Transarterial Embolization Modulates the Immune Response within Target and Nontarget Hepatocellular Carcinomas in a Rat Model

Combination locoregional and systemic therapies in hepatocellular carcinoma

Locoregional therapies play a fundamental role in the treatment of patients with early and intermediate and locally advanced hepatocellular carcinomas. With encouraging recent advances in immunotherapy-based systemic therapies, locoregional therapies are being both promoted and challenged by new systemic therapy options. Combined locoregional and systemic therapies might enhance treatment outcomes compared with either option alone. This Series paper summarises the existing data on locoregional and systemic therapies for hepatocellular carcinoma, and discusses evidence from studies investigating their combination with a focus on their synergistic efficacy and safety.

Comparison of Liquid with Particle Embolics in a Translational Rat Model of Hepatocellular Carcinoma: Histologic and Radiographic Responses

PURPOSE

To compare the effectiveness of transarterial embolization (TAE) using a liquid embolic (LE) with that of TAE using a particle embolic (PE) based on radiographic and histologic responses in a translational rat model of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

HCC was induced in Wistar rats using diethylnitrosamine. Tumor response was determined through Response Evaluation Criteria in Solid Tumors applied to T2-weighted magnetic resonance (MR) imaging scans. Tumor necrosis and hypoxia were assessed through hematoxylin and eosin and pimonidazole staining, respectively. Statistical analyses were performed using chi-square tests, Kaplan-Meier estimates, logistic regression, and 1-way analysis of variance, with significance set at P < .05.

RESULTS

Twenty-nine rats were randomized to TAE with LE (n = 13), PE (n = 13), or sham (n = 3). LE TAE demonstrated a significantly higher objective response rate (83%) compared with PE TAE (28%; χ2 = 11.25; P = .0008). Complete responses were observed in 50% of the LE-treated tumors versus 10% in the PE-treated group. LE TAE prolonged local progression-free survival (hazard ratio, 0.31; P = .032). Histologic analysis of an additional 16 rats randomized to TAE with LE (n = 7), PE (n = 6), or sham (n = 3) showed greater necrosis in LE-treated tumors compared to PE-treated tumors. LE induced a significantly greater reduction in viable tumor tissue (P = .009) and proportionally larger necrotic and necrotic + hypoxic tissue areas compared with PE (P = .003).

CONCLUSIONS

LE significantly enhanced the therapeutic effectiveness of TAE in a rat model of HCC compared with PE. These results highlight the potential of LEs to improve ischemia and necrosis, thereby offering a promising option for improving the effectiveness of embolization for HCC treatment.

The efficacy of transcatheter arterial chemoembolization for hepatocellular carcinoma: is the alteration of the inflammation index important?

Introduction

Transcatheter arterial chemoembolization (TACE) is widely applied for locoregional malignant lesions control in intermediate and selected advanced hepatocellular carcinoma (HCC). Various inflammation indices, such as neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), systemic immune inflammatory index (SII), and Lymphocyte-to-C Reactive Protein Ratio (LCR) have been explored as tools for predicting the efficacy of TACE. However, the role and predictive value for dynamic changes of peripheral inflammatory indicators pre- and post-TACE remains unclear.

Objective

To explore the association between the alteration in inflammatory index and the efficacy and prognosis of TACE and to provide more evidence for early prediction of the efficacy of TACE.

Methods

This was a retrospective single-center study. HCC patients who received TACE as initial treatment were enrolled. The relationship between the alteration of inflammation indices (calculated as post-TACE minus pre-TACE measurements) and TACE efficacy and prognosis was investigated. Progression-free survival (PFS) was the primary endpoint, and treatment efficacy was evaluated based on mRECIST criteria.

Results

Before propensity score matching (PSM), the change in LMR was significantly associated with treatment effective rate, with the unelevated ΔLMR group achieving a 79.4% treatment effective rate compared to 36.4% in the elevated group (p < 0.001). The estimated median PFS was 9.7 months and 4.5 months in the unelevated and elevated group, with a significant difference (p = 0.016). After PSM, the treatment effective rate was 48.7 and 38.5% (p = 0.214), and the estimated median PFS was 8.9 and 5.5 months (p = 0.173) for the unelevated and elevated group, respectively.

Conclusion

Our study demonstrated that alteration of indices of peripheral inflammation, including ΔNLR, ΔLMR, ΔSII, and ΔPLR, may not be valuable prognostic markers for HCC patients who received TACE.

Efficacy and Safety of Transarterial Chemoembolization Combined with Lenvatinib Plus Programmed Death-1 Inhibitor for Hepatocellular Carcinoma with the Hepatic Vein and/or Inferior Vena Cava Tumor Thrombus

PURPOSE

The aim of this study was to assess the safety and effectiveness of transarterial chemoembolization (TACE) plus lenvatinib with a programmed death-1 (PD-1) inhibitor compared with TACE plus lenvatinib and TACE alone for hepatocellular carcinoma (HCC) with the hepatic vein and/or inferior vena cava tumor thrombus (HVTT and IVCTT).

METHODS

Data on HCC accompanied by HVTT and IVCTT from June 2015 to August 2022 were analyzed in this single-center retrospective study. Drug-eluting bead TACE (DEB-TACE) or conventional TACE (cTACE) was used. The primary study outcomes were overall survival (OS) and progression-free survival (PFS). Univariate and multivariate Cox analyses were performed to determine the predictive factors for OS and PFS. A subgroup analysis was conducted.

RESULTS

Overall, 214 patients were enrolled. Among them, 60 received triple therapy consisting of TACE, lenvatinib, and PD-1 inhibitors (TACE + L + P), 72 received dual therapy consisting of TACE and lenvatinib (TACE + L), and 82 received TACE alone. The TACE + L + P group (16.2; 95% confidence interval [CI]: 12.8-19.5 months) had a significantly longer median OS compared with the TACE + L group (11.2; 95% CI: 10.0-12.3 months) (P = 0.001) and the TACE group (8.3; 95% CI: 7.7-8.5 months) (P < 0.001); the TACE + L + P group (12.3; 95% CI: 10.9-13.7 months) had a significantly longer median PFS compared with the TACE + L group (8.5; 95% CI: 7.7-9.2 months) (P < 0.001) and the TACE group (6.2; 95% CI: 5.8 ~ 6.3 months) (P < 0.001). Multivariate Cox analysis demonstrated that treatment strategy was a significant factor for OS and PFS. Skin rash was more common in the triple therapy group and might be attributed to PD-1 ligand inhibitor therapy (33.33% vs. 16.66%, P = 0.026).

CONCLUSIONS

Triple therapy consisting of TACE plus lenvatinib with a PD-1 inhibitor showed promising efficacy for advanced HCC patients with HVTT and IVCTT, with manageable safety profiles.

