The role of magnetic resonance-guided laser ablation in neurooncology

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.

Laser interstitial thermal therapy (LITT) for pediatric low-grade glioma-case presentations and lessons learned

BACKGROUND

The surgical treatment of brain tumors has developed over time, offering customized strategies for patients and their specific lesions. One of the most recent advances in pediatric neuro-oncological surgery is laser interstitial thermal therapy (LITT). However, its effectiveness and indications are still being evaluated. The aim of this work is to review the current literature on LITT for pediatric low-grade gliomas (pLGG) and evaluate our initial results in this context.

METHODS

We retrospectively reviewed our pediatric neurosurgery database for patients who received LITT treatment between November 2019 and December 2023. We collected data on the indications for LITT, technical issues during the procedure, and clinical and radiological follow-up.

RESULTS

Three patients underwent 5 LITT procedures for pLGG. The lesion was thalamo-peduncular in one patient, cingulate in one, and deep parietal in one patient. Two patients had a previous open resection done and were diagnosed with pLGG. One patient underwent a stereotaxic biopsy during the LITT procedure that was non-diagnostic. The same patient underwent a later open resection of the tumor in the cingulate gyrus. There were no surgical complications and all patients were discharged home on the first post-operative day. The follow-up period was between 20 and 40 months. Radiological follow-up showed a progressive reduction of the tumor in patients with LGG.

CONCLUSION

Laser interstitial thermal therapy is a minimally invasive treatment that shows promise in treating deep-seated pLGG in children. The treatment has demonstrated a reduction in tumor volume, and the positive results continue over time. LITT can be used as an alternative treatment for tumors located in areas that are difficult to access surgically or in cases where other standard treatment options have failed.

How modern treatments have modified the role of surgery in pediatric low-grade glioma

Low-grade gliomas are the most common brain tumor of childhood, and complete resection offers a high likelihood of cure. However, in many instances, tumors may not be surgically accessible without substantial morbidity, particularly in regard to gliomas arising from the optic or hypothalamic regions, as well as the brainstem. When gross total resection is not feasible, alternative treatment strategies must be considered. While conventional chemotherapy and radiation therapy have long been the backbone of adjuvant therapy for low-grade glioma, emerging techniques and technologies are rapidly changing the landscape of care for patients with this disease. This article seeks to review the current and emerging modalities of treatment for pediatric low-grade glioma.

Non-Fourier Bioheat Transfer Analysis in Brain Tissue During Interstitial Laser Ablation: Analysis of Multiple Influential Factors

This work presents the dual-phase lag-based non-Fourier bioheat transfer model of brain tissue subjected to interstitial laser ablation. The finite element method has been utilized to predict the brain tissue's temperature distributions and ablation volumes. A sensitivity analysis has been conducted to quantify the effect of variations in the input laser power, treatment time, laser fiber diameter, laser wavelength, and non-Fourier phase lags. Notably, in this work, the temperature-dependent thermal properties of brain tissue have been considered. The developed model has been validated by comparing the temperature obtained from the numerical and ex vivo brain tissue during interstitial laser ablation. The ex vivo brain model has been further extended to in vivo settings by incorporating the blood perfusion effects. The results of the systematic analysis highlight the importance of considering temperature-dependent thermal properties of the brain tissue, non-Fourier behavior, and microvascular perfusion effects in the computational models for accurate predictions of the treatment outcomes during interstitial laser ablation, thereby minimizing the damage to surrounding healthy tissue. The developed model and parametric analysis reported in this study would assist in a more accurate and precise prediction of the temperature distribution, thus allowing to optimize the thermal dosage during laser therapy in the brain.

Magnetic resonance-guided laser interstitial thermal therapy vs. stereoelectroencephalography-guided radiofrequency thermocoagulation in epilepsy patients with focal cortical dysplasia: a systematic review and meta-analysis

Background

Magnetic resonance-guided laser interstitial thermal therapy (MRgLiTT) and stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-RFTC) are two effective, minimally invasive treatments for epilepsy with focal cortical dysplasia (FCD). The purpose of this study is to conduct a meta-analysis to evaluate and compare the efficacy and safety of these two therapies in epilepsy patients with FCD.

