The role of hyperthermia in the treatment of tumor

Despite recent advancements in the diagnosis and treatment options for cancer, it remains one of the most serious threats to health. Hyperthermia (HT) has emerged as a highly promising area of research due to its safety and cost-effectiveness. Currently, based on temperature, HT can be categorized into thermal ablation and mild hyperthermia. Thermal ablation involves raising the temperature within the tumor to over 60°C, resulting in direct necrosis in the central region of the tumor. In contrast, mild hyperthermia operates at relatively lower temperatures, typically in the range of 41-45°C, to induce damage to tumor cells. Furthermore, HT also serves as an immune adjuvant strategy in radiotherapy, chemotherapy, and immunotherapy, enhancing the effectiveness of radiotherapy, increasing the uptake of chemotherapy drugs, and reprogramming the tumor microenvironment through the induction of immunogenic cell death, thereby promoting the recruitment of endogenous immune cells. This article reviews the current status and development of hyperthermia, outlines potential mechanisms by which hyperthermia inhibits tumors, describes clinical trial attempts combining hyperthermia with radiotherapy, chemotherapy, and immunotherapy, and discusses the relationship between nanoparticles and hyperthermia.

A bibliometric analysis of radiation-induced brain injury: a research of the literature from 1998 to 2023

BACKGROUND

Radiation-induced brain injury (RIBI) is a debilitating sequela after cranial radiotherapy. Research on the topic of RIBI has gradually entered the public eye, with more innovations and applications of evidence-based research and biological mechanism research in the field of that. This was the first bibliometric analysis on RIBI, assessing brain injury related to radiation articles that were published during 1998-2023, to provide an emerging theoretical basis for the future development of RIBI.

METHODS

Literature were obtained from the Web of Science Core Collection (WOSCC) from its inception to December 31, 2023. The column of publications, author details, affiliated institutions and countries, publication year, and keywords were also recorded.

RESULTS

A total of 2543 journal articles were selected. The annual publications on RIBI fluctuated within a certain range. Journal of Neuro-oncology was the most published journal and Radiation Oncology was the most impactful one. LIMOLI CL was the most prolific author with 37 articles and shared the highest h-index with BARNETT GH. The top one country and institutions were the USA and the University of California System, respectively. Clusters analysis of co-keywords demonstrated that the temporal research trends in this field primarily focused on imaging examination and therapy for RIBI.

CONCLUSION

This study collects, visualizes, and analyzes the literature within the field of RIBI over the last 25 years to map the development process, research frontiers and hotspots, and cutting-edge directions in clinical practice and mechanisms related to RIBI.

The Role of Laser and Microwave in Treatment of Endocrine Disorders: A Systematic Review

Introduction: The treatment of endocrine problems like thyroid disease, diabetes mellitus (DM), and polycystic ovary syndrome (PCOS) faces significant challenges so that medical professionals worldwide try to find a new therapeutic approach. However, along with common treatments which include medications, hormone replacement therapy, and surgery; there is a growing interest in alternative therapies like laser therapy, which offers a non-invasive and unique technique for treating endocrine disorders alone or in combination with traditional methods. The main goal of this review was to do a systematic review on the role of the laser and Microwave in the treatment endocrine disorders. Methods: In the present systematic review, the most important databases, including PubMed, Scopus and Google Scholar, were searched for the studies examining the effect of lasers on the treatment of endocrine problems by using appropriate keywords and specific strategies from 1995 to 2023. All the studies that were not about lasers and endocrine were excluded. Results: Based on 51 reviewed studies, lasers and radiofrequency ablation such as RFA are effective in the treatment of thyroid diseases, hyperparathyroidism, pancreatic disorders, and sexual dysfunctions. Laser-induced interstitial thermal therapy (LITT) and microwave ablation (MWA) are genuine minimally invasive methods for the treatment of benign nodules, adenomas, and tumor ablation including pancreatic carcinomas and adrenal tumors. Intravenous laser blood irradiation (ILBI) which uses red, UV, and blue light could be effective in treating various metabolic disorders, such as DM. Conclusion: Laser as a cutting-edge and minimally invasive approach could treat various endocrine disorders. It has a great potential to treat and regulate hormonal imbalances, decrease inflammation, and relieve symptoms of various ailments, such as endocrine disorders.

Cerebral cavernous malformations - An overview on genetics, clinical aspects and therapeutic strategies

Cerebral cavernous malformations (CCMs) are abnormally packed blood vessels lined with endothelial cells, that do not exhibit intervening tight junctions, lack muscular and elastic layers and are usually surrounded by hemosiderin and gliosis. CCMs may be sporadic or familial autosomal dominant (FCCMs) caused by loss of function mutations in CCM1 (KRIT1), CCM2 (MGC4607), and CCM3 (PDCD10) genes. In the FCCMs, patients have multiple CCMs, different family members are affected, and developmental venous anomalies are absent. CCMs may be asymptomatic or may manifest with focal neurological deficits with or without associated hemorrhage andseizures. Recent studies identify a digenic "triple-hit" mechanism involving the aquisition of three distinct genetic mutations that culminate in phosphatidylinositol-3-kinase (PIK3CA) gain of function, as the basis for rapidly growing and clinically symptomatic CCMs. The pathophysiology of CCMs involves signaling aberrations in the neurovascular unit, including proliferative dysangiogenesis, blood-brain barrier hyperpermeability, inflammation and immune mediated processes, anticoagulant vascular domain, and gut microbiome-driven mechanisms. Clinical trials are investigating potential therapies, magnetic resonance imaging and plasma biomarkers for hemorrhage and CCMs-related epilepsy, as well as different techniques of neuronavigation and neurosonology to guide surgery in order to minimize post-operatory morbidity and mortality. This review addresses the recent data about the natural history, genetics, neuroimaging and therapeutic approaches for CCMs.

Laser interstitial thermal therapy (LITT) for intracranial lesions: a single-institutional series, outcomes, and review of the literature

INTRODUCTION

Laser interstitial thermal therapy (LITT) is a minimally invasive treatment method in managing primary brain neoplasms, brain metastases, radiation necrosis, and epileptogenic lesions, many of which are located in operative corridors that would be difficult to address. Although the use of lasers is not a new concept in neurosurgery, advances in technology have enabled surgeons to perform laser treatment with the aid of real-time MRI thermography as a guide. In this report, we present our institutional series and outcomes of patients treated with LITT.

METHODS

We retrospectively evaluated 19 patients (age range, 28-77 years) who underwent LITT at one or more targets from 2015 to 2019. Primary endpoint observed was mean progression free survival (PFS) and overall survival (OS).

