favor of combined treatment, i.e. ferrofluid carrying drug in presence of a permanent magnet (p = 0.01). The microspheres in conjunction with the magnet did deliver pingyangmycin to the tumour and hence may be of use in future as far as magnetic drug targeting is concerned. However, more studies are still required to establish biodistribution and biostability not to forget drug release of ferrofluid of different chemotherapeutic agents available.

Development of carbonyl iron/ethylcellulose core/shell nanoparticles for biomedical applications

A reproducible method for the preparation of mixed colloidal nanoparticles, consisting of a magnetic carbonyl iron nucleus and a biocompatible ethylcellulose latex shell, is described in this article. The heterogeneous structure of the particles can confer them both the possibility of being used as drug delivery systems and the responsiveness to external magnetic fields, allowing a selective guidance of drug molecules to specific target tissues without a concurrent increase in its level in healthy tissues. The preparation method is based on an emulsion solvent evaporation process. A complete physicochemical characterization of the composite particles was carried out, and this preliminary investigation showed that the surface behavior of the core/shell particles is similar to that of bare ethylcellulose particles. This was confirmed, in particular, by zeta potential determinations as a function of pH and ionic strength. This fact points to the ethylcellulose shell efficiently coating carbonyl iron, and leading to composite particles which, from the electrokinetic point of view, are almost indistinguishable from latex. The thermodynamic analysis agrees with the electrokinetic one in suggesting that the coverage has been complete, since the components of the surface free energy of mixed particles coincide almost exactly with those corresponding to the cellulose-based pseudolatex. Moreover, the hydrophilic nature of carbonyl iron is modified and the particles become hydrophobic, just like the latex, when they are covered by ethylcellulose. The magnetic behaviors of the carbonyl iron and composite particles were also checked, and the similarities between both types of particles were demonstrated, except that the polymeric shell reduces the magnetization of the sample.

Surgical management of metastatic spine tumors

Recent advances in diagnostic tests and radiologic imaging, and the development of novel chemotherapeutic agents and radiation methods have greatly altered the treatment options in patients who have spinal tumors. Improvements in fundamental understanding of the mechanisms of bone metastases, developments in spinal instrumentation, and recent introduction of recombinant bone morphogenetic proteins for spinal reconstruction offer promising strategies in selected patients. Clear applications of the fundamental surgical oncology still apply to spinal tumors. This article considers recent advances in management of the metastatic tumors to the spine.

Chemoembolization Using Cisplatin Crystals as Neoadjuvant Treatment of Oral Cancer

Chemoembolization for cancer of the head and neck has been used very rarely in the past owing to local characteristics and risks. By combining the antineoplastic activity and embolizing effect in the same drug, a more routine use seems possible. A cisplatin suspension in normal saline (5 mg in 1 mL) with precipitation of microembolizing cisplatin crystals and without additional drugs was prepared. The cisplatin dosage was 150 mg/m2, the maximum absolute dose 300 mg, and the maximum amount of fluid 60 mL. One hundred and three consecutive patients with previously untreated squamous cell carcinomas of the oral cavity and the anterior oropharynx were treated in a neoadjuvant setting with superselective chemoembolization using the cisplatin suspension. Acceptance by the patients has been excellent with no refusal. Overall response after one intervention has been 73%, with 18.5% showing pathological complete remissions. The highest response rates could be seen in T1-3 tumors and tumors of the oral tongue and floor of the mouth. Measurable acute systemic toxicity has been low. Postembolization syndrome, especially swelling, had to be observed carefully. There have been 3.5% interventional and 10% local complications, which could be significantly reduced by the use of this procedure only in cancers of the oral tongue, floor of the mouth, and mandibular alveolar ridge. Chemoembolization of cancer in the head and neck area can be carried out regularly and safely using this method, and it is highly effective. It could be used as an induction before definitive surgery or radiotherapy. Further investigation is mandatory to assess the potential of chemoembolization for the improvement of local control and survival.

