Pediatric Cranial Stereotactic Radiosurgery: Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines.

BACKGROUND: There are limited data on the use of stereotactic radiosurgery (SRS) for pediatric patients. The aim of this systematic review was to summarize indications and outcomes specific to pediatric cranial SRS to inform consensus guidelines on behalf of the International Stereotactic Radiosurgery Society (ISRS). METHODS: A systematic review, using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), analyzed English-language articles on SRS, published between 1989 and 2021, that included outcomes for at least 5 pediatric patients. MEDLINE database terms included tumor types and locations, and radiosurgical and age-specific terms. We excluded nonclinical reports, expert opinions, commentaries, and review articles. Meta-regressions for associations with local control were performed for medulloblastoma, craniopharyngioma, ependymoma, glioma, and arteriovenous malformation (AVM). RESULTS: Of the 113 articles identified for review, 68 met the inclusion criteria. These articles described approximately 400 pediatric patients with benign and malignant brain tumors and 5119 with AVMs who underwent cranial SRS. The rates of local control for benign tumors, malignant tumors, and AVMs were 89% (95% CI, 82%-95%), 71% (95% CI, 59%-82%), and 65% (95% CI, 60%-69%), respectively. No significant associations were identified for local control with patient-, tumor-, or treatment-related variables. CONCLUSIONS: This review is the first to summarize outcomes specific to SRS for pediatric brain tumors and AVMs. Although data reporting is limited for pediatric patients, SRS appears to provide acceptable rates of local control. We present ISRS consensus guidelines to inform the judicious use of cranial SRS for pediatric patients.

Quantitative brain T1 maps derived from T1-weighted MRI acquisitions: a proof-of-concept study.

BACKGROUND: Longitudinal T1 relaxation time is a key imaging biomarker. In addition, T1 values are modulated by the administration of T1 contrast agents used in patients with tumors and metastases. However, in clinical practice, dedicated T1 mapping sequences are often not included in brain MRI protocols. The aim of this study is to address the absence of dedicated T1 mapping sequences in imaging protocol by deriving T1 maps from standard T1-weighted sequences. METHODS: A phantom, composed of 144 solutions of paramagnetic agents at different concentrations, was imaged with a three-dimensional (3D) T1-weighed turbo spin-echo (TSE) sequence designed for brain imaging. The relationship between the T1 values and the signal intensities was established using this phantom acquisition. T1 mapping derived from 3D T1-weighted TSE acquisitions in four healthy volunteers and one patient with brain metastases were established and compared to reference T1 mapping technique. The concentration of Gd-based contrast agents in brain metastases were assessed from the derived T1 maps. RESULTS: Based on the phantom acquisition, the relationship between T1 values and signal intensity (SI) was found equal to T1 = 0.35 × SI-1.11 (R2 = 0.97). TSE-derived T1 values measured in white matter and gray matter in healthy volunteers were equal to 0.997 ± 0.096 s and 1.358 ± 0.056 s (mean ± standard deviation), respectively. Mean Gd3+ concentration value in brain metastases was 94.7 ± 30.0 µM. CONCLUSION: The in vivo results support the relevance of the phantom-based approach: brain T1 maps can be derived from T1-weighted acquisitions. RELEVANCE STATEMENT: High-resolution brain T1 maps can be generated, and contrast agent concentration can be quantified and imaged in brain metastases using routine 3D T1-weighted TSE acquisitions. KEY POINTS: Quantitative T1 mapping adds significant value to MRI diagnostics. T1 measurement sequences are rarely included in routine protocols. T1 mapping and concentration of contrast agents can be derived from routine standard scans. The diagnostic value of MRI can be improved without additional scan time.

A qualitative study of specialist multidisciplinary clinician perspectives on barriers/facilitators to care for children with brain cancer and their families: "We're a little bit different to our adult counterparts".