RESULTS

Seven patients with glial neoplasms and 12 patients with metastatic disease were reviewed. Average hospitalization was 2.4 days. Median PFS was 7 and 4 months in the metastatic group and primary glial neoplasm group, respectively (p = 0.01). Median OS from time of diagnosis was 41 and 32 months (p = 0.02) and median OS after LITT therapy was 25 and 24 months (p = 0.02) for the metastatic and primary glial neoplasm groups, respectively. One patient experienced immediate post-procedural morbidity secondary to increased intracerebral edema peri-lesionally while one patient experienced post-operative mortality and expired secondary to hemorrhage 1-month post-procedure. Median follow-up was 10 months.

CONCLUSION

Laser interstitial thermal therapy (LITT) is a safe, minimally invasive treatment method that provides surgeons with cytoreductive techniques to treat neurosurgical conditions. Both PFS and OS appear to be more favorable after LITT in patients with metastatic disease. In properly selected patients, this modality offers improved survival outcomes in conjunction with other salvage therapies.

Multimodal neuro-nanotechnology: Challenging the existing paradigm in glioblastoma therapy

Integrating multimodal neuro- and nanotechnology-enabled precision immunotherapies with extant systemic immunotherapies may finally provide a significant breakthrough for combatting glioblastoma (GBM). The potency of this approach lies in its ability to train the immune system to efficiently identify and eradicate cancer cells, thereby creating anti-tumor immune memory while minimizing multi-mechanistic immune suppression. A critical aspect of these therapies is the controlled, spatiotemporal delivery of structurally defined nanotherapeutics into the GBM tumor microenvironment (TME). Architectures such as spherical nucleic acids or poly(beta-amino ester)/dendrimer-based nanoparticles have shown promising results in preclinical models due to their multivalency and abilities to activate antigen-presenting cells and prime antigen-specific T cells. These nanostructures also permit systematic variation to optimize their distribution, TME accumulation, cellular uptake, and overall immunostimulatory effects. Delving deeper into the relationships between nanotherapeutic structures and their performance will accelerate nano-drug development and pave the way for the rapid clinical translation of advanced nanomedicines. In addition, the efficacy of nanotechnology-based immunotherapies may be enhanced when integrated with emerging precision surgical techniques, such as laser interstitial thermal therapy, and when combined with systemic immunotherapies, particularly inhibitors of immune-mediated checkpoints and immunosuppressive adenosine signaling. In this perspective, we highlight the potential of emerging treatment modalities, combining advances in biomedical engineering and neurotechnology development with existing immunotherapies to overcome treatment resistance and transform the management of GBM. We conclude with a call to action for researchers to leverage these technologies and accelerate their translation into the clinic.

Meta-analysis of the impact of laser interstitial hyperthermia on wound healing complications in brain tumors

High-grade gliomas (HGGs) may be amenable to the neurosurgical technique known as laser interstitial thermal therapy (LITT), which delivers thermal energy to interstitial brain injuries and wounds with pinpoint accuracy. The purpose of this extensive meta-analysis was to evaluate the effects of LITT on wound complications among patients who have brain tumours. Diverse conclusions emerge from a systematic review of pertinent studies, necessitating a comprehensive examination. The meta-analysis, performed utilizing the meta library provided by the R package meta, reveals an initial significant overall effect (RR: -2.1262, 95% CI [-2.7466, -1.5059], p < 0.0001) accompanied by considerable heterogeneity among studies (I2  = 61.13%). Following analyses that specifically examined the incidence of wounds, a complex correlation was found (RR: 0.0471, 95% CI [0.0264, 0.0842], p < 0.0001), indicating that LITT has a discernible but insignificant effect on the occurrence of wounds. Although the meta-analysis emphasizes a notable decrease in wound complications subsequent to LITT treatment, additional research is warranted due to constraints in standardized reporting, data accessibility, and small sample sizes. The results of this study underscore the need for exhaustive protocols to analyse wound complications in patients with brain tumours undergoing LITT.

Laser interstitial thermal therapy is effective and safe for the treatment of brain tumors in NF1 patients after cerebral revascularization for moyamoya angiopathy: a report on two cases

Background

The co-occurrence of moyamoya vasculopathy and extra-optic pathway tumors is rare in neurofibromatosis type 1 (NF1), with only four cases described in the literature. Brain surgery in these patients may be challenging because of the risk of brain infarction after skin and dural incision. Given its percutaneous and minimally invasive nature, laser interstitial thermal therapy (LITT) is an ideal option for the treatment of brain tumors in these patients. Here, we report on two patients with NF1 and moyamoya syndrome (MMS) treated for a brain glioma with LITT, after cerebral revascularization.

Cases

The first patient, with familial NF1, underwent bilateral indirect revascularization with multiple burr holes (MBH) for symptomatic MMS. Two years later, she was diagnosed with a left temporal tumor, with evidence of radiologic progression over 10 months. The second patient, also with familial NF1, developed unilateral MMS when he was 6 years old and was treated with MBH. At the age of 15 years, MRI showed a right cingular lesion, growing on serial MRIs. Both patients underwent LITT with no perioperative complications; they are progression free at 10 and 12 months, respectively, and the tumors have decreased in volume.

Discussion

While the association of extra-optic neoplasm and moyamoya angiopathy is seldom reported in NF1, tumor treatment is challenging in terms of both avoiding stroke and achieving oncological control. Here, we show in 2 cases, that LITT could be a safe and effective option in these rare conditions.

Modeling and in vivo experimental validation of 1,064 nm laser interstitial thermal therapy on brain tissue

Introduction

Laser interstitial thermal therapy (LITT) at 1064 nm is widely used to treat epilepsy and brain tumors; however, no numerical model exists that can predict the ablation region with careful in vivo validation.

Methods

In this study, we proposed a model with a system of finite element methods simulating heat transfer inside the brain tissue, radiative transfer from the applicator into the brain tissue, and a model for tissue damage.

Results

To speed up the computation for practical applications, we also validated P1-approximation as an efficient and fast method for calculating radiative transfer by comparing it with Monte Carlo simulation. Finally, we validated the proposed numerical model in vivo on six healthy canines and eight human patients with epilepsy and found strong agreement between the predicted temperature profile and ablation area and the magnetic resonance imaging-measured results.

Discussion

Our results demonstrate the feasibility and reliability of the model in predicting the ablation area of 1,064 nm LITT, which is important for presurgical planning when using LITT.

A cost analysis of MR-guided laser interstitial thermal therapy for adult refractory epilepsy

OBJECTIVE

MR-guided laser interstitial thermal therapy (LITT) is used increasingly for refractory epilepsy. The goal of this investigation is to directly compare cost and short-term adverse outcomes for adult refractory epilepsy treated with temporal lobectomy and LITT, as well as to identify risk factors for increased costs and adverse outcomes.

METHODS

The National Inpatient Sample (NIS) was queried for patients who received LITT between 2012 and 2019. Patients with adult refractory epilepsy were identified. Multivariable mixed-effects models were used to analyze predictors of cost, length of stay (LOS), and complications.