Newtonian fluid meets an elastic solid: coupling lattice Boltzmann and lattice-spring models

We integrate the lattice Boltzmann model (LBM) and lattice spring model (LSM) to capture the coupling between a compliant bounding surface and the hydrodynamic response of an enclosed fluid. We focus on an elastic, spherical shell filled with a Newtonian fluid where no-slip boundary conditions induce the interaction. We calculate the "breathing mode" oscillations for this system and find good agreement with analytical solutions. Furthermore, we simulate the impact of the fluid-filled, elastic shell on a hard wall and on an adhesive surface. Understanding the dynamics of fluid-filled shells, especially near adhesive surfaces, can be particularly important in the design of microcapsules for pharmaceutical and other technological applications. Our studies reveal that the binding of these capsules to specific surfaces can be sensitive to the physical properties of both the outer shell and the enclosed fluid. The integrated LBM-LSM methodology opens up the possibility of accurately and efficiently capturing the dynamic coupling between fluid flow and a compliant bounding surface in a broad variety of systems.

Absorption characteristics of compounds with different molecular weights after application to the unilateral kidney surface in rats

The aim of the present study is to clarify the absorption mechanism of a drug from the kidney surface membrane in rats. We studied the absorption characteristics of phenolsulfonphthalein (PSP) and other compounds with different molecular weights after their application to the rat kidney surface in vivo, employing a cylindrical diffusion cell (i.d. 6 mm, area 0.28 cm(2)). The time course of free PSP amounts remaining in the diffusion cell obeyed first-order kinetics at a dose of 1 mg, and its rate constant k(a) was calculated to be 0.0137 min(-1). Absorption ratios of PSP in 4 h were calculated (from the amount recovered from the diffusion cell) to be 91.4, 96.4 and 97.7% at doses of 0.5, 1 and 1.5 mg, respectively. The area under the curve for the plasma concentration profile of free PSP was proportional to the application dose. It is thus suggested that the absorption process of PSP from the rat kidney surface does not approach saturation at a dose of 1.5 mg. Also, no significant difference was seen in the k(a) values within the dose range of 0.5-1.5 mg, which were estimated by curve-fitting the plasma concentration profiles of free PSP in a two-compartment model with first-order absorption. Furthermore, we examined the importance of molecular weight on the absorption from the kidney surface using fluorescein isothiocyanate-dextrans (FDs) with molecular weights of 4400 (FD-4), 11,000 (FD-10), 40,500 (FD-40) or 69,000 (FD-70), including the organic anions bromphenol blue and bromosulfonphthalein. The absorption ratios of FDs from the rat kidney surface in 6 h decreased with an increase in the molecular weight (76.1% for FD-4, 54.4% for FD-10, 11.5% for FD-40 and 3.9% for FD-70). A linear relationship was observed between k(a) and the reciprocal value of z the square root of the molecular weight of these compounds. The limit of absorption from the rat kidney surface was extrapolated to be at a molecular weight of approximately 130,000.

Further studies on the kidney- and site-selective delivery of 5-fluorouracil following kidney surface application in rats

The present study was undertaken to elucidate the kidney- and site-selective delivery of 5-fluorouracil (5-FU) following kidney surface application in rats. We selected an experimental system utilizing a cylindrical diffusion cell attached to the right kidney surface. After 5-FU was applied to this surface, approximately 60% was absorbed in 180 min. A semi-log plot of the remaining amount of 5-FU in the diffusion cell gave a straight line. The cumulative amount of urinary excretion of 5-FU for up to 180 min from the right ureter was significantly higher than that from the left ureter. On the other hand, the cumulative amount of urinary excretion of 5-FU from the right and left ureters after intravenous administration of the drug was similar. The 5-FU concentration at four sites in the right kidney after intravenous administration was also similar, while the drug was site-selectively delivered in the kidney after its surface application. 5-FU accumulated at the site under the diffusion cell was rapidly eliminated after its removal from the diffusion cell. From these results, we demonstrated that the absorption of 5-FU on the kidney surface in rats is explained mostly by passive diffusion. It was further elucidated that kidney surface application of this drug in rats results in its the kidney- and site-selective delivery.