Methods

We searched PubMed, Embase, Cochrane, and other databases for articles published before March 2023. The primary objective was to compare the effectiveness and complications of MRgLiTT and SEEG-RFTC in epilepsy patients with FCD. The second objective was to determine which method provides a better prognosis for specific subgroup patients.

Results

According to the inclusion and exclusion criteria, 18 studies were included, comprising 270 FCD patients including 37 patients from 6 MRgLiTT studies and 233 from 12 SEEG-RFTC studies. There were no significant differences between MRgLiTT and SEEG-RFTC groups in the seizure-freedom rate (59%, 95% CI 44-74%; 52%, 95% CI 47-57%, P = 0.86) and the rate of ≥50% seizure-reduction of FCD (90%, 95% CI 80-100%; 90%, 95% CI 86-94%, P = 0.42). Both methods had low complication rates (17.1%, 28/159) and long-term complication (2.5%, 4/159) rate, with no significant difference between them (P = 0.17).

Conclusion

Both MRgLiTT and SEEG-RFTC are safe and minimally invasive treatments for patients with FCD. They have comparable performance in terms of postoperative seizure-freedom rates in patients with FCD, and both can be used as treatment options for patients with FCD. Our study found that SEEG-RFTC had a better therapeutic effect in the FCD2b subgroup.

LITT for biopsy proven radiation necrosis: A qualitative systematic review

INTRODUCTION

With the widespread use of stereotactic radiosurgery (SRS), post-radiation treatment effects (PTREs) are increasing in prevalence. Radiation necrosis (RN) is a serious PTRE which carries a poor prognosis. Since 2012, laser interstitial thermal therapy (LITT) has been used to treat RN. However, reviews have attempting to generalise the efficacy of LITT against biopsy-proven RN are limited. In this systematic review, patient demographic characteristics and post-LITT clinical outcomes are characterised.

METHODS

A systematic literature search was conducted in four major databases for cohort studies and case reports published between 2012 and 2022, following the PRISMA 2020 checklist. Data was extracted and descriptively analysed. Quality of reporting was assessed using the PROCESS criteria and reporting bias was evaluated using the ROBINS-I scoring system.

RESULTS

Eleven studies met our inclusion criteria, with an overall moderate risk of reporting bias being observed. Mean pre-LITT target lesion volume was 6.75 cm3, and was independent of gender, time since SRS, age and number of interventions prior to LITT.

DISCUSSION AND CONCLUSION

LITT is a versatile treatment option which may be used to treat a vast range of patients with refractory biopsy-proven RN. However, neurosurgeons should exercise caution when selecting patients for LITT due to insufficient data on the treatment's efficacy against biopsy-proven RN. This warrants further studies to unequivocally determine the safety and clinical outcomes.

Laser interstitial thermal therapy (LITT) for pediatric patients affected by intracranial tumors

Introduction

The surgical treatment of brain tumors has evolved over time, offering different strategies tailored to patients and their specific lesions. Among these strategies, Laser Interstitial Thermal Therapy (LITT) is one of the most recent advances in pediatric neurooncological surgery, and its results and evolution are still under assessment.

Methods

We retrospectively analyzed data from six pediatric patients with deep-seated brain tumors treated with LITT at a single center between November 2019 and June 2022. A total of four patients underwent a stereotaxic biopsy during the same operating session. The indications and preparation for LITT, technical issues, clinical and radiological follow-up, impact on quality of life, and oncological treatment are discussed.

Results

The mean patient age eight years (ranging from 2 to 11 years). The lesion was thalamic in four patients, thalamo-peduncular in one, and occipital posterior periventricular in one. In total, two patients had been previously diagnosed with low-grade glioma (LGG). Biopsies revealed LGG in two patients, ganglioglioma grade I in one, and diffuse high-grade glioma (HGG) in one. Postoperatively, two patients presented with transient motor deficits. The mean follow-up period was 17 months (ranging from 5 to 32 months). Radiological follow-up showed a progressive reduction of the tumor in patients with LGG.

Conclusion

Laser interstitial thermal therapy is a promising, minimally invasive treatment for deep-seated tumors in children. The results of lesion reduction appear to be relevant in LGGs and continue over time. It can be used as an alternative treatment for tumors located at sites that are difficult to access surgically or where other standard treatment options have failed.