RESULTS

LITT was associated with reduced LOS and overall cost relative to temporal lobectomy, with a statistical trend toward lower incidence of postoperative complications. High-volume surgical epilepsy centers had lower LOS overall. Longer LOS was a significant driver of increased cost for LITT, and higher comorbidity was associated with non-routine discharge.

SIGNIFICANCE

LITT is an affordable alternative to temporal lobectomy for adult refractory epilepsy with an insignificant reduction in inpatient complications. Patients may benefit from expanded access to this treatment modality for both its reduced LOS and lower cost.

Opportunities and Alternatives of Modern Radiation Oncology and Surgery for the Management of Resectable Brain Metastases

Postsurgical radiotherapy (RT) has been early proven to prevent local tumor recurrence, initially performed with whole brain RT (WBRT). Subsequent to disadvantageous cognitive sequalae for the patient and the broad distribution of modern linear accelerators, focal irradiation of the tumor has omitted WBRT in most cases. In many studies, the effectiveness of local RT of the resection cavity, either as single-fraction stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic RT (hFSRT), has been demonstrated to be effective and safe. However, whereas prospective high-level incidence is still lacking on which dose and fractionation scheme is the best choice for the patient, further ablative techniques have come into play. Neoadjuvant SRS (N-SRS) prior to resection combines straightforward target delineation with an accelerated post-surgical phase, allowing an earlier start of systemic treatment or rehabilitation as indicated. In addition, low-energy intraoperative RT (IORT) on the surgical bed has been introduced as another alternative to external beam RT, offering sterilization of the cavity surface with steep dose gradients towards the healthy brain. This consensus paper summarizes current local treatment strategies for resectable brain metastases regarding available data and patient-centered decision-making.

Feasibility and Morbidity for the Use of MR-Guided Laser-Induced Thermotherapy for the Treatment of Skull Base Tumors: A Report of Three Cases

Background  Laser-induced thermotherapy (LITT) is a minimally invasive technique that has been demonstrated as an effective treatment of many pathologies; however, it has never been investigated for the use in skull base tumors. Case Series  Three patients underwent LITT for treatment of skull base meningiomas. All three patients were determined to be poor candidates for open resection. Each patient was treated with a single laser fiber. Postoperative imaging confirmed ablation zones along the tract of the catheter in all three patients. Ablation zones were estimated to be 9 to 20% of the intended to treat tumor volume. Two of three treated patients suffered cranial nerve injury following the procedure with one patient diagnosed with neurotrophic keratitis and one patient with symptoms consistent with anesthesia dolorosa. Conclusion  LITT is a technically feasible, minimally invasive treatment modality for skull base lesions. Significant risk to cranial nerves and small ablation zones afforded by a single cannula placement proposes serious obstacles. Further investigation is warranted prior to using this technique outside of a palliative indication.

Laser Interstitial Thermal Therapy for the Treatment of a Pineal Region Glioma Through an Infratentorial Approach: A Case Report

Laser interstitial thermal therapy (LITT) is a minimally invasive surgical option for the treatment of brain tumors introduced in 1983. The innovative technique was welcomed for its ability to access deep-seated supratentorial and posterior cranial fossa lesions. Surgical approaches to pineal region tumors are challenging and require a high degree of precision since the critical vasculature, such as the vein of Galen and precentral vein, in the area pose significant anatomical challenges to operating surgeons. To minimize the risk of damaging this key venous anatomy, an infratentorial approach may be more advantageous. We present a case where LITT was utilized through an infratentorial approach to a pineal region tumor. A 62-year-old male with no significant past medical history presented to his primary care physician complaining of ataxia and headaches for the past four weeks. An MRI was concerning for multicentric glioma within the cerebellar hemispheres, brainstem extending to the middle cerebellar peduncle, upper cervical spinal cord, and pineal region. An enhancing lesion of the midbrain tectum was concerning for a high-grade tumor. We decided to proceed with stereotactic biopsy and magnetic resonance-guided LITT via an infratentorial approach. Supratentorial trajectory planning did not allow for a safe corridor due to the venous anatomy; thus, it was decided to proceed with an infratentorial approach. The patient was positioned prone, had his bone fiducial CT fused with MRI, and the tumor was targeted using robotic guidance (ROSA, Zimmer Biomet, Warsaw, Indiana). Postoperatively, he suffered from transient diplopia due to cranial nerve VI palsy. Additionally, the postoperative MRI revealed a decrease in the size of the enhancing lesion and the hyperintense T2 signal within the brainstem. Open surgical approaches to tumors within the pineal region often pose an anatomic and neurovascular challenge. We describe the safe utilization of a novel, previously unreported infratentorial approach utilizing LITT with promising treatment, morbidity, and efficacy outcomes. A larger series will be necessary to ensure the safety and efficacy of this approach.

Laser hyperthermia: Past, present, and future

Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) is an ablative procedure using heat from a laser to provide cytoreduction in tissue. It is a minimally invasive procedure that has been used in intracranial pathologies such as high-grade gliomas, metastatic lesions, epilepsy, and other lesions. While LITT may offer a more acceptable complication profile compared to open surgery, the role of laser therapy for intracranial lesions in current treatment paradigms continues to evolve. This review will focus on the background and application of LITT, the current evidence for its use, and future directions for the technology.

Medical Device Advances in the Treatment of Glioblastoma

Despite decades of research and the growing emergence of new treatment modalities, Glioblastoma (GBM) frustratingly remains an incurable brain cancer with largely stagnant 5-year survival outcomes of around 5%. Historically, a significant challenge has been the effective delivery of anti-cancer treatment. This review aims to summarize key innovations in the field of medical devices, developed either to improve the delivery of existing treatments, for example that of chemo-radiotherapy, or provide novel treatments using devices, such as sonodynamic therapy, thermotherapy and electric field therapy. It will highlight current as well as emerging device technologies, non-invasive versus invasive approaches, and by doing so provide a detailed summary of evidence from clinical studies and trials undertaken to date. Potential limitations and current challenges are discussed whilst also highlighting the exciting potential of this developing field. It is hoped that this review will serve as a useful primer for clinicians, scientists, and engineers in the field, united by a shared goal to translate medical device innovations to help improve treatment outcomes for patients with this devastating disease.

