Transarterial Radioembolization (TARE) Agents beyond 90Y-Microspheres

The Deterioration of Sarcopenia Post-Transarterial Radioembolization with Holmium-166 Serves as a Predictor for Disease Progression at 3 Months in Patients with Advanced Hepatocellular Carcinoma: A Pilot Study

PURPOSE

The aim of this pilot study is to explore the relationship between changes in sarcopenia before and after one to three months of Transarterial Radioembolization (TARE) treatment with Holmium-166 (166Ho) and its effect on the rate of local response. Our primary objective is to assess whether the worsening of sarcopenia can function as an early indicator of a subgroup of patients at increased risk of disease progression in cases of hepatocellular carcinoma (HCC).

METHODS

A single-center retrospective analysis was performed on 25 patients with HCC who underwent 166Ho-TARE. Sarcopenia status was defined according to the measurement of the psoas muscle index (PMI) at baseline, one month, and three months after TARE. Radiological response according to mRECIST criteria was assessed and patients were grouped into responders and non-responders. The loco-regional response rate was evaluated for all patients before and after treatment, and was compared with sarcopenia status to identify any potential correlation.

RESULTS

A total of 20 patients were analyzed. According to the sarcopenia status at 1 month and 3 months, two groups were defined as follows: patients in which the deltaPMI was stable or increased (No-Sarcopenia group; n = 12) vs. patients in which the deltaPMI decreased (Sarcopenia group; n = 8). Three months after TARE, a significant difference in sarcopenia status was noted (p = 0.041) between the responders and non-responders, with the non-responder group showing a decrease in the sarcopenia values with a median deltaPMI of -0.57, compared to a median deltaPMI of 0.12 in the responder group. Therefore, deltaPMI measured three months post-TARE can be considered as a predictive biomarker for the local response rate (p = 0.028). Lastly, a minor deltaPMI variation (>-0.293) was found to be indicative of positive treatment outcomes (p = 0.0001).

CONCLUSION

The decline in sarcopenia three months post-TARE with Holmium-166 is a reliable predictor of worse loco-regional response rate, as evaluated radiologically, in patients with HCC. Sarcopenia measurement has the potential to be a valuable assessment tool in the management of HCC patients undergoing TARE. However, further prospective and randomized studies involving larger cohorts are necessary to confirm and validate these findings.

177 Lu-Microspheres Selective Intra-arterial Radionuclide Therapy : A Facile and Biocompatible Permanent Micro-Seed Implants for Unresectable Hepatocellular Carcinoma

ABSTRACT

Hepatocellular carcinoma (HCC) is an aggressive malignancy with a poor prognosis. Surgical resection is limited. Selective intra-arterial radionuclide therapy (SIRT) emerged as a potential cure for intermediate HCC with portal vein thrombosis. We report a pilot study of a 48-year-old man with recurrent HCC who underwent 177 Lu-microsphere SIRT (2.2 GBq) in segment III. Posttherapy SPECT/CT images (24 hours to 3 months) demonstrated excellent localization and prolonged retention within the tumor. Pre- and 3-month post-SIRT CECT showed a notable decrease in arterial enhancement and tumor size. Time-activity curve of the standard and the lesion demonstrated similar decay pattern indicating that 177 Lu-microspheres act as permanent implant.

Synthesis and characterization of 3-in-1 multifunctional lipiodol-doped Fe3O4@Poly (diallyl isophthalate) microspheres for arterial embolization, chemotherapy, and imaging

Transcatheter arterial embolization plays a pivotal role in treating various diseases. However, the efficacy of embolization therapy in cancer treatment can be limited by several factors, such as inevitable incomplete or non-target embolization, and the tumor recurrence and metastasis caused by the hypoxic microenvironment. Moreover, it is essential to explore simpler, more economical, and efficient methods for microsphere synthesis. Herein, we achieved one-step photocatalytic synthesis of lipiodol-doped Fe3O4@Poly (diallyliso-phthalate) multifunctional microspheres (IFeD MS) for arterial embolization, chemotherapy, and imaging. The prepared microspheres are in the shape of dried plums, with a particle size of 100-300 μm. Lipiodol demonstrates a certain degree of chemotherapeutic activity, and the incorporation of Fe3O4enables the microspheres to exhibit magnetothermal response and magnetic resonance imaging capabilities. Furthermore, the radiopaque characteristics of both agents provide the microspheres with promising potential for computed tomography and digital radiography imaging. The renal embolization experiment in rabbits demonstrated that IFeD MS achieved significant embolization and chemotherapeutic effects. Biocompatibility experiments revealed that this embolic agent did not induce tissue damage or inflammation beyond the treatment area. Additionally, IFeD MS exhibited promising imaging potential. The results of this study imply that the developed multifunctional embolic agent IFeD MS may have significant potential in transforming tumors previously only suitable for palliative cares into resectable radical treatments.

Cirrhotic hepatocellular carcinoma-based decellularized liver cancer model for local chemoembolization evaluation

Transarterial chemoembolization (TACE) is a common treatment for unresectable intermediate stage hepatocellular carcinoma (HCC) and involves the combination of chemotherapy agents and embolic materials to target and block the blood supply to the tumor, leading to localized treatment. However, the selection of clinical chemoembolization agents remains limited, and the effectiveness of various agents is still under investigation. Meanwhile, replicating the complex vasculature and extracellular matrix (ECM) circumstances of HCC in in vitro models for evaluating embolic agents proves to be challenging. Herein, we developed a decellularized cancerous liver model with translucent appearance, a complicated hepatic vascular system and tissue-specific ECM for the evaluation of embolic agents. Inkpad oil and microparticles were used to illustrate different systems of vascular structures between healthy and HCC rats' livers. Quantitative analysis with AngioTool revealed significant differences in vessel density and lacunarity between the two groups. Proteomics showed higher secretion of collagens in the HCC rat liver models than in healthy livers. Utilizing this in vitro model, we investigated the impact of tumor-specific vascular structure and ECM composition on chemoembolization performance, the two key factors inaccessible by currently available drug release testing platforms. Our findings revealed that the presence of an aberrant vascular system and the distorted ECM within the model led to drug retention. This preclinical model holds great promise as a valuable tool for evaluating embolic agents and studying their performance in the tumor microenvironment. STATEMENT OF SIGNIFICANCE: Transarterial chemoembolization (TACE), which employs drug-eluting embolic agents to obstruct the tumor-feeding vessels while locally releasing chemotherapeutic drugs into the tumor, has become the first-line treatment of unresectable liver cancer over past two decades. Nevertheless, the advancement of effective drug-eluting embolic agents has been retarded due to the lack of appropriate in vitro models for assessing the local embolization and chemotherapy performances in TACE. Here we developed a cirrhotic hepatocellular carcinoma-based decellularized liver cancer model, which preserves the aberrant vasculatures and tumor-specific extracellular matrix of liver cancer, for TACE evaluation. This model incorporates a blood flow simulation component to assess the dynamics of drug release behaviors of chemoembolic agents within tumor-mimicking conditions, more accurately replicating the in vivo environment for the locoregional assessments as compared to conventional in vitro models.

