Activation of tumor-specific T lymphocytes after laser-induced thermotherapy in patients with colorectal liver metastases

Gold Nanostars Obviate Limitations to Laser Interstitial Thermal Therapy (LITT) for the Treatment of Intracranial Tumors

PURPOSE

Laser interstitial thermal therapy (LITT) is an effective minimally invasive treatment option for intracranial tumors. Our group produced plasmonics-active gold nanostars (GNS) designed to preferentially accumulate within intracranial tumors and amplify the ablative capacity of LITT.

EXPERIMENTAL DESIGN

The impact of GNS on LITT coverage capacity was tested in ex vivo models using clinical LITT equipment and agarose gel-based phantoms of control and GNS-infused central "tumors." In vivo accumulation of GNS and amplification of ablation were tested in murine intracranial and extracranial tumor models followed by intravenous GNS injection, PET/CT, two-photon photoluminescence, inductively coupled plasma mass spectrometry (ICP-MS), histopathology, and laser ablation.

RESULTS

Monte Carlo simulations demonstrated the potential of GNS to accelerate and specify thermal distributions. In ex vivo cuboid tumor phantoms, the GNS-infused phantom heated 5.5× faster than the control. In a split-cylinder tumor phantom, the GNS-infused border heated 2× faster and the surrounding area was exposed to 30% lower temperatures, with margin conformation observed in a model of irregular GNS distribution. In vivo, GNS preferentially accumulated within intracranial tumors on PET/CT, two-photon photoluminescence, and ICP-MS at 24 and 72 hours and significantly expedited and increased the maximal temperature achieved in laser ablation compared with control.

CONCLUSIONS

Our results provide evidence for use of GNS to improve the efficiency and potentially safety of LITT. The in vivo data support selective accumulation within intracranial tumors and amplification of laser ablation, and the GNS-infused phantom experiments demonstrate increased rates of heating, heat contouring to tumor borders, and decreased heating of surrounding regions representing normal structures.

Interventional Oncology and Immuno-Oncology: Current Challenges and Future Trends

Personalized cancer treatments help to deliver tailored and biologically driven therapies for cancer patients. Interventional oncology techniques are able to treat malignancies in a locoregional fashion, with a variety of mechanisms of action leading to tumor necrosis. Tumor destruction determines a great availability of tumor antigens that can be recognized by the immune system, potentially triggering an immune response. The advent of immunotherapy in cancer care, with the introduction of specific immune checkpoint inhibitors, has led to the investigation of the synergy of these drugs when used in combination with interventional oncology treatments. The aim of this paper is to review the most recent advances in the field of interventional oncology locoregional treatments and their interactions with immunotherapy.

In-situ tumor vaccination by percutaneous ablative therapy and its synergy with immunotherapeutics: An update on combination therapy

Percutaneous tumor ablation is now a widely accepted minimally invasive local treatment option offered by interventional radiology and applied to various organs and tumor histology types. It utilizes extreme temperatures to achieve irreversible cellular injury, where ablated tumor interacts with surrounding tissue and host via tissue remodeling and inflammation, clinically manifesting as post-ablation syndrome. During this process, in-situ tumor vaccination occurs, in which tumor neoantigens are released from ablated tissue and can prime one’s immune system which would favorably affect both local and remote site disease control. Although successful in priming the immune system, this rarely turns into clinical benefits for local and systemic tumor control due to intrinsic negative immune modulation of the tumor microenvironment. A combination of ablation and immunotherapy has been employed to overcome these and has shown promising preliminary results of synergistic effect without significantly increased risk profiles. The aim of this article is to review the evidence on post-ablation immune response and its synergy with systemic immunotherapies.

Role of Interventional Radiology in Pediatric Cancer Patients

PURPOSE OF REVIEW

Pediatric interventional radiology (IR) is a growing subspecialty. Here, we review the current role of IR in children with cancer, which uses imaging such as ultrasound, fluoroscopy, and computed tomography to perform minimally invasive procedures. These include biopsy, needle localization, central venous access, thermal ablation, transarterial chemoembolization, transarterial radioembolization with yttrium-90, non-tunneled/tunneled drainage catheter placement, and lymphatic interventions.

