Tumor Surgery Research Articles

Health-related quality of life in patients treated with en bloc resection for primary tumors of the spine.

Retrospective analysis. The aim of this study is to evaluate the functional outcomes and the health-related quality of life (HRQOL) in patients undergoing en bloc resection of spinal tumor. En bloc resection in the spine is a surgical procedure designed to completely remove a tumor in one piece, with wide margins preserved, in order to reduce the risk of local recurrences. This demanding procedure has been shown to improve local control and survival rate, besides a relatively high morbidity. Between 2016 and 2021, 70 patients underwent en bloc resection surgery for a primary spine tumor and 38 came out to be eligible for this analysis. Eligibility criteria include at least one follow-up visit within a two-year period from surgery and Patient Reported Outcomes evaluation collected prospectively at baseline and at least one follow- up in the range 4-24 months. The outcome variables (EQ5D Numeric Scale and Index, SF36 scores and NRS score) were analyzed with multilevel linear mixed-effects regression. Baseline- (age, gender, localization, histotype, number of levels of resection, previous surgery) and time-dependent covariates (adverse events, spinal cord damage) were included. Beside a slight improvement of all the scores, no significant differences were found between baseline and follow up times for EQ-5D-3L Numeric Scale and Index and for SF-36 Standardized Physical component. SF-36 Standardized Mental component appeared to be significantly better at 12-month FU compared to baseline. Ultimately, age over 50 years old and the occurrence of adverse events emerged to be as the two main factor determining worsening in several HRQOL scores. Pain came out to be significantly reduce at 24-month compared to baseline. The aim of en bloc resection in the treatment of primary spinal tumors is to improve survival rates and reduce local recurrences. Despite its radicality, our preliminary results suggest that patients experience a slight to moderate improvement postoperatively compared to their preoperative perceived health status.

Comparison of 18F-FDG and 68Ga-DOTATATE PET/CT in surgically treated lung carcinoid tumors

Aims: This study aims to compare the efficacy of FDG-18 PET/CT and 68Ga-DOTATATE PET/CT imaging techniques in patients with lung carcinoid tumors, identifying the most appropriate preoperative nuclear medicine technique for diagnosis and staging. Methods: We retrospectively analyzed data from 123 patients who underwent surgery for lung carcinoid tumors at our center between 2009 and 2021. All of the patients were scanned with FDG-18 PET/CT before surgery. In addition to FDG-18 PET/CT, 68Ga-DOTATATE PET/CT scanning was performed in 28 patients: 17 in the preoperative and 11 in the postoperative period. Demographic data, mean higher maximal standard uptake (SUVmax) values of primary mass, lymph nodes and extrathoracic foci, pathologic subtype, and type of surgery were recorded. Compliance with normal distribution for numerical data was assessed using the Shapiro-Wilk test. The Wilcoxon signed-rank test was employed for groups meeting normal distribution to compare continuous numerical variables. The Mann-Whitney U and Kruskal-Wallis tests were used when normal distribution assumptions were unsatisfied. Results: The mean SUVmax value in 68Ga-DOTATATE PET/CT was significantly higher than FDG-18 PET/CT in patients with a lung carcinoid tumor (20 vs 4.4). For 68Ga-DOTATATE PET/CT scan, typical carcinoids had higher mean SUVmax value than atypical carcinoids (26 and 5.6 respectively), and the difference was statistically significant (p=0.002). For that FDG18 PET/CT, on the contrary, the mean SUVmax value was higher in atypical carcinoids than typical carcinoids (5.4 and 3.8, respectively), and the difference was not significant (p=0.126) Conclusion: The SUVmax values from 68Ga-DOTATATE PET/CT and FDG-18 PET/CT in lung carcinoid tumors vary by tumor subtype. 68Ga-DOTATATE PET/CT demonstrates higher SUVmax values in typical carcinoid tumors, indicating its superiority over FDG-18 PET/CT for this subtype. Although 68Ga-DOTATATE PET/CT also shows elevated SUVmax in atypical carcinoid tumors, the difference compared to FDG-18 PET/CT does not reach statistical significance.