Cell-cell communication characteristics in breast cancer metastasis

Breast cancer, a highly fatal disease due to its tendency to metastasize, is the most prevalent form of malignant tumors among women worldwide. Numerous studies indicate that breast cancer exhibits a unique predilection for metastasis to specific organs including the bone, liver, lung, and brain. However, different types of, The understanding of the heterogeneity of metastatic breast cancer has notably improved with the recent advances in high-throughput sequencing techniques. Focusing on the modification in the microenvironment of the metastatic organs and the crosstalk between tumor cells and in situ cells, noteworthy research points include the identification of two distinct modes of tumor growth in bone metastases, the influence of type II pneumocyte on lung metastases, the paradoxical role of Kupffer cells in liver metastases, and the breakthrough of the blood-brain barrier (BBB) breach in brain metastases. Overall, this review provides a comprehensive overview of the characteristics of breast cancer metastases, shedding light on the pivotal roles of immune and resident cells in the development of distinct metastatic foci.

Any role for transarterial radioembolization in unresectable intrahepatic cholangiocarcinoma in the era of advanced systemic therapies?

Intrahepatic cholangiocarcinoma (iCCA) is recognized as the second most frequently diagnosed liver malignancy, following closely after hepatocellular carcinoma. Its incidence has seen a global upsurge in the past several years. Unfortunately, due to the lack of well-defined risk factors and limited diagnostic tools, iCCA is often diagnosed at an advanced stage, resulting in a poor prognosis. While surgery is the only potentially curative option, it is rarely feasible. Currently, there are ongoing investigations into various treatment approaches for unresectable iCCA, including conventional chemotherapies, targeted therapies, immunotherapies, and locoregional treatments. This study aims to explore the role of transarterial radioembolization (TARE) in the treatment of unresectable iCCA and provide a comprehensive review. The findings suggest that TARE is a safe and effective treatment option for unresectable iCCA, with a median overall survival (OS) of 14.9 months in the study cohort. Studies on TARE for unresectable iCCA, both as a first-line treatment (as a neo-adjuvant down-staging strategy) and as adjuvant therapy, have reported varying median response rates (ranging from 34% to 86%) and median OS (12-16 mo). These differences can be attributed to the heterogeneity of the patient population and the limited number of participants in the studies. Most studies have identified tumor burden, portal vein involvement, and the patient's performance status as key prognostic factors. Furthermore, a phase 2 trial evaluated the combination of TARE and chemotherapy (cisplatin-gemcitabine) as a first-line therapy for locally advanced unresectable iCCA. The results showed promising outcomes, including a median OS of 22 mo and a 22% achievement in down-staging the tumor. In conclusion, TARE represents a viable treatment option for unresectable iCCA, and its combination with systemic chemotherapy has shown promising results. However, it is important to consider treatment-independent factors that can influence prognosis. Further research is necessary to identify optimal treatment combinations and predictive factors for a favorable response in iCCA patients.

Biological efficacy of simulated radiolabeled Lipiodol® ultra-fluid and microspheres for various beta emitters: study based on VX2 tumors

BACKGROUND

Radioembolization is one therapeutic option for the treatment of locally early-stage hepatocellular carcinoma. The aim of this study was to evaluate the distribution of Lipiodol® ultra-fluid and microspheres and to simulate their effectiveness with different beta emitters (90Y, 188Re, 32P, 166Ho, 131I, and 177Lu) on VX2 tumors implanted in the liver of 30 New Zealand rabbits.

RESULTS

Twenty-three out of 30 rabbits had exploitable data: 14 in the group that received Lipiodol® ultra-fluid (group L), 6 in the group that received microspheres (group M), and 3 in the control group (group C). The histologic analysis showed that the Lipiodol® ultra-fluid distributes homogeneously in the tumor up to 12 days after injection. The X-ray μCT images showed that Lipiodol® ultra-fluid has a more distal penetration in the tumor than microspheres. The entropy (disorder of the system) in the L group was significantly higher than in the M group (4.06 vs 2.67, p = 0.01). Equivalent uniform biological effective doses (EUBED) for a tumor-absorbed dose of 100 Gy were greater in the L group but without statistical significance except for 177Lu (p = 0.03). The radionuclides ranking by EUBED (from high to low) was 90Y, 188Re, 32P, 166Ho, 131I, and 177Lu.

CONCLUSIONS

This study showed a higher ability of Lipiodol® ultra-fluid to penetrate the tumor that translated into a higher EUBED. This study confirms 90Y as a good candidate for radioembolization, although 32P, 166Ho, and 188Re can achieve similar results.

Microfluidic Controllable Preparation of Iodine-131-Labeled Microspheres for Radioembolization Therapy of Liver Tumors

Transcatheter arterial radioembolization (TARE) is of great significance for the treatment of advanced hepatocellular carcinoma (HCC). However, the existing radioembolic microspheres still have problems such as non-degradability, non-uniform size, and inability to directly monitor in vivo, which hinders the development of TARE. In this paper, a novel radioembolic agent, 131 I-labeled methacrylated gelatin microspheres (131 I-GMs), is prepared for the treatment of HCC. Water-in-oil (W/O) emulsion templates are prepared by a simple one-step microfluidic method to obtain methacrylated gelatin microspheres (GMs) after UV irradiation. A series of GMs with uniform and controllable size is obtained by adjusting the flow rate of each fluid. Both air-dried and freeze-dried GMs can quickly restore their original shape and size, and still have good monodispersity, elasticity, and biocompatibility. The radiolabeling experiments show that 131 I can efficiently bind to GMs by chloramine-T method, and the obtained 131 I-GMs have good radioactive stability in vitro. The results of in vivo TARE treatment in rats show that 131 I-GMs can be well retained in the hepatic artery and have a good inhibitory effect on the progression of liver cancer, showing the potential for the treatment of HCC.

