Experimental and Preliminary Clinical Study of Real-Time Registration in Liver Tumors During Respiratory Motion Based on a Multimodality Image Navigation System.

PURPOSE: To develop a fusion imaging system that combines ultrasound and computed tomography for real-time tumor tracking and to validate the accuracy of performing registration via this approach during a specific breathing phase. MATERIALS AND METHODS: The initial part of the experimental study was performed using iodized oil injection in pig livers and was focused on determining the accuracy of registration. Eight points (A1-4 and B1-4) at different positions and with different target sizes were selected as target points. During respiratory motion, we used our self-designed system to perform the procedure either with (experimental group, E) or without (control group, C) the respiratory monitoring module. The registration errors were then compared between the 2 groups and within group E. The second part of this study was designed as a preliminary clinical study and was performed in 18 patients. Screening was performed to determine the combination of points on the body surface that provided the highest sensitivity to respiratory motion. Registration was performed either with (group E) or without (group C) the respiratory monitoring module. Registration errors were compared between the 2 groups. RESULTS: In part 1 of this study, there were fewer registration errors at each point in group E than at the corresponding points in group C (P < .01). In group E, there were more registration errors at points A1 and B1 than at the other points (P < .05). There was no significant difference in registration errors among the remaining points. During part 2 of the study, there was a significant difference in the registration errors between the 2 groups (P < .01). CONCLUSIONS: Real-time fusion registration is feasible and can be accurately performed during respiratory motions when using this system.

Whole tumor ablation of locally recurred hepatocellular carcinoma including retained iodized oil after transarterial chemoembolization improves progression-free survival.

OBJECTIVES: To evaluate and compare clinical outcomes of two different radiofrequency ablation (RFA) methods for locally recurred hepatocellular carcinoma (LrHCC) after locoregional treatment. METHODS: Our institutional review board approved this study with a waiver of informed consent. A total of 313 patients previously treated with transarterial chemoembolization (TACE) (n = 167) and RFA (n = 146) with a single LrHCC ≤ 3 cm was included from five tertiary referral hospitals. RFA was done for LrHCCs using either viable tumor alone ablation (VTA) method (VTA: n = 61 in the TACE group and n = 127 in the RFA group) or whole tumor ablation (WTA) method which includes both viable tumor and retained iodized oil or previously ablated zone (WTA: n = 106 in the TACE group and n = 19 in the RFA group). Local tumor progression (LTP)-free survival as well as progression-free survival (PFS) were estimated using the Kaplan-Meier method, and prognostic factors were evaluated using the Cox proportional hazards regression model. RESULTS: In 167 patients with LrHCC who underwent TACE, the 5-year LTP-free survival after RFA was significantly higher with the VTA method than with the WTA method (26.9% vs. 87.8%; p < 0.001; hazard ratio (HR) = 8.53 [4.16-17.5]). The estimated 5-year PFS after RFA for LrHCC after TACE using the VTA method was 5.7%, which was significantly lower than that with the WTA method (26.4%) (p = 0.014; HR = 1.62 [1.10-2.38]). However, in 146 patients with LrHCC after initial RFA, there were no significant differences in cumulative incidence of LTP (p = 0.514) or PFS (p = 0.905) after RFA between the two ablation methods. CONCLUSIONS: For RFA of LrHCC after TACE, the WTA method including both viable tumor and retained iodized oil could significantly lower LTP and improve PFS than VTA. KEY POINTS: • Whole tumor ablation (WTA) could provide significantly better local tumor control for locally recurred HCC (LrHCC) after TACE than viable tumor alone ablation (VTA). • WTA for LrHCC after TACE could also provide significantly better progression-free survival than VTA. • Regarding LrHCC after RFA, VTA would provide a comparable clinical outcome to WTA.

Preventative effects of prostaglandin E1 in combination with iodized olive oil on liver fibrosis after transcatheter arterial chemoembolization in a rabbit model of CCl4-induced liver fibrosis.