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.

Combination Laser Interstitial Thermal Therapy Plus Stereotactic Radiotherapy (SRT) Increases Time to Progression for Biopsy-Proven Recurrent Brain Metastases

Background

Improved survival for patients with brain metastases has been accompanied by a rise in tumor recurrence after stereotactic radiotherapy (SRT). Laser interstitial thermal therapy (LITT) has emerged as an effective treatment for SRT failures as an alternative to open resection or repeat SRT. We aimed to evaluate the efficacy of LITT followed by SRT (LITT+SRT) in recurrent brain metastases.

Methods

A multicenter, retrospective study was performed of patients who underwent treatment for biopsy-proven brain metastasis recurrence after SRT at an academic medical center. Patients were stratified by “planned LITT+SRT” versus “LITT alone” versus “repeat SRT alone.” Index lesion progression was determined by modified Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria.

Results

Fifty-five patients met inclusion criteria, with a median follow-up of 7.3 months (range: 1.0–30.5), age of 60 years (range: 37–86), Karnofsky Performance Status (KPS) of 80 (range: 60–100), and pre-LITT/biopsy contrast-enhancing volume of 5.7 cc (range: 0.7–19.4). Thirty-eight percent of patients underwent LITT+SRT, 45% LITT alone, and 16% SRT alone. Median time to index lesion progression (29.8, 7.5, and 3.7 months [P = .022]) was significantly improved with LITT+SRT. When controlling for age in a multivariate analysis, patients treated with LITT+SRT remained significantly less likely to have index lesion progression (P = .004).

Conclusions

These data suggest that LITT+SRT is superior to LITT or repeat SRT alone for treatment of biopsy-proven brain metastasis recurrence after SRT failure. Prospective trials are warranted to validate the efficacy of using combination LITT+SRT for treatment of recurrent brain metastases.

Supralesional Ablation Volumes Are Feasible in the Posterior Fossa and May Provide Enhanced Symptomatic Relief

BACKGROUND

Laser interstitial thermal therapy (LITT) for posterior fossa lesions remains rare as the small size of the infratentorial compartment, proximity to the brainstem, and thickness/angulation of the occipital bone creates barriers to procedural success. Furthermore, evaluation of the effect of ablation volume on outcomes is limited.

OBJECTIVE

To analyze our institutional experience with LITT in the posterior fossa stratifying perioperative and long-term outcomes by ablation volumes.

METHODS

Seventeen patients with posterior fossa lesions treated with LITT from 2013 to 2020 were identified. Local progression-free survival (PFS), overall survival, steroid dependence, and edema reduction were evaluated with Kaplan-Meier analysis grouped by ablation volume. Preoperative, postoperative, and last known Karnofsky Performance Status (KPS) were compared using a matched paired t test.

RESULTS

No differences in pathology, preoperative KPS, or preoperative lesion volume were found between patients with total (100%-200% increase in pre-LITT lesion volume) versus radical (>200% increase in pre-LITT lesion volume) ablations. Patients who underwent radical ablation had a higher postoperative KPS (93 vs 82, P = .02) and higher KPS (94 vs 87, P = .04) and greater reduction in perilesional edema at last follow-up (P = .01). Median follow-up was 80.8 wk.

CONCLUSION

Despite obvious anatomical challenges, our results demonstrate that radical ablations are both feasible and safe in the posterior fossa. Furthermore, radical ablations may lead to greater decreases in perilesional edema and improved functional status both immediately after surgery and at last follow-up. Thus, LITT should be considered for patients with otherwise unresectable or radioresistant posterior fossa lesions.

Computer-assisted surgery in medical and dental applications

INTRODUCTION

Computer-assisted surgery (CAS) is a broad surgical methodology that utilizes computer technology to both plan and execute surgical intervention. CAS is widespread in both medicine and dentistry as it allows for minimally invasive and precise surgical procedures. Key innovations in volumetric imaging, virtual surgical planning software, instrument tracking, and robotics have assisted in facilitating the transfer of surgical plans to precise execution of surgical procedures. CAS has long been used in certain medical specialties including neurosurgery, cardiology, orthopedic surgery, otolaryngology, and interventional radiology, and has since expanded to oral and maxillofacial application, particularly for computer-assisted implant surgery.