Iodine-131 radioembolization boosts the immune activation enhanced by icaritin/resiquimod in hepatocellular carcinoma

Transarterial radioembolization (TARE) is a recommended locoregional strategy for intermediate hepatocellular carcinoma (HCC), whereas, the effect is insufficient to reverse the immunosuppression tumor microenvironment, and the overall benefits for patients remain to be improved. In this study, a multifunctional microsphere (MS) 131I-ICT/R848-MS is developed to propose an approach combined with TARE, icaritin (ICT) and immune modulator resiquimod (R848). ICT and iodine-131 (131I) radiation can induce immunogenic cell death, which, in combination with R848, will boost dendritic cell (DC) maturation. Decellularized liver model and SPECT/CT imaging revealed high specificity and long retention of microspheres. Radioactive distribution of 131I in tumor on 7 d following 131I-MS injection was over 7 times of that in normal liver tissue (4.26 ± 1.21 % ID/g vs 0.57 ± 0.23 % ID/g). 131I-ICT/R848-MS embolization brought significant immune activation, where the ratio of cytotoxic T lymphocytes to regulatory T cells in tumor sites upregulated from 1.75 ± 0.20 to 24.31 ± 1.79, and DC maturation in lymph nodes increased from 8.90 ± 1.51 % to 34.70 ± 3.12 %. Enhanced anti-tumor efficacy with no relapse was proved in rat orthotopic N1S1 HCC models. These results demonstrated the great potential of this multifunctional embolic agent to treat HCC through transarterial radio-immuno-chemoembolization (TARICE).

Transarterial Embolization Using an Inorganic Phosphate Binder Modulates Immunity- and Angiogenesis-Related Factors in a Rat Model of Liver Cancer

PURPOSE

To determine how low inorganic phosphate stress (LIPS) induced by sevelamer particle transarterial embolization (S-TAE) affects immune regulation and angiogenesis in hepatocellular carcinoma.

MATERIAL AND METHODS

Transcatheter arterial embolization (TAE) using conventional ethiodized oil plus polyvinyl alcohol microspheres and S-TAE, which depletes intratumoral inorganic phosphate, were conducted on a McA-RH7777 orthotopic liver tumor model in rats, followed by the assessment of alterations in immunity-related and angiogenesis-related factors. The cells were cultured under hypoxic conditions and stimulated with LIPS to analyze the modulation of programmed cell death 1 ligand (PD-L1), vascular endothelial growth factor (VEGF)-α, and transforming growth factor-β1 expression using western blotting, quantitative real-time polymerase chain reaction, and immunofluorescence assays. Cell migratory capacity and angiogenesis were also evaluated.

RESULTS

TAE increased the expression of neoplastic PD-L1 and VEGF-α, and S-TAE downregulated the expression of PD-L1, VEGF-α, and transforming growth factor TGF-β1 and augmented the infiltration of CD8+ T cells, and thereby inhibited angiogenesis and activated anticancer immunity. In vitro, the study demonstrated that LIPS inhibited hypoxia-induced upregulation of PD-L1 expression and the hypoxia-inducible factor-1α/VEGF-α axis. Moreover, LIPS inhibited the tube formation ability of human umbilical vein endothelial cells and the migration ability and epithelial-mesenchymal transition process of cancer cells under hypoxic conditions.

CONCLUSIONS

S-TAE inhibited the expression of PD-L1 and VEGF-α, thereby activating antitumor immunity and suppressing tumor angiogenesis. The biology of tumors under LIPS suggests the potential therapeutic value of phosphate depletion using sevelamer for S-TAE.

Transarterial Chemoembolization With or Without Systemic Therapy for Unresectable Hepatocellular Carcinoma: A Retrospective Comparative Study

INTRODUCTION

Standard treatments provide limited benefits for patients with intermediate- or advanced-stage hepatocellular carcinoma (HCC). This retrospective observational study aimed to assess the potential improvements in outcomes associated with systemic therapies in patients receiving transarterial chemoembolization (TACE) for initially unresectable HCC.

METHODS

Between February 2019 and March 2023, we reviewed patients diagnosed with intermediate-to-advanced HCC who were treated with either TACE or TACE combined with antiangiogenic agents and immune checkpoint inhibitors (combination therapy) as their initial treatment. To address potential confounding biases, patients were further stratified into surgical and non-surgical cohorts, and separate analyses were conducted. The primary endpoints were progression-free survival (PFS) and overall survival (OS), with safety profiles also evaluated.

RESULTS

Among 279 patients with initially unresectable intermediate or advanced HCC, 156 successfully underwent curative-intent liver resection after preoperative treatments (TACE group, n = 69; combination group, n = 87), while 123 patients continued with non-surgical treatments (TACE group, n = 31; combination group, n = 92). After propensity score matching, 26 matched patient pairs were generated within the non-surgical cohort. The combination group exhibited significantly improved PFS in non-surgical patients compared with the TACE group (9.4 vs. 7.2 months, p = 0.043). Cox proportional hazards analysis further confirmed that combination therapy was associated with improved PFS (hazard ratio = 0.476, 95% confidence interval: 0.257-0.883, p = 0.019). For surgical patients exceeding the up-to-seven criteria, the combination group demonstrated superior median PFS (18.0 vs. 14.6 months, p = 0.03) and OS (not reached vs. 50.1 months, p = 0.049) compared with the TACE group. Adverse events were manageable, with no treatment-related fatalities reported.

CONCLUSION

Combination therapy with TACE demonstrated enhanced survival benefits for patients with intermediate to advanced HCC, particularly in surgical patients with higher tumor burdens.

The prognostic role of ACSL4 in postoperative adjuvant TACE-treated HCC: implications for therapeutic response and mechanistic insights

BACKGROUND

The response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE) treatment and its underlying mechanisms remain elusive. This study investigates the role of enzymes involved in fatty acid activation, specifically Acyl-CoA synthetase long chain 4 (ACSL4), in HCC patients treated with postoperative adjuvant TACE (PA-TACE) and in nutrient-deprived HCC cells.

METHODS

We examined the expression of ACSL4 and its family members in HCC clinical samples and cell lines. The clinical significance of ACSL4, particularly regarding the prognosis of patients treated with PA-TACE, was assessed using two independent HCC cohorts. We further explored the role of ACSL4 in glucose starvation-induced cell death in HCC cells and xenograft mouse models.

RESULTS

Among the family members, ACSL4 is the most up-regulated enzyme, associated with poor survival in HCC patients, particularly in post-recurrent TACE-treated patients in a Singapore cohort. ACSL4 is essential for HCC cell survival in response to glucose starvation, rather than to hypoxia or to the combination of hypoxia with doxorubicin or cisplatin. ACSL4-mediated arachidonic acid (AA) metabolism supports mitochondrial β-oxidation and energy production. CCAAT/enhancer binding protein α (CEBPA) transcriptionally regulates ACSL4 by binding 3 motifs (-623 to -613, -1197 to -1187 and -1745 to -1735) of ACSL4 upstream promoter region, enhancing its pro-survival effects. Furthermore, canagliflozin (Cana), a clinical-approved drug for type 2 diabetes, mimics glucose starvation and inhibits the growth of ACSL4-low xenograft tumors. Moreover, high ACSL4 or CEBPA expressions correlate with increased recurrence susceptibility after PA-TACE in the China-Guangxi HCC cohort.