To explore the preventative effects of prostaglandin E1 (PGE1) on a rabbit model of CCl4-induced liver fibrosis after transcatheter arterial chemoembolization (TACE), we generated a rabbit model of CCl4-induced liver fibrosis by treatment with 40% CCl4 in iodized olive oil for 16 weeks. Body mass and serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein (TP), albumin (ALB), albumin:globulin ratio (A:G), total bilirubin (TBIL), and direct bilirubin (DBIL) were measured. After TACE, the levels of hyaluronic acid (HA), procollagen III (PC III), laminin (LN), and collagen IV (IV-C) were measured, and the severity of liver fibrosis as well as the morphology of liver tissues were determined. Body mass in the model group was significantly decreased from 10 to 16 weeks, and the serum levels of ALT, AST, TP, TBIL, and DBIL levels were significantly increased while the model was being generated; the levels of ALB and A:G were significantly decreased. After TACE, serum levels of HA, PC III, and LN in the group injected with 1.0 mL iodized olive oil (Group B) were higher than in the group that were injected with 1.0 mL iodized olive oil + 0.2 mL PGE1 (Group C), whereas the serum levels of IV-C were lower. The severity of liver fibrosis was ameliorated in Group C. The combination of PGE1 and iodized olive oil prevented the development of liver fibrosis following TACE.

Radiographic lymphangiography in the dog using iodized oil.

The objective of this study was to develop a clinically applicable technique to visualize the medial retropharyngeal, superficial cervical, axillary, superficial inguinal and medial iliac lymph nodes on radiographs. Direct and indirect lymphangiographic methods using iodized oil were repeated for a minimum of five times at eight different locations to enhance the various lymph nodes, using 16 healthy research dogs. Direct lymphangiography, although more invasive than indirect lymphangiography, resulted in uniform contrast uptake by an increased number of nodes and increased enhancement of the lymphatic vasculature, and is recommended for imaging the medial iliac and superficial cervical lymph nodes. Side effects were more frequent after indirect lymphangiography (10/20 injection sites) than after direct lymphangiography (3/16 injection sites). The small size of afferent lymphatic vessels did not allow use of direct lymphangiography for the medial retropharyngeal, axillary and superficial inguinal lymph nodes; however, indirect techniques allowed adequate visualization of these nodes.

Block-copolymer-stabilized iodinated emulsions for use as CT contrast agents.

The objective of this study was to develop radiopaque iodinated emulsions for use as CT blood pool contrast agents. Three hydrophobic iodinated oils were synthesized based on the 2,3,5-triiodobenzoate moiety and formulated into emulsions using either phospholipids or amphiphilic polymers, i.e. Pluronic F68 and poly(butadiene)-b-poly(ethylene glycol) (PBD-PEO), as emulsifiers. The size, stability and cell viability was investigated for all stabilized emulsions. Three emulsions stabilized with either lipids or PBD-PEO were subsequently tested in vivo as a CT blood pool contrast agent in mice. While the lipid-stabilized emulsions turned out unstable in vivo, polymer-stabilized emulsions performed well in vivo. In blood, a contrast enhancement of 220 Hounsfield Units (HU) was measured directly after intravenous administration of 520 mg I/kg. The blood circulation half-life of a PBD-PEO stabilized emulsion was approximately 3 h and no noticeable in vivo toxicity was observed. These results show the potential of above emulsions for use as blood pool agents in contrast enhanced CT imaging.

Liposomes coloaded with iopamidol/lipiodol as a RES-targeted contrast agent for computed tomography imaging.

PURPOSE: The need for computed tomography (CT) of reticuloendothelial system (RES)-rich organs such as the liver is increasing, particularly in patients with suspected hepatic metastasis. CT images of the liver have been improved by encapsulating currently used, water-soluble iodine contrast agent in liposomes. The present study was performed to investigate a possibility to overcome the limitations of entrapped iodine in liposomes by preparing liposomes co-loaded with iopamidol, a water-soluble iodinated compound, and lipiodol, an iodized oil. METHODS: Iopamidol and lipiodol were simultaneously loaded in liposomes by modified reverse-phase evaporation method. The entrapped iodine concentration, mean particle size and polydispersity index of resulting liposomes were evaluated. Following intravenous injection of these liposomes into rats, CT scanning was performed. RESULTS: Simultaneous loading of iopamidol and lipiodol into liposomes resulted in entrapped iodine concentrations as high as 49.2 iodine mg/ml. The mean particle size was 280 nm, and the mean polydispersity index was 0.230. CT scanning with these iopamidol/lipiodol (I/L) liposomes into rats resulted in more pronounced and more persistent increases in RES-rich organs, liver and spleen, compared with free liposomes or liposomes loaded with iopamidol alone. CONCLUSIONS: These findings indicate that I/L liposomes have the potential to allow thorough CT examination of RES-rich organs.

Biodistribution of phenylboric acid derivative entrapped lipiodol and 4-borono-2-18F-fluoro-L-phenylalanine-fructose in GP7TB liver tumor bearing rats for BNCT.