OBJECTIVES: Children with brain cancer and their families have complex care needs throughout diagnosis, active treatment, long-term survivorship, and the palliative phase of illness. This study aimed to explore the perspectives of Australian specialist clinicians on barriers and facilitators to health care for children with brain cancer and their families. METHODS: A qualitative approach was taken using semi-structured interviews. Eligible participants were clinicians of any discipline providing care to children with brain cancer and their families in Australia. Interviews were conducted by telephone and asked about perceived strengths and weaknesses in health care and available resources for this population. Qualitative content analysis used a directed approach with inductive refinement. RESULTS: Eleven clinicians participated, 5 of whom were medical, 3 nursing, and 3 allied health. The overarching theme was that the rarity and diversity of brain tumors in children confers challenges to care that lead to variation in practice. Participants reported having to adapt care from guidelines and patient/family resources designed for adults with brain cancer and children with other cancers, and rely on clinical and research networks. Specialist comprehensive cancer care was generally perceived to offer the best model for accommodating the unique needs of each child/family, but barriers to access were highlighted for children in remote Australia, and long-term follow-up was perceived to be inadequate regardless of where children lived. SIGNIFICANCE OF RESULTS: Until further brain cancer-specific paediatric guidelines become available, our findings highlight the need for communities of practice to share resources and reduce unwarranted variation. CONCLUSION: Future research should focus on developing and evaluating guidelines and other resources specific to children with brain cancer, as well as informing suitable models for long-term follow-up care for survivors.

Consensus guidelines for the management of adult low-grade gliomas for low and middle-income countries.

Low-grade gliomas (LGG) are brain tumors of glial cells origin. They are grade 1 and grade 2 tumors according to the WHO classification. Diagnosis of LGG is made through imaging, histopathological analysis, and use of molecular markers. Imaging alone does not establish the grade of the tumor and thus a histopathological examination of tissue is crucial in establishing the definite histopathological diagnosis. Clinical presentation varies according to the location and size of the tumor. Surgical resection is strongly recommended in LGG over observation to improve overall survival as surgery leads to greater benefit due to progression-free survival. Radiation has shown benefits in LGG patients in randomized controlled trials and chemotherapy with temozolomide has also shown good results. This paper covers the principles of low-grade gliomas management and summarizes the recommendations for the LMICs.

Consensus guidelines for the management of pediatric medulloblastoma in low and middle-income countries.

The management of medulloblastoma, a pediatric brain tumor, has evolved significantly with the advent of genomic subgrouping, yet morbidity and mortality remain high in LMICs like Pakistan due to inadequate multidisciplinary care infrastructure. This paper aims to establish evidence-based guidelines tailored to the constraints of such countries. An expert panel comprising neuro-oncologists, neurosurgeons, radiologists, radiation oncologists, neuropathologists, and pediatricians collaborated to develop these guidelines, considering the specific challenges of pediatric brain tumor care in Pakistan. The recommendations cover various aspects of medulloblastoma treatment, including pre-surgical workup, neurosurgery, neuropathology, chemotherapy, radiation therapy, and supportive care. They offer both minimum required and additional optional protocols for more advanced centers, ensuring comprehensive patient management with attention to complications and complexities encountered in Pakistan. The paper's consensus guidelines strive for uniformity in healthcare delivery and address significant gaps in diagnosis, treatment, and follow-up of pediatric medulloblastoma patients.

Preoperative Cortical Mapping for Brain Tumor Surgery Using Navigated Transcranial Stimulation: Analysis of Accuracy.

Transcranial magnetic stimulation (TMS) represents a distinctive technique for non-invasive brain stimulation. Recent advancements in image processing have enabled the enhancement of TMS by integrating magnetic resonance imaging (MRI) modalities with TMS via a neuronavigation system. The aim of this study is to assess the efficacy of navigated TMS for cortical mapping in comparison to surgical mapping using direct electrical stimulation (DES). This study involved 30 neurosurgical procedures for tumors located in or adjacent to the precentral gyrus. The DES points were compared with TMS responses based on the original distances of vectorial modules. There was a notable similarity in the points obtained from the two mapping methods. The distances between the geometric centers of TMS and DCS were 4.85 ± 1.89 mm. A strong correlation was identified between these vectorial points (r = 0.901, p < 0.001). The motor threshold in TMS was highest in the motor cortex adjacent to the tumor compared to the normal cortex (p < 0.001). Patients with deficits exhibited excellent accuracy in both methods. In view of this, TMS demonstrated reliable and precise application in brain mapping, which is a promising method for preoperative functional mapping in motor cortex tumor surgery.

Judicious and evidence-based use of radiosurgery - recommendations for low-middle income countries.