AREAS COVERED

This review provides an updated overview of the most current research for CAS in medicine and dentistry, with a focus on neurosurgery and dental implant surgery. The MEDLINE electronic database was searched and relevant original and review articles from 2005 to 2020 were included.

EXPERT OPINION

Recent literature suggests that CAS performs favorably in both neurosurgical and dental implant applications. Computer-guided surgical navigation is well entrenched as standard of care in neurosurgery. Whereas static computer-assisted implant surgery has become established in dentistry, dynamic computer-assisted navigation is newly poised to trend upward in dental implant surgery.

Current applications and safety profile of laser interstitial thermal therapy in the pediatric population: a systematic review of the literature

OBJECTIVE

Laser interstitial thermal therapy (LITT) provides a minimally invasive alternative to open brain surgery, making it a powerful neurosurgical tool especially in pediatric patients. This systematic review aimed to highlight the indications and complications of LITT in the pediatric population.

METHODS

In line with the PRISMA guidelines, the authors conducted a systematic review to summarize the current applications and safety profiles of LITT in pediatrics. PubMed and Embase were searched for studies that reported the outcomes of LITT in patients < 21 years of age. Retrospective studies, case series, and case reports were included. Two authors independently screened the articles by title and abstract followed by full text. Relevant variables were extracted from studies that met final eligibility, and results were pooled using descriptive statistics.

RESULTS

The selection process captured 303 pediatric LITT procedures across 35 studies. Males comprised approximately 60% of the aggregate sample, with a mean age of 10.5 years (range 0.5-21 years). The LITT technologies used included Visualase (89%), NeuroBlate (9%), and Multilase 2100 (2%). The most common indication was treatment of seizures (86%), followed by brain tumors (16%). The mean follow-up duration was 15.6 months (range 1.3-48 months). The overall complication rate was 15.8%, which comprised transient neurological deficits, cognitive and electrolyte disturbances, hemorrhage, edema, and hydrocephalus. No deaths were reported.

CONCLUSIONS

As of now, LITT's most common applications in pediatrics are focused on treating medically refractory epilepsy and brain tumors that can be difficult to resect. The safety of LITT can provide an attractive alternative to open brain surgery in the pediatric population.

A Cohort Study on Prognostic Factors for Laser Interstitial Thermal Therapy Success in Newly Diagnosed Glioblastoma

BACKGROUND

Laser interstitial thermal therapy (LITT) is a promising approach for cytoreduction of deep-seated gliomas. However, parameters contributing to treatment success remain unclear.

OBJECTIVE

To identify extent of ablation (EOA) and time to chemotherapy (TTC) as predictors of improved overall and progression-free survival (OS, PFS) and suggest laser parameters to achieve optimal EOA.

METHODS

Demographic, clinical, and survival data were collected retrospectively from 20 patients undergoing LITT for newly diagnosed glioblastoma (nGBM). EOA was calculated through magnetic resonance imaging-based volumetric analysis. Kaplan-Meier and multivariate Cox regression were used to examine the relationship between EOA with OS and PFS accounting for covariates (age, isocitrate dehydrogenase-1 (IDH1) mutation, O6-methylguanine-DNA methyltransferase hypermethylation). The effect of laser thermodynamic parameters (power, energy, time) on EOA was identified through linear regression.

RESULTS

Median OS and PFS for the entire cohort were 36.2 and 3.5 mo respectively. Patient's with >70% EOA had significantly improved PFS compared to ≤70% EOA (5.2 vs 2.3 mo, P = .01) and trended toward improved OS (36.2 vs 11 mo, P = .07) on univariate and multivariate analysis. Total laser power was a significant predictor for increased EOA when accounting for preoperative lesion volume (P = .001). Chemotherapy within 16 d of surgery significantly predicted improved PFS compared to delaying chemotherapy (9.4 vs 3.1 mo, P = .009).

CONCLUSION

Increased EOA was a predictor of improved PFS with evidence of a trend toward improved OS in LITT treatment of nGBM. A strategy favoring higher laser power during tumor ablation may achieve optimal EOA. Early transition to chemotherapy after LITT improves PFS.