Development and physicochemical characterization of a biodegradable microspheres formulation loaded with samarium-153 and doxorubicin for chemo-radioembolization of liver tumours

Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are promising treatments for unresectable liver tumours. Some recent studies suggested that combining TACE and TARE in one treatment course might improve treatment efficacy through synergistic cytotoxicity effects. Nonetheless, current formulations do not facilitate a combination of chemo- and radio-embolic agents in one delivery system. Therefore, this study aimed to synthesise a hybrid biodegradable microsphere loaded with both radioactive agent, samarium-153 (153 Sm) and chemotherapeutic drug, doxorubicin (Dox) for potential radio-chemoembolization of advanced liver tumours. 152 Sm and Dox-loaded polyhydroxybutyrate-co-3-hydroxyvalerate (PHBV) microspheres were prepared using water-in-oil-in-water solvent evaporation method. The microspheres were then sent for neutron activation in a neutron flux of 2 × 1012  n/cm2 /s. The physicochemical properties, radioactivity, radionuclide purity, 153 Sm retention efficiency, and Dox release profile of the Dox-153 Sm-PHBV microspheres were analysed. In addition, in vitro cytotoxicity of the formulation was tested using MTT assay on HepG2 cell line at 24 and 72 h. The mean diameter of the Dox-153 Sm-PHBV microspheres was 30.08 ± 2.79 μm. The specific radioactivity was 8.68 ± 0.17 GBq/g, or 177.69 Bq per microsphere. The 153 Sm retention efficiency was more than 99%, tested in phosphate-buffered saline (PBS) and human blood plasma over 26 days. The cumulative release of Dox from the microspheres after 41 days was 65.21 ± 1.96% and 29.96 ± 0.03% in PBS solution of pH 7.4 and pH 5.5, respectively. The Dox-153 Sm-PHBV microspheres achieved a greater in vitro cytotoxicity effect on HepG2 cells (85.73 ± 3.63%) than 153 Sm-PHBV (70.03 ± 5.61%) and Dox-PHBV (74.06 ± 0.78%) microspheres at 300 μg/mL at 72 h. In conclusion, a novel biodegradable microspheres formulation loaded with chemotherapeutic drug (Dox) and radioactive agent (153 Sm) was successfully developed in this study. The formulation fulfilled all the desired physicochemical properties of a chemo-radioembolic agent and achieved better in vitro cytotoxicity on HepG2 cells. Further investigations are needed to evaluate the biosafety, radiation dosimetry, and synergetic anticancer properties of the formulation.

Polydopamine-Coated Radiolabeled Microspheres for Combinatorial Radioembolization and Photothermal Cancer Therapy

Transarterial radioembolization (TARE) is a local radionuclide therapy and is successfully used in hepatocellular carcinoma (HCC) treatment. Radioactive microspheres have been widely studied for TARE. Preparation of ideal radioactive microspheres is significant for clinical research and patient treatment. In this study, we have designed a novel multifunctional microsphere, i.e., polydopamine (PDA)-coated ¹⁷⁷Lu-radiolabeled silica microspheres (MS) denoted as ¹⁷⁷Lu-MS@PDA, which can be used for TARE and photothermal therapy (PTT). The radiostability of ¹⁷⁷Lu-MS@PDA was significantly improved by coating ¹⁷⁷Lu-MS with PDA. In addition, the coating of PDA makes microspheres have excellent photothermal performance. MicroSPECT/CT images showed that ¹⁷⁷Lu-MS@PDA was accurately embolized and remained in the tumor during the observation time. At the time, it also showed that ¹⁷⁷Lu-MS@PDA was very stable in vivo. Furthermore, the anti-tumor results demonstrated that TARE combined with PTT of ¹⁷⁷Lu-MS@PDA can significantly inhibit tumor growth without obvious side effects. ¹⁷⁷Lu-MS@PDA holds great potential as a promising radioactive microsphere for HCC.

Rational Design of Biomaterials to Potentiate Cancer Thermal Therapy

Cancer thermal therapy, also known as hyperthermia therapy, has long been exploited to eradicate mass lesions that are now defined as cancer. With the development of corresponding technologies and equipment, local hyperthermia therapies such as radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound, have has been validated to effectively ablate tumors in modern clinical practice. However, they still face many shortcomings, including nonspecific damages to adjacent normal tissues and incomplete ablation particularly for large tumors, restricting their wide clinical usage. Attributed to their versatile physiochemical properties, biomaterials have been specially designed to potentiate local hyperthermia treatments according to their unique working principles. Meanwhile, biomaterial-based delivery systems are able to bridge hyperthermia therapies with other types of treatment strategies such as chemotherapy, radiotherapy and immunotherapy. Therefore, in this review, we discuss recent progress in the development of functional biomaterials to reinforce local hyperthermia by functioning as thermal sensitizers to endow more efficient tumor-localized thermal ablation and/or as delivery vehicles to synergize with other therapeutic modalities for combined cancer treatments. Thereafter, we provide a critical perspective on the further development of biomaterial-assisted local hyperthermia toward clinical applications.

Microspheres as a Carrier System for Therapeutic Embolization Procedures: Achievements and Advances

The targeted delivery of anti-cancer drugs and isotopes is one of the most pursued goals in anti-cancer therapy. One of the prime examples of such an application is the intra-arterial injection of microspheres containing cytostatic drugs or radioisotopes during hepatic embolization procedures. Therapy based on the application of microspheres revolves around vascular occlusion, complemented with local therapy in the form of trans-arterial chemoembolization (TACE) or radioembolization (TARE). The broadest implementation of these embolization strategies currently lies within the treatment of untreatable hepatocellular cancer (HCC) and metastatic colorectal cancer. This review aims to describe the state-of-the-art TACE and TARE technologies investigated in the clinical setting for HCC and addresses current trials and new developments. In addition, chemical properties and advancements in microsphere carrier systems are evaluated, and possible improvements in embolization therapy based on the modification of and functionalization with therapeutical loads are explored.