RECENT FINDINGS

Although locoregional therapies for the treatment of cancer in adults are common, they are less common in children, perhaps due to the relative rarity of cancer in children, their typically better performance status, and paucity of comorbidities. Preliminary results from small-scale studies for ablation, transarterial chemoembolization, and transarterial radioembolization with yttrium-90 used in the front-line armamentarium of curative therapy are encouraging. Pediatric IR offers an array of minimally invasive procedures intended to diagnose and treat pediatric cancer patients. However, more research is required to determine the efficacy of locoregional therapy in children and to define the clinical scenarios where benefit is likely to be optimized.

Laser ablation: Heating up the anti-tumor response in the intracranial compartment

Immunotherapies, such as immune checkpoint inhibition (ICI), have had limited success in treating intracranial malignancies. These failures are due partly to the restrictive blood-brain-barrier (BBB), the profound tumor-dependent induction of local and systemic immunosuppression, and immune evasion exhibited by these tumors. Therefore, novel approaches must be explored that aim to overcome these stringent barriers. LITT is an emerging treatment for brain tumors that utilizes thermal ablation to kill tumor cells. LITT provides an additional therapeutic benefit by synergizing with ICI and systemic chemotherapies to strengthen the anti-tumor immune response. This synergistic relationship involves transient disruption of the BBB and local augmentation of immune function, culminating in increased CNS drug penetrance and improved anti-tumor immunity. In this review, we will provide an overview of the challenges facing immunotherapy for brain tumors, and discuss how LITT may synergize with the endogenous anti-tumor response to improve the efficacy of ICI.

CIRSE Standards of Practice on Hepatic Transarterial Chemoembolisation

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing transarterial chemoembolisation. It has been developed by an expert writing group under the guidance of the CIRSE Standards of Practice Committee. It will encompass all technical details reflecting European practice of different TACE procedures (Lp-TACE, DEM-TACE, DSM-TACE, b-TACE) as well as revising the existing literature on the various clinical indications (HCC, mCRC, ICC, NET). Finally, new frontiers of development will also be discussed.

Local Destruction of Tumors and Systemic Immune Effects

Current immune-based therapies signify a major advancement in cancer therapy; yet, they are not effective in the majority of patients. Physically based local destruction techniques have been shown to induce immunologic effects and are increasingly used in order to improve the outcome of immunotherapies. The various local destruction methods have different modes of action and there is considerable variation between the different techniques with respect to the ability and frequency to create a systemic anti-tumor immunologic effect. Since the abscopal effect is considered to be the best indicator of a relevant immunologic effect, the present review focused on the tissue changes associated with this effect in order to find determinants for a strong immunologic response, both when local destruction is used alone and combined with immunotherapy. In addition to the T cell-inflammation that was induced by all methods, the analysis indicated that it was important for an optimal outcome that the released antigens were not destroyed, tumor cell death was necrotic and tumor tissue perfusion was at least partially preserved allowing for antigen presentation, immune cell trafficking and reduction of hypoxia. Local treatment with controlled low level hyperthermia met these requisites and was especially prone to result in abscopal immune activity on its own.

Analysis of damage-associated molecular pattern molecules due to electroporation of cells in vitro