Surgical removal remains the primary treatment for most brain tumours. However, radiosurgery presents an effective, less invasive alternative or additional treatment for certain types. Our goal was to explore radiosurgery's roles in treating various brain tumours, focussing on its application in low- and middle-income countries (LMICs). We reviewed all relevant systematic reviews, metaanalyses, and guidelines to determine the most effective radiosurgical approaches. Additionally, we consulted a panel of experts with over ten years of experience in LMICs, such as Pakistan. For brain tumours, stereotactic radiosurgery should generally follow a confirmed histopathological diagnosis. Exceptions include tumours identified through Magnetic Resonance Imaging (MRI), like Vestibular Schwannoma (VS), pre-diagnosed Neurofibromatosis type 2 (NF2), multiple typical meningiomas, and metastases with a known histology from another site. While radiosurgery is gaining traction as a primary and adjunct treatment in some LMICs, the lack of regional guidelines, trained personnel, and collaboration among specialists hinders its wider adoption. Addressing these gaps is crucial for expanding radiosurgical care in these regions.

Clinical and imaging manifestations of intracerebral hemorrhage in brain tumors and metastatic lesions: a comprehensive overview.

PURPOSE: This observational study aims to provide a detailed clinical and imaging characterization/workup of acute intracerebral hemorrhage (ICH) due to either an underlying metastasis (mICH) or brain tumor (tICH) lesion. METHODS: We conducted a retrospective, single-center study, evaluating patients presenting with occult ICH on initial CT imaging, classified as tICH or mICH on follow-up MRI imaging according to the H-Atomic classification. Demographic, clinical and radiological data were reviewed. RESULTS: We included 116 patients (tICH: 20/116, 17.24%; mICH: 96/116, 82.76%). The most common malignancies causing ICH were lung cancer (27.59%), malignant melanoma (18.10%) and glioblastoma (10.34%). The three most common stroke-like symptoms observed were focal deficit (62/116, 53.45%), dizziness (42/116, 36.21%) and cognitive impairment (27/116, 23.28%). Highest mICH prevalence was seen in the occipital lobe (mICH: 28.13%, tICH: 0.00%; p = 0.004) with tICH more in the corpus callosum (tICH: 10.00%, mICH: 0.00%; p = 0.029). Anticoagulation therapy was only frequent in mICH patients (tICH: 0.00%, mICH: 5.21%; p = 0.586). Hemorrhage (tICH: 12682 mm3, mICH: 5708 mm3, p = 0.020) and edema volumes (tICH: 49389 mm3, mICH: 20972 mm3, p = 0.035) were significantly larger within tICH patients. CONCLUSION: More than half of the patients with neoplastic ICH exhibited stroke-like symptoms. Lung cancer was most common in mICH, glioblastoma in tICH. While clinical presentations were similar, significant differences in tumor location and treatments were discernible.

Characteristics of Patients Hospitalized to Community Hospitals With Malignant Brain Tumors and Factors Associated With Discharge Destination.

Background: Our main objective was to compare the characteristics and hospital outcomes of patients with primary and metastatic brain malignancies and to investigate the associated factors related to hospital outcomes. Methods: We conducted a retrospective, cross-sectional study of 1628 patients with brain malignancies from 8 community hospitals between 2017 and 2022 who were identified using International Classification of Disease codes. A stepwise logistic regression was used to identify demographics and clinical characteristics associated with in-hospital mortality and home discharge. Results: The median age was 65 years old, with 72.5% of patients having metastatic brain malignancies. After 7.2 days of hospital stay, 49.2% were discharged home, and 102 patients expired during hospitalization. Increased age, medical coverage by Medicare, hemiplegia or paraplegia, lower initial hemoglobin level, increased length of stay, and the use of electrolyte replacement, antibiotics, laxatives, heparin, and anticonvulsants were associated with a decreased likelihood of discharge to home. No medical insurance, Medicaid insurance coverage, comorbidities of cerebrovascular disorder, the need to stay in the intensive care unit, patient safety indicator events, and the use of antibiotics, oral analgesics, and ipratropium-albuterol were associated with increased odds of in-hospital mortality. Conclusion: We identified several predictor variables that delineate differences between both mortality risk and home discharge in patients with primary and metastatic brain tumors. Understanding these predictor variables can be helpful in improving the acute and post-acute care of this population.

Evaluation of glial tumors: correlation between magnetic resonance imaging and histopathological analysis.

