Comparative analysis of the immune response to RFA and cryoablation in a colon cancer mouse model

Non-surgical ablation for breast cancer: an emerging therapeutic option

Non-surgical ablation is emerging as an alternative local therapy option for patients with early-stage breast cancer and encompasses two main types of percutaneous therapeutic procedures: radiofrequency ablation and cryoablation. Both techniques involve obliteration of a spherical lesion and feasibility studies have shown that complete tumour ablation is achievable with good or excellent cosmetic results. Although few clinical studies have directly compared non-surgical ablation with conventional surgical resection, observational studies indicate that clinical outcomes are favourable with acceptable rates of local control and no detriment to long-term survival. There remain outstanding issues with these percutaneous ablative techniques that require resolution before they could be incorporated into routine clinical practice. Hence, a consensus meeting was convened to discuss the challenges of non-surgical ablation and clarify indications for its use alongside clinical management pathways. In this Policy Review we will address some of the broader biological aspects of non-surgical ablation, including immune-modulatory effects and potential novel applications for the future.

Effect of Incomplete Cryoablation and Matrix Metalloproteinase Inhibition on Intratumoral CD8+ T-Cell Infiltration in Murine Hepatocellular Carcinoma

Background Image-guided tumor ablation is the first-line therapy for early-stage hepatocellular carcinoma (HCC), with ongoing investigations into its combination with immunotherapies. Matrix metalloproteinase (MMP) inhibition demonstrates immunomodulatory potential and reduces HCC tumor growth when combined with ablative treatment. Purpose To evaluate the effect of incomplete cryoablation with or without MMP inhibition on the local immune response in residual tumors in a murine HCC model. Materials and Methods Sixty 8- to 10-week-old female BALB/c mice underwent HCC induction with use of orthotopic implantation of syngeneic Tib-75 cells. After 7 days, mice with a single lesion were randomized into treatment groups: (a) no treatment, (b) MMP inhibitor, (c) incomplete cryoablation, and (d) incomplete cryoablation and MMP inhibitor. Macrophage and T-cell subsets were assessed in tissue samples with use of immunohistochemistry and immunofluorescence (cell averages calculated using five 1-μm2 fields of view [FOVs]). C-X-C motif chemokine receptor type 3 (CXCR3)- and interferon γ (IFNγ)-positive T cells were assessed using flow cytometry. Groups were compared using unpaired Student t tests, one-way analysis of variance with Tukey correction, and the Kruskal-Wallis test with Dunn correction. Results Mice treated with incomplete cryoablation (n = 6) showed greater infiltration of CD206+ tumor-associated macrophages (mean, 1.52 cells per FOV vs 0.64 cells per FOV; P = .03) and MMP9-expressing cells (mean, 0.89 cells per FOV vs 0.11 cells per FOV; P = .03) compared with untreated controls (n = 6). Incomplete cryoablation with MMP inhibition (n = 6) versus without (n = 6) led to greater CD8+ T-cell (mean, 15.8% vs 8.29%; P = .04), CXCR3+CD8+ T-cell (mean, 11.64% vs 8.47%; P = .004), and IFNγ+CD8+ T-cell infiltration (mean, 11.58% vs 5.18%; P = .02). Conclusion In a mouse model of HCC, incomplete cryoablation and systemic MMP inhibition showed increased cytotoxic CD8+ T-cell infiltration into the residual tumor compared with either treatment alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Gemmete in this issue.