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 Role of Laser Interstitial Thermal Therapy in Surgical Neuro-Oncology: Series of 100 Consecutive Patients

BACKGROUND

Laser interstitial thermal therapy (LITT) is an adjuvant treatment for intracranial lesions that are treatment refractory or in deep or eloquent brain. Initial studies of LITT in surgical neuro-oncology are limited in size and follow-up.

OBJECTIVE

To present our series of LITT in surgical neuro-oncology to better evaluate procedural safety and outcomes.

METHODS

An exploratory cohort study of all patients receiving LITT for brain tumors by a single senior neurosurgeon at a single center between 2013 and 2018. Primary outcomes included extent of ablation (EOA), time to recurrence (TTR), local control at 1-yr follow-up, and overall survival (OS). Secondary outcomes included complication rate. Outcomes were compared by tumor subtype. Predictors of outcomes were identified.

RESULTS

A total of 91 patients underwent 100 LITT procedures; 61% remain alive with 72% local control at median 7.2 mo follow-up. Median TTR and OS were 31.9 and 16.9 mo, respectively. For lesion subtypes, median TTR (months, not applicable [N/A] if <50% rate observed), local control rates at 1-yr follow-up, and median OS (months) were the following: dural-based lesions (n = 4, N/A, 75%, 20.7), metastases (n = 45, 55.9, 77.4%, 16.9), newly diagnosed glioblastoma (n = 11, 31.9, 83.3%, 32.3), recurrent glioblastoma (n = 14, 5.6, 24.3%, 7.3), radiation necrosis (n = 20, N/A, 67.2%, 16.4), and other lesions (n = 6, 12.3, 80%, 24.4). TTR differed by tumor subtype (P = .02, log-rank analysis). EOA predicted local control (P = .009, multivariate proportional hazards regression); EOA > 85% predicted longer TTR (P = .006, log-rank analysis). Complication rate was 4%.

CONCLUSION

Our series of LITT in surgical neuro-oncology, 1 of the largest to date, further evidences its safety and outcomes profile.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of emerging developments in the management of newly diagnosed glioblastoma

TARGET POPULATION

These recommendations apply to adult patients with newly diagnosed or suspected glioblastoma.

IMAGING

Question What imaging modalities are in development that may be able to provide improvements in diagnosis, and therapeutic guidance for individuals with newly diagnosed glioblastoma?

RECOMMENDATION

Level III: It is suggested that techniques utilizing magnetic resonance imaging for diffusion weighted imaging, and to measure cerebral blood and magnetic spectroscopic resonance imaging of N-acetyl aspartate, choline and the choline to N-acetyl aspartate index to assist in diagnosis and treatment planning in patients with newly diagnosed or suspected glioblastoma.

SURGERY

Question What new surgical techniques can be used to provide improved tumor definition and resectability to yield better tumor control and prognosis for individuals with newly diagnosed glioblastoma?

RECOMMENDATIONS

Level II: The use of 5-aminolevulinic acid is recommended to improve extent of tumor resection in patients with newly diagnosed glioblastoma. Level II: The use of 5-aminolevulinic acid is recommended to improve median survival and 2 year survival in newly diagnosed glioblastoma patients with clinical characteristics suggesting poor prognosis. Level III: It is suggested that, when available, patients be enrolled in properly designed clinical trials assessing the value of diffusion tensor imaging in improving the safety of patients with newly diagnosed glioblastoma undergoing surgery.

NEUROPATHOLOGY

Question What new pathology techniques and measurement of biomarkers in tumor tissue can be used to provide improved diagnostic ability, and determination of therapeutic responsiveness and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: Assessment of tumor MGMT promoter methylation status is recommended as a significant predictor of a longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level II: Measurement of tumor expression of neuron-glia-2, neurofilament protein, glutamine synthetase and phosphorylated STAT3 is recommended as a predictor of overall survival in patients with newly diagnosed with glioblastoma. Level III: Assessment of tumor IDH1 mutation status is suggested as a predictor of longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level III: Evaluation of tumor expression of Phosphorylated Mitogen-Activated Protein Kinase protein, EGFR protein, and Insulin-like Growth Factor-Binding Protein-3 is suggested as a predictor of overall survival in patients with newly diagnosed with glioblastoma.