Interstitial Photothermal Therapy Generates Durable Treatment Responses in Neuroblastoma

Photothermal therapy (PTT) represents a promising modality for tumor control typically using infrared light-responsive nanoparticles illuminated by a wavelength-matched external laser. However, due to the constraints of light penetration, PTT is generally restricted to superficially accessible tumors. With the goal of extending the benefits of PTT to all tumor settings, interstitial PTT (I-PTT) is evaluated by the photothermal activation of intratumorally administered Prussian blue nanoparticles with a laser fiber positioned interstitially within the tumor. This interstitial fiber, which is fitted with a terminal diffuser, distributes light within the tumor microenvironment from the "inside-out" as compared to from the "outside-in" traditionally observed during superficially administered PTT (S-PTT). I-PTT improves the heating efficiency and heat distribution within a target treatment area compared to S-PTT. Additionally, I-PTT generates increased cytotoxicity and thermal damage at equivalent thermal doses, and elicits immunogenic cell death at lower thermal doses in targeted neuroblastoma tumor cells compared to S-PTT. In vivo, I-PTT induces significantly higher long-term tumor regression, lower rates of tumor recurrence, and improved long-term survival in multiple syngeneic murine models of neuroblastoma. This study highlights the significantly enhanced therapeutic benefit of I-PTT compared to traditional S-PTT as a promising treatment modality for solid tumors.

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.

Laser Interstitial Thermal Therapy for Cavernous Malformations: A Systematic Review

Background

Microsurgical resection of intracranial cavernous malformations (CM) is regarded as the standard treatment, but in recent years, there has been a trend toward minimally invasive procedures like ablation of such lesions by using laser interstitial thermal therapy (LITT).

Methods

A systematic search using keywords ‘laser interstitial thermal therapy’ OR ‘LITT’ AND ‘cavernoma’ OR ‘cavernous angiomas’ OR ‘cavernous malformations’ was conducted in MEDLINE (PubMed), Scopus, Embase, and Cochrane electronic bibliographic databases and studies reporting the outcome of LITT procedure on intracranial CM were included. The demographic data, symptoms of patients, location and size of the lesion, and surgical outcome were extracted from the articles.

Result

Six studies, reporting the outcome of 33 patients were included in this review. In 26 patients, CM was identified as the epileptogenic foci and in others, CM was the source of headache or focal neurological deficits. LITT led to a satisfactory outcome in all patients except for three who achieved improvement in symptoms after the open resection of the lesion. Most of the post-operative complications were transient and resolved at the time of the last follow up. Cyst formation at the previous ablated CM site was reported as the long-term complication of LITT in one case.

Conclusion

LITT can provide a comparable outcome to the open resection of CMs, by having less invasiveness, even in deep and eloquent area lesions, and complications that are often temporary and disappear gradually. However, technical issues, such as thermal monitoring during the procedure, are considered a challenge for this procedure in CMs. Further studies with a larger population are needed to report this method's long-term outcome and complications on CMs.

Laser Interstitial Thermal Therapy in Grade 2/3 IDH1/2 Mutant Gliomas: A Preliminary Report and Literature Review

Laser interstitial thermal therapy (LITT) has become an increasingly utilized alternative to surgical resection for the treatment of glioma in patients. However, treatment outcomes in isocitrate dehydrogenase 1 and 2 (IDH1/2) mutant glioma, specifically, have not been reported. The objective of this study was to characterize a single institution’s cohort of IDH1/2 mutant grade 2/3 glioma patients treated with LITT. We collected data on patient presentation, radiographic features, tumor molecular profile, complications, and outcomes. We calculated progression-free survival (PFS) and tested factors for significant association with longer PFS. Overall, 22.7% of our cohort experienced progression at a median follow up of 1.8 years. The three- and five-year estimates of PFS were 72.5% and 54.4%, respectively. This is the first study to characterize outcomes in patients with IDH1/2 mutant glioma after LITT. Our results suggest that LITT is an effective treatment option for IDH1/2 mutant glioma.

Surgical Management of Brain Metastasis: Challenges and Nuances

Brain metastasis is the most common type of intracranial tumor. The contemporary management of brain metastasis is a challenging issue and traditionally has carried a poor prognosis as these lesions typically occur in the setting of advanced cancer. However, improvement in systemic therapy, advances in radiation techniques and multimodal therapy tailored to the individual patient, has given hope to this patient population. Surgical resection has a well-established role in the management of brain metastasis. Here we discuss the evolving role of surgery in the treatment of this diverse patient population.

Self-assembled tocopherol-albumin nanoparticles with full biocompatibility for chemo-photothermal therapy against breast cancer

BACKGROUND

The combination of photothermal therapy (PTT) and chemotherapy has proven to be a promising strategy for cancer treatment. Various nanomaterials have shown great potential in combination therapy, including gold, graphene oxide, iron oxide, and other nanoparticles. However, their undefinable toxicity in vivo greatly slowed down their development for clinical applications.

OBJECTIVE

The present work aimed to develop a multifunctional nanoparticle for chemo-photothermal therapy composed of acknowledged biocompatible materials.

METHODS

A novel biocompatible nanoparticle (HIT-NPs) was self-assembled through the intrinsic interaction between D-α-tocopherol Succinate (TOS), human serum albumin (HSA) and indocyanine green (ICG). Doxorubicin (DOX) was then loaded due to the ion pairing between DOX and TOS. The feasibility of combined chemo-photothermal therapy induced by DOX-loaded HIT-NPs was carefully evaluated.

RESULTS

In vitro, HIT-NPs showed no cytotoxicity on human normal liver cells (HL-7702 cells) but obvious killing effects murine breast cancer cells (4T1 cells). The combined chemo-photothermal therapeutic effect on 4T1 cells was successfully obtained. DOX-loaded HIT-NPs could effectively accumulate in 4T1 subcutaneous tumors after intravenous injection, and the tumor temperature rapidly increased under laser exposure, indicating the feasibility of PTT in vivo.

CONCLUSION

The self-assembled HIT-NPs could provide a promising platform for combined chemo-photothermal cancer therapy with full biocompatibility.

Enhanced intratumoural activity of CAR T cells engineered to produce immunomodulators under photothermal control

Treating solid malignancies with chimeric antigen receptor (CAR) T cells typically results in poor responses. Immunomodulatory biologics delivered systemically can augment the cells' activity, but off-target toxicity narrows the therapeutic window. Here we show that the activity of intratumoural CAR T cells can be controlled photothermally via synthetic gene switches that trigger the expression of transgenes in response to mild temperature elevations (to 40-42 °C). In vitro, heating engineered primary human T cells for 15-30 min led to over 60-fold-higher expression of a reporter transgene without affecting the cells' proliferation, migration and cytotoxicity. In mice, CAR T cells photothermally heated via gold nanorods produced a transgene only within the tumours. In mouse models of adoptive transfer, the systemic delivery of CAR T cells followed by intratumoural production, under photothermal control, of an interleukin-15 superagonist or a bispecific T cell engager bearing an NKG2D receptor redirecting T cells against NKG2D ligands enhanced antitumour activity and mitigated antigen escape. Localized photothermal control of the activity of engineered T cells may enhance their safety and efficacy.