Delivery of an anticancer drug and a chemosensitizer to murine breast sarcoma by intratumoral injection of sulfopropyl dextran microspheres

Intratumoral injection of controlled-release microsphere formulations of anticancer compounds has the potential to selectively increase tumour exposure to drugs. This work aimed to evaluate the therapeutic effect and toxicity of microsphere formulations containing the anticancer drug, doxorubicin, in a murine tumour model. The effect of co-administration of verapamil, a P-glycoprotein modulator or chemosensitizer, was investigated. Initial in-vitro studies confirmed the ability of verapamil to enhance the accumulation of both doxorubicin and [(99mTc)]sestamibi, also a P-glycoprotein substrate, in EMT6 murine breast sarcoma cells and a doxorubicin-selected multidrug-resistant variant, EMT6/AR1.0. Ex-vivo studies using confocal microscopy demonstrated release of doxorubicin from microspheres and diffusion of the drug through tissue. For in-vivo studies, EMT6 and EMT6/AR1.0 cells were grown in BALB/c mice. Following intratumoral injection of doxorubicin-loaded microspheres, alone or in combination with verapamil-loaded microspheres, the tumour diameter was measured serially as an indication of therapeutic effect, while the weight, appearance, and behaviour of the mice were monitored as an indication of general toxicity. Intratumoral injections of doxorubicin-loaded microspheres were tolerated much better than systemic administration of equivalent drug concentrations. There was a modest (up to 34%) delay of tumour growth compared with groups receiving no treatment or blank microspheres. Co-injection of verapamil microspheres with doxorubicin microspheres produced a moderate increase in toxicity but no further delay in tumour growth. Controlled-release microsphere formulations of anticancer agents administered intratumorally were an efficient way to deliver high drug doses to the tumour with little systemic toxicity.

Studies on alginate-chitosan microcapsules and renal arterial embolization in rabbits

Spherical and well-dispersed alginate-chitosan microcapsules, with a mean diameter of 77.28+/-0.93 microm (n=3), were prepared by the emulsification-gelation method. Adriamycin hydrochloride (ADM) was used as a model drug to investigate the drug loading capacity and release characteristics of the microcapsules. The drug/carrier ratio and chitosan concentration influenced the encapsulation efficiency of adriamycin. The adriamycin release from microcapsules was obviously different in 0.1 mol/l HCl from that in phosphate-buffered saline (PBS, pH 7.4). The drug was completely and rapidly released in 0.1 mol/l HCl, while it showed a sustained release after a burst release in PBS. The increase in chitosan concentration had no effect on adriamycin release in PBS. Using sulforhodamin B (SRB)-staining survival assay, the inhibition of adriamycin alginate-chitosan microcapsules (ADM-ACM) to different cancer cell lines (human BGC-823 cells, Bel-7402 cells and Hela cells) in vitro was determined. The inhibitory rate of ADM-ACM suspension to the three cell lines significantly outran that of ADM solution, no matter at high or low concentration. The effects of blank alginate-chitosan microcapsules (BACM) on renal arterial embolization were examined with transcatheter arterial embolization in rabbits. The angiogram and histopathological results indicated the blank microcapsules had excellent short- and long-term effects on renal arterial embolization.

Kidney- and site-selective delivery of 5-fluorouracil utilizing the absorption on the kidney surface in rats

The present study was undertaken to elucidate the kidney- and site-selective delivery of 5-fluorouracil (5-FU) utilizing the absorption on the kidney surface in rats. An experimental system utilizing a cylindrical diffusion cell attached to the right kidney surface was established. After intravenous administration of 5-FU, the concentration of 5-FU in the right and left kidneys was almost the same and was rapidly eliminated. After right kidney surface application of 5-FU, however, the concentration of 5-FU in the right kidney was significantly higher than in the left kidney and other tissues. The 5-FU concentration in four sites of the right kidney after intravenous administration was almost the same. In contrast, 5-FU was site selectively delivered in the kidney after kidney surface application. The blood concentration of 5-FU was low (<1.7 microg/ml) until 120 min after kidney surface application. The maximum blood concentration of 5-FU after kidney surface application was much lower than after intravenous administration.