RADIATION

Question What radiation therapy techniques are in development that may be used to provide improved tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level III: It is suggested that patients with newly diagnosed glioblastoma undergo pretreatment radio-labeled amino acid tracer positron emission tomography to assess areas at risk for tumor recurrence to assist in radiation treatment planning. Level III: It is suggested that, when available, patients be with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of radiation dose escalation, altered fractionation, or new radiation delivery techniques.

CHEMOTHERAPY

Question What emerging chemotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no emerging chemotherapeutic agents or techniques were identified in this review that improved tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of chemotherapy.

MOLECULAR AND TARGETED THERAPY

Question What new targeted therapy agents are available to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no new molecular and targeted therapies have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of molecular and targeted therapies IMMUNOTHERAPY: Question What emerging immunotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no immunotherapeutic agents have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of immunologically-based therapies.

NOVEL THERAPIES

Question What novel therapies or techniques are in development to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: The use of tumor-treating fields is recommended for patients with newly diagnosed glioblastoma who have undergone surgical debulking and completed concurrent chemoradiation without progression of disease at the time of tumor-treating field therapy initiation. Level II: It is suggested that, when available, enrollment in properly designed studies of vector containing herpes simplex thymidine kinase gene and prodrug therapies be considered in patients with newly diagnosed glioblastoma.

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.

Evolving Strategies to Potentially Further Optimize Surgical Interventions in Brain Cancer

PURPOSE OF REVIEW

Provide an overview, the indications for use, and a synopsis of current literature regarding two evolving neurosurgical interventions-GammaTile therapy (GTT) and laser interstitial thermal therapy (LITT).

RECENT FINDINGS

GTT delivers immediate, uniform, high-dose radiation with avoidance of direct brain-to-seed contact. Innate properties of the novel carrier system and cesium-131 source may explain lower observed rate of radiation-induced necrosis (RIN) and support use in larger and previously irradiated lesions. LITT delivers focal laser energy to cause heat-generated necrosis. Case series suggest use in difficult-to-access lesions and treatment of RIN. Collaboration among subspecialties and remaining up-to-date on evolving technology is critical in developing individualized treatment plans for patients with brain cancer. While patients should be thoroughly counseled that these interventions are not standard of care, in optimal clinical scenarios, GTT and LITT could extend quantity and quality of life for patients with few remaining options. Prospective studies are needed to establish specific treatment parameters.

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.

Recent technological advancements in thermometry

Thermometry is the key factor for achieving successful thermal therapy. Although invasive thermometry with a probe has been used for more than four decades, this method can only detect the local temperature within the probing volume. Noninvasive temperature imaging using a tomographic technique is ideal for monitoring hot-spot formation in the human body. Among various techniques, such as X-ray computed tomography, microwave tomography, echo sonography, and magnetic resonance (MR) imaging, the proton resonance frequency shift method of MR thermometry is the only method currently available for clinical practice because its temperature sensitivity is consistent in most aqueous tissues and can be easily observed using common clinical scanners. New techniques are being proposed to improve the robustness of this method against tissue motion. MR techniques for fat thermometry were also developed based on relaxation times. One of the latest non-MR techniques to attract attention is photoacoustic imaging.

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.

Histologic findings associated with laser interstitial thermotherapy for glioblastoma multiforme

Background

Laser-interstitial thermal therapy (LITT) has been supported by some authors as an ablative treatment of glioblastoma multiforme (GBM). Although the effects of LITT have been modeled in vivo, the histologic effects in a clinical circumstance have not been described. We analyzed tissue from a patient who underwent LITT as primary treatment for GBM.

Case presentation

A 62-year-old male was diagnosed with a left temporal GBM and underwent LITT at an outside institution. Despite corticosteroid therapy, the patient was referred with increasing headache and acalculia associated with progressive peritumoral edema two weeks after LITT procedure. En bloc resection of the enhancing lesion and adjacent temporal lobe was performed with steroid-independent symptom resolution (follow-up, > 2 years). Histologic analysis revealed three distinct histologic zones concentrically radiating from the center of the treatment site. An acellular central region of necrosis (Zone 1) was surrounded by a rim of granulation tissue with macrophages (CD68) (Zone 2; mean thickness, 1.3 ± 0.3 mm [±S.D.]). Viable tumor cells (identified by Ki-67, p53 and Olig2 immunohistochemistry) were found (Zone 3) immediately adjacent to granulation tissue. The histologic volume of thermal tissue ablation/granulation was consistent with preoperative (pre-resection) magnetic resonance (MR)-imaging.