CONCLUSIONS

The CEBPA-ACSL4 pathway is critical in protecting HCC cells from glucose starvation-induced cell death, suggesting that ACSL4 and CEBPA could serve as valuable prognostic indicators and potential therapeutic targets in the context of PA-TACE treatment for HCC.

Efficacy of Atezolizumab Plus Bevacizumab Combined with Transarterial Chemoembolization for Unresectable Hepatocellular Carcinoma: A Real-World Study

Purpose

Transarterial chemoembolization (TACE), when used in combination with immunotherapy and antiangiogenic therapy, has been shown to have synergistic anticancer effects. The aim of this study was to further assess the efficacy and safety of TACE combined with atezolizumab and bevacizumab in the treatment of unresectable hepatocellular carcinoma (HCC) in the real world.

Methods

Between August 2021 and September 2023, clinical information was collected from consecutive HCC patients who received treatment via TACE-Atezo/Bev at four tertiary institutions. This study evaluated the objective response rate (ORR), overall survival (OS), and progression-free survival (PFS) as outcomes. Predictors for OS and PFS were also analyzed. Treatment-related adverse events (TRAEs) were recorded and assessed.

Results

Ninety-two patients were enrolled in this study, with a median follow-up duration of 14.1 months. The ORRs based on the modified Response Evaluation Criteria in Solid Tumors (RECIST) and RECIST 1.1 criteria were 54.3% and 41.3%, respectively. The median OS and PFS of the patients were 15.9 months [95% confidence interval (CI), 14.5-17.2 months] and 9.1 months (95% CI, 7.4-10.8 months), respectively. Multivariate analyses revealed that the Eastern Cooperative Oncology Group score and neutrophil‒lymphocyte ratio were independent risk factors for OS, whereas tumor size and extrahepatic metastasis were independent risk factors for PFS. Grade 3/4 TRAEs occurred in 16.3% (15/92) of the patients and were controlled conservatively.

Conclusion

The combination of Atezo/Bev with TACE demonstrated acceptable synergistic therapeutic effects and manageable safety profiles in patients with unresectable HCC.

Transarterial Embolization Enhances Programmed Cell Death Ligand 1 Expression and Influences CD8+T Lymphocytes Cytotoxicity in an Orthotopic Hepatocellular Carcinoma Rat Model

PURPOSE

To investigate the influence of transarterial embolization (TAE) on programmed cell death-ligand 1(PD-L1) expression and CD8+T tumour infiltrative lymphocyte cytotoxicity in the Sprague-Dawley (SD) rat model of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

An orthotopic HCC model was established in twenty SD rats treated with TAE (lipiodol, n = 10) or sham (normal saline, n = 10) using homologous N1S1 hepatoma cells. Rats were euthanized 1 week after embolization. Flow cytometry was used to assess the proportion of CD4+T, CD8+T and programmed cell death-1+(PD-1+) CD8+T lymphocytes in the spleens and tumours. Distribution of CD8+T, granzyme-B+CD8+T lymphocytes and PD-L1+ cells was assessed by immunohistochemistry (IHC) or multiplex IHC. p value < 0.05 was considered statistically significant.

RESULTS

The CD4/CD8 ratio and PD-1+CD8+ T lymphocytes exhibited higher values in TAE-treated tumours compared to sham-treated tumours (p = 0.021 and p = 0.071, respectively). Conversely, the number of CD8+T lymphocytes was decreased in TAE-treated tumours (p = 0.043), especially in the central region (p = 0.045). However, more CD8+T lymphocytes were found infiltrating the marginal region than central region in TAE-treated tumours (p = 0.046). The proportion of granzyme-B+CD8+T lymphocytes and the PD-L1 positive areas was elevated in tumours that treated with TAE (p all < 0.05). There was a negative correlation between PD-L1 expression and the number of infiltration of CD8+ T lymphocytes (p = 0.036).

CONCLUSIONS

Immune cells are distributed unevenly in the tumours after TAE. The intrinsic induction state of the tumour after embolization may be insufficient to elicit a maximal response to PD-1/PD-L1 inhibitors.

Advancements in hydrogel-based embolic agents: Categorized by therapeutic mechanisms

BACKGROUND

Transcatheter arterial embolization (TAE) is a crucial technique in interventional radiology. Hydrogel-based embolic agents show promise due to their phase transition and drug-loading capabilities. However, existing categorizations of these agents are confusing.

AIMS

This review tackles the challenge of categorizing hydrogel-based embolic agents based on their therapeutic mechanisms, including transportation, accumulation, interaction, and elimination. It also addresses current challenges and controversies in the field while highlighting future directions for hydrogel-based embolicagents.

MATERIALS AND METHODS

We conducted a systematic review of papers published in PUBMED from 2004 to 2024, focusing primarily on preclinical trials.

RESULTS

Various kinds of hydrogel embolic agents were introduced according to their therapeutic mechanisms.

DISCUSSION

Most hydrogel embolic agents were specifically designed for effective accumulation and interaction. Recent advancement highlight the potential of multifunctional hydrogel embolic agents.

CONCLUSION

This new categorizations provided valuable insights into hydrogel embolic agents, potentially guiding material scientists and interventional radiologists in the development of novel hydrogel embolic agents in transarterial embolization.

Combined transarterial chemoembolization and tislelizumab for patients with unresectable hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) often presents as unresectable, necessitating effective treatment modalities. Combining transarterial chemoembolization (TACE) with immunotherapy and targeted therapy has shown promise, yet real-world evidence is needed.

AIM

To investigate effectiveness and safety of TACE with tislelizumab ± targeted therapy for unresectable HCC in real-world setting.

METHODS

This retrospective study included patients with unresectable HCC receiving combined treatment of TACE and tislelizumab. The clinical outcomes included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and disease control rate (DCR). All patients were evaluated according to the mRECIST criteria. The adverse event (AE) was also assessed.

RESULTS

In this study of 56 patients with median follow-up of 10.9 months, 7 had previous immunotherapy. Tislelizumab was administered before TACE in 21 (37.50%) and after in 35 (62.50%) patients, with 91.07% receiving concurrent targeted therapy. Median PFS was 14.0 (95%CI: 7.0-18.00) months, and OS was 28 (95%CI: 2.94-53.05) months. Patients with prior immunotherapy had shorter PFS (6 vs. 18 months, P = 0.006). Overall ORR and DCR were 82.14% and 87.50%. Grade ≥ 3 treatment-related AEs included increased alanine aminotransferase (8.93%), aspartate aminotransferase (10.71%), and total bilirubin (3.57%).

CONCLUSION

The combination of TACE and tislelizumab, with or without targeted therapy, demonstrated promising efficacy and safety in unresectable HCC, especially in immunotherapy-naive patients, warranting further prospective validation studies.