THE CRYOGENIC TECHNOLOGIES APPLICATION IN THE COMPLEX TREATMENT OF GALLBLADDER ADENOCARCINOMA WITH INVASION INTO THE PORTAL VEIN BRANCHES: CASE REPORT

The right trisectionectomy is the main treatment modality for locally advanced gallbladder cancer with invasion of the intraparenchymal portal vein branches because it allows the achievement of negative resection margins (R0). However, only 10%-25% of such patients are eligible for surgery. The cryosurgical method has been successfully used in the complex treatment of hepatopancreatobiliary malignant neoplasms for many years. The possibility of its application close to major blood vessels is one of its advantages. In the presented case, the cryodestruction of the residual tumor with invasion into the anterior wall of the left branch of the portal vein was used as a debulking option during liver resection (R2) due to locally advanced gallbladder cancer. The cryodestruction was performed with application method with a double cryocycle and spontaneous thawing using a Cryo-Pulse device and liquid nitrogen as a cryoagent. No postoperative complications related to cryodestruction were noted. The cryogenic technologies application in the debulking surgery of gallbladder cancer can be a safe treatment modality for residual tumors with invasion into the intraparenchymal branches of the portal vein.

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.

Perfluorocarbon nanodrug induced oxygen self-enriching sonodynamic therapy improves cancer immunotherapy after insufficient radiofrequency ablation

Residual lesions and undetectable metastasis after insufficient radiofrequency ablation (iRFA) are associated with earlier new metastases and poor survival in cancer patients, for induced aggressive tumor phenotype and immunosuppression. Programmed cell death protein 1(PD-1) blockade has been reported to enhance the radiofrequency ablation-elicited antitumor immunity, but its ability to eliminate incompletely ablated residual lesions has been questioned. Here, we report a combined treatment modality post iRFA based on integrating an oxygen self-enriching nanodrug PFH-Ce6 liposome@O2 nanodroplets (PCL@O2)-augmented noninvasive sonodynamic therapy (SDT) with PD-1 blockade. PCL@O2 containing Ce6 as the sonosensitizer and PFH as O2 reservoir, was synthesized as an augmented SDT nanoplatform and showed increased ROS generation to raise effective apoptosis of tumor cells, which also exposed more calreticulin to induce stronger immunogenic cell death (ICD). Combining with PD-1 blockade post iRFA, this optimized SDT induced a better anti-tumor response in MC38 tumor bearing mouse model, which not only arrested residual primary tumor progression, but also inhibited the growth of distant tumor, therefore prolonging the survival. Profiling of immune populations within the tumor draining lymph nodes and tumors further revealed that combination therapy effectively induced ICD, and promoted the maturation of dendritic cells, tumor infiltration of T cells, as well as activation of cytotoxic T lymphocytes. While iRFA alone could result in an increase of regulatory T cells (Tregs) in the residual tumors, SDT plus PD-1 blockade post iRFA reduced the number of Tregs in both primary and distant tumors. Moreover, the combined treatment could significantly initiate long-term immune memory, manifesting as elevated levels of CD8+ and CD4+ central memory cells. Therefore, this study establishes the preclinical proof of concept to apply oxygen self-enriching SDT to augment cancer immunotherapy after iRFA.

Engineering the Tumor Immune Microenvironment through Minimally Invasive Interventions

The tumor microenvironment (TME) is a unique landscape that poses several physical, biochemical, and immune barriers to anti-cancer therapies. The rapidly evolving field of immuno-engineering provides new opportunities to dismantle the tumor immune microenvironment by efficient tumor destruction. Systemic delivery of such treatments can often have limited local effects, leading to unwanted offsite effects such as systemic toxicity and tumor resistance. Interventional radiologists use contemporary image-guided techniques to locally deliver these therapies to modulate the immunosuppressive TME, further accelerating tumor death and invoking a better anti-tumor response. These involve local therapies such as intratumoral drug delivery, nanorobots, nanoparticles, and implantable microdevices. Physical therapies such as photodynamic therapy, electroporation, hyperthermia, hypothermia, ultrasound therapy, histotripsy, and radiotherapy are also available for local tumor destruction. While the interventional radiologist can only locally manipulate the TME, there are systemic offsite recruitments of the immune response. This is known as the abscopal effect, which leads to more significant anti-tumoral downstream effects. Local delivery of modern immunoengineering methods such as locoregional CAR-T therapy combined with immune checkpoint inhibitors efficaciously modulates the immunosuppressive TME. This review highlights the various advances and technologies available now to change the TME and revolutionize oncology from a minimally invasive viewpoint.