Background Tumor cells can die via immunogenic cell death pathway, in which damage-associated molecular pattern molecules (DAMPs) are released from the cells. These molecules activate cells involved in the immune response. Both innate and adaptive immune response can be activated, causing a destruction of the remaining infected cells. Activation of immune response is also an important component of tumor treatment with electrochemotherapy (ECT) and irreversible electroporation (IRE). We thus explored, if and when specific DAMPs are released as a consequence of electroporation in vitro. Materials and methods In this in vitro study, 100 μs long electric pulses were applied to a suspension of Chinese hamster ovary cells. The release of DAMPs - specifically: adenosine triphosphate (ATP), calreticulin, nucleic acids and uric acid was investigated at different time points after exposing the cells to electric pulses of different amplitudes. The release of DAMPs was statistically correlated with cell permeabilization and cell survival, e.g. reversible and irreversible electroporation. Results In general, the release of DAMPs increases with increasing pulse amplitude. Concentration of DAMPs depend on the time interval between exposure of the cells to pulses and the analysis. Concentrations of most DAMPs correlate strongly with cell death. However, we detected no uric acid in the investigated samples. Conclusions Release of DAMPs can serve as a marker for prediction of cell death. Since the stability of certain DAMPs is time dependent, this should be considered when designing protocols for detecting DAMPs after electric pulse treatment.

The intersection between immunotherapy and laser interstitial thermal therapy: a multipronged future of neuro-oncology

The rise of immunotherapy (IT) in oncological treatment has greatly improved outcomes in a number of disease states. However, its use in tumors of the central nervous system (CNS) remains limited for multiple reasons related to the unique immunologic tumor microenvironment. As such, it is valuable to consider the intersection of IT with additional treatment methods that may improve access to the CNS and effectiveness of existing IT modalities. One such combination is the pairing of IT with localized hyperthermia (HT) generated through technologies such as laser interstitial thermal therapy (LITT). The wide-ranging immunomodulatory effects of localized and whole-body HT have been investigated for some time. Hyperthermia has demonstrated immunostimulatory effects at the level of tumor cells, immune cells, and the broader environment governing potential immune surveillance. A thorough understanding of these effects as well as the current and upcoming investigations of such in combination with IT is important in considering the future directions of neuro-oncology.

High-Voltage Electrical Pulses in Oncology: Irreversible Electroporation, Electrochemotherapy, Gene Electrotransfer, Electrofusion, and Electroimmunotherapy

This review summarizes the use of high-voltage electrical pulses (HVEPs) in clinical oncology to treat solid tumors with irreversible electroporation (IRE) and electrochemotherapy (ECT). HVEPs increase the membrane permeability of cells, a phenomenon known as electroporation. Unlike alternative ablative therapies, electroporation does not affect the structural integrity of surrounding tissue, thereby enabling tumors in the vicinity of vital structures to be treated. IRE uses HVEPs to cause cell death by inducing membrane disruption, and it is primarily used as a radical ablative therapy in the treatment of soft-tissue tumors in the liver, kidney, prostate, and pancreas. ECT uses HVEPs to transiently increase membrane permeability, enhancing cellular cytotoxic drug uptake in tumors. IRE and ECT show immunogenic effects that could be augmented when combined with immunomodulatory drugs, a combination therapy the authors term electroimmunotherapy. Additional electroporation-based technologies that may reach clinical importance, such as gene electrotransfer, electrofusion, and electroimmunotherapy, are concisely reviewed. HVEPs represent a substantial advancement in cancer research, and continued improvement and implementation of these presented technologies will require close collaboration between engineers, interventional radiologists, medical oncologists, and immuno-oncologists.

Postablation Immune Microenvironment: Synergy between Interventional Oncology and Immuno-oncology

Current tumor thermal ablation techniques rely on extreme temperatures to induce irreversible cellular injury and coagulative tissue necrosis. Ablation-induced cellular injury or death releases cancer neoantigens and activates the cancer-immunity cycle, potentially generating tumor-specific immune effectors. However, multiple negative regulatory modulators exist at each step of the cycle, mitigating meaningful and therapeutic anticancer effect provided by the immune system. Recent studies have focused on the introduction and testing of adjuvant immunotherapy combined with ablation to synergistically shift the equilibrium out of inhibitory immune modulation. This article reviews the immune microenvironment in relation to image-guided ablation techniques and discusses current and upcoming novel strategies to take advantage of antitumor immunity.