Laser thermal therapy in the management of high-grade gliomas

Laser interstitial thermal therapy (LITT) is a minimally invasive therapy that have been used for brain tumors, epilepsy, chronic pain, and other spine pathologies. This therapy is performed under imaging and stereotactic guidance to precisely direct the probe and ablate the area of interest using real-time magnetic resonance (MR) thermography. LITT has gained popularity as a treatment for glioma because of its minimally invasive nature, small skin incision, repeatability, shorter hospital stay, and the possibility of receiving adjuvant therapy shortly after surgery instead of several weeks as required after open surgical resection. Several reports have demonstrated the usefulness of LITT in the treatment of newly-diagnosed and recurrent gliomas. In this review, we will summarize the recent evidence of this therapy in the field of glioma surgery and the future perspectives of the use of LITT combined with other treatment strategies for this devastating disease.

The effect of thermal therapy on the blood-brain barrier and blood-tumor barrier

The blood-brain and blood-tumor barriers represent highly specialized structures responsible for tight regulation of molecular transit into the central nervous system. Under normal circumstances, the relative impermeability of the blood-brain barrier (BBB) protects the brain from circulating toxins and contributes to a brain microenvironment necessary for optimal neuronal function. However, in the context of tumors and other diseases of central nervous system, the BBB and the more recently appreciated blood-tumor barrier (BTB) represent barriers that prevent effective drug delivery. Overcoming both barriers to optimize treatment of central nervous system diseases remains the subject of intense scientific investigation. Although many newer technologies have been developed to overcome these barriers, thermal therapy, which dates back to the 1890 s, has been known to disrupt the BBB since at least the early 1980s. Recently, as a result of several technological advances, laser interstitial thermal therapy (LITT), a method of delivering targeted thermal therapy, has gained widespread use as a surgical technique to ablate brain tumors. In addition, accumulating evidence indicates that laser ablation may also increase local BBB/BTB permeability after treatment. We herein review the structure and function of the BBB and BTB and the impact of thermal injury, including LITT, on barrier function.

Precise Tumor Photothermal Therapy Guided and Monitored by Magnetic Resonance/Photoacoustic Imaging using A Safe and pH-Responsive Fe(III) Complex

Photothermal agents with strong near infrared (NIR) optical absorbance and excellent biocompatibility and traceability are highly desired for precise photothermal therapy. This study reports the development of a dual-functional Fe³⁺ complex (Fe-ZDS) for imaging-guided, precise photothermal therapy of tumors. The complex has stable structure and obvious zwitterionic features, resulting in excellent biocompatibility and efficient renal clearance. The iron-dopa core structure renders the complex capable of generating magnetic resonance imaging (MRI) contrast, while synergistically exhibiting optical absorption in the red and NIR regions. Interestingly, the optical absorption of the complex is pH-sensitive, with significantly higher absorption intensity in a weakly acidic environment than in a neutral environment. Thus the complex can respond to acidic tumor stimuli and confine the energy of the laser to the tumor tissue. The MRI contrast and photoacoustic signal of the complex is taken advantage of to monitor the probe injection process and optimize the injection position and dosage for maximally covering the tumor tissue and assessing the activation of the complex in tumor tissues. The evolution of temperature inside the tissue during the laser irradiation is also monitored. Using Fe-ZDS as the theranostic probe, satisfactory treatment outcomes are achieved for photothermal therapy of tumors.

Laser interstitial thermotherapy (LITT) for the treatment of tumors of the brain and spine: a brief review

INTRODUCTION

Laser Interstitial Thermotherapy (LITT; also known as Stereotactic Laser Ablation or SLA), is a minimally invasive treatment modality that has recently gained prominence in the treatment of malignant primary and metastatic brain tumors and radiation necrosis and studies for treatment of spinal metastasis has recently been reported.

METHODS

Here we provide a brief literature review of the various contemporary uses for LITT and their reported outcomes.

RESULTS

Historically, the primary indication for LITT has been for the treatment of recurrent glioblastoma (GBM). However, indications have continued to expand and now include gliomas of different grades, brain metastasis (BM), radiation necrosis (RN), other types of brain tumors as well as spine metastasis. LITT is emerging as a safe, reliable, minimally invasive clinical approach, particularly for deep seated, focal malignant brain tumors and radiation necrosis. The role of LITT for treatment of other types of tumors of the brain and for spine tumors appears to be evolving at a small number of centers. While the technology appears to be safe and increasingly utilized, there have been few prospective clinical trials and most published studies combine different pathologies in the same report.

CONCLUSION

Well-designed prospective trials will be required to firmly establish the role of LITT in the treatment of lesions of the brain and spine.

A phase II study of laser interstitial thermal therapy combined with doxorubicin in patients with recurrent glioblastoma

Background

The blood-brain barrier (BBB) is a major limiting factor for drug delivery in brain tumors. Laser interstitial thermal therapy (LITT) disrupts the peritumoral BBB. In this study, we examine survival in patients with recurrent glioblastoma (GBM) treated with LITT followed by low-dose doxorubicin, a potent anti-neoplastic drug with poor BBB permeability.

Methods

Forty-one patients with recurrent GBM were enrolled; thirty patients were evaluable. Participants underwent LITT followed by 6 weekly doxorubicin treatments starting within one week (Early Arm) or at 6–8 weeks (Late Arm) after LITT. The overall survival (OS), local progression-free survival (PFS), and any PFS were compared to historical controls treated with bevacizumab salvage therapy (n = 50) or LITT with standard BBB-permeable salvage therapy (n = 28). Cox proportional-hazards models examined the contribution of age, gender, MGMT promoter status, and IDH-mutation status on any PFS and OS. Adverse events were also cataloged.

Results

The Late Arm and all patients (Early Arm + Late Arm) demonstrated significant improvement in OS compared to historical controls treated with bevacizumab (p < 0.001) and LITT with standard salvage therapy (p < 0.05). No significant difference in any PFS was observed between either arm and historical controls. Low-dose doxorubicin was well tolerated with comparable adverse event rates between the arms.

Conclusions

Low-dose doxorubicin given after LITT is well tolerated and correlated with higher OS compared to historical controls treated with bevacizumab or LITT with standard salvage chemotherapy. A larger study is needed to further characterize survival and progression patterns.

Brain Metastases: A Modern Multidisciplinary Approach

Brain metastases (BM) are the most common intracranial neoplasm and represent a major clinical challenge across many medical disciplines. The incidence of BM is increasing, largely due to improvements in primary disease therapeutics conferring greater systemic control, and advancements in neuroimaging techniques and availability leading to earlier diagnosis. In recent years, the landscape of BM treatment has changed significantly with the advent of personalized targeted chemotherapies and immunotherapy, the adoption of focal radiotherapy (RT) for higher intracranial disease burden, and the implementation of new surgical strategies. The increasing permutations of options available for the treatment of patients diagnosed with BM necessitate coordinated care by a multidisciplinary team. This review discusses the current treatment regimens for BM as well as examines the salient features of a modern multidisciplinary approach.