Epstein-Barr Virus (EBV) Epithelial Associated Malignancies: Exploring Pathologies and Current Treatments

Epstein-Barr virus (EBV) is one of eight known herpesviruses with the potential to infect humans. Globally, it is estimated that between 90-95% of the population has been infected with EBV. EBV is an oncogenic virus that has been strongly linked to various epithelial malignancies such as nasopharyngeal and gastric cancer. Recent evidence suggests a link between EBV and breast cancer. Additionally, there are other, rarer cancers with weaker evidence linking them to EBV. In this review, we discuss the currently known epithelial malignancies associated with EBV. Additionally, we discuss and establish which treatments and therapies are most recommended for each cancer associated with EBV.

Transarterial Yttrium-90 Radioembolization in Intrahepatic Cholangiocarcinoma Patients: Outcome Assessment Applying a Prognostic Score

Radioembolization (RE) is a viable therapy option in patients with intrahepatic cholangiocarcinoma (ICC). This study delineates a prognostic score regarding overall survival (OS) after RE using routine pre-therapeutic parameters. A retrospective analysis of 39 patients (median age, 61 [range, 32−82] years; 26 females, 13 males) with ICC and 42 RE procedures was conducted. Cox regression for OS included age, ECOG, hepatic and extrahepatic tumor burden, thrombosis of the portal vein, ascites, laboratory parameters and dose reduction due to hepatopulmonary shunt. Median OS after RE was 8.0 months. Using univariable Cox, ECOG ≥ 1 (hazard ratio [HR], 3.8), AST/ALT quotient (HR, 1.86), high GGT (HR, 1.002), high CA19-9 (HR, 1.00) and dose reduction of 40% (HR, 3.8) predicted shorter OS (each p < 0.05). High albumin predicted longer OS (HR, 0.927; p = 0.045). Multivariable Cox confirmed GGT ≥ 750 [U/L] (HR, 7.84; p < 0.001), ECOG > 1 (HR, 3.76; p = 0.021), albumin ≤ 41.1 [g/L] (HR, 3.02; p = 0.006) as a three-point pre-therapeutic prognostic score. More specifically, median OS decreased from 15.3 months (0 risk factors) to 7.6 months (1 factor) or 1.8 months (≥2 factors; p < 0.001). The proposed score may aid in improved pre-therapeutic patient identification with (un-)favorable OS after RE and facilitate the balance between potential life prolongation and overaggressive patient selection.

Rhenium Radioisotopes for Medicine, a Focus on Production and Applications

In recent decades, the use of alpha; pure beta; or beta/gamma emitters in oncology, endocrinology, and interventional cardiology rheumatology, has proved to be an important alternative to the most common therapeutic regimens. Among radionuclides used for therapy in nuclear medicine, two rhenium radioisotopes are of particular relevance: rhenium-186 and rhenium-188. The first is routinely produced in nuclear reactors by direct neutron activation of rhenium-186 via 185Re(n,γ)186Re nuclear reaction. Rhenium-188 is produced by the decay of the parent tungsten-188. Separation of rhenium-188 is mainly performed using a chromatographic 188W/188Re generator in which tungsten-188 is adsorbed on the alumina column, similar to the 99Mo/99mTc generator system, and the radionuclide eluted in saline solution. The application of rhenium-186 and rhenium-188 depends on their specific activity. Rhenium-186 is produced in low specific activity and is mainly used for labeling particles or diphosphonates for bone pain palliation. Whereas, rhenium-188 of high specific activity can be used for labeling peptides or bioactive molecules. One of the advantages of rhenium is its chemical similarity with technetium. So, diagnostic technetium analogs labeled with radiorhenium can be developed for therapeutic applications. Clinical trials promoting the use of 186/188Re-radiopharmaceuticals is, in particular, are discussed.

Oncopharmacology in Interventional Radiology

The broad scope of malignancies treated in interventional oncology is mirrored by the breadth of oncotherapeutics, drugs used to treat cancer. Many of these treatments are administered endovascularly, though a group of therapies can be delivered percutaneously. Perhaps the best taxonomy of oncotherapeutics is based on their biological inactivity or activity and the mechanism by which they interact with treated and targeted tissues. As the fields of interventional oncology and oncotherapeutics continue to grow and expand, this framework may provide a more organized approach in helping distinguish and select the best therapy for patients.

Clinical consensus statement: Selective internal radiation therapy with yttrium 90 resin microspheres for hepatocellular carcinoma in Asia

BACKGROUND

Hepatocellular carcinoma (HCC) is subject to different management approaches and guidelines according to Eastern and Western therapeutic algorithms. Use of selective internal radiation therapy (SIRT) with resin yttrium 90 microspheres for HCC has increased in Asia in recent years, without clearly defined indications for its optimal application. The objective of this systematic review and expert consensus statement is to provide guidance and perspectives on the use of SIRT among patients with HCC in Asia.

MATERIALS AND METHODS

A systematic literature review identified current publications on HCC management and SIRT recommendations. A group of 10 experts, representing stakeholder specialties and countries, convened between August 2020 and March 2021 and implemented a modified Delphi consensus approach to develop guidelines and indications for use of SIRT for HCC in Asia. Final recommendations were organized and adjudicated based on the level of evidence and strength of recommendation, per approaches outlined by the American College of Cardiology/American Heart Association and Oxford Centre for Evidence-Based Medicine.

RESULTS

The experts acknowledged a general lack of evidence relating to use of SIRT in Asia and identified as an unmet need the lack of phase 3 randomized trials comparing clinical outcomes and survival following SIRT versus other therapies for HCC. Through an iterative process, the expert group explored areas of clinical relevance and generated 31 guidance statements and a patient management algorithm that achieved consensus.

CONCLUSION

These recommendations aim to support clinicians in their decision-making and to help them identify and treat patients with HCC using SIRT in Asia. The recommendations also highlight areas in which further clinical trials are needed to define the role of SIRT in management of HCC among Asian populations.

Circumsporozoite Protein of Plasmodium berghei- and George Baker Virus A-Derived Peptides Trigger Efficient Cell Internalization of Bioconjugates and Functionalized Poly(ethylene glycol)-b-poly(benzyl malate)-Based Nanoparticles in Human Hepatoma Cells

In order to identify the peptides, selected from the literature, that exhibit the strongest tropism towards human hepatoma cells, cell uptake assays were performed using biotinylated synthetic peptides bound to fluorescent streptavidin or engrafted onto nanoparticles (NPs), prepared from biotin-poly(ethylene glycol)-block-poly(benzyl malate) (Biot-PEG-b-PMLABe) via streptavidin bridging. Two peptides, derived from the circumsporozoite protein of Plasmodium berghei- (CPB) and George Baker (GB) Virus A (GBVA10-9), strongly enhanced the endocytosis of both streptavidin conjugates and NPs in hepatoma cells, compared to primary human hepatocytes and non-hepatic cells. Unexpectedly, the uptake of CPB- and GBVA10-9 functionalized PEG-b-PMLABe-based NPs by hepatoma cells involved, at least in part, the peptide binding to apolipoproteins, which would promote NP’s interactions with cell membrane receptors of HDL particles. In addition, CPB and GBVA10-9 peptide–streptavidin conjugates favored the uptake by hepatoma cells over that of the human macrophages, known to strongly internalize nanoparticles by phagocytosis. These two peptides are promising candidate ligands for targeting hepatocellular carcinomas.