Conclusion

These findings are the first in vivo in humans to reveal that LITT causes a defined pattern of tissue necrosis, concentric destruction of tumor and tissue with viable tumor cells just beyond the zones of central necrosis and granulation. Furthermore, MR-imaging appears to be an accurate surrogate of tissue/tumor ablation in the early period (2 weeks) post-LITT treatment. Surgery is an effective strategy for patients with post-LITT swelling which does not respond to steroids.

MR Thermography-Guided Head and Neck Lesion Laser Ablation

Interstitial laser ablation has been successfully used as a minimally invasive treatment option for tumors in many parts of the body, including the head and neck. In this article, we describe the use of MR imaging guidance and mapping sequences for accurate localization of the target lesion, percutaneous interstitial laser ablation methods, and the use of MR thermography for temperature monitoring during laser ablation, with a focus on applications in the head and neck region.

Contemporaneous biopsy and laser interstitial thermal therapy for two treatment-refractory brain metastases

Recurrent treatment-refractory brain metastases can be treated with modern adjuvant therapies such as laser interstitial thermal therapy (LITT). Since previously radiated lesions may be indolent (treatment effect) or recurrent tumor, histological confirmation may be helpful. The authors present the utility of contemporaneous biopsy and LITT using intraoperative O-arm navigation in a patient who presented with multiple refractory metastases. The authors demonstrate the utility of O-arm navigation to confirm intraoperative biopsy and LITT placement. Concurrent stereotactic biopsy and LITT may be a safe and efficacious method for both the diagnosis and treatment of deep lesions that are unamenable to standard adjuvant treatment modalities.

The video can be found here: https://youtu.be/SUY-qiahMyo.

Comparison between whole-body and head and neck neurovascular coils for 3-T magnetic resonance proton resonance frequency shift thermography guidance in the head and neck region

The purpose of this study is to compare the image quality of magnetic resonance (MR) treatment planning images and proton resonance frequency (PRF) shift thermography images and inform coil selection for MR-guided laser ablation of tumors in the head and neck region. Laser ablation was performed on an agar phantom and monitored via MR PRF shift thermography on a 3-T scanner, following acquisition of T1-weighted (T1W) planning images. PRF shift thermography images and T2-weighted (T2W) planning images were also performed in the neck region of five normal human volunteers. Signal-to-noise ratios (SNR) and temperature uncertainty were calculated and compared between scans acquired with the quadrature mode body integrated coil and a head and neck neurovascular coil. T1W planning images of the agar phantom produced SNRs of 4.0 and 12.2 for the quadrature mode body integrated coil and head and neck neurovascular coil, respectively. The SNR of the phantom MR thermography magnitude images obtained using the quadrature mode body integrated coil was 14.4 versus 59.6 using the head and neck coil. The average temperature uncertainty for MR thermography performed on the phantom with the quadrature mode body integrated coil was 1.1 versus 0.3 °C with the head and neck coil. T2W planning images of the neck in five human volunteers produced SNRs of 28.3 and 91.0 for the quadrature mode body integrated coil and head and neck coil, respectively. MR thermography magnitude images of the neck in the volunteers obtained using the quadrature mode body integrated coil had a signal-to-noise ratio of 8.3, while the SNR using the head and neck coil was 16.1. The average temperature uncertainty for MR thermography performed on the volunteers with the body coil was 2.5 versus 1.6 °C with the head and neck neurovascular coil. The quadrature mode body integrated coil provides inferior image quality for both basic treatment planning sequences and MR PRF shift thermography compared with a neurovascular coil, but may nevertheless be adequate for clinical purposes.

Laser Ablation of Newly Diagnosed Malignant Gliomas: a Meta-Analysis

BACKGROUND

Magnetic resonance-guided laser-interstitial thermotherapy (MR-LITT) is a minimally invasive technique that shows promise in neuro-oncology because of its superiority in delivering precise minimally invasive thermal energy with minimal collateral damage.