A Strategy for Precise Treatment of Cardiac Malignant Neoplasms

The prevalence of cardiac malignant neoplasms in the general population has been shown to be significant higher than what was previously estimated, yet their treatment has remained difficult and effective therapies are lacking. In the current study, we developed a novel thermotherapy in which PEG-functionalized carbon nanotubes were injected into the tumor regions to assist in the targeted delivery of infrared radiation energy with minimal hyperthermic damage to the surrounding normal tissues. In a mouse model of cardiac malignant neoplasms, the injected carbon nanotubes could rapidly induce coagulative necrosis of tumor tissues when exposed to infrared irradiation. In accordance, the treatment was also found to result in a restoration of heart functions and a concomitant increase of survival rate in mice. Taken together, our carbon nanotube-based thermotherapy successfully addressed the difficulty facing conventional laser ablation methods with regard to off-target thermal injury, and could pave the way for the development of more effective therapies against cardiac malignant neoplasms.

The Immunogenicity of Colorectal Cancer in Relation to Tumor Development and Treatment

Although most cancer types have been viewed as immunologically silent until recently, it has become increasingly clear that the immune system plays key roles in the course of tumor development. Remarkable progress towards understanding cancer immunogenicity and tumor-immune system interactions has revealed important implications for the design of novel immune-based therapies. Natural immune responses, but also therapeutic interventions, can modulate the tumor phenotype due to selective outgrowth of resistant subtypes. This is the result of heterogeneity of tumors, with genetic instability as a driving force, and obviously changes the immunogenicity of tumors. In this review, we discuss the immunogenicity of colorectal cancer (CRC) in relation to tumor development and treatment. As most tumors, CRC activates the immune system in various ways, and is also capable of escaping recognition and elimination by the immune system. Tumor-immune system interactions underlie the balance between immune control and immune escape, and may differ in primary tumors, in the circulation, and in liver metastases of CRC. Since CRC immunogenicity varies between tumors and individuals, novel immune-based therapeutic strategies should not only anticipate the molecular profile, but also the immunological profile of a specific tumor.

Additive antitumour response to the rabbit VX2 hepatoma by combined radio frequency ablation and toll like receptor 9 stimulation

INTRODUCTION

Radiofrequency ablation (RFA), a palliative therapeutic option for solid hepatic tumours, stimulates localised and systemic antitumour cytotoxic T cells. We studied how far addition of CpG B oligonucleotides, toll like receptor (TLR) 9 agonists, would increase the antitumoural T cell response of RFA in the highly aggressive VX2 hepatoma.

METHODS

Rabbits were randomised to receive RFA, CpG B, their combination or no therapy. The antitumour efficacy of RFA alone or in combination with CpG B was further tested by rechallenging a separate group with intravenously injected VX2 tumour cells after 120 days. Animals were assessed for survival, tumour size and spread, and tumour and immune related histological markers after 120 days. Peripheral blood mononuclear cells were tested for tumour-specific T cell activation and cytotoxicity. Immune modulatory cytokines tumour necrosis factor α, interleukin (IL)-2/IL-8/IL-10/IL-12 and interferon γ, and vascular endothelial growth factor were measured in serum.

RESULTS

Mean survival of untreated animals was 36 days, as compared with 97, 78 and 114 days for RFA, CpG and combination therapy, respectively. Compared with untreated controls, antitumour T cell stimulation/cytotoxicity increased 26/16-fold, 32/17-fold and 50/38-fold 2 weeks after RFA, CpG and combination treatments, respectively. The combination inhibited tumour spread to lungs and peritoneum significantly and prohibited new tumour growth in animals receiving a secondary systemic tumour cell injection. RFA alone induced a Th1 cytokine pattern, while IL-8 and IL-10 were only upregulated in CpG treated animals and controls.

CONCLUSIONS

The combination of TLR9 stimulation with RFA resulted in a potentiated antitumour T cell response and cytotoxicity in the VX2 tumour model. Only this combination prevented subsequent tumour spread and resulted in a significantly improved survival, justifying the need for further exploration of the combination of ablative therapies and TLR9 agonists in liver cancer.