Successful Transcatheter Arterial Radioembolization of Hepatocellular Carcinoma Via Left Internal Mammary Artery: A Case Report

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Late-stage presentation, co-morbidities, and limited donor availability enable only a few patients to receive curative therapies. HCC is treated with liver resection and transplantation as the first line of treatment. Patients in advanced stages, on the other hand, are treated with a variety of locoregional treatments. Transarterial embolization (TAE), transarterial chemoembolization (TACE), and transarterial radioembolization (TARE) are different modalities of locoregional therapy for HCC with robust collateral circulation. One of the characteristics of HCC is that it is hypervascular, therefore, parasitic supply is not unusual. The left internal mammary artery (LIMA) is considered to be an uncommon parasitic supply in HCC. While TACE has been extensively reviewed in the literature, herein we report a successful case of TARE via the LIMA which was a safe and practical alternative for a patient with HCC.

Prognosis of patients with hepatocellular carcinoma and portal vein tumor thrombus treated with combination of transarterial chemoembolization and palliative thermal ablation

PURPOSE

Transarterial chemoembolization (TACE) was obtained acceptable benefit for advanced hepatocellular carcinoma (HCC). Here in this study, we compared the benefit of TACE combined palliative thermal ablation with TACE alone for HCC with portal vein tumor thrombus (PVTT).

METHODS

Patients with HCC and PVTT were retrospectively analyzed from January 2012 to December 2017, who accepted treatment of TACE alone (TACE group) or TACE plus palliative thermal ablation (TACE + P-ablation group). Propensity score matching (PSM) was applied to balance differences between the two groups. Overall survival (OS) and progression-free survival (PFS) rates were compared between groups.

RESULTS

Median follow-up time was 7.4 (3.0-60.0) months. In the cohort, 142 patients were enrolled in TACE group and 86 patients were enrolled in TACE + P-ablation group. The pre-PSM estimated 6-, 12-, and 18-month OS rates for the TACE + P-ablation group were 70.9, 46.5, and 31%, respectively, whereas rates for the TACE group were 57, 23.1, and 10%, respectively. After PSM, OS and PFS rates remained coincident with the pre-PSM. Risk factors for poor OS included PVTT type III and type II relative to type I (HR = 1.76; 95% CI, 1.13-2.74; p = .01) and (HR = 1.86; 95% CI, 1.2-2.88; p = .006), TACE alone (HR = 1.40; 95% CI, 1.01-1.96; p = .04), a single TACE treatment (HR = 2.69; 95% CI, 1.79-4.03; p < .001), 2 or 3 TACE treatments (HR = 2.02; 95% CI, 1.32-3.09; p = .001).

CONCLUSIONS

The combination of TACE and palliative thermal ablation for HCC with PVTT could obtain delayed progression and longer survival.

Preparation and Dosimetry Assessment of 166Dy₂O₃/166Ho₂O₃-iPSMA Nanoparticles for Targeted Hepatocarcinoma Radiotherapy

This research aimed to prepare ¹⁶⁶Dy₂O₃-iPSMA/¹⁶⁶Ho₂O₃-iPSMA nanoparticles (¹⁶⁶Dy₂O₃/¹⁶⁶Ho₂O₃-iPSMA NPs) and assess the radiation absorbed dose produced by the nanosystem to hepatic cancer cells by using experimental in vitro and in vivo biokinetic data. Dy₂O₃NPs were synthesized and functionalized with the prostate-specific membrane antigen inhibitor peptide (iPSMA). Fourier transform infrared (FTIR) spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DSL) and zeta potential analyses indicated the formation of Dy₂O₃-iPSMA NPs (46.11 ± 13.24 nm). After neutron activation, a stable ¹⁶⁶Dy₂O₃/¹⁶⁶Ho₂O₃- iPSMA nanosystem was obtained, which showed adequate affinity to the PSMA receptor in HepG2 cancer cells (K_d = 9.87 ± 2.27 nM). in vitro studies indicated high ¹⁶⁶Dy₂O₃/¹⁶⁶Ho₂O₃-iPSMA internalization in cancer cells, with high radiation doses to cell nuclei (107 Gy) and cytotoxic effects, resulting in a significant reduction in HepG2 cell viability (decreasing to 2.12 ± 0.31%). After intratumoral administration in mice, the nanosystem biokinetic profile indicated significant retention into the tumoral mass, producing ablative radiation doses (>70 Gy).

Locoregional Therapies for Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis

Hepatocellular carcinoma is the fourth leading cause of cancer worldwide, and the fastest increasing cause of cancer mortality in the United States. Its propensity for vascular invasion leads to the presence of portal vein tumor thrombus in up to half of patients. PVTT results in a classification of advanced disease, given the risk recurrence secondary to intravascular spread, and formal guidelines recommend systemic therapy in these patients. However, recent advances in locoregional therapies including TACE, TARE, and ablation have demonstrated the potential to drastically improve overall survival in patients with HCC complicated by PVTT.

A deep-learning-based prediction model for the biodistribution of 90 Y microspheres in liver radioembolization

BACKGROUND

Radioembolization with ⁹⁰ Y microspheres is a treatment approach for liver cancer. Currently, employed dosimetric calculations exhibit low accuracy, lacking consideration of individual patient, and tissue characteristics.

PURPOSE

The purpose of the present study was to employ deep learning (DL) algorithms to differentiate patterns of pretreatment distribution of ^99m Tc-macroaggregated albumin on SPECT/CT and post-treatment distribution of ⁹⁰ Y microspheres on PET/CT and to accurately predict how the ⁹⁰ Y-microspheres will be distributed in the liver tissue by radioembolization therapy.