Novel Treatment Strategies for Glioblastoma

Glioblastoma (GBM) is the most common primary central nervous system tumor in adults. It is a highly invasive disease, making it difficult to achieve a complete surgical resection, resulting in poor prognosis with a median survival of 12–15 months after diagnosis, and less than 5% of patients survive more than 5 years. Surgical, instrument technology, diagnostic and radio/chemotherapeutic strategies have slowly evolved over time, but this has not translated into significant increases in patient survival. The current standard of care for GBM patients involving surgery, radiotherapy, and concomitant chemotherapy temozolomide (known as the Stupp protocol), has only provided a modest increase of 2.5 months in median survival, since the landmark publication in 2005. There has been considerable effort in recent years to increase our knowledge of the molecular landscape of GBM through advances in technology such as next-generation sequencing, which has led to the stratification of the disease into several genetic subtypes. Current treatments are far from satisfactory, and studies investigating acquired/inherent resistance to current therapies, restricted drug delivery, inter/intra-tumoral heterogeneity, drug repurposing and a tumor immune-evasive environment have been the focus of intense research over recent years. While the clinical advancement of GBM therapeutics has seen limited progression compared to other cancers, developments in novel treatment strategies that are being investigated are displaying encouraging signs for combating this disease. This aim of this editorial is to provide a brief overview of a select number of these novel therapeutic approaches.

Multicenter Investigation of Channel-Based Subcortical Trans-Sulcal Exoscopic Resection of Metastatic Brain Tumors: A Retrospective Case Series

BACKGROUND

Recent advancements have aimed to optimize visualization and minimize insult to healthy cortical and subcortical tissue through the use of tubular-based retractors.

OBJECTIVE

To investigate outcomes following resection of cerebral metastases using an integrated tubular retraction system with an exoscope and neuronavigation.

METHODS

A multicenter retrospective analysis of surgical outcomes in consecutive patients who underwent resection of a brain metastasis using a tubular retraction system and exoscope was performed.

RESULTS

Twenty-five patients were included, with a mean age of 61 yr (24-81 yr). Primary sources included lung (n = 13), breast (n = 3), renal cell (n = 3), and other (n = 6). Locations were frontal (n = 5), parietal (n = 8), cerebellar (n = 8), occipital (n = 3), and splenium (n = 1). Most lesions had a maximum diameter > 3.0 cm (n = 20) and a tumor depth > 4 cm (n = 14). Conversion to open (microscopic) craniotomy was not required in any case. Gross total resection was achieved in 20 cases (80.0%) and subtotal resection in 5 cases (20.0%). Median hospital stay was 2 d (1-12 d). All patients underwent postoperative radiation therapy. Perioperative complications developed in 1 patient (4.0%; hemiparesis and subsequent deep vein thrombosis). At 3-mo follow-up, no mortalities were observed, 19 patients (76.0%) demonstrated neurological improvements, 5 patients (20.0%) had a stable neurological exam, and 1 patient (4.0%) had a neurological decline.

CONCLUSION

Utilization of a channel-based, navigable retractor and exoscope is a feasible option for surgical resection of metastatic brain lesions.

Prediction of recurrent glioblastoma after laser interstitial thermal therapy: The role of diffusion imaging

Background

Evaluate the utility of diffusion-weighted imaging (DWI) for the assessment of local recurrence of glioblastoma (GBM) on imaging performed 24 h following MRI-guided laser interstitial thermal therapy (LITT). We hypothesize that microscopic peritumoral infiltration correlates with early subtle variations on DWI images and apparent diffusion coefficient (ADC) maps.

Methods

Of 64 patients with GBM treated with LITT, 39 had MRI scans within 24 h after undergoing LITT. Patterns on DWI images and ADC maps 24 h following LITT were correlated with areas of future GBM recurrence identified through coregistration of subsequent MRI examinations. In the areas of suspected recurrence within the periphery of post-LITT lesions, signal intensity values on ADC maps were recorded and compared with the remaining peritumoral ring.

Results

Thirty-nine patients with GBM met the inclusion criteria. For predicting recurrent GBM, areas of decreased DWI signal and increased signal on ADC maps within the expected peritumoral ring of restricted diffusion identified 24 h following LITT showed 86.1% sensitivity, 75.2% specificity, and high correlation (r = 0.53) with future areas of GBM recurrence (P < .01). Areas of future recurrence demonstrated a 37% increase in the ADC value (P < .001), compared with findings in the surrounding treated peritumoral region. A significantly greater area under the receiver operating characteristics curve was determined for ADC values (P < .01).

Conclusions

DWI obtained 24 h following LITT can help predict the location of GBM recurrence months before the development of abnormal enhancement. This may alter future treatment planning, perhaps suggesting areas that may be targeted for additional therapy.

In vitro evidence for glioblastoma cell death in temperatures found in the penumbra of laser-ablated tumors

The concept of thermal therapy toward the treatment of brain tumors has gained traction in recent years. Traditionally, thermal therapy has been subdivided into hyperthermia, with mild elevation of temperature in treated tissue above the physiologic baseline; and thermal ablation, where even higher temperatures are achieved. The recent surge in interest has been driven by the use of novel thermal ablation technologies, including laser interstitial thermal therapy (LITT), that are implemented in brain tumor treatment. Here, we review previous scientific literature on the biologic effects of thermal therapy on brain tumors, with an emphasis on glioblastoma (GBM), an aggressive brain malignancy. In addition, we present in vitro evidence from our laboratory that even moderate elevations in temperature achieved in the penumbra around laser-ablated coagulum may also produce GBM cell death. While much remains to be elucidated in terms of the biology of thermal therapy, we propose that it is a welcome addition to the neuro-oncology armamentarium, in particular with regard to GBM, which is generally resistant to current chemoradiotherapeutic regimens.

Hyperthermia treatment advances for brain tumors

Hyperthermia therapy (HT) of cancer is a well-known treatment approach. With the advent of new technologies, HT approaches are now important for the treatment of brain tumors. We review current clinical applications of HT in neuro-oncology and ongoing preclinical research aiming to advance HT approaches to clinical practice. Laser interstitial thermal therapy (LITT) is currently the most widely utilized thermal ablation approach in clinical practice mainly for the treatment of recurrent or deep-seated tumors in the brain. Magnetic hyperthermia therapy (MHT), which relies on the use of magnetic nanoparticles (MNPs) and alternating magnetic fields (AMFs), is a new quite promising HT treatment approach for brain tumors. Initial MHT clinical studies in combination with fractionated radiation therapy (RT) in patients have been completed in Europe with encouraging results. Another combination treatment with HT that warrants further investigation is immunotherapy. HT approaches for brain tumors will continue to a play an important role in neuro-oncology.