Efficacy of Atezolizumab Plus Bevacizumab-Transcatheter Arterial Chemoembolization Sequential Therapy for Patients with Intermediate-Stage Hepatocellular Carcinoma

This retrospective study aimed to evaluate the impact of atezolizumab plus bevacizumab-transcatheter arterial chemoembolization (TACE) sequential therapy in unresectable hepatocellular carcinoma (HCC), especially in patients with intermediate-stage HCC. A total of 212 patients were enrolled and categorized into the Atez/Bev-TACE sequential therapy (n = 23) or Atez/Bev monotherapy group (n = 189) between 2020 and 2024. Of these, patients with intermediate-stage HCC were categorized into the Atez/Bev-TACE sequential (n = 18) or Atez/Bev monotherapy group (n = 91). The best objective response rate, disease control rate, and median progression-free survival (PFS) after TACE were 73.9%, 82.6%, and 6.1 months, respectively. The PFS after TACE was significantly higher in the Atez/Bev sequential therapy group than in the no-Atez/Bev-administration group after TACE (6.9 months vs. 5.0 months, p = 0.025). The median overall survival (OS) was significantly higher in the Atez/Bev-TACE sequential therapy group than in the Atez/Bev monotherapy group for intermediate-stage HCC (34.9 months vs. 17.8 months; p = 0.016). Independent factors associated with OS were low alpha-fetoprotein levels, modified albumin-bilirubin 1 or 2a levels, and Atez/Bev-TACE sequential therapy. Atez/Bev-TACE sequential therapy improved prognosis compared with Atez/Bev monotherapy in patients with intermediate-stage HCC. Moreover, Atez/Bev should be readministered after TACE.

Immunotherapy and transarterial embolization in patients with metastatic melanoma: a retrospective cohort study

Aim: To investigate how the sequence of checkpoint immunotherapy (CPI) and transarterial embolization (TAE) affects overall survival (OS) of patients with metastatic melanoma.Materials & methods: This retrospective cohort study included 65 patients with metastatic melanoma who underwent both TAE and CPI between September 2011 and January 2022.Results: Significantly higher OS was seen in patients who received CPI before and after embolization (22 months, 95% CI 14-NR, p < 0.001) compared with only before embolization (4.5 months 95% CI, 14-NR). ≤3 hepatic metastasis (p < 0.01), more TAE procedures (p < 0.001) and CPI sequence (before and after embolization) (p < 0.001) were independent predictors of survival.Conclusion: Metastatic melanoma patients who underwent TAE have longer survival when CPI was sequenced both before and after embolization.

Consistent efficacy of hepatic artery infusion chemotherapy irrespective of PD‑L1 positivity in unresectable hepatocellular carcinoma

Atezolizumab/bevacizumab is the first line of treatment for unresectable hepatocellular carcinoma (HCC), combining immune checkpoint inhibitor and anti-VEGF monoclonal antibodies. Hepatic arterial infusion chemotherapy (HAIC) is administered when the above-described combination fails to confer sufficient clinical benefit. The present study aimed to explore the association between tumor programmed cell death-ligand 1 (PD-L1) positivity and HAIC response. A total of 40 patients with HCC who had undergone HAIC with available biopsy samples obtained between January 2020 and May 2023 were retrospectively enrolled. Tumor response, progression-free survival (PFS), disease control rate (DCR) and overall survival (OS) were evaluated. PD-L1 expression in tumor samples was assessed using a combined positivity score. The response rates of HAIC-treated patients with advanced HCC after failure of atezolizumab/bevacizumab combination therapy were recorded. OS (P=0.9717) and PFS (P=0.4194) did not differ between patients with and without PD-L1 positivity. The objective response rate (P=0.7830) and DCR (P=0.7020) also did not differ based on PD-L1 status. In conclusion, the current findings highlight the consistent efficacy of HAIC, regardless of PD-L1 positivity.

Landscape and prognostic values of lymphocytes in patients with hepatocellular carcinoma undergoing transarterial embolization

Transarterial embolization, the first-line treatment for hepatocellular carcinoma, does not always lead to promising outcomes in all patients. A better understanding of how the immune lymphocyte changes after transarterial embolization might be the key to improve the efficacy of transarterial embolization. However, there are few studies evaluating immune lymphocytes in transarterial embolization patients. Therefore, we aimed to evaluate the short- and long-term effects of transarterial embolization on lymphocyte subsets in patients with hepatocellular carcinoma to identify those that predict transarterial embolization prognosis. Peripheral blood samples were collected from 44 patients with hepatocellular carcinoma at the following time points: 1 d before the initial transarterial embolization, 3 d after the initial transarterial embolization, and 1 mo after the initial transarterial embolization and subjected to peripheral blood mononuclear cell isolation and flow cytometry. Dynamic changes in 75 lymphocyte subsets were recorded, and their absolute counts were calculated. Tumor assessments were made every 4 to 6 wk via computed tomography or magnetic resonance imaging. Our results revealed that almost all lymphocyte subsets fluctuated 3 d after transarterial embolization, but only Tfh and B cells decreased 1 mo after transarterial embolization. Univariate and multivariate Cox regression showed that high levels of Th2 and conventional killer Vδ2 cells were associated with longer progressive-free survival after transarterial embolization. Longer overall survival after transarterial embolization was associated with high levels of Th17 and viral infection-specific Vδ1 cells and low levels of immature natural killer cells. In conclusion, transarterial embolization has a dynamic influence on the status of lymphocytes. Accordingly, several lymphocyte subsets can be used as prognostic markers for transarterial embolization.

Histoplasty Modification of the Tumor Microenvironment in a Murine Preclinical Model of Breast Cancer

PURPOSE

To develop a noninvasive therapeutic approach able to alter the biophysical organization and physiology of the extracellular matrix (ECM) in breast cancer.

MATERIALS AND METHODS

In a 4T1 murine model of breast cancer, histoplasty treatment with a proprietary 700-kHz multielement therapy transducer using a coaxially aligned ultrasound (US) imaging probe was used to target the center of an ex vivo tumor and deliver subablative acoustic energy. Tumor collagen morphology was qualitatively evaluated before and after histoplasty with second harmonic generation. Separately, mice bearing bilateral 4T1 tumors (n = 4; total tumors = 8) were intravenously injected with liposomal doxorubicin. The right flank tumor was histoplasty-treated, and tumors were fluorescently imaged to detect doxorubicin uptake after histoplasty treatment. Next, 4T1 tumor-bearing mice were randomized into 2 treatment groups (sham vs histoplasty, n = 3 per group). Forty-eight hours after sham/histoplasty treatment, tumors were harvested and analyzed using flow cytometry.

RESULTS

Histoplasty significantly increased (P = .002) liposomal doxorubicin diffusion into 4T1 tumors compared with untreated tumors (2.12- vs 1.66-fold increase over control). Flow cytometry on histoplasty-treated tumors (n = 3) demonstrated a significant increase in tumor macrophage frequency (42% of CD45 vs 33%; P = .022) and a significant decrease in myeloid-derived suppressive cell frequency (7.1% of CD45 vs 10.3%; P = .044). Histoplasty-treated tumors demonstrated increased CD8+ (5.1% of CD45 vs 3.1%; P = .117) and CD4+ (14.1% of CD45 vs 11.8%; P = .075) T-cell frequency.