Monocomponent chemoembolization in oral and oropharyngeal cancer using an aqueous crystal suspension of cisplatin

Intensification of intra-arterial chemotherapy with high-dose cisplatin and concomitant reduction of toxicity under the conditions of the head and neck was aimed at by combination of antineoplastic activity and embolizing effect in the same pharmacon. A cisplatin suspension in normal saline (5 mg in 1 ml) with precipitation of microembolizing cisplatin crystals was prepared. No additional pharmacons. Cisplatin dosage was 150 mg m(-2), maximum absolute dose 300 mg, maximum amount of fluid 60 ml. Thirty patients (UICC-Classification of tumours: I/2 patients, II/6, III/2; IV/20) were treated in a neoadjuvant setting with superselective chemoembolization using the cisplatin suspension. A control group (n=30) with the same tumour and nodal staging was treated with a usual cisplatin solution (150 mg m(-2) dissolved in 500 ml saline). In both groups, parallel intravenous infusion of sodium thiosulphate (9 g m(-2)). Endpoints were toxicity and response. Continuation of treatment by surgery or radiation. Overall remission was 70% in the study group and 46.7% in the control group after one cycle respectively. Systemic side-effects were very low (grade I WHO) in both groups. Side-effects were found to be similar to post-embolization syndrome (swelling, mild to moderate pain, leucocytosis without fever) in the study group. Chemoembolization in the head and neck area can be carried out routinely using this method.

Chemoembolization of oral and oropharyngeal cancer using a high-dose cisplatin crystal suspension and degradable starch microspheres

The aim of the study was to achieve intensification of intraarterial chemotherapy of head and neck cancer with high-dose cisplatin by establishing a new method of chemoembolization which can be routinely used without the earlier drawbacks of the method (low drug dosage due to early occlusion of the small head and neck vessels, danger of local damage). Thirty two patients with previously untreated oral and oropharyngeal squamous cell carcinomas of all stages were treated by at least one superselective chemoembolization via femoral approach using a new preparation format of 150 mg/m(2) cisplatin which is an aqueous crystal suspension. In defined cases, combination with the delivery of degradable starch microspheres (DSM). Systemic neutralization with sodium thiosulfate. Primary end points were tolerance and response. Subsequent treatment was surgery or radiation. Chemoembolization succeeded in all 37 interventions to date. Overall response after one cycle was 64.7% using the cisplatin crystal suspension only (n=17) and 86.6% using additional DSM chemoembolization (n=15), as assessed 3 weeks after treatment. Systemic toxicity was extremely low, local side-effects (pain, swelling, small necrosis) were pronounced after additional delivery of DSM. There have been three complications (tracheotomy due to swelling, temporary facial paralysis twice due to embolization of the geniculate ganglion). Using the high-dose cisplatin crystal suspension, chemoembolization can routinely be used in the head and neck area as neoadjuvant therapy. Response was better than with former comparable regimens. The additional delivery of DSM was complicated, restricted to certain areas and unreliable in the dosage needed and might be omitted, therefore.

Tumour embolization of the Vx2 rabbit head and neck cancer model with Dextran hydrogel and Holmium-poly(L-lactic acid) microspheres: a radionuclide and histological pilot study

INTRODUCTION

Intra-arterial embolization of unresectable malignant tumours with biodegradable microspheres is an effective way of selective anti-tumour therapy. Promising candidates are Dextran hydrogel (Dex) microspheres for chemo-embolization and Holmium-166 poly(L-lactic acid) (166HoPLA) microspheres for radio-embolization. This study was performed to investigate the distribution of intra-arterially injected microspheres both in vivo and histologically in order to establish an optimal size of particles for embolization of head and neck tumours.

MATERIAL

Twenty rabbits with Vx2 auricular tumours were embolized via the caudal auricular artery with 4 different batches of microspheres: Radioactive (166)HoPLA microspheres sieved between 20 and 50 microm and Dextran hydrogel microspheres sieved between 20 and 100 microm (Dex20), 30 and 100 microm (Dex30) or 50 and 100 microm (Dex50). Dex20 and Dex50 microspheres were labelled with 99mTechnetium in six cases.

METHODS

The average particle size of the microspheres was determined. The proportion of microspheres entrapped in the tumour was measured with a gamma camera. The distribution of microspheres around the primary tumour and spill of particles over into lungs or other organs was analysed from histological sections.

RESULTS

The mean particle diameter varied from 19 to 66 microm: (166)HoPLA 19+/-11 microm, Dex20 40+/-19 microm, Dex30 50+/-19 microm, Dex50 66+/-21 microm. The 19 microm(166)HoPLA particles proved inadequate for embolization as 51% spilled over into the lungs, whereas over 95% of the 40-66 microm Dex microspheres were retained within the primary tumour area. Particle density in lung tissues proved significantly lower for the Dex50 group. Stray emboli to the brain occurred in two rabbits.

CONCLUSION

The results of this investigation show that both Dextran hydrogel and holmium-166 poly(L-lactic acid) microspheres are potential candidates for embolization of head and neck cancer. In future studies, arterio-arteriolar anastomoses which might confound treatment should be identified and occluded. Particles with a number weighted mean diameter of at least 40 microm and a volume weighted mean size up to 70 microm should be used.

Intra-arterial embolization of head-and-neck cancer with radioactive holmium-166 poly(L-lactic acid) microspheres: an experimental study in rabbits

A total of 22 NZW rabbits with VX2 squamous cell carcinomas transplanted into the auricles were intra-arterially (i.a.) embolized with radioactive or inactive holmium-labelled poly(L-lactic acid) (HoPLA) microspheres with a mean diameter of 38-80 microm. The effects on tumour growth, the efficiency of i.a. infusion, the efficacy of retention of microspheres in the primary tumour and the excretion of free holmium-166 were analyzed. Complete tumour remissions were obtained in 79% and 86% following embolization with radioactive and inactive microspheres, respectively. Over 95% of the microspheres were retained in the tumour and the leaching of holmium-166 in urine and faeces was less than 0.1% in 2 days. The injection efficiency was not optimal, as 40% of the microspheres were retained in the cannulation system. Arterio-arteriolar connections should be detected and closed prior to embolization to prevent stray emboli from entering the brain. It is concluded that 166HoPLA microspheres are promising candidates for further studies on radio-embolization of unresectable head-and-neck cancer.

Triton-X-100-modified polymer and microspheres for reversal of multidrug resistance

Triton X-100 is a non-ionic detergent capable of reversing multidrug resistance (MDR) due to its interaction with cell membranes. However, it interacts with cells in a non-specific way, causing cytotoxicity. This work aimed to develop polymeric chemosensitizers that possess the ability to reverse MDR and lower toxic side effects. When being delivered to tumours, the polymeric chemosensitizers may also have longer retention times in tumours than the free detergent. Triton-X-100-immobilized dextran microspheres (T-MS) and inulin (T-IN) were prepared and characterized. Their cytotoxicity against multidrug-resistant Chinese hamster ovary cells (CH(R)C5) was compared with that of free Triton X-100 solutions. The in-vitro effect of the products on 3H-vinblastine accumulation by CH(R)C5 cells was determined. Both T-MS and T-IN showed a marked decrease in the cytotoxicity, as compared with free Triton solutions at equivalent concentrations. Drug accumulation by CH(R)C5 cells was increased over two fold in the presence of T-MS or T-IN. These results suggest that polymeric drug carriers with MDR-reversing capability and lower cytotoxicity may be prepared by immobilization of chemosensitizers.

Activity of doxorubicin covalently bound to a novel human serum albumin microcapsule

Doxorubicin is widely used in the treatment of human malignancies, however is associated with significant cardiac, bone marrow and gastro-intestinal toxicity. Delivery systems may ameliorate this toxicity and increase treatment specificity by increasing the proportion of drug delivered to sites of disease. We have developed a novel preparation of doxorubicin (Dox) covalently linked to a heat stabilised human serum albumin microparticle (HSAM) carrier (median particle diameter of 4 microm) and assessed its activity in 4 malignant cell lines.

MATERIALS AND METHODS

Doxorubicin microcapsules were compared with free doxorubicin in the rat carcinoma cell line, WRC256, and the human lines, OVCAR3, MCF7 and the Dox resistant MCF7/Dox, using a cell counting technique. IC50 were calculated from regression analysis of the resulting survival curves. Endocytosis of the microcapsules by cells in culture was observed. The rate of microcapsule uptake was assessed using dual wavelength filtered fluorescence microscopy and flow cytometry.

RESULTS

The mean IC50 following incubation with the Dox microcapsules was around 5 times greater than Dox for WRC256 (p < 0.001), MCF7 (p < 0.01) and for OVCAR3 (p < 0.01). MCF7/Dox was significantly more sensitive to Dox microcapsules than free Dox (p = 0.034). A negative correlation between the rate of microcapsule uptake and the IC50 values for each cell line in culture exists (r = -0.96, p = 0.04).

CONCLUSIONS

We conclude that: 1) Doxorubicin microcapsules retain activity in vitro and appear to overcome p-glycoprotein mediated Dox resistance. 2) The observed activity of Dox microcapsules correlates with the rate of particle uptake. Further studies in animal tumour models are in progress.

Extrahepatic regional chemotherapy: use of technetium-99m labeled macroaggregated albumin

The purpose of this study was to verify the applicability of nuclear techniques with technetium-99m labeled macroaggregated albumin (Tc-99m-MAA) in extrahepatic regional chemotherapy. Of 98 patients in whom arterial Port-a-caths were implanted by transcutaneous access, 13 were treated by regional extrahepatic chemotherapy (breast, one; pancreas, four; kidney, one; uterus, three; vagina, two; bladder, two). In all 13 patients, Tc-99m-MAA was slowly infused intraarterially. The examination showed the perfusion of the area with the neoplasm and excluded the presence of important misperfusions of Tc-99m-MAA to the nearest areas. To detect the presence of an arteriovenous shunt with systemic misperfusion, an anterior image of the thorax was obtained in all patients and an index of misperfusion was calculated. In 12 patients, the index was < 5%; in one patient it was about 40%. In conclusion, our preliminary experience concerns the monitoring of intraarterial infusion chemotherapy of extrahepatic districts. In all 13 patients, we evaluated the correct positioning of the intraarterial catheter and the distribution pattern of the arterial flow, with a semiquantitative indication of arteriovenous shunting. This method gave us an instrument of study that was inexpensive, harmless, and free of collateral complications.

In vitro investigation of ionic polysaccharide microspheres for simultaneous delivery of chemosensitizer and antineoplastic agent to multidrug-resistant cells

Insufficient intratumoral concentration of therapeutic agents and multidrug resistance are major factors responsible for failure of treatment of solid tumors. Simultaneous delivery of chemosensitizing and antineoplastic agents by microspheres could lead to enhanced chemotherapy of multidrug-resistant (MDR) tumors. Ionic polysaccharide microspheres derived from dextran were used to load chemosensitizers (e.g., verapamil) and anticancer drugs such as vinblastine. High drug loading was achieved for both a single agent and dual agents. The equilibrium drug loading was dependent on the ratio of the microspheres (MS) to the drug, as well as the relative affinity of the agents to the MS in the case of dual agents. The drug release from drug-MS involved hydration and swelling of the MS in addition to ion exchange. The effectiveness of MS-delivered chemosensitizers in the reversal of drug resistance was evaluated by measuring the uptake of [3H]vinblastine by MDR cells (CHRC5). The concomitant delivery of verapamil with vinblastine by the MS led to a 6-7-fold increase in the uptake of vinblastine, a level similar to the uptake obtained with free drug solutions. The results suggest that the antineoplastic and chemosensitizing agents were released effectively from the MS and the bioactivity of the chemosensitizer was preserved during the process.