METHODS

Data for 19 patients with liver cancer (10 with hepatocellular carcinoma, 5 with intrahepatic cholangiocarcinoma, 4 with liver metastases) who underwent radioembolization with ⁹⁰ Y microspheres were used for the DL training. We developed a 3D voxel-based variation of the Pix2Pix model, which is a special type of conditional GANs designed to perform image-to-image translation. SPECT and CT scans along with the clinical target volume for each patient were used as inputs, as were their corresponding post-treatment PET scans. The real and predicted absorbed PET doses for the tumor and the whole liver area were compared. Our model was evaluated using the leave-one-out method, and the dose calculations were measured using a tissue-specific dose voxel kernel.

RESULTS

The comparison of the real and predicted PET/CT scans showed an average absorbed dose difference of 5.42% ± 19.31% and 0.44% ± 1.64% for the tumor and the liver area, respectively. The average absorbed dose differences were 7.98 ± 31.39 Gy and 0.03 ± 0.25 Gy for the tumor and the non-tumor liver parenchyma, respectively. Our model had a general tendency to underpredict the dosimetric results; the largest differences were noticed in one case, where the model underestimated the dose to the tumor area by 56.75% or 72.82 Gy.

CONCLUSIONS

The proposed deep-learning-based pretreatment planning method for liver radioembolization accurately predicted ⁹⁰ Y microsphere biodistribution. Its combination with a rapid and accurate 3D dosimetry method will render it clinically suitable and could improve patient-specific pretreatment planning.

Prognostic factors of unresectable hepatocellular carcinoma treated with yttrium-90 radioembolization: results from a large cohort over 13 years at a single center

Background

A previous study of patients with unresectable hepatocellular carcinoma (HCC) was extended to further examine factors associated with overall survival (OS) after selective internal radiation therapy with yttrium-90 resin microspheres (Y90 SIRT).

Methods

Data from patients of any age diagnosed with unresectable HCC and treated with Y90 SIRT at our institution from 2004 through 2017 were retrospectively analyzed. Among other criteria, patients had to have Eastern Cooperative Oncology Group performance status 0 to 2, not have received Y90 SIRT previously, and not have extrahepatic disease. Primary outcome was OS; secondary outcomes included tumor response and adverse events (AEs). Kaplan-Meier survival analyses and multivariable Cox proportional hazards models were used to evaluate prognostic factors for OS.

Results

Of the 226 patients, 59% were White, 77% were male, and the mean age at first SIRT procedure was 65.1±9.4 years. More than half had received previous treatment for HCC. The most common etiology was hepatitis C (n=138/224 available, 62%), followed by alcohol use (n=45, 20%), and nonalcoholic steatohepatitis (n=27, 12%). The mean model for end-stage liver disease score at baseline was 8.8±2.2. Patients were followed-up for a median of 12.2 months (95% CI, 0.0-62.6). Median OS was 16.6 months (95% CI, 13.1 to not reached). Bilobar disease, higher albumin-bilirubin score at baseline, prior treatment with sorafenib, alcohol use etiology, and higher administered dose were associated with shorter survival, whereas subsequent liver transplant [in 26 patients (11.5%)] was associated with longer survival. Of the 186 patients with AEs data, 75 (40.3%) patients reported an event and, of these, 13 (17.3%) patients had grade 4 bilirubin values.

Conclusions

In a large, diverse population treated at a single center over 13 years, Y90 SIRT produced a median OS of 16.6 months in patients with unresectable HCC and enabled subsequent transplantation in a subset of patients. Factors affecting the length of survival should be considered when making treatment decisions for unresectable HCC.

Transarterial Radioembolization Agents: a Review of the Radionuclide Agents and the Carriers

Liver tumors, both primary and secondary to metastatic disease, remain a major challenge, with an increasing incidence. In this context, taking advantage of the dual blood supply of the liver, and the fact that liver tumors derive majority of their blood supply from the hepatic artery, intraarterial therapies are gaining popularity. Intraarterial liver-directed therapy (IALDT) is the option when the surgery is not feasible due to the number of metastases or for other reasons. Transarterial radioembolization (TARE) is a specific type of IALDT, where a carrier particle/microsphere is labeled with a radioactive substance and then is injected into hepatic artery for therapeutic purposes. As this field is rapidly evolving, with multiple agents being investigated and being introduced into clinical practice, it is hard for the practitioners and researchers to encompass all the available information concisely. This article aims to present a comprehensive review of the prominent TARE technologies.

Labeling of Hinokitiol with 90Y for Potential Radionuclide Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the most common form of primary liver tumors, is the fifth cancer in the world in terms of incidence, and third in terms of mortality. Despite significant advances in the treatment of HCC, its prognosis remains bleak. Transarterial radioembolization with radiolabeled microspheres and Lipiodol has demonstrated significant effectiveness. Here we present a new, simple radiolabeling of Lipiodol with Yttrium-90, for the potential treatment of HCC.

Clinical Evaluation of a Three-Dimensional Internal Dosimetry Technique for Liver Radioembolization with 90Y Microspheres Using Dose Voxel Kernels

Background: The purpose of this study was to develop a rapid, reliable, and efficient tool for three-dimensional (3D) dosimetry treatment planning and post-treatment evaluation of liver radioembolization with ⁹⁰Y microspheres, using tissue-specific dose voxel kernels (DVKs) that can be used in everyday clinical practice. Materials and Methods: Two tissue-specific DVKs for ⁹⁰Y were calculated through Monte Carlo (MC) simulations. DVKs for the liver and lungs were generated, and the dose distribution was compared with direct MC simulations. A method was developed to produce a 3D dose map by convolving the calculated DVKs with the activity biodistribution derived from clinical single-photon emission computed tomography (SPECT) or positron emission tomography (PET) images. Image registration for the SPECT or PET images with the corresponding computed tomography scans was performed before dosimetry calculation. The authors first compared the DVK convolution dosimetry with a direct full MC simulation on an XCAT anthropomorphic phantom. They then tested it in 25 individual clinical cases of patients who underwent ⁹⁰Y therapy. All MC simulations were carried out using the GATE MC toolkit. Results: Comparison of the measured absorbed dose using tissue-specific DVKs and direct MC simulation on 25 patients revealed a mean difference of 1.07% ± 1.43% for the liver and 1.03% ± 1.21% for the tumor tissue, respectively. The largest difference between DVK convolution and full MC dosimetry was observed for the lung tissue (10.16% ± 1.20%). The DVK statistical uncertainty was <0.75% for both media. Conclusions: This semiautomatic algorithm is capable of performing rapid, accurate, and efficient 3D dosimetry. The proposed method considers tissue and activity heterogeneity using tissue-specific DVKs. Furthermore, this method provides results in <1 min, making it suitable for everyday clinical practice.