Objective: To determine the correlation of conventional and diffusion-weighted imaging findings on magnetic resonance imaging (MRI) of the brain, based on Visually AcceSAble Rembrandt Images (VASARI) criteria, with the histopathological grading of gliomas: low-grade or high-grade. Materials and Methods: Preoperative MRI scans of 178 patients with brain gliomas and pathological confirmation were rated by two neuroradiologists for tumor size, location, and tumor morphology, using a standardized imaging feature set based on the VASARI criteria. Results: In the univariate analysis, more than half of the MRI characteristics evaluated showed a significant association with the tumor grade. The characteristics most significantly associated with the tumor grade were hemorrhage; restricted diffusion; pial invasion; enhancement; and a non-contrast-enhancing tumor crossing the midline. In a multivariable regression model, the presence of enhancement and hemorrhage maintained a significant association with high tumor grade. The absence of contrast enhancement and restricted diffusion were associated with the presence of an isocitrate dehydrogenase gene mutation. Conclusion: Our data illustrate that VASARI MRI features, especially intratumoral hemorrhage, contrast enhancement, and multicentricity, correlate strongly with glial tumor grade.

Objetivo: Determinar a correlação dos achados de imagem convencional e de difusão na ressonância magnética (RM) do encéfalo, com base nos critérios Visually AcceSAble Rembrandt Images (VASARI), com a classificação histopatológica de gliomas: gliomas de baixo grau e gliomas de alto grau. Materiais e Métodos: Imagens de RM pré-cirúrgicas de 178 pacientes com gliomas cerebrais e confirmação patológica foram avaliadas por dois neurorradiologistas quanto ao tamanho, localização e morfologia do tumor usando um padrão de imagem baseado nos critérios VASARI. Resultados: Na análise univariada, mais da metade das características avaliadas apresentou associação significativa com o grau do tumor. Hemorragia, restrição à difusão, invasão pial, realce e tumor sem realce cruzando a linha média foram as características com associação mais significativa. No modelo de regressão multivariada, a presença de realce e hemorragia manteve associação significativa com tumores de alto grau. A ausência de realce pelo meio de contraste e a restrição da difusão foram associados à presença da mutação do gene isocitrato desidrogenase. Conclusão: Nossos dados ilustram que as características de RM do VASARI, especialmente hemorragia intratumoral, presença de realce de contraste e multicentricidade, forneceram uma correlação importante com o grau da neoplasia glial.

Developing a non-cadaveric brain tumour surgery lab in resource-constrained settings.

OBJECTIVE: To develop the country's first brain tumour surgery lab in resource-constrained settings, for training young neurosurgeons and residents. METHODS: A workshop was developed using mixed-fidelity models for assessing and training a participant's psychomotor skills, hand-eye coordination, and teaching the principles of brain tumour surgery. Affordable noncadaveric models were used to compare and contrast the benefit of each teaching model. Within the existing space for wet labs at our institution, 8 different dissection stations were set up with adequate space for 2 people to work at a time. Each station was equipped with an operating room-Caliber microscope, a lighting system and a camera linked to a screen and high-powered electric drills and basic surgical equipment. RESULTS: Our team was able to develop and use 3D-printed skull models and animal brain models for training in complex approaches and craniotomy. CONCLUSIONS: Surgical simulation training, in a cost-effective manner, provides the benefit of training residents and students in neurosurgical techniques in a safe, controlled environment leading to improvement in skills and technique.

The need for economic evaluations for neuro-oncology in low- and middleincome: the Pakistan perspective.

The incidence and prevalence of brain tumours have steadily increased within low- and middle-income countries, similar to patterns seen in high-income countries. In addition to the epidemiological landscape of brain tumours in Pakistan, it is important to consider the economics of brain tumour diagnosis and management to inform policy on neuro-oncological healthcare service delivery. The challenges associated with conducting economic evaluations in LMICs include the ability to receive funding for country-specific estimates, dearth of existing data and methodological development, and the need for investment in economic evaluations of health. Economic evaluations are most useful when funding support is given to country-specific initiatives to allocate resources. Cost and cost components must also be meticulously collected to enable accurate calculations of economic evidence for the decision-making process. To put neuro-oncological care at the forefront of the national health agenda, it is crucial for vigorous epidemiological and economic evidence to be available for policymakers.

Use of artificial intelligence and radio genomics in neuroradiology and the future of brain tumour imaging and surgical planning in low- and middleincome countries.