Enhancement of Intratumoral Chemotherapy with Cisplatin with or without Microwave Ablation and Lipiodol. Future Concept for Local Treatment in Lung Cancer

Novel therapies for lung cancer are being explored nowadays with local therapies being the tip of the arrow. Intratumoral chemotherapy administration and local microwave ablation have been investigated in several studies. It has been previously proposed that lipiodol has the ability to modify the microenvironment matrix. In our current study we investigated this theory in BALBC mice. In total 160 BALBC mice were divided in eight groups: a) control, b) cisplatin, c) microwave, d) microwave and lipiodol, e) cisplatin and lipiodol, f) microwave and cisplatin, g) lipiodol and h) lipiodol, cisplatin and microwave. Lewis lung carcinoma cell lines (10⁶) were injected into the right back leg of each mouse. After the 8th day, when the tumor volume was about 100mm³ the therapy application was initiated, once per week for four weeks. Magnetic resonance imaging was performed for each tumor when a mouse died or when sacrificed if they were still alive by the end of the experiment (8-Canal multifunctional spool; NORAS MRI products, Gmbh, Germany). Imaging and survival revealed efficient tumor apoptosis for the groups b,c,d,e and f. However; severe toxicity was observed in group h and no follow up was available for this group after the second week of therapy administration. Lipiodol in its current form does assist in a more efficient way the distribution of cisplatin, as the microwave apoptotic effect. Future modification of lipiodol might provide a more efficient method of therapy enhancement. Combination of drug and microwave ablation is possible and has an efficient apoptotic effect.

Systematic review of ablation techniques for the treatment of malignant or aggressive benign lesions in children

BACKGROUND

Ablation techniques are widely used for solid malignant tumors in adults. There is no large series assessing the effectiveness of local ablative therapies in the treatment of malignant or aggressive benign lesions in children.

OBJECTIVE

To review the existing evidence on the techniques and results of ablation for pediatric solid malignant or aggressive benign tumors.

MATERIALS AND METHODS

We searched MEDLINE for papers published between 1995 and 2012 that reported outcomes of radiofrequency, microwave and cryoablation, interstitial laser therapy, irreversible electroporation and percutaneous ethanol injection for patients younger than 18 years old. Data collection included factors related to the patient, tumor biology, ablation technique and cancer-specific endpoints. Additional series of predominantly adults including data on patients younger than 18 years old were also identified.

RESULTS

We identified 28 patients treated by ablation in 29 regions: 5 patients undergoing ablation for liver lesions, 9 patients for lung metastases, 11 patients for bone and/or soft tissue and 4 patients for kidney or pancreas. The ablation was performed to treat primary tumors, local recurrences and metastases. The histology of the tumors was osteosarcoma in 6 patients, Wilms tumor in 3, rhabdomyosarcoma in 3, hepatoblastoma in 3, desmoid tumor in 3, adrenocortical carcinoma in 2 and a single case each of leiomyosarcoma, Ewing sarcoma, paraganglioma, solid-pseudopapillary neoplasm, sacrococcygeal teratoma, hepatic adenoma, juxtaglomerular cell tumor and plantar fibromatosis. Eighteen of the patients (64%) experienced a complication, but only 6 (21%) of these needed treatment other than supportive care.

CONCLUSIONS

Although ablative techniques are feasible and promising treatments for certain pediatric tumors, large multicenter prospective trials will be needed to establish efficacy.

Synthesis and effects of conjugated tocopherol analogues on peptide nucleic acid hybridisation

To the N-terminus of a nonamer peptide nucleic acid sequence, H-GCACGACTT-NH2, was attached a number of lipophilic conjugate molecules including three synthetic tocopherol (vitamin E) analogues. Studies were then undertaken with complementary PNA and DNA sequences to explore the effects of the conjugates using the techniques of UV monitored melting curves and isothermal calorimetry. Duplex formation was observed when the benzopyran group of vitamin E was conjugated. However, in the presence of the phytyl chain of vitamin E, binding was found to be temperature dependent.