Multiphysics simulation of liposome release from hydrogels for cavity filling following patient-specific breast tumor surgery

Several studies have recommended the use of hydrogels for localized targeted delivery of chemotherapeutic drugs following tumor removal surgery. This approach aims to both fill the cavity and prevent cancer recurrence. The use of Multiphysics-based simulation emerges as a valuable strategy for minimizing experimental work, providing detailed insights into how drug release occurs in the tissue, and enabling the optimization of the design.In this study, we introduced a mathematical model, utilizing experimental data, to investigate the transport of liposomes carrying MZ1 from a thermosensitive hydrogel and their impact on the viability of breast cancer cells. The proposed comprehensive model considers not just the transport within the interstitial tissue, represented as a porous medium, but also the uptake by cells and its influence on cell viability, along with the potential lymphatic drainage.The six real patient-specific tumor shapes extracted from MRI scans were used to investigate how the size and form of the tumor can modify the transport pattern. The computational results revealed that the concentration of liposomes in the tissue is significantly influenced by their release from the hydrogel, which proved to be the limiting step. Liposome concentrations of approximately 0.1 % weight were found to be sufficient in ensuring minimal cell survival in the vicinity of the tumor.

Automatic Image Registration Provides Superior Accuracy Compared with Surface Matching in Cranial Navigation.

The precision of neuronavigation systems relies on the correct registration of the patient's position in space and aligning it with radiological 3D imaging data. Registration is usually performed by the acquisition of anatomical landmarks or surface matching based on facial features. Another possibility is automatic image registration using intraoperative imaging. This could provide better accuracy, especially in rotated or prone positions where the other methods may be difficult to perform. The aim of this study was to validate automatic image registration (AIR) using intraoperative cone-beam computed tomography (CBCT) for cranial neurosurgical procedures and compare the registration accuracy to the traditional surface matching (SM) registration method based on preoperative MRI. The preservation of navigation accuracy throughout the surgery was also investigated. Adult patients undergoing intracranial tumor surgery were enrolled after consent. A standard SM registration was performed, and reference points were acquired. An AIR was then performed, and the same reference points were acquired again. Accuracy was calculated based on the referenced and acquired coordinates of the points for each registration method. The reference points were acquired before and after draping and at the end of the procedure to assess the persistency of accuracy. In total, 22 patients were included. The mean accuracy was 6.6 ± 3.1 mm for SM registration and 1.0 ± 0.3 mm for AIR. The AIR was superior to the SM registration (p < 0.0001), with a mean improvement in accuracy of 5.58 mm (3.71-7.44 mm 99% CI). The mean accuracy for the AIR registration pre-drape was 1.0 ± 0.3 mm. The corresponding accuracies post-drape and post-resection were 2.9 ± 4.6 mm and 4.1 ± 4.9 mm, respectively. Although a loss of accuracy was identified between the preoperative and end-of-procedure measurements, there was no statistically significant decline during surgery. AIR for cranial neuronavigation consistently delivered greater accuracy than SM and should be considered the new gold standard for patient registration in cranial neuronavigation. If intraoperative imaging is a limited resource, AIR should be prioritized in rotated or prone position procedures, where the benefits are the greatest.

When Would Minimally Invasive Spinal Surgery Not Be Preferable for Metastatic Spine Disease?

Metastatic spine tumor surgery (MSTS) is an important treatment modality of metastatic spinal disease (MSD). Open spine surgery (OSS) was previously the gold standard of treatment till the early 2010s. However, advancements in MSTS in recent years have led to the advent of minimally invasive spinal surgery (MISS) techniques for the treatment of MSD. The clear benefits of MISS have resulted in a current paradigm shift toward today's gold standard of MISS and early adjuvant radiotherapy in treating MSD patients. Nonetheless, despite improvements in surgical techniques and the rise of literature supporting MISS for MSD, there are still certain situations whereby MISS is not desirable or even suitable. There has also yet to be any literature describing the considerations of not using MISS in MSD in today's clinical context. A narrative review was conducted for this manuscript. All studies related to OSS and MISS in MSTS were included. A total of 54 studies were included in this review. These studies discussed various advantages of MISS for MSD in today's clinical context, including the patient profile, location of vertebrae involved with metastasis requiring treatment, tumor characteristics, as well as equipment availability. This study establishes situations in which MISS can be less applicable despite the advantages it may confer over traditional OSS. MSTS should be individualized, depending on the experience of the surgeon. OSS is a time-tested approach that still holds weight in MSTS and should be readily utilized depending on the clinical situation.