Seizure freedom from recurrent insular low-grade glioma following laser interstitial thermal therapy

Pediatric low-grade gliomas (LGGs) are found in approximately 1-3% of patients with childhood epilepsy that is often medically refractory. Magnetic resonance guided laser interstitial thermal therapy (MRgLITT) is a minimal access technique FDA-approved since 2007 to ablate soft tissue lesions including brain tumors and seizure foci in children. The authors describe the case of an 11-year-old boy who presented with focal right-sided seizures and was found to have a growing left insular mass determined to be a WHO grade II diffuse astrocytoma. After the initial open resection using frontotemporal craniotomy with transsylvian approach, gross total resection was achieved; however, the tumor recurred, as did the seizures. Six months postoperatively, the patient underwent laser ablation with MRgLITT for the recurrent tumor with complete removal. At both 1- and 6-months post re-operation, he has remained seizure free. MRgLITT management of LGG allows for both successfully reducing tumor burden and the amelioration of secondary seizures.

Lessons Learned in Using Laser Interstitial Thermal Therapy for Treatment of Brain Tumors: A Case Series of 238 Patients from a Single Institution

BACKGROUND

Laser interstitial thermal therapy (LITT) is a novel, minimally invasive alternative to craniotomy, and as with any new technology, comes with a learning curve.

OBJECTIVE

We present our experience detailing the evolution of this technology in our practice in one of the largest patient cohorts to date regarding LITT in neuro-oncology.

METHODS

We reviewed 238 consecutive patients with brain tumor treated with LITT at our institution. Data on patient, surgery and tumor characteristics, and follow-up were collected. Patients were categorized into 2 cohorts: early (<2014, 100 patients) and recent (>2015, 138 patients). Median follow-up for the entire cohort was 8.4 months.

RESULTS

The indications for LITT included gliomas (70.2%), radiation necrosis (21.0%), and metastasis (8.8%). Patient demographics stayed consistent between the 2 cohorts, with the exception of age (early, 54.3; recent, 58.4; P = 0.04). Operative time (6.6 vs. 3.5; P < 0.001) and number of trajectories (53.1% vs. 77.9% with 1 trajectory; P < 0.001) also decreased in the recent cohort. There was a significant decrease in permanent motor deficits over time (15.5 vs. 4.4%; P = 0.005) and 30-day mortality (4.1% vs. 1.5%) also decreased (not statistically significant) in the recent cohort. In terms of clinical outcomes, poor preoperative Karnofsky Performance Status (≤70) were significantly correlated with increased permanent deficits (P = 0.001) and decreased overall survival (P < 0.001 for all time points).

CONCLUSIONS

We observed improvement in operative efficiency and permanent deficits over time and also patients with poor preoperative Karnofsky Performance Status achieved suboptimal outcomes with LITT. As many other treatment modalities, patient selection is important in this procedure.

Thermal ablation of biological tissues in disease treatment: A review of computational models and future directions

Percutaneous thermal ablation has proven to be an effective modality for treating both benign and malignant tumours in various tissues. Among these modalities, radiofrequency ablation (RFA) is the most promising and widely adopted approach that has been extensively studied in the past decades. Microwave ablation (MWA) is a newly emerging modality that is gaining rapid momentum due to its capability of inducing rapid heating and attaining larger ablation volumes, and its lesser susceptibility to the heat sink effects as compared to RFA. Although the goal of both these therapies is to attain cell death in the target tissue by virtue of heating above 50°C, their underlying mechanism of action and principles greatly differs. Computational modelling is a powerful tool for studying the effect of electromagnetic interactions within the biological tissues and predicting the treatment outcomes during thermal ablative therapies. Such a priori estimation can assist the clinical practitioners during treatment planning with the goal of attaining successful tumour destruction and preservation of the surrounding healthy tissue and critical structures. This review provides current state-of-the-art developments and associated challenges in the computational modelling of thermal ablative techniques, viz., RFA and MWA, as well as touch upon several promising avenues in the modelling of laser ablation, nanoparticles assisted magnetic hyperthermia and non-invasive RFA. The application of RFA in pain relief has been extensively reviewed from modelling point of view. Additionally, future directions have also been provided to improve these models for their successful translation and integration into the hospital work flow.

The role of neutrophil-to-lymphocyte ratio in predicting overall survival in patients undergoing laser interstitial thermal therapy for glioblastoma

Laser interstitial thermal therapy (LITT) offers a minimally-invasive treatment option for glioblastomas (GBM) which are relatively small or in eloquent areas. While laser ablation for malignant gliomas has been shown to be safe and effective, the role of the subsequent immune response in not well established. In this study we aim to analyze the prognostic potential of edema volume and acute inflammation, quantified as neutrophil-to-lymphocyte ratio (NLR), in predicting overall survival. Twenty-one patients were identified with new or recurrent GBMs that were candidates for LITT. Laser ablation was performed using standard solid tumor protocol for treatment volume, intensity and duration. Edema volume was quantified using MRI imaging, while retrospective chart review was performed to calculate NLR and survival. In patients treated with LITT for GBM, peri-tumoral vasogenic edema volumes did not significantly change post-operatively, p > 0.200, while NLR significantly increased, p = 0.0002. The degree of NLR increase correlated with longer overall survivals, and ROC analysis demonstrated an area under the curve of 0.827, p = 0.0112. A delta-NLR cutoff of 7.0 results in positive and negative predictive values of 78% and 75%, respectively, in predicting overall survival >1 year. Patients with with delta-NLR > 7.0 lived significantly longer that those with delta-NLR < 7.0, median survival 440 days compared to 239 days, p = 0.0297. We demonstrate preliminary data that monitoring the inflammatory response after LITT in GBM patients offers a potential prognostic measurement to assist in predicting treatment efficacy and overall survival.

Neurosurgical applications of MRI guided laser interstitial thermal therapy (LITT)

MRI-guided laser interstitial thermal therapy (LITT) is the selective ablation of a lesion or a tissue using heat emitted from a laser device. LITT is considered a less invasive technique compared to open surgery that provides a nonsurgical solution for patients who cannot tolerate surgery. Although laser ablation has been used to treat brain lesions for decades, recent advances in MRI have improved lesion targeting and enabled real-time accurate monitoring of the thermal ablation process. These advances have led to a plethora of research involving the technique, safety, and potential applications of LITT.LITT is a minimally invasive treatment modality that shows promising results and is associated with decreased morbidity. It has various applications, such as treatment of glioma, brain metastases, radiation necrosis, and epilepsy. It can provide a safer alternative treatment option for patients in whom the lesion is not accessible by surgery, who are not surgical candidates, or in whom other standard treatment options have failed. Our aim is to review the current literature on LITT and provide a descriptive review of the technique, imaging findings, and clinical applications for neurosurgery.