Highly Tumor-Specific and Long-Acting Iodine-131 Microbeads for Enhanced Treatment of Hepatocellular Carcinoma with Low-Dose Radio-Chemoembolization

Transarterial radioembolization (TARE) is considered the standard treatment for intermediate-stage hepatocellular carcinoma (HCC). Iodine-131 (¹³¹I)-labeled lipiodol TARE is an effective treatment for HCC but has been withdrawn due to its poor retention in tumor lesions and significant distribution in normal tissues with severe side effects. In this work, a highly tumor-specific ¹³¹I-TARE agent with long-time retention is developed by simply introducing tyrosine to poly(vinyl alcohol) (PVA) drug-eluting microbeads (Tyr-PVA-DEBs). The labeling efficiency of ¹³¹I-labeled microbeads remains above 85% in 50% serum for 31 days. Micro-single-photon emission computed tomography/computed tomography (μSPECT/CT) evidences that the ¹³¹I-labeled microbeads accumulate in the orthotopic N1S1 hepatoma of rats for 31 days following intra-arterial injection. The cumulative radiation dose per cubic centimeter of the tumor is at least 13 678-fold higher than that of normal tissues. The highly tumor-selective radiation of the ¹³¹I-labeled microbeads allows localized delivery of 345.04 ± 139.16 Gy to the tumor following a single injection dose as low as 0.2 mCi of ¹³¹I. Moreover, the ¹³¹I-labeled microbeads are loaded with doxorubicin hydrochloride (DOX) through the carboxy groups on tyrosine of the polymer. The ¹³¹I-DOX-loaded microbeads present a synergetic antitumor effect without recurrence in comparison with the microbeads labeled with ¹³¹I or loading DOX alone, attributed to the sensitization of DOX to ¹³¹I-induced ionizing radiation damage to DNA under the embolization-induced hypoxia. Our results demonstrate a high tumor retention of ¹³¹I-labeled embolic agent for low-dose transarterial radio-chemoembolization (TARCE) with a synergetic therapeutic effect on treating HCC, showing potential for clinical application.

Diagnostic Performance of Theranostic Radionuclides Used in Transarterial Radioembolization for Liver Cancer

Primary liver tumor with hepatocellular carcinoma accounting for 75–80% of all such tumors, is one of the global leading causes of cancer-related death, especially in cirrhotic patients. Liver tumors are highly hypervascularized via the hepatic artery, while normal liver tissues are mainly supplied by the portal vein; consequently, intra-arterially delivered treatment, which includes transarterial chemoembolization (TACE) and transarterial radioembolization (TARE), is deemed as a palliative treatment. With the development of nuclear technology and radiochemistry, TARE has become an alternative for patients with hepatic cancer, especially for patients who failed other therapies, or for patients who need tumor downstaging treatment. In practice, some radionuclides have suitable physicochemical characteristics to act as radioactive embolism agents. Among them, ⁹⁰Y emits β rays only and is suitable for bremsstrahlung single photon emission computed tomography (BS SPECT) and positron emission tomography (PET); meanwhile, some others, such as ¹³¹I, ¹⁵³Sm, ¹⁶⁶Ho, ¹⁷⁷Lu, ¹⁸⁶Re, and ¹⁸⁸Re, emit both β and γ rays, enabling embolism beads to play a role in both therapy and single photon emission computed tomography (SPECT) imaging. During TARE, concomitant imaging provide additive diagnostic information and help to guide the course of liver cancer treatment. Therefore, we review the theranostic radionuclides that have been used or could potentially be used in TARE for liver cancer and focus on the clinical benefits of diagnostic applications, including real-time monitoring of embolism beads, evaluating irradiation dose, predicting therapy effects, and corresponding adjustments to TARE.

Timeline of Translational Formulation Technologies for Cancer Therapy: Successes, Failures, and Lessons Learned Therefrom

Over the past few decades, the field of cancer therapy has seen a significant change in the way in which formulations are designed and developed, resulting in more efficient products that allow us to ultimately achieve improved drug bioavailability, efficacy, and safety. However, although many formulations have entered the market, many others have fallen by the wayside leaving the scientific community with several lessons to learn. The successes (and failures) achieved with formulations that have been approved in Europe and/or by the FDA for the three major types of cancer therapy (peptide-based therapy, chemotherapy, and radiotherapy) are reviewed herein, covering the period from the approval of the first prolonged-release system for hormonal therapy to the appearance of the first biodegradable microspheres intended for chemoembolization in 2020. In addition, those products that have entered phase III clinical trials that have been active over the last five years are summarized in order to outline future research trends and possibilities that lie ahead to develop clinically translatable formulations for cancer treatment.

Identification of APEX2 as an oncogene in liver cancer

BACKGROUND

DNA damage is one of the critical contributors to the occurrence and development of some cancers. APEX1 and APEX2 are the most important molecules in the DNA damage, and APEX1 has been identified as a diagnostic and prognostic biomarker in liver hepatocellular carcinoma (LIHC). However, the expression of APEX2 and its functional mechanisms in LIHC are still unclear.

AIM

To examine the expression of APEX2 and the potential mechanism network in LIHC.

METHODS

We conducted a pan-cancer analysis of the expression of APEX1 and APEX2 using the interactive TIMER tool. GEO datasets, including GSE14520, GSE22058, and GSE64041, were used to compare the APEX2 expression level in tumor tissues and adjacent non-tumor tissues. Then, we calculated the 5-year survival rate according to the web-based Kaplan-Meier analysis. We included the TCGA liver cancer database in GSEA analysis based on the high and low APEX2 expression, showing the potential mechanisms of APEX2 in LIHC. After that, we conducted Pearson correlation analysis using GEPIA2. Next, we performed quantitative polymerase chain reaction (qPCR) assay to examine the APEX2 levels in normal liver cell line LO2 and several liver cancer cell lines, including HepG2, Huh7, SMMC7721, and HCCLM3. APEX2 in HCCLM3 cells was knocked down using small interfering RNA. The role of APEX2 in cell viability was confirmed using CCK-8. Dual-luciferase reporter assay was performed to examine the promoter activity of CCNB1 and MYC.