Brain tumour diagnosis involves assessing various radiological and histopathological parameters. Imaging modalities are an excellent resource for disease monitoring. However, manual inspection of imaging is laborious, and performance varies depending on expertise. Artificial Intelligence (AI) driven solutions a non-invasive and low-cost technology for diagnostics compared to surgical biopsy and histopathological diagnosis. We analysed various machine learning models reported in the literature and assess its applicability to improve neuro-oncological management. A scoping review of 47 full texts published in the last 3 years pertaining to the use of machine learning for the management of different types of gliomas where radiomics and radio genomic models have proven to be useful. Use of AI in conjunction with other factors can result in improving overall neurooncological management within LMICs. AI algorithms can evaluate medical imaging to aid in the early detection and diagnosis of brain tumours. This is especially useful where AI can deliver reliable and efficient screening methods, allowing for early intervention and treatment.

Serum liquid biopsy for brain tumours: a scoping analysis of practicable approaches in low- and middle-income countries.

Approaches to brain tumour diagnosis and detecting recurrence after treatment are costly and significantly invasive. Developing peripheral-sample liquid biopsy tools is the key to enhancing our ability to prognosticate brain tumour subtypes and molecular heterogeneity. The present scoping review was designed to discuss current updates in liquid biopsy tools for diagnosis and guiding clinical management of brain tumours; we evaluated the literature within the context of low-and-middle-income country challenges. Circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), cell-free DNA (cfDNA), extracellular vesicle-associated biomarkers, protein biomarkers, microRNAs, and serum metabolites are discussed with the collation of current data supporting their utility in liquid biopsy. Further challenges to implanting liquid biopsy tools at a systematic level are highlighted.

A guideline on guidelines: neuro-oncology guideline standards for low- and middle-income countries.

Guidelines for low- and middle-income countries (LMICs) are needed in complex, multidisciplinary areas such as oncology, requiring mobilising considerable resources and specialists for coordinated care. Neuro-oncology guidelines have been primarily established in countries where technological advancements and robust care pathways facilitate broad resource utilisation. In contrast, LMICs require complex and region-specific interventions to provide equitable care. The present opinion paper is a culmination of our own centre's experience collaborating and developing loco-regional guidelines for brain tumour care, keeping in mind LMIC experiences and expertise available. We intend for the process and methodology to apply to a broader audience of other LMIC authors and clinicians collaborating with LMIC institutions to develop guidelines and clinical recommendations.

Consensus guidelines for the management of intracranial metastases for low- and middle-income countries.

Metastatic tumours are among the most common types of brain tumours. However, in low- and middle-income countries (LMICs), the numbers are considerably lower. This does not necessarily indicate a decreased incidence but rather points to decreased survival rates or limited access to healthcare. The challenge of achieving better outcomes, along with associated costs and resource constraints, often hinders the effective management of brain metastasis. Even in cases where localised disease can potentially be managed to improve survival, these challenges persist. The purpose of these guidelines is to address these challenges and outline a management strategy within the context of LMICs.

Consensus guidelines for the management of intracranial meningioma for low- and middle-income countries.

Intra-cranial meningiomas represent the most common type of extra-axial brain tumour in adults. Characteristically slow-growing and often asymptomatic, these tumours may only require observation in some cases. However, lesions that cause a significant mass effect necessitate intervention, primarily through surgical means. Additionally, in cases of significant unresectable low-grade residual meningioma or high-grade tumours, radiation therapy becomes essential. Notably, current management guidelines predominantly reflect data derived from high-income countries, failing to address constraints prevalent in the developing world, such as limited financial resources and restricted access to advanced surgical facilities. This manuscript introduces guidelines specifically tailored for the management of meningioma in patients from low- and middle-income countries, considering their unique healthcare challenges and resources.

Surgical resection versus stereotactic radiosurgery for the treatment of brain metastases in the motor cortex; a meta-analysis and systematic review.

Brain metastasis in the motor cortex is a challenging condition to treat. Surgical resection or stereotactic radiosurgery (SRS)/hypofractionated stereotactic radiotherapy (hypoSRT) are valuable options up to now. Due to its unique location and potential for neurologic deficits, neither treatment is entirely satisfactory. There is still a lack of data on the treatment result of motor cortex metastasis. This study provides a comprehensive review and meta-analysis comparing surgery and SRS/hypoSRT for treating brain metastasis in the motor cortex. Core databases, including PubMed, Embase, and the Cochrane Library, were systematically searched for brain metastasis in the motor cortex, demonstrating the clinical outcomes of both surgery and SRS/hypoSRT. Motor power outcome and treatment-associated complication rates were thoroughly evaluated. Twenty-five articles were listed for full-text review. Among them, 13 articles were eligible for inclusion criteria: retrospective cohort studies comparing surgery and SRS/hypoSRT. There are 323 patients in the surgery group and 220 in the SRS/hypoSRT group. The motor outcome is better in surgery group, but without statistical significance (0.49 vs 0.37, p = 0.3937) and treatment-related complication is lower in surgery group with statistical significance (0.09 vs 0.26, p = 0.0218). Treatment modality should be tailored by the patient's performance status, history of radiation, presence of ongoing chemotherapy, or extracranial progression status.