A new phenylboric acid derivative entrapped lipiodol (PBAD-lipiodol) was developed as a boron carrier for the boron neutron capture therapy (BNCT) of hepatoma in Taiwan. The biodistribution of both PBAD-lipiodol and BPA-fructose was assayed in GP7TB hepatoma-bearing rat model. The highest uptake of PBAD-lipiodol was found at 2h post injection. The application of BNCT for the hepatoma treatment in tumor-bearing rats is suggested to be 2-4h post PBAD-lipiodol injection.

The antitumor effect and hepatotoxicity of a hexokinase II inhibitor 3-bromopyruvate: in vivo investigation of intraarterial administration in a rabbit VX2 hepatoma model.

OBJECTIVE: The purpose of this study was to compare the antitumor effect and hepatotoxicity of an intraarterial delivery of low-dose and high-dose 3-bromopyruvate (3-BrPA) and those of a conventional Lipiodol-doxorubicin emulsion in a rabbit VX2 hepatoma model. MATERIALS AND METHODS: This experiment was approved by the animal care committee at our institution. VX2 carcinoma was implanted in the livers of 36 rabbits. Transcatheter intraarterial administration was performed using low dose 3-BrPA (25 mL in a 1 mM concentration, n = 10), high dose 3-BrPA (25 mL in a 5 mM concentration, n = 10) and Lipiodol-doxorubicin emulsion (1.6 mg doxorubicin/ 0.4 mL Lipiodol, n = 10), and six rabbits were treated with normal saline alone as a control group. One week later, the proportion of tumor necrosis was calculated based on histopathologic examination. The hepatotoxicity was evaluated by biochemical analysis. The differences between these groups were statistically assessed with using Mann-Whitney U tests and Kruskal-Wallis tests. RESULTS: The tumor necrosis rate was significantly higher in the high dose group (93% +/- 7.6 [mean +/- SD]) than that in the control group (48% +/- 21.7) (p = 0.0002), but the tumor necrosis rate was not significantly higher in the low dose group (62% +/- 20.0) (p = 0.2780). However, the tumor necrosis rate of the high dose group was significantly lower than that of the Lipiodol-doxorubicin treatment group (99% +/- 2.7) (p = 0.0015). The hepatotoxicity observed in the 3-BrPA groups was comparable to that of the Lipiodol-doxorubicin group. CONCLUSION: Even though intraarterial delivery of 3-BrPA shows a dose-related antitumor effect, single session treatment seems to have limited efficacy when compared with the conventional method.

[Three (3) cases of advanced hepatocellular carcinoma (HCC) treated successfully by transcatheter arterial chemoembolization (TACE) using lipiodol and a fine- powder formulated cisplatin (DH)].

Although great advances have been made in therapies for patients with hepatocellular carcinoma(HCC), the prognosis for advanced HCC remains poor because liver transplantation is not applicable. We report three(3)cases of HCC treated successfully by transcatheter arterial chemoembolization(TACE)using a suspension of Lipiodol and a fine powder formulation of cisplatin(DDPH). Case No. 1 was a 64-year-old man with multiple HCCs who had undergone several sessions of TACE using doxorubicin(ADM). During the course of the treatment, the HCC became intractable and residual tumors were observed repeatedly within a short period. He was then treated by TACE using DDPH instead of ADM. The tumor marker levels decreased in response to this treatment and no recurrence of HCC has been observed. Case No. 2 was a 71-year-old man who had been diagnosed with multiple HCCs in 2004. He was treated by TACE with ADM, but the procedure had to be repeated more than three(3)times due to residual tumors. Despite the treatment, the tumor grew gradually and a formation of tumor thrombus was observed in the inferior vena cava. Both the tumor and tumor thrombus reduced in size after TACE with DDPH. Case No. 3 was a 52-year-old man who had been monitored diabetes mellitus and chronic hepatitis at our hospital. Multiple HCCs were diagnosed in 2006. TACE with DDPH was performed as an initial therapy. The tumors shrank or disappeared in response to this treatment. These results propose that TACE with DDHP against advanced HCC is effective.

Dosimetric evaluation and therapeutic response to internal radiation therapy of hepatocarcinomas using iodine-131-labelled lipiodol.