Non-Ionizing Radiation in Swedish Health Care-Exposure and Safety Aspects

The main aim of the study was to identify and describe methods using non-ionizing radiation (NIR) such as electromagnetic fields (EMF) and optical radiation in Swedish health care. By examining anticipated exposure levels and by identifying possible health hazards we also aimed to recognize knowledge gaps in the field. NIR is mainly used in health care for diagnosis and therapy. Three applications were identified where acute effects cannot be ruled out: magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS) and electrosurgery. When using optical radiation, such as class 3 and 4 lasers for therapy or surgical procedures and ultra-violet light for therapy, acute effects such as unintentional burns, photo reactions, erythema and effects on the eyes need to be avoided. There is a need for more knowledge regarding long-term effects of MRI as well as on the combination of different NIR exposures. Based on literature and after consulting staff we conclude that the health care professionals' knowledge about the risks and safety measures should be improved and that there is a need for clear, evidence-based information from reliable sources, and it should be obvious to the user which source to address.

Use of a flexible hollow-core carbon dioxide laser for microsurgical resection of vestibular schwannomas

OBJECTIVE

The CO2 laser has been used on an intermittent basis in the microsurgical resection of brain tumors for decades. These lasers were typically cumbersome to use due to the need for a large, bulky design since infrared light cannot be transmitted via fiber-optic cables. Development of the OmniGuide cable, which is hollow and lined with an omnidirectional dielectric mirror, has facilitated the reintroduction of the CO2 laser in surgical use in a number of fields. This device allows for handheld use of the CO2 laser in a much more ergonomically favorable configuration, holding promise for microneurosurgical applications. This device was introduced into the authors’ practice for use in the microsurgical resection of skull base tumors, including vestibular schwannomas.

METHODS

The authors reviewed the initial 41 vestibular schwannomas that were treated using the OmniGuide CO2 laser during an 8-month period from March 2010 to October 2010. The laser was used for all large tumors, and select medium-sized tumors were treated via both the translabyrinthine and retrosigmoid approaches. The estimated time of tumor resection and estimated blood loss were obtained from operating room records. Data regarding complications, facial nerve and hearing outcomes, and further treatment were collected from hospital and clinic records, MRI reports, and direct review of MR images. Time of resection and blood loss were compared to a control group (n = 18) who underwent surgery just prior to use of the laser.

RESULTS

A total of 41 patients with vestibular schwannomas were surgically treated. The median estimated time of tumor resection was 150 minutes, and the median estimated blood loss was 300 ml. The only operative complication was 1 CSF leak. Thirty-eight patients had normal facial nerve function at late follow-up. The median MRI follow-up was 52 months, and, during that time, only 1 patient required further treatment for regrowth of a residual tumor.

CONCLUSIONS

The OmniGuide CO2 laser is a useful adjunct in the resection of large vestibular schwannomas. This device was used primarily as a cutting tool rather than for tumor vaporization, and it was found to be of most use for very large and/or firm tumors. There were no laser-associated complications, and the results compared favorably to earlier reports of vestibular schwannoma resection.

Volumetric response of progressing post-SRS lesions treated with laser interstitial thermal therapy

We analyzed volumetric response of metastatic brain tumors that progressed despite treatment with stereotactic radiosurgery (SRS) after treatment with laser interstitial thermal therapy (LITT). We retrospectively reviewed consecutive patients treated from 1/2012 to 10/2015 with LITT for metastatic brain tumors demonstrating progression after SRS. Volumes were quantified using MRI with contrast-enhanced T1-weighted (T1W) and fluid-attenuated inversion recovery (FLAIR). Fifty lesions from 36 patients were studied. Lesions were assessed prior to LITT, immediately after LITT, 0-90 days after LITT, 90-180 days after LITT, 180-270 days after LITT, and 270-360 days after LITT. The median T1W volume was 5.05 cc (range 0.54-23.31 cc) before LITT treatment (n = 50), 7.70 cc (range 1.72-38.76 cc) 0-90 days after LITT (n = 47), and 3.68 cc (range 1.282-48.31 cc) 180-270 days after LITT (n = 21). The median FLAIR volume was 43.36 cc (range 3.09-233.01 cc) before LITT treatment (n = 50), 37.13 cc (range 3.48-244.23 cc) 0-90 days after LITT (n = 43), 31.68 cc (range 1.6-248.75 cc) 180-270 days after LITT (n = 18). The 6-month FLAIR volume showed a statistically significant reduction compared to pretreatment (p = 0.04). After selecting for cases where patients had two or more post-operative MRIs, we found that 24 lesions (63%) demonstrated an overall downward trend and 14 lesions (37%) demonstrated an upward trend. The median pre-treatment T1W volume for the patients whose lesions demonstrated volumetric reduction after LITT was 3.54 cc (range 0.539-10.06 cc) and for those who did not demonstrate volumetric reduction after LITT it was 8.81 cc (range 0.926-23.313 cc). The pre-treatment tumor volume plays a significant role in determining response to LITT with smaller tumor volumes responding better to LITT than tumors with larger volumes.

Neurosurgical management of brain metastases

Brain metastases present a significant public health issue, affecting more than 100,000 patients per year in the U.S. and result in significant morbidity. Brain metastases can occur in a variety of clinical situations ranging from multiple brain metastases with uncontrolled systemic disease to a solitary metastasis in the setting of controlled systemic disease. Additionally, advances in genomics have broadened the opportunities for targeted treatment options and potentially more durable systemic responses. As such, the treatment of brain metastases is now more tailored and multimodal, involving systemic, radiation, and surgical therapies, often in combination. This review discusses the historical and current role of neurosurgical techniques in the treatment of brain metastases.

Determination of temperature distribution in tissue for interstitial cancer photothermal therapy

BACKGROUND

Temperature increase in tumour tissue during photothermal therapy (PTT) is a significant factor in determining the outcomes of the treatment. Therefore, controlling and optimising temperature distribution in target tissue is crucial for PTT. In this study, we developed a unique ex vivo device to study the temperature distribution during PTT to be used as a guide for the desired photothermal effects for cancer treatment.

METHODS

Bovine liver tissue buried inside agarose gel served as a phantom tumour surrounded by normal tissue. A thermostatic incubator was used to simulate tissue environment in live animals. The temperature distributions were measured by thermocouples with needle probes at different locations inside the target tissue, during laser irradiation using an 805-nm laser.

RESULTS

The results obtained using the ex vivo device were verified by comparing the tissue temperature directly measured in animal tumours irradiated under the same conditions. With this model, the spatial distribution of temperature in target tissue can be monitored in real time. A two-dimensional temperature distribution in target tissue allows us to establish the correlations among laser parameters, temperature distribution and tumour size. In addition, the optimal temperature range for tumour destruction and immunological stimulation was determined using metastatic rat mammary tumour model.

CONCLUSION

The device and method developed in this study can provide guidance for choosing the appropriate treatment parameters for optimal photothermal effects, particularly when combined with immunotherapy, for cancer treatment.