Intratumoral chemotherapy for lung cancer: re-challenge current targeted therapies

Strategies to enhance the already established doublet chemotherapy regimen for lung cancer have been investigated for more than 20 years. Initially, the concept was to administer chemotherapy drugs locally to the tumor site for efficient diffusion through passive transport within the tumor. Recent advances have enhanced the diffusion of pharmaceuticals through active transport by using pharmaceuticals designed to target the genome of tumors. In the present study, five patients with non-small cell lung cancer epidermal growth factor receptor (EGFR) negative stage IIIa–IV International Union Against Cancer 7 (UICC-7), and with Eastern Cooperative Oncology Group (ECOG) 2 scores were administered platinum-based doublet chemotherapy using combined intratumoral-regional and intravenous route of administration. Cisplatin analogues were injected at 0.5%–1% concentration within the tumor lesion and proven malignant lymph nodes according to pretreatment histological/cytological results and the concentration of systemic infusion was decreased to 70% of a standard protocol. This combined intravenous plus intratumoral-regional chemotherapy is used as a first line therapy on this short series of patients. To the best of our knowledge this is the first report of direct treatment of involved lymph nodes with cisplatin by endobronchial ultrasound drug delivery with a needle without any adverse effects. The initial overall survival and local response are suggestive of a better efficacy compared to established doublet cisplatin–based systemic chemotherapy in (higher) standard concentrations alone according to the UICC 7 database expected survival. An extensive search of the literature was performed to gather information of previously published literature of intratumoral chemo-drug administration and formulation for this treatment modality. Our study shows a favorable local response, more than a 50% reduction, for a massive tumor mass after administration of five sessions of intratumoral chemotherapy plus two cycles of low-dose intravenous chemotherapy according to our protocol. These encouraging results (even in very sick ECOG 2 patients with central obstructive non-small cell lung cancer having a worse prognosis and quality of life than a non-small cell lung cancer in ECOG 0 of the same tumor node metastasis [TNM]-stage without central obstruction) for a chemotherapy-only protocol that differs from conventional cisplatin-based doublet chemotherapy by the route, target site, and dose paves the way for broader applications of this technique. Finally, future perspectives of this treatment and pharmaceutical design for intratumoral administration are presented.

Treatment of a supratentorial primitive neuroectodermal tumor using magnetic resonance-guided laser-induced thermal therapy

Supratentorial primitive neuroectodermal tumors (PNETs) are rare tumors that carry a poorer prognosis than those arising from the infratentorial compartment (such as medulloblastoma). The overall prognosis for these patients depends on several factors including the extent of resection, age at diagnosis, CSF dissemination, and site in the supratentorial space. The authors present the first case of a patient with a newly diagnosed supratentorial PNET in which cytoreduction was achieved with MR-guided laser-induced thermal therapy. A 10-year-old girl presented with left-sided facial weakness and a large right thalamic mass extending into the right midbrain. The diagnosis of supratentorial PNET was made after stereotactic biopsy. Therapeutic options for this lesion were limited because of the risks of postoperative neurological deficits with resection. The patient underwent MR-guided laser-induced thermal ablation of her tumor. Under real-time MR thermometry, thermal energy was delivered to the tumor at a core temperature of 90°C for a total of 960 seconds. The patient underwent follow-up MR imaging at regular intervals to evaluate the tumor response to the thermal ablation procedure. Initial postoperative scans showed an increase in the size of the lesion as well as the amount of the associated edema. Both the size of the lesion and the edema stabilized by 1 week and then decreased below preablation levels at the 3-month postsurgical follow-up. There was a slight increase in the size of the lesion and associated edema at the 6-month follow-up scan, presumably due to concomitant radiation she received as part of her postoperative care. The patient tolerated the procedure well and has had resolution of her symptoms since surgery. Further study is needed to assess the role of laser-induced thermal therapy for the treatment of intracranial tumors. As such, it is a promising tool in the neurosurgical armamentarium. Postoperative imaging has shown no evidence of definitive recurrence at the 6-month follow-up period, but longer-term follow-up is required to assess for late recurrence.