OBJECTIVE: Vectorized internal radiation therapy using lipiodol-labelled with iodine-131 (131 I-lipiodol) is an effective treatment for inoperable hepatocellular carcinomas. However, few dosimetric data are available based on this approach. We have developed a dosimetric protocol based on scintiscan imaging and that is designed to calculate the tumoural absorbed dose during the treatment of hepatocarcinoma by 131 I-lipiodol. METHODS: This concept was developed on a gamma-camera coupled to a computed tomography scanner. It integrates corrections for attenuation phenomena, scattering and dead time. The tumoural absorbed dose calculation was carried out according to the Medical Internal Radiation Dose Committee formalism. This protocol was applied to a series of 41 patients in the framework of a retrospective study. RESULTS: The mean tumoural absorbed dose with the first treatment is 248 Gy (+/-176), as opposed to 152 Gy (+/-122) during the second. We highlighted a correlation between the tumoural absorbed dose, calculated in tomographic mode, and the morphological response to the first treatment (P=0.0071). Moreover, a tumoural absorbed dose of 280 Gy seems to be an effective absorbed dose threshold in our population. Above this absorbed dose, 84% of the patients are responders after the first treatment, whereas no responses are recorded below this threshold. CONCLUSION: These results are promising because, for the first time, they allow us to predict the effectiveness of a treatment by 131 I-lipiodol. They are required to be validated on a broader exploratory trial, including a dosimetric study of the critical organs, so an individualized dosimetry can be defined for each patient.

Influence of lipiodol agent on proton beam range in radiotherapy planning using computed tomography for hepatocellular carcinoma.

PURPOSE: To evaluate the influence of lipiodol on the proton beam range, which has not yet been determined. METHODS AND MATERIALS: Two computed tomography (CT) data sets were obtained with a T25-flask containing lipiodol and water that was placed above a water phantom. The plan with the lipiodol CT images was performed, and then a verification plan was applied to the water CT images. The actual proton beam ranges in the lipiodol and water were measured under same conditions, and we compared the calculated proton beam range in the treatment planning system with measured values. RESULTS: The calculated distal range in the treatment planning system was 12 cm in water, which was 3.87 cm longer than that in lipiodol (8.13 cm). In contrast, the measured distal range was 12 +/- 0.01 cm in water, which was 0.21 +/- 0.01 cm longer than that of lipiodol (11.78 +/- 0.01 cm). A 3.65 +/- 0.01-cm range shift was found in the calculated range compared with the measured range. For 10 hepatocellular carcinoma patients, the distal range in the verification plan with the corrected CT images in which the Hounsfield unit (HU) value of lipiodolized lesion was replaced with the average HU value of the surrounding tissue was 0.61 +/- 0.26 cm (range, 0.26-0.99) longer than that in the plan with uncorrected CT images. CONCLUSIONS: It could be relevant for the purposes of range calculation of proton beams in the treatment planning system that the HU value of a lipiodolized lesion is replaced by the average HU value of the surrounding normal tissue.

Liquid embolisation material reduces the delivered radiation dose: a physical experiment.

OBJECTIVE: To test a new hypothesis that the glue/contrast admixture used for embolisation reduces the dose delivered to AVMs using an experimental model. METHOD: A model was created using a block of "solid water" (6 x 5 x 2 cm) with twelve wells of different depths. Different concentrations of the glue admixture (Enbucrilate + Lipiodol) were used. The model was irradiated using a 5MV beam with a clinical LINAC system and the dose was checked upstream and downstream. Dose was measured using Kodak XV film, a Vidar 16 bit film scanner and software for therapeutic film dosimetry measurements (RIT software). RESULTS: The radiation dose varied with the distance beyond the glue solid water interface. For distances of 0, 2 and 5 mm to the film, the mean reduction was 13.65% (SD = 2.94), 6.87% (SD = 1.95) and 1.75% (SD = 1.14), respectively. There was also correlation with the Lipiodol concentration in the mixture. The maximum reductions for 80, 50 and 20% Lipiodol concentrations were 16.1% (SD = 1.32), 14.85% (SD = 0.98) and 10% (SD = 1.21), respectively. There was no correlation between the glue depth and the dose delivered. CONCLUSION: The hypothesis that the glue mixture used for embolisation reduces the radiation dose delivered was experimentally confirmed with this study.

Temporal evolution of spinal cord infarction in an in vivo experimental study of canine models characterized by diffusion-weighted imaging.