CONCLUSIONS

Histoplasty is a nonablative focused US approach to noninvasively modify the tumor ECM, increase chemotherapeutic uptake, and alter the tumor immune microenvironment.

Locoregional therapies for hepatocellular carcinoma: The current status and future perspectives

Hepatocellular carcinoma (HCC) is one of the most common cancers and a leading cause of cancer-related mortality. Locoregional therapies (LRTs) play a crucial role in HCC management and are selectively adopted in real-world practice across various stages. Choosing the best form of LRTs depends on technical aspects, patient clinical status and tumour characteristics. Previous studies have consistently highlighted the efficacy of combining LRTs with molecular targeted agents in HCC treatment. Recent studies propose that integrating LRTs with immune checkpoint inhibitors and molecular targeted agents could provide substantial therapeutic benefits, a notion underpinned by both basic and clinical evidence. This review summarised the current landscape of LRTs in HCC and discussed the anticipated outcomes of combinations with immunotherapy regimens.

Utility and predictive value of the CRAFITY score in advanced hepatocellular carcinoma treated with transarterial chemoembolization plus tyrosine kinase inhibitors and PD-1 inhibitor

BACKGROUND

The prognostic significance of the CRAFITY score (CRP and AFP in ImmunoTherapY) has been demonstrated in hepatocellular carcinoma (HCC) patients receiving immunotherapy. The purpose of this study was to investigate the utility and the predictive value of CRAFITY score in HCC after transarterial chemoembolization (TACE) in combination with tyrosine kinase inhibitors (TKIs) and immunotherapy.

MATERIALS AND METHODS

Data from patients with advanced HCC treated with TACE plus TKIs and PD-1 inhibitor from January 2019 to June 2022 were collected and analyzed retrospectively. Patients with AFP ≥ 100 ng/mL and those with CRP ≥ 1 mg/dL were assigned a CRAFITY score of 1 point. Patients were divided into three groups according to their CRAFITY score (CRAFITY-low, 0 points; CRAFITY-intermediate, 1 point; and CRAFITY-high, 2 points). The differences in overall survival (OS), progression-free survival (PFS) and adverse events (AEs) were compared among the three groups. Tumor response was evaluated at 3, 6 and 12 months after the first combination treatment. Risk factors for OS and PFS were assessed.

RESULTS

A total of 70 patients were included. The patients were assigned CRAFITY scores of 0 points (CRAFITY-low, n = 25 [35.71%]), 1 point (CRAFITY-intermediate, n = 29 [41.42%]), and 2 points (CRAFITY-high, n = 16 [22.81%]). Multivariate analysis showed that lower CRAFITY score was an independent factor for the improved OS (P =.045) and PFS (P <.001). TACE session was also associated with the OS (P =.048) in the multivariate analysis. The CRAFITY-low cohort achieved a higher objective response rate (ORR) at the 3-month evaluation of tumor response. However, there was no significant difference in ORR and disease control rate (DCR) observed at the 6-month follow-up. DCR showed a statistically significant difference among three groups during the 12-month follow-up period. The percentage of patients with protein urea was highest in the CRAFITY-high group. No significance differences were observed in grade ≥ 3 AEs in three groups.

CONCLUSION

The CRAFITY score is simple and could be useful for predicting treatment outcomes, tumor response and AEs of the HCC patients receiving TACE plus TKIs and PD-1 inhibitor therapy.

Improvement of rat hepatocellular carcinoma model induced by diethylnitrosamine

OBJECTIVE

To construct a new diethylnitrosamine (DEN)-induced rat hepatocellular carcinoma (HCC) model with short induction time, high incidence, and survival rate.

METHODS

60 male Sprague-Dawley rats were randomly divided into 4 groups: the control group, the model A (MA) group, the model B (MB) group, and the model C (MC) group. The control group was intraperitoneally injected with 0.9% saline for 6 weeks. The MA group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks. The MB group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks, and discontinued the induction for 2 weeks. The MC group was injected with the DEN solution at 30 mg/kg three times a week for 8 weeks. The levels of albumin (ALB), alanine transaminase (ALT), and aspartate aminotransferase (AST) in serum were assayed. Meanwhile, the pathological conditions, apoptosis of hepatocytes, expression of NF-κBp65, and the reactive oxygen species level were detected.

RESULTS

All rats in the control group and the MA group survived, and none of the rats occurred HCC. HCC occurred in rats of the MB group and the MC group. The serum ALB level in the MB group was higher than that in the MC group. The serum ALT and AST levels and the number of proliferating and apoptotic hepatocyte cells in the MB group were lower than those in the MC group. The expression of ROS- and NF-κBp6- positive cells in the MA group, MB group, and MC group were significantly higher than that of the control group.

CONCLUSION

This study developed a new DEN-induced rat HCC model with short induction time, high incidence, and survival rate. NF-κB pathway may be one of the main pathways involved in the development of this model.

Advances and Challenges in Interventional Immuno-Oncology Locoregional Therapies

Interventional immuno-oncology is making strides in locoregional therapies to address complex tumor microenvironments. Long-standing interventional radiology cancer therapies, such as tumor ablation and embolization, are being recharacterized in the context of immunotherapy. Intratumoral injections, such as those of genetically engineered or unaltered viruses, and the delivery of immune cells, antibodies, proteins, or cytokines into targeted tumors, along with advancements in delivery techniques, have produced promising results in preliminary studies, indicating their antitumor effectiveness. Emerging strategies using DNA scaffolding, polysaccharides, glycan, chitosan, and natural products are also showing promise in targeted cancer therapy. The future of interventional immuno-oncology lies in personalized immunotherapies that capitalize on individual immune profiles and tumor characteristics, along with the exploration of combination therapies. This study will review various interventional immuno-oncology strategies and emerging technologies to enhance delivery of therapeutics and response to immunotherapy.

PD1 and TIM3 Expression is Associated with Very Early Hepatocellular Carcinoma Recurrence After Percutaneous Thermal Ablation

Purpose

Percutaneous thermal ablation (PTA) is a cornerstone in the management of early-stage hepatocellular carcinoma (HCC). However, intrahepatic distant recurrence (IDR) occurs in the majority of patients after PTA. The aim of this study was to evaluate the immune signature associated with very early IDR.

Patients and Methods

Thirty-one patients (26 men, 5 women; mean age:72.4 ± 8.6; age range:57-86 years) who underwent PTA for HCC were included in this study. After PTA for HCC, patients were followed and later divided into two groups: a "very early recurrence" group in case of IDR within 12 months after PTA, and a "prolonged recurrence-free" group in case of no recurrence before 12 months of follow-up. Freshly harvested intratumoral and nontumoral liver tissues and peripheral blood were obtained before PTA and explored by multiparametric flow cytometry.

Results

The frequency of PD1+CD4+ T cells was higher in the early recurrence group than in the prolonged recurrence-free group in the peripheral blood (24.3%, IQR: 22.3-36.5 vs 14.0%, IQR: 11.5-16.4, p<0.0001), in the nontumoral liver (37.9%, IQR: 36.0-50.0 vs 22.5%, IQR: 18.0-29.9, p=0.0004), and in the tumor (37.6%, IQR: 32.3-39.3 vs 24.0%, IQR: 20.0-30.3, p=0.0137). Similarly, the frequency of TIM+CD8+ T cells was higher in the very early recurrence group in the peripheral blood (p=0.0021), non-tumoral liver (p=0.0012), and tumor (p=0.0239).

Conclusion

The expression of immune checkpoint molecules, such as PD1 and TIM3 on T cells identified HCC patients at risk of very early IDR after PTA who would likely benefit from adjuvant immunotherapy. Thus, our study contributes to a better understanding of the potential association of PTA with adjuvant immunotherapies.

Circulating Regulatory T Cells: A Novel Marker Associated with Liver Metastasis and the Treatment Response of Transarterial Embolization in Gastroenteropancreatic Neuroendocrine Tumors

INTRODUCTION

The aim of this study was to investigate the role of circulating regulatory T cells (Tregs) as a novel marker associated with liver metastases and treatment response to transarterial embolization (TAE) in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

Circulating Tregs, defined as the CD4+CD25+CD127low/- population, were examined by flow cytometry in peripheral blood mononuclear cells from patients with GEP-NETs. Clinicopathological parameters, radiologic response, and hepatic progression-free survival (hPFS) data were collected.

RESULTS

The association between circulating Tregs and clinicopathological parameters was analyzed in 139 GEP-NET patients. Higher Treg levels were significantly associated with more progressive clinical features, including a higher WHO grade, more advanced TNM stage, and the presence of liver metastases. A Treg level ≥8.015% distinguished between patients with and without liver metastases. Among a cohort of 51 GEP-NET patients who were subjected to TAE for reducing liver metastasis burden, patients with higher Treg levels depicted unfavorable responses and significantly reduced hPFS after TAE treatment. We also revealed that patients with Treghigh (≥8.975%) displayed significantly shorter median hPFS than patients with Treglow (<8.975%). Additionally, after adjusting for other confounding clinical parameters, the association between Tregs and treatment response as well as hPFS remained significant, suggesting that Tregs may have a strong and independent prognostic impact in GEP-NETs.

CONCLUSION

Our data suggest that circulating Tregs are a novel immunological marker associated with liver metastases and treatment response to TAE in patients with GEP-NETs.

Lenvatinib Mitigates Transarterial Embolization-Induced Polarization of Tumor-Associated Macrophages in a Rat Hepatocellular Carcinoma Model

PURPOSE

To investigate the effect of transarterial embolization (TAE) on macrophage polarization and the modulatory effect of lenvatinib when used in combination with TAE in a rat hepatocellular carcinoma model.

MATERIALS AND METHODS

A N1S1-bearing orthotopic rat model was subjected to TAE and administered 5 mg/kg of lenvatinib. CD8+, CD68+, and CD206+ cells were examined in 4 groups: sham (n = 5), lenvatinib (n = 5), TAE (n = 5), and combination of TAE and lenvatinib (n = 5). Transcriptome analysis was performed to assess gene expression related to macrophage polarization in the sham, TAE, and combination groups. An in vitro coculture experiment with bone marrow-derived macrophages was performed to identify lenvatinib target in macrophage polarization.

RESULTS

There were no significant differences in the number of CD8+ and CD68+ cells among the 4 groups. Tumor-associated macrophage positivity for CD206 was significantly higher in the TAE group (58.1 ± 20.9) than in the sham (11.2 ± 14.3; P < .001) and combination (27.1 ± 19.7; P = .003) groups. In the transcriptome analysis, compared with the genes in the sham group, 5 macrophage polarization-related genes, including St6gal1, were upregulated by more than 1.5 fold in the TAE group and downregulated by more than 1.5 fold in the combination group. The coculture experiment showed that lenvatinib did not affect macrophages but affected N1S1 cells, leading to macrophage polarization.

CONCLUSIONS

TAE-induced M2 macrophage polarization. Lenvatinib administration with TAE could reprogram macrophage polarization, improving tumor immune microenvironment.

Combination Therapy of Immune Checkpoint Inhibitors with Locoregional Therapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is estimated to be the fourth leading cause of cancer-related deaths globally, and its overall prognosis is dismal because most cases are diagnosed at a late stage and are unamenable to curative treatment. The emergence of immune checkpoint inhibitors (ICIs) has dramatically improved the therapeutic efficacy for advanced hepatocellular carcinoma; however, their response rates remain unsatisfactory, partly because >50% of HCC exhibit an ICI-nonresponsive tumor microenvironment characterized by a paucity of cytotoxic T cells (immune-cold), as well as difficulty in their infiltration into tumor sites (immune excluded). To overcome this limitation, combination therapies with locoregional therapies, including ablation, transarterial embolization, and radiotherapy, which are usually used for early stage HCCs, have been actively explored to enhance ICI efficacy by promoting the release of tumor-associated antigens and cytokines, and eventually accelerating the so-called cancer-immunity cycle. Various combination therapies have been investigated in early- to late-phase clinical trials, and some have shown promising results. This comprehensive article provides an overview of the immune landscape for HCC to understand ICI efficacy and its limitations and, subsequently, reviews the status of combinatorial therapies of ICIs with locoregional therapy for HCC.

Comparable Clinical Outcomes Between Transarterial Chemoembolization or Hepatic Arterial Infusion Chemotherapy Combined with Tyrosine Kinase Inhibitors and PD-1 Inhibitors in Unresectable Hepatocellular Carcinoma

Purpose

To compare the treatment efficacy and safety of transarterial chemoembolization (TACE) or hepatic arterial infusion chemotherapy (HAIC) combined with tyrosine kinase inhibitors (TKIs) and programmed cell death protein-1 (PD-1) inhibitors for patients with unresectable hepatocellular carcinoma (HCC).

Patients and Methods

81 unresectable HCC patients were retrospectively analyzed, including 30 or 51 patients treated with either TKIs and PD-1 inhibitors combined with TACE (TTP) or HAIC (HTP), respectively. Tumor response and survival outcomes were compared.

Results

The median overall survival (mOS) was 21.0 months in the TTP group and 15.0 months in the HTP group (P = 0.525; HR = 1.23; 95% CI 0.66-2.29). The median progression-free survival (mPFS) was 6.7 months in the TTP group and 9.9 months in the HTP group (P = 0.160; HR = 0.70; 95% CI 0.42-1.16). After Propensity Score Matching (PSM), the mOS was 21.0 months in the TTP group and 18.0 months in the HTP group (P = 0.644; HR = 1.20; 95% CI 0.56-2.58). The mPFS was 6.4 months in the TTP group and 15.0 months in the HTP group (P = 0.028; HR = 0.49; 95% CI 0.26-0.93). The disease control rate in overall response (90.2% vs 76.7%, P = 0.116, before PSM; 91.7% vs 75.0%, P = 0.121, after PSM) and intrahepatic response (94.1% vs 80.0%, P = 0.070, before PSM; 91.7% vs 79.2%, P = 0.220, after PSM) were higher in the HTP group than in the TTP group.

Conclusion

Though including more advanced tumors, the clinical outcomes of HAIC combined with TKIs and PD-1 inhibitors are comparable to TACE-based combination therapy for unresectable HCC. Nevertheless, HTP significantly improved the PFS benefits in HCC patients with with large tumor burden or vascular invasion.

Silk fibroin-based embolic agent for transhepatic artery embolization with multiple therapeutic potentials

BACKGROUND

The excellent physicochemical and biomedical properties make silk fibroin (SF) suitable for the development of biomedical materials. In this research, the silk fibroin microspheres (SFMS) were customized in two size ranges, and then carried gold nanoparticles or doxorubicin to evaluate the performance of drug loading and releasing. Embolization efficiency was evaluated in rat caudal artery and rabbit auricular artery, and the in vivo distribution of iodinated SFMS (125I/131I-SFMS) after embolization of rat hepatic artery was dynamically recorded by SPECT. Transhepatic arterial radioembolization (TARE) with 131I-SFMS was performed on rat models with liver cancer. The whole procedure of selective internal radiation was recorded with SPECT/CT, and the therapeutic effects were evaluated with 18 F-FDG PET/CT. Lastly, the enzymatic degradation was recorded and followed with the evaluation of particle size on clearance of sub-micron silk fibroin.

RESULTS

SFMS were of smooth surface and regular shape with pervasive pores on the surface and inside the microspheres, and of suitable size range for TAE. Drug-loading functionalized SFMS with chemotherapy or radio-sensitization, and the enhanced therapeutic effects were proved in treating HUH-7 cells as lasting doxorubicin release or more lethal radiation. For artery embolization, SFMS effectively blocked the blood supply; when 131I-SFMS serving as the embolic agent, the good labeling stability and embolization performance guaranteed the favorable therapeutic effects in treating in situ liver tumor. At the 5th day post TARE with 37 MBq/3 mg 131I-SFMS per mice, tumor activity was quickly inhibited to a comparable glucose metabolism level with surrounding normal liver. More importantly, for the fragments of biodegradable SFMS, smaller sized SF (< 800 nm) metabolized in gastrointestinal tract and excreted by the urinary system, while SF (> 800 nm) entered the liver within 72 h for further metabolism.

CONCLUSION

The feasibility of SFMS as degradable TARE agent for liver cancer was primarily proved as providing multiple therapeutic potentials.

Efficacy and safety of lenvatinib plus PD-1 inhibitor with or without transarterial chemoembolization in unresectable hepatocellular carcinoma

PURPOSE

To compare the clinical benefit and tolerability of triple therapy of lenvatinib, programmed death 1 (PD-1) inhibitor, and transarterial chemoembolization (TACE) versus dual therapy of lenvatinib and PD-1 inhibitor in unresectable hepatocellular carcinoma (HCC) patients.

METHODS

Between October 2018 and September 2021, patients with unresectable HCC who received triple therapy of lenvatinib, PD-1 inhibitor, and TACE or dual therapy of lenvatinib and PD-1 inhibitor participated in this study. The efficacy was evaluated by survival and therapeutic response, and the tolerability was evaluated by the frequency and severity of key adverse events (AEs).

RESULTS

In total, 118 eligible patients with unresectable HCC who received combination therapy were included in this study. Among them, 60 patients received triple therapy of lenvatinib, PD-1 inhibitor, and TACE (L-P-T group), and 58 eligible patients received dual therapy of lenvatinib and PD-1 inhibitor (L-P group). Patients who received triple therapy had better overall survival (OS) [median, 29.0 vs. 17.8 months, p < 0.01] and progression-free survival (PFS) [median, 16.2 vs. 10.2 months, p < 0.01] than those who received dual therapy. The objective response rate (76.7 vs. 44.9%, p < 0.01) and disease control rate (96.7 vs. 75.9%, p < 0.01) in the L-P-T group were higher than in the L-P group, respectively. Multivariate analyses revealed that the treatment option and BCLC stage were independent prognostic factors for OS, while treatment option and tumor number were independent prognostic factors for PFS. The incidence and severity of AEs in the L-P-T group were comparable to those in the L-P group (any grade, 95.0 vs. 94.8%, p = 1.00; grade ≥ 3, 30.0 vs. 27.6%, p = 0.93).

CONCLUSION

Triple therapy of lenvatinib, PD-1 inhibitor, and TACE may achieve more favorable survival benefits than dual therapy of lenvatinib and PD-1 inhibitor in unresectable HCC patients with manageable safety profiles.

How Biology Guides the Combination of Locoregional Interventional Therapies and Immunotherapy for Hepatocellular Carcinoma: Cytokines and Their Roles

As most patients with hepatocellular carcinoma (HCC) are diagnosed at the intermediate or advanced stage and are no longer eligible for curative treatment, the overall survival rate of HCC remains unsatisfactory. Locoregional interventional therapies (LITs), and immune checkpoint inhibitor (ICI)-based immunotherapy, focus on treating HCC, but the efficacy of their individual application is limited. Therefore, the purpose of this review was to discuss the biological roles of cytokines and their therapeutic potential in the combination therapy of LITs and ICI-based immunotherapy. The two common techniques of LITs are ablative and transarterial therapies. Whether LITs are complete or incomplete can largely affect the antitumor immune response and tumor progression. Cytokines that induce both local and systemic responses to LITs, including interferons, interleukins, chemokines, TNF-α, TGF-β, VEGF, and HGF, and their roles are discussed in detail. In addition, specific cytokines that can be used as therapeutic targets to reduce immune-related adverse events (irAEs) are introduced. Overall, incomplete LITs in a tumor, combined with specific cytokines, are thought to be effective at improving the therapeutic efficacy and reducing treatment-induced irAEs, and represent a new hope for managing unresectable HCC.

Transarterial chemoembolization with PD-(L)1 inhibitors plus molecular targeted therapies for hepatocellular carcinoma (CHANCE001)

There is considerable potential for integrating transarterial chemoembolization (TACE), programmed death-(ligand)1 (PD-[L]1) inhibitors, and molecular targeted treatments (MTT) in hepatocellular carcinoma (HCC). It is necessary to investigate the therapeutic efficacy and safety of TACE combined with PD-(L)1 inhibitors and MTT in real-world situations. In this nationwide, retrospective, cohort study, 826 HCC patients receiving either TACE plus PD-(L)1 blockades and MTT (combination group, n = 376) or TACE monotherapy (monotherapy group, n = 450) were included from January 2018 to May 2021. The primary endpoint was progression-free survival (PFS) according to modified RECIST. The secondary outcomes included overall survival (OS), objective response rate (ORR), and safety. We performed propensity score matching approaches to reduce bias between two groups. After matching, 228 pairs were included with a predominantly advanced disease population. Median PFS in combination group was 9.5 months (95% confidence interval [CI], 8.4-11.0) versus 8.0 months (95% CI, 6.6-9.5) (adjusted hazard ratio [HR], 0.70, P = 0.002). OS and ORR were also significantly higher in combination group (median OS, 19.2 [16.1-27.3] vs. 15.7 months [13.0-20.2]; adjusted HR, 0.63, P = 0.001; ORR, 60.1% vs. 32.0%; P < 0.001). Grade 3/4 adverse events were observed at a rate of 15.8% and 7.5% in combination and monotherapy groups, respectively. Our results suggest that TACE plus PD-(L)1 blockades and MTT could significantly improve PFS, OS, and ORR versus TACE monotherapy for Chinese patients with predominantly advanced HCC in real-world practice, with an acceptable safety profile.