Intraoperative MRI in pediatric epilepsy and neuro-oncology: a systematic review and meta-analysis.

OBJECTIVE: Intraoperative magnetic resonance imaging (iMRI) use is becoming increasingly widespread in neurosurgical practice, and most of the data reporting its use are in adult populations. There is less evidence on the use of iMRI in pediatric neurosurgery. The aim of this paper was to synthesize the available literature into a systematic review and meta-analysis to evaluate the evidence for iMRI in pediatric neurosurgery, with a particular focus on neuro-oncology and epilepsy surgery. METHODS: This review was registered on PROSPERO and conducted according to PRISMA guidelines. A comprehensive search strategy of Medline via Ovid and Embase was conducted with predetermined key terms. Studies in English reporting the outcomes of patients < 21 years of age who underwent neuro-oncological or epilepsy surgery with the use of iMRI were included in the study. The types of studies eligible for inclusion were observational case-control and cohort studies, randomized clinical trials, cross-sectional studies, editorials, case series, and commentaries. Articles were de-duplicated and abstracts independently screened for inclusion by two reviewers. Full texts were screened, and data on demographic characteristics, etiology, outcome (extent of resection for neuro-oncology and Engel class for epilepsy), and technical iMRI data were extracted. RESULTS: Thirty-five articles were included in the review, 25 of which were observational cohort studies. Four articles were suitable for meta-analysis. In total, 1217 patients underwent iMRI-guided neuro-oncology surgery in 26 studies, most commonly for gliomas (n = 443). A total of 148 patients underwent iMRI-guided epilepsy surgery in 9 studies, with focal cortical dysplasia being the most common diagnosis (n = 95). The mean ± SD operating time was 357 ± 94 minutes (12 studies), with a mean of 1.32 scans per patient. There was a mean re-entry rate into the operative field of 42% (across 20 studies). Complications were noted in 21% of epilepsy surgery patients and 11% of neuro-oncology surgery patients. Meta-analysis of 4 eligible studies revealed that iMRI was more likely to lead to better Engel outcomes in terms of seizure freedom (OR 3.84, 95% CI 1.38-10.68, p = 0.69) and complete tumor resection (OR 3.19, 95% CI 0.28-36.92, p = 0.06). CONCLUSIONS: iMRI appears to be a useful adjunct in optimizing resective pediatric epilepsy and neuro-oncology surgery, with a low complication rate.

The prognostic utility of the neutrophil to lymphocyte ratio in paediatric brain tumours: a retrospective case control study.

INTRODUCTION: Paediatric brain tumours (PBT) are the most common cause of death among all childhood cancers. The neutrophil to lymphocyte ratio (NLR) has been shown to prognosticate many adult cancers. There is a paucity of literature on the NLR in PBTs. This study aims to study the link between PBTs and the NLR by comparing the preoperative serum NLR in children under 16 with brain tumours with their outcome in terms of grade of brain tumour and overall survival. METHODS: This is a retrospective case control study. The NLRs were compared between patients with benign or malignant PBTs and patients who were alive or dead. Receiver-operating characteristic (ROC) curve analyses were performed and Youden indexes were calculated to evaluate the predictive potential of the NLR. A cut-off point of NLR > 4 was selected for the calculation of odds ratios. RESULTS: A total of 515 patients were included in this study. 53.8% were male. 66.2% had benign PBTs. 81.0% were alive at the time of the study. Patients with malignant PBTs had a higher NLR compared to patients with benign PBTs (p = 0.0066**). There was no difference in the NLR between patients who were dead compared to those who were alive (p = 0.1682 ns). The NLR had a Youden's index of 0.1567 to predict malignant PBTs and 0.1285 to predict survival. CONCLUSION: A high NLR was associated with an increased odds of having a malignant PBT but a reliable cut-off point was not identified and the underlying mechanisms for this remain unknown. The NLR is a poor diagnostic biomarker due to its poor overall sensitivity and specificity. More research is required to further study the role of immunity in PBTs.