RESULTS

APEX1 and APEX2 are both highly expressed in the tumor tissues of BLCA, BRCA, CHOL, COAD, ESCA, HNSC, LIHC, LUAD, LUSC, READ, and STAD. APEX2 overexpression in LIHC was validated using GSE14520, GSE22058, and GSE64041 datasets. The survival analysis showed that LIHC patients with high expression of APEX2 had a lower overall survival rate, even in the AJCC T1 patients. High level of APEX2 could indicate a lower overall survival rate in patients with or without viral hepatitis. The GSEA analysis identified that kinetochore and spindle microtubules are the two main cellular components of APEX2 in GO Ontology. APEX2 was also positively associated with molecular function regulation of chromosome segregation and DNA replication. The results of KEGG analysis indicated that APEX2 expression was positively correlated with cell cycle pathway and pro-oncogenic MYC signaling. Pearson correlation analysis showed that APEX2 had a significant positive correlation with CCNB1 and MYC. APEX2 level was higher in liver cancer cell lines than in normal liver LO2 cells. Small interfering RNA could knock down the APEX2 expression in HCCLM3 cells. Knockdown of APEX2 resulted in a decrease in the viability of HCCLM3 cells as well as the expression and promoter activity of CCNB1 and MYC.

CONCLUSION

APEX2 is overexpressed in LIHC, and the higher APEX2 level is associated with a worse prognosis in overall survival. APEX2 is closely involved in the biological processes of chromosome segregation and DNA replication. APEX2 expression is positively correlated with the pro-oncogenic pathways. Knockdown of APEX2 could inhibit the cell viability and CCNB1 and MYC pathways, suggesting that APEX2 is an oncogene in LIHC, which could be a potential pharmaceutic target in the anti-tumor therapy.

Apoptin as a Tumor-Specific Therapeutic Agent: Current Perspective on Mechanism of Action and Delivery Systems

Cancer remains one of the leading causes of death worldwide in humans and animals. Conventional treatment regimens often fail to produce the desired outcome due to disturbances in cell physiology that arise during the process of transformation. Additionally, development of treatment regimens with no or minimum side-effects is one of the thrust areas of modern cancer research. Oncolytic viral gene therapy employs certain viral genes which on ectopic expression find and selectively destroy malignant cells, thereby achieving tumor cell death without harming the normal cells in the neighborhood. Apoptin, encoded by Chicken Infectious Anemia Virus' VP3 gene, is a proline-rich protein capable of inducing apoptosis in cancer cells in a selective manner. In normal cells, the filamentous Apoptin becomes aggregated toward the cell margins, but is eventually degraded by proteasomes without harming the cells. In malignant cells, after activation by phosphorylation by a cancer cell-specific kinase whose identity is disputed, Apoptin accumulates in the nucleus, undergoes aggregation to form multimers, and prevents the dividing cancer cells from repairing their DNA lesions, thereby forcing them to undergo apoptosis. In this review, we discuss the present knowledge about the structure of Apoptin protein, elaborate on its mechanism of action, and summarize various strategies that have been used to deliver it as an anticancer drug in various cancer models.

A kit based methodology for convenient formulation of 166Ho-Chitosan complex for treatment of liver cancer

The effectiveness of ¹⁶⁶Ho-chitosan complex as a radiopharmaceutical for trans-arterial radiation therapy of liver cancer has been established in clinical trials. We have developed a simple kit-bade strategy for convenient formulation of therapeutically relevant doses of ¹⁶⁶Ho-chitosan complex in a hospital radiopharmacy in order to facilitate its widespread utilization. Quality control studies established the suitability of the radiopharmaceutical formulated using the developed strategy for in vivo administration. Biodistribution studies in normal Wistar rats showed excellent retention of the radiopharmaceutical in the liver, thus, paving the way towards utility of this approach in clinical context.

Optimization of the radiolabelling method for improved in vitro and in vivo stability of 90Y-albumin microspheres

Biologically stable ⁹⁰Y-labelled albumin microspheres (AMS) were developed by optimizing the process of their preparation. Three formulations of ⁹⁰Y-AMS were initially prepared with high radiolabelling yield but depending on the step when the radionuclide ⁹⁰Y and DTPA chelator were added, radiolabelled microspheres with different in vitro and in vivo stability were obtained. DTPA was proved as a useful chelating agent that tightly links radionuclide ⁹⁰Y to albumin. Also, AMS radiolabelled via DTPA during preparation and before microspheres stabilization, showed significant in vitro and in vivo stability ready for the potential use in selective internal radiation therapy.

Rhenium-188 Labeled Radiopharmaceuticals: Current Clinical Applications in Oncology and Promising Perspectives

Rhenium-188 (¹⁸⁸Re) is a high energy beta-emitting radioisotope with a short 16.9 h physical half-life, which has been shown to be a very attractive candidate for use in therapeutic nuclear medicine. The high beta emission has an average energy of 784 keV and a maximum energy of 2.12 MeV, sufficient to penetrate and destroy targeted abnormal tissues. In addition, the low-abundant gamma emission of 155 keV (15%) is efficient for imaging and for dosimetric calculations. These key characteristics identify ¹⁸⁸Re as an important therapeutic radioisotope for routine clinical use. Moreover, the highly reproducible on-demand availability of ¹⁸⁸Re from the ¹⁸⁸W/¹⁸⁸Re generator system is an important feature and permits installation in hospital-based or central radiopharmacies for cost-effective availability of no-carrier-added (NCA) ¹⁸⁸Re. Rhenium-188 and technetium-99 m exhibit similar chemical properties and represent a “theranostic pair.” Thus, preparation and targeting of ¹⁸⁸Re agents for therapy is similar to imaging agents prepared with ^99mTc, the most commonly used diagnostic radionuclide. Over the last three decades, radiopharmaceuticals based on ¹⁸⁸Re-labeled small molecules, including peptides, antibodies, Lipiodol and particulates have been reported. The successful application of these ¹⁸⁸Re-labeled therapeutic radiopharmaceuticals has been reported in multiple early phase clinical trials for the management of various primary tumors, bone metastasis, rheumatoid arthritis, and endocoronary interventions. This article reviews the use of ¹⁸⁸Re-radiopharmaceuticals which have been investigated in patients for cancer treatment, demonstrating that ¹⁸⁸Re represents a cost effective alternative for routine clinical use in comparison to more expensive and/or less readily available therapeutic radioisotopes.