Ideal Size Range for Embolic Agents in Interventional Oncology Experiments Involving Rat Models of Hepatocellular Carcinoma

PURPOSE

To optimize future translational research, this study aimed to determine the ideal range of sizes for embolic agents in interventional oncology experiments utilizing rat models of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Fifty-five male Sprague-Dawley rats were divided into 2 groups to evaluate the distribution of microparticles and tumor response rates. After implanting hepatoma cells into the rodent liver, fluorescent microparticles of sizes ranging from 5 to 35 μm were administered via the hepatic artery. In the first group, the distribution of microparticles was evaluated in hepatoma-free rats, and the tumor necrosis rates following administration of a predetermined aliquot of microparticles (0.4 mL) were measured in tumor-bearing rats. Thereafter, the 3 microparticle sizes associated with the best tumor response rates were chosen for analysis of the tumor necrosis rates following hepatic artery embolization until angiographic stasis is achieved in the second group.

RESULTS

The tendency for microparticles to distribute in nontarget organs increased as the microparticle size decreased below 15 μm. Tumor necrosis rates tended to be higher in rats treated with 15-19-μm microparticles than in those treated with 19-24-μm or 19-24-μm microparticles. The in-group deviation of the tumor necrosis rates was highest for microparticle sizes of 19-24 and 25-35 μm, which implies the proximal embolization of the hepatic artery for larger microparticle sizes. However, there was no statistical significance among the 3 groups (P = .095).

CONCLUSIONS

The 15-19-μm embolic agents were the most favorable for causing tumor necrosis without nontarget toxicity in the transarterial treatments of rat HCC models.

Prospective Evaluation of Immune Activation Associated with Response to Radioembolization Assessed with PET/CT in Women with Breast Cancer Liver Metastasis

Background The impact of transarterial radioembolization (TARE) of breast cancer liver metastasis (BCLM) on antitumor immunity is unknown, which hinders the optimal selection of candidates for TARE. Purpose To determine whether response to TARE at PET/CT in participants with BCLM is associated with specific immune markers (cytokines and immune cell populations). Materials and Methods This prospective pilot study enrolled 23 women with BCLM who planned to undergo TARE (June 2018 to February 2020). Peripheral blood and liver tumor biopsies were collected at baseline and 1-2 months after TARE. Monocyte, myeloid-derived suppressor cell (MDSC), interleukin (IL), and tumor-infiltrating lymphocyte (TIL) levels were assessed with use of gene expression studies and flow cytometry, and immune checkpoint and cell surface marker levels with immunohistochemistry. Modified PET Response Criteria in Solid Tumors was used to determine complete response (CR) in treated tissue. After log-transformation, immune marker levels before and after TARE were compared using paired t tests. Association with CR was assessed with Wilcoxon rank-sum or unpaired t tests. Results Twenty women were included. After TARE, peripheral IL-6 (geometric mean, 1.0 vs 1.6 pg/mL; P = .02), IL-10 (0.2 vs 0.4 pg/mL; P = .001), and IL-15 (1.9 vs 2.4 pg/mL; P = .01) increased. In biopsy tissue, lymphocyte activation gene 3-positive CD4+ TILs (15% vs 31%; P < .001) increased. Eight of 20 participants (40% [exact 95% CI: 19, 64]) achieved CR. Participants with CR had lower baseline peripheral monocytes (10% vs 29%; P < .001) and MDSCs (1% vs 5%; P < .001) and higher programmed cell death protein (PD) 1-positive CD4+ TILs (59% vs 26%; P = .006) at flow cytometry and higher PD-1+ staining in tumor (2% vs 1%; P = .046). Conclusion Complete response to transarterial radioembolization was associated with lower baseline cytokine, monocyte, and myeloid-derived suppressor cell levels and higher programmed cell death protein 1-positive tumor-infiltrating lymphocyte levels. © RSNA, 2022 Online supplemental material is available for this article.

Immune modulation by molecularly targeted photothermal ablation in a mouse model of advanced hepatocellular carcinoma and cirrhosis

Immunotherapy is a promising new treatment approach for hepatocellular carcinoma (HCC), but there are numerous barriers to immunotherapy in HCC, including an immunosuppressive microenvironment and the "immunotolerance" of the liver. Hyperthermia treatment modalities are standard of care for early stage HCC, and hyperthermia is known to have immunomodulatory effects. We have developed a molecularly targeted photothermal ablation (MTPA) technology that provides thermally tunable, tumor-specific heat generation. The purpose of this study was to evaluate the morphologic and immunologic effects of MTPA in an immunotherapy-resistant syngeneic mouse model of HCC in a background of toxin-induced cirrhosis. We found that the anatomic, cellular, and molecular features of this model recapitulate the characteristics of advanced human HCC. MTPA as a monotherapy and in combination with immune checkpoint therapy significantly increased intratumoral CD3+ and activated CD8+ T cells while decreasing regulatory T cells relative to control or immune checkpoint therapy alone based on immunohistochemistry, flow cytometry, and single cell RNA sequencing data. Furthermore, we identified evidence of MTPA's influence on systemic tumor immunity, with suppression of remote tumor growth following treatment of orthotopic tumors. The results of this study suggest that tumor-specific hyperthermia may help overcome resistance mechanisms to immunotherapy in advanced HCC.

Techniques for Profiling the Cellular Immune Response and Their Implications for Interventional Oncology

In recent years there has been increased interest in using the immune contexture of the primary tumors to predict the patient's prognosis. The tumor microenvironment of patients with cancers consists of different types of lymphocytes, tumor-infiltrating leukocytes, dendritic cells, and others. Different technologies can be used for the evaluation of the tumor microenvironment, all of which require a tissue or cell sample. Image-guided tissue sampling is a cornerstone in the diagnosis, stratification, and longitudinal evaluation of therapeutic efficacy for cancer patients receiving immunotherapies. Therefore, interventional radiologists (IRs) play an essential role in the evaluation of patients treated with systemically administered immunotherapies. This review provides a detailed description of different technologies used for immune assessment and analysis of the data collected from the use of these technologies. The detailed approach provided herein is intended to provide the reader with the knowledge necessary to not only interpret studies containing such data but also design and apply these tools for clinical practice and future research studies.