Injectable Polydopamine Nanoparticle-Incorporated Hydrogels for Antiangiogenesis and Stimulating Tumoricidal Immunity to Inhibit Metastasis and Recurrence Postresection.

Surgical resection is still the main means for clinical treatments of breast cancer, but the postoperative immunosuppressive microenvironment and neoangiogenesis of the residual tumors easily lead to tumor metastasis and recurrence, which will further endanger patients' lives. The combination of antiangiogenic therapy and immunotherapy may promote the mutually reinforced cycle of immune reprogramming and vascular normalization to avoid tumor metastasis and recurrence. Herein, we prepared polydopamine nanoparticles for improving tissue adhesion and enriching tumor-associated antigens. This nanoregulator together with regorafenib (REG) was further incorporated into a hydrogel developed from grafting adipic acid dihydrazide onto 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized chitin and oxidized hyaluronic acid, which was injectable at the cavity after subcutaneous tumor surgery with good mechanical properties and degradability. The system showed long-term release of REG. After combining with anti-PD-L1, the hydrogel applied to the surgical wound exhibited a reduction in tumor metastasis and recurrence. This effect was achieved by suppressing angiogenesis and enhancing antitumor immunity, characterized by increased levels of effector T lymphocytes and activation of dendritic cells within tumors, spleens, and draining lymph nodes. The injectable hydrogel offers a promising strategy for postoperative management aimed at preventing tumor metastasis and recurrence.

Effects of preoperative neoadjuvant chemotherapy on postoperative delirium in patients with gynecological tumor surgery: an observational study

PurposeTo investigate whether neoadjuvant chemotherapy (NACT) increases the incidence of postoperative delirium (POD) in patients with gynecological tumors undergoing radical hysterectomy.MethodsThis study included 60 patients in the neoadjuvant chemotherapy exposure group and 60 in the non-exposure group. Preoperative cognitive function, the incidence of POD and other physiological parameters were assessed on preoperative day 1 (POD-1), postoperative day 1 (POD1), postoperative day 2 (POD2), and postoperative day 3 (POD3). Additionally, preoperative olfactory function was evaluated using an olfactory detection kit on POD-1. The primary outcome was the incidence of POD within three days after surgery.ResultsThe incidence of POD was 28.33% in the exposed group and 8.33% in the non-exposed group (P = 0.005). Compared to the non-exposed group, the exposed group had a higher rate of cognitive dysfunction (33.33% vs 13.33%; P = 0.010), and a higher rate of olfactory dysfunction (OD) (25.00% vs 10.00%; P = 0.031). A restricted cubic spline analysis revealed a non-linear relationship between olfactory test scores and Montreal Cognitive Assessment Scale (MoCA) scores (P for overall < 0.001, P for nonlinear = 0.001). Logistic regression identified NACT, mild and moderate cognitive dysfunction, OD, and depression as independent risk factors for POD, with all factors showing significant associations (P < 0.05). The area under the curve (AUC) of OD for predicting POD was 0.783 (95%CI 0.656–0.909).ConclusionsThis single-blind observational study suggests that NACT increases the incidence of POD in patients with gynecological tumors undergoing radical hysterectomy. Moreover, the results indicate that preoperative OD may reflect preoperative cognitive dysfunction, and have predictive value for the incidence of POD.

OGC SO12 - Extended Venous Thromboembolism Prophylaxis in Postoperative Oesophagogastric Cancer Patients: A Completed Audit

Abstract Background Venous thromboembolism (VTE) is a life-threatening complication for cancer patients undergoing oesophