Transcatheter arterial embolization combined with radiofrequency ablation activates CD8(+) T-cell infiltration surrounding residual tumors in the rabbit VX2 liver tumors

Clinical outcomes and tumor microenvironment response to radiofrequency ablation therapy: a systematic review and meta-analysis

Background

Radiofrequency ablation (RFA) utilizes minimally invasive high-energy current to precisely ablate tumor cells. It has been utilized in many cancer types including thyroid, lung, and liver cancer. It has been shown to provide adequate ablative margins with minimal complications; however, incomplete RFA may lead to recurrence of tumor. The underlying cellular mechanism and behavior of ablated cancer tissue is poorly understood.

Methods

A systematic review was performed, searching EMBASE, Web of Science, PubMed, and Scopus for studies published up to March 2022 and reported following PRISMA guidelines. Collection was performed by two groups of investigators to avoid risk of bias. The Cochrane Collaboration's tool was used for assessing risk of bias. We identified human, in vivo, and in vitro research studies utilizing RFA for tumor tissues. We required that the studies included at least one of the following: complications, recurrence, or survival, and took interest to studies identifying cellular signaling pathway patterns after RFA. Descriptive statistical analysis was performed in 'R' software including mean and confidence interval.

Results

The most frequent cancers studied were liver and lung cancers accounting for 57.4% (N=995) and 15.4% (N=267), followed by esophageal (N=190) and breast cancer (N=134). The most common reported complications were bleeding (19%) and post-operative pain (14%). In our literature search, four independent studies showed upregulation and activation of the VEGF pathway following RFA, four showed upregulation and activation of the AKT pathway following RFA, three studies demonstrated involvement of matrix metalloproteinases, and four showed upregulation of c-Met protein following RFA.

Conclusions

In our review and meta-analysis, we identify several proteins and pathways of interest of which are important in wound healing, angiogenesis, and cellular growth and survival. These proteins and pathways of interest may implicate areas of research towards RFA resistance and cancer recurrence.

Rabbit VX2 Liver Tumor Model: A Review of Clinical, Biology, Histology, and Tumor Microenvironment Characteristics

The rabbit VX2 is a large animal model of cancer used for decades by interventional radiologists to demonstrate the efficacy of various locoregional treatments against liver tumors. What do we know about this tumor in the new era of targeted therapy and immune-oncology? The present paper describes the current knowledge on the clinics, biology, histopathology, and tumor microenvironment of VX2 based on a literature review of 741 publications in the liver and in other organs. It reveals the resemblance with human cancer (anatomy, vascularity, angiogenic profile, drug sensitivity, immune microenvironment), the differences (etiology, growth rate, histology), and the questions still poorly explored (serum and tissue biomarkers, genomic alterations, immune checkpoint inhibitors efficacy).

Imaging, Pathology, and Immune Correlates in the Woodchuck Hepatic Tumor Model

Background

Woodchucks chronically infected with woodchuck hepatitis virus (WHV), which resembles human hepatitis B virus, develop spontaneous hepatic tumors and may be an important biological and immunological model for human HCC. Nonetheless, this model requires further validation to fully realize its translational potential.

Methods

Woodchucks infected at birth with WHV that had developed HCC (n=12) were studied. Computed tomography, ultrasound, and magnetic resonance imaging were performed under anesthesia. LI-RADS scoring and correlative histologic analysis of sectioned tissues were performed. For immune characterization of tumors, CD3 (T cells), CD4 (T helpers), NCAM (Natural killers), FOXP3 (T-regulatory), PDL-1 (inhibitory checkpoint protein), and the human hepatocellular carcinoma (HCC) biomarker alpha-fetoprotein (AFP) immunohistochemical stains were performed.

Results

Forty tumors were identified on imaging of which 29 were confirmed to be HCC with 26 categorized as LR-4 or 5. The remainder of the tumors had benign histology including basophilic foci, adenoma, and lipidosis as well as pre-malignant dysplastic foci. LR-4 and LR-5 lesions showed high sensitivity (90%) and specificity (100%) for malignant and pre-malignant tumors. Natural killers count was found to be 2–5 times lower in tumors relative to normal parenchyma while other immune cells were located in the periphery of tumors. Tumors expressed AFP and did not express PD-L1.

Conclusion

Woodchucks chronically infected with WHV developed diverse hepatic tumor types with diagnostic imaging, pathology, and immune patterns comparable to that in humans. This unique animal model may provide a valuable tool for translation and validation of novel image-guided and immune-therapeutic investigations.

Hepatic Arterial Bland Embolization Increases Th17 Cell Infiltration in a Syngeneic Rat Model of Hepatocellular Carcinoma

PURPOSE

To determine the tumor immune cell landscape after transcatheter arterial bland embolization (TAE) in a clinically relevant rat hepatocellular carcinoma (HCC) model.

MATERIALS AND METHODS

Buffalo rats (n = 21) bearing syngeneic McArdle RH-7777 rat hepatoma cells implanted into the left hepatic lobe underwent TAE using 70-150 µm beads (n = 9) or hepatic artery saline infusion (n = 12). HCC nodules, peritumoral margin, adjacent non-cancerous liver, and splenic parenchyma were collected and disaggregated to generate single-cell suspensions for immunological characterization 14 d after treatment. Changes in tumor-infiltrating immune subsets including CD4 T cells (Th17 and Treg), CD8 cytotoxic T cells (IFNγ), and neutrophils were evaluated by multiparameter flow cytometry. Migration and colony formation assays were performed to examine the effect of IL-17, a signature cytokine of Th17 cells, on McArdle RH-7777 hepatoma cells under conditions simulating post-embolization environment (i.e., hypoxia and nutrient privation). Statistical significance was determined by the Student unpaired t test or one-way ANOVA.

RESULTS

TAE induces increased infiltration of Th17 cells in liver tumors when compared with controls 14 d after treatment (0.29 ± 0.01 vs. 0.19 ± 0.02; p = 0.02). A similar pattern was observed in the spleen (1.41 ± 0.13 vs. 0.57 ± 0.08; p < 0.001), indicating both local and systemic effect. No significant differences in the percentage of FoxP3 + Tregs, IFNγ-producing CD4 T cells, and CD8 T cells were observed between groups (p > 0.05). In vitro post-embolization assays demonstrated that IL-17 reduces McA-RH7777 cell migration at 24-48 h (p = 0.003 and p = 0.002, respectively).

CONCLUSION

Transcatheter hepatic arterial bland embolization induces local and systemic increased infiltration of Th17 cells and expression of their signature cytokine IL-17. In a simulated post-embolization environment, IL-17 significantly reduced McA-RH7777 cell migration.

Ablation plus Transarterial Embolic Therapy for Hepatocellular Carcinoma Larger than 3 cm: Science, Evidence, and Future Directions

Thermal ablation is widely regarded as definitive therapy for early-stage hepatocellular carcinoma, but its efficacy decreases in tumors greater than 3 cm. Extensive clinical studies have supported improved outcomes provided through combining transarterial embolic therapy with ablation in the treatment of larger tumors. This article will provide a survey of the science and data for combination therapy in both thermal and nonthermal ablation modalities, as well as describe emerging applications.

Immunomodulatory Changes Following Isolated RF Ablation in Colorectal Liver Metastases: A Case Report

Background: Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related deaths in developed countries. The liver is the most prevalent site of metastasis from CRC. Currently, the gold-standard treatment for colorectal liver metastases (CLMs) is surgical resection. However, depending on the pattern of the disease, a significant number of patients may require different approaches alone or in combination with surgery, including thermal ablation (radiofrequency (RFA) or microwave (MWA) ablation) or transarterial liver-directed therapies, although the latter is not yet part of the standard treatment for CRC liver metastases. Methods and Results: We present the case of a 63-yearold man with bilobar CLM who was treated with transarterial embolization (TAE) and RFA followed by chemotherapy. A post-RFA study of immune parameters revealed the downregulation of CD39 expression in the circulating CD4⁺ T cell population and a reduction of the serum levels of cytokines IL-10, TGF-β, IFN-gamma and IL-17, which positively correlated with the diminished serum level of gamma-glutamyl transferase (GGT) and the subdued inflammatory markers: the neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR). Later, the patient underwent chemotherapy. Liver failure developed within two years and nine months following tumour ablation, leading to the death of the patient. Conclusions: However, the denial of adjuvant chemotherapy by the patient gave us the opportunity to assess the immunomodulatory changes following RFA in the absence of any other therapeutic modalities.

Combined locoregional-immunotherapy for liver cancer

Locoregional therapies are commonly used to treat patients with hepatocellular carcinoma. It has been noted for many years that locoregional therapies may have additional systemic effects other than simple tumour elimination. Immunological "side effects" have been described in response to locoregional therapies in animal studies and in patients. With the advent of immunotherapy for hepatocellular carcinoma, there is increasing interest in determining the best way to combine immunotherapy with locoregional therapies. Herein, we provide a compact summary of answered and unanswered questions in the field, including: What animal model is best suited to test combined immune-locoregional treatments? How does tumour cell death affect immune responses? What type of immune responses have been observed in patients treated with different types of locoregional therapies? What can be surmised from the results of the first study testing the combination of locoregional therapy with immune checkpoint blockade? Finally, we discuss the outlook for this rapidly growing area of research, focussing on the issues which must be overcome to bridge the gap between interventional radiology and cancer immunology.

Lung metastases regression with increased CD8+ T lymphocyte infiltration following preoperative spinal embolization and total en bloc spondylectomy using tumor-bearing frozen autograft in a patient with spinal metastatic leiomyosarcoma

PURPOSE

To report systemic immunological enhancement following preoperative spinal embolization and total en bloc spondylectomy (TES) using tumor-bearing frozen autograft in a patient with spinal metastatic leiomyosarcoma.

METHODS

A 44-year-old woman with metastatic uterine leiomyosarcoma of the lung and L1 vertebra underwent TES following bilateral three-level preoperative segmental artery embolization. Resected tumor-bearing lamina was frozen using liquid nitrogen and used as tumor-bearing bone graft for spinal reconstruction.

RESULTS

Tumor necrosis and obstructing material used in preoperative embolization were detected in the resected specimen of L1. Five days after TES, chest computed tomography scan demonstrated decreased solitary lung mass size without adjuvant treatment. Lobectomy was performed for the lung metastasis 42 days after TES. Infiltration of CD8+ T lymphocyte into tumor tissue significantly increased in shrunk lung metastasis. On the other hand, slight infiltration in both the resected L1 and primary uterine lesion was observed. Six months after TES, activities of daily living were normal with no evidence of local recurrence or distant metastasis. One year after TES, however, lung CT revealed occurrence of another lung metastasis, and molecular-targeting therapy (pazopanib) was initiated.

CONCLUSIONS

There were no reports demonstrating metastasis regression with CD8+ T lymphocyte infiltration after TES. This case demonstrated that preoperative tumor embolization combined with TES using tumor-bearing autograft provided both a local radical cure and systemic antitumor immunological enhancement, although the long-term effect can be limited.