PURPOSE: To determine the temporal evolution of diffusion abnormalities of in vivo experimental spinal cord infarction. MATERIALS AND METHODS: Guided by a digital subtract angiography (DSA) monitor, an agent of 1:1 match of lipiodol and diatrizoate meglumine was injected into bilateral T9-11 intercostal arteries of six dogs to embolize the spinal branches of intercostal arteries and establish the canine spinal cord infarction models. The progression of experimental spinal cord infarction was followed by dynamic MRI, including diffusion-weighted imaging (DWI) on a 1.5 Tesla MR system from one hour to 168 hours postembolization. Apparent diffusion coefficient (ADC) values were calculated and analyzed. At the end of the MRI experiments, the spinal cords of the animals were fixed for histology. RESULTS: A total of six experimental models were successfully established. In all cases, DWI images showed slight hyperintensity within one hour postembolization, whereas only four cases presented slight hyperintensity on T2-weighted images. ADC values of spinal cord infarction lesions decreased rapidly at early stage (several hours to 24 hours) and then increased gradually. CONCLUSION: The temporal evolution of diffusion abnormality of experimental spinal cord infarction may help us better understand various DWI signals in the process of spinal cord infarction.

Radiofrequency ablation in a porcine liver model: effects of transcatheter arterial embolization with iodized oil on ablation time, maximum output, and coagulation diameter as well as angiographic characteristics.

AIM: To evaluate the effects of combined radiofrequency ablation and transcatheter arterial embolization with iodized oil on ablation time, maximum output, coagulation diameter, and portal angiography in a porcine liver model. METHODS: Radiofrequency ablation (RFA) was applied to in vivo livers of 10 normal pigs using a 17-gauge 3.0 cm expandable LeVeen RF needle electrode with or without transcatheter arterial embolization (TAE) with iodized oil (n=5). In each animal, 2 areas in the liver were ablated. Direct portography was performed before and after RFA. Ablation was initiated at an output of 30 W, and continued with an increase of 10 W per minute until roll-off occurred. Ablation time and maximum output until roll-off, and coagulated tissue diameter were compared between the 2 groups. Angiographic changes on portography before and after ablation were also reviewed. RESULTS: For groups with and without TAE with iodized oil, the ablation times until roll-off were 320.6 +/- 30.9 seconds and 445.1 +/- 35.9 seconds, respectively, maximum outputs were 69.0 +/- 7.38 W and 87.0 +/- 4.83 W and maximal diameters of coagulation were 41.7 +/- 3.85 mm and 33.2 +/- 2.28 mm. Significant reductions of ablation time and maximum output, and significantly larger coagulation diameter were obtained with RFA following TAE with iodized oil compared to RFA alone. Portography after RFA following TAE with iodized oil revealed more occlusion of the larger portal branches than with RFA alone. CONCLUSION: RFA following TAE with iodized oil can increase the volume of coagulation necrosis with lower output and shorter ablation time than RFA alone in normal pig liver tissue.

Docetaxel labeled with iodine 131 radionuclide--a possible new anticancer drug? (The pilot study).

The cytotoxic potentials of the lipiodol emulsion with dissolved 131I-docetaxel, the 131I-lipiodol emulsion and non-labeled docetaxel were tested on the HeLa Hep2 cell line during 24 hours. The pilot study confirmed that the radio-labeled docetaxel was significantly more toxic than the radionuclide or docetaxel alone.

Lipiodol alters murine uterine dendritic cell populations: a potential mechanism for the fertility-enhancing effect of lipiodol.

OBJECTIVE: To determine whether treatment with lipiodol alters the leukocyte population in the uterus. DESIGN: Randomized controlled animal study. SETTING: University research laboratory. ANIMAL(S): Sixty female Swiss white mice at proestrous. INTERVENTION(S): Infusion of the female reproductive tract with lipiodol versus infusion with saline versus sham treatment. MAIN OUTCOME MEASURE(S): Counts of uterine macrophages, dendritic cells, and total leukocytes assessed by immunohistochemistry. RESULT(S): No statistically significant differences were found in the mean number of total leukocytes or macrophages between the three treatment groups. The mean number of CD205+ dendritic cells showed a statistically significant decrease following lipiodol treatment compared with the sham treatment and saline treatment. The mean number of CD1+ dendritic cells showed a statistically significant increase following lipiodol treatment compared with the sham treatment. CONCLUSION(S): Intrauterine lipiodol infusion is associated with a change in the uterine dendritic cell populations in mice. This change may alter the uterine immune response to the fetus, leading to improved fertility.

Regression of Novikoff rat hepatocellular carcinoma following locoregional administration of a novel formulation of clofazimine in lipiodol.

We report here that, clofazimine (CFZ) treatment (0.1-10 microM) led to inhibition of in vitro proliferation of hepatocellular carcinoma (HCC) cell lines Hep3-beta, HuH-7, HepG2, SKHEP-1, PLC/PRF-5 and Novikoff. A 24 h exposure of human HuH-7 cells to various concentrations of CFZ dissolved in lipiodol (CFZ-L 10-160 microM), followed by 4 days treatment with medium alone, also led to dose-dependant inhibition of post-treatment cell growth. In vivo, direct intratumoural and intrahepatic arterial injection (IHA) of CFZ-L led to profound inhibition of orthotopic growth of rat Novikoff liver tumours (P < 0.0001 and P < 0.005, respectively). On the contrary, daily oral administration of 150 mg/kg CFZ for 7 days, did not influence the rate of Novikoff tumour growth. Histological examination of rat tumours, revealed the presence of lipiodol in tumour cells, 7 days after treatment with a single IHA dose. Histopathology did not show any abnormality in liver, lung or bowel sections taken from animals 1 week after IHA administration of CFZ-L. Similarly, liver function tests were all normal compared to saline treated animals. Deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labelling revealed the presence of large numbers of apoptotic cells in the CFZ-L treated tumours. Thus, intraarterial administration of the highly lipophilic antiproliferative agent CFZ in lipiodol solution may represent an effective and yet safe strategy for the regional treatment of HCCs.

Synthesis and in vitro evaluation of the phenylboric acid derivative entrapped lipiodol in boron neutron capture therapy for hepatoma.

BACKGROUND: Hepatoma, a common cancer in Taiwan, responds poorly to conventional therapies. Boron neutron capture therapy (BNCT) may provide a promising approach for hepatoma therapy. In this study, a pharmaceutical composition, phenylboric acid derivative entrapped lipiodol (PBAD-lipiodol), was synthesized and characterized. In vitro study was used for evaluation of PBAD-lipiodol for the BNCT of hepatoma. MATERIALS AND METHODS: alpha Track observation was used to identify the boron compound in the TLC plate and to evidence the uniform distribution of boron in the PBAD-lipiodol. Inductively coupled plasma-atomic emission spectroscopy and neutron activation analysis were used to determine the concentrations of boron and lipiodol, respectively. Human hepatoma HepG2 cells were used for in vitro experiments. A Nomarski optical microscope was used to investigate the uptake of PBAD-lipiodol globules in individual hepatoma cells. RESULTS: PBAD-lipiodol was stable in human serum. The boron source, PBAD, was uniformly distributed in PBAD-lipiodol. Many of the PBAD-lipiodol globules were internalized and retained in HepG2 cells, and the boron concentration of HepG2 cells reached 269 ppm after 72 hours of PBAD-lipiodol treatment. CONCLUSION: In vitro studies revealed that PBAD-lipiodol could deliver a therapeutically effective amount of PBAD as a boron source for the BNCT of hepatoma. PBAD-lipiodol is a potential new boron drug for the BNCT of hepatoma.

Hepatic intra-arterial injection of 1,25-dihydroxyvitamin D3 in lipiodol: Pilot study in patients with hepatocellular carcinoma.

1,25-dihydroxycholecalciferol [1,25-(OH)2 D3] has been shown to have antiproliferative effects in a wide variety of cancer cell lines. In vivo studies, although often limited by the development of hypercalcemia, have also shown the potential usefulness of 1,25-(OH)2 D3 in inhibiting tumor growth. The potential usefulness of the drug has been hampered by the development of hypercalcemia. This pilot clinical study was designed to evaluate the preclinical results that have shown, locoregional administration of 1,25-(OH)2 D3 in lipiodol can prevent the development of hypercalcemia. Eight patients with refractory HCC were given a single intrahepatic arterial dose (50, 75 or 100 microg) of 1,25-(OH)2 D3 dissolved in 5 ml of lipiodol. Following this, for 4 weeks serum calcium, 1,25-(OH)2 D3, alpha-fetoprotein and a range of biochemical indices were monitored. While, in 3 patients the calcium levels exceeded the normal range, even at these extremely high doses, non of the patients developed grade 3 hypercalcemia. 1,25-(OH)2 D3 administration also led to transient stabilization of serum alpha-fetoprotein in these patients. The data obtained support the hypothesis that, in patients with HCC, locoregional delivery of 1,25-(OH)2 D3 in lipiodol can allow administration of supra-pharmacological doses of the drug without the development of hypercalcemia.