OBJECTIVE

In this analysis, we investigate initial data on the use of MR-LITT in the treatment of newly diagnosed high-grade gliomas.

METHODS

With the use of the PubMed, OVID, and Google-scholar database systems, a comprehensive search of the English literature was performed. Eighty-five articles were identified plus 1 that is pending publication. Four articles were accounted for in this review, including 25 patients with newly diagnosed high-grade gliomas who underwent MR-LITT treatment. We evaluated safety, progression-free survival, and overall survival.

RESULTS

Twenty-five patients with a mean age of 53.8 years underwent LITT treatments. On average, 82.9% of the pretreatment lesion volume was ablated. The average tumor volume treated was 16.5 cm. The mean follow-up time was 7.6 months. Median overall survival was found to be 14.2 months (range 0.1-23 months). The median progression-free survival was 5.1 months (range 2.4-23 months); however, these data are limited by the relatively short follow-up of the patients reviewed and small sample size of only 25 patients. There was 1 (3.4%) major perioperative complication, which was a central nervous system infection.

CONCLUSION

MR-LITT is a promising technology for the treatment of small, yet difficult-to-treat newly diagnosed high-grade gliomas. This study demonstrates that MR-LITT is safe, and future randomized studies are needed to evaluate its role as a treatment adjunct for newly diagnosed high-grade gliomas.

ABBREVIATIONS

BBB, blood-brain barrierHGG, high-grade gliomaLITT, laser-interstitial thermal therapyWHO, World Health Organization.

Does the Thermal Damage Estimate Correlate With the Magnetic Resonance Imaging Predicted Ablation Size After Laser Interstitial Thermal Therapy?

BACKGROUND

Magnetic resonance guided laser induced thermal therapy (LITT) is a minimally invasive method to treat a wide range of intracranial pathologies. The Arrhenius model is used to generate a thermal damage estimate (TDE) predicting ablation extent.

OBJECTIVE

Evaluation and correlation of the TDE to magnetic resonance imaging (MRI)-estimated ablation extent in human cases.

METHODS

The Medtronic Visualase system (Medtronic Inc, Dublin, Ireland) was utilized. Postablation axial T1-contrast enhanced images were acquired and intraoperative TDE image was obtained from the Visualase console. OsiriX DICOM Viewer (Pixmeo Inc, Bernex, Switzerland) was utilized to calculate cross-sectional area on MRI. ImageJ (National Institutes of Health, Bethesda, Maryland) was utilized for TDE area. Two blinded raters performed all measures. Statistical testing included Pearson correlation and the Student's t-test.

RESULTS

Twenty-two cases including tumor and epilepsy were evaluated. Average MRI predicted tumor ablation area was 4.72 ± 2.22 cm2 and average predicted epilepsy ablation area was 4.12 ± 1.89 cm2. Average tumor TDE was 4.02 ± 1.95 cm2 and average epilepsy TDE was 4.36 ± 2.21 cm2. Rater 1’s ablation areas and TDEs correlated with r = 0.89 (P &lt; .0001) and no significant difference (P &gt; .5). Rater 2’s ablation areas and TDEs correlated with r = 0.91 (P &lt; .0001) and no significant difference (P &gt; .7). Rater 1 vs Rater 2 showed a strong correlation for TDE (r = 0.98, P &lt; .000001) and ablation area (r = 0.96, P &lt; .0001) and no significant difference (P &gt; .5).

CONCLUSION

The TDE is an accurate and reliable measure of ablated area in LITT in human cases as assessed on postoperative MRI. Future studies should be larger and assess reliability of the TDE when multiple lasers and planes are used.

Magnetic Resonance Thermometry and Laser Interstitial Thermal Therapy for Brain Tumors

Recent technological advancements in intraoperative imaging are shaping the way for a new era in brain tumor surgery. Magnetic resonance thermometry has provided intraoperative real-time imaging feedback for safe and effective application of laser interstitial thermal therapy (LITT) in neuro-oncology. Thermal ablation has also established itself as a surgical option in epilepsy surgery and is currently used in spine oncology with promising results. This article reviews the principles and rationale as well as the clinical application of LITT for brain tumors. It also discusses the technical nuances of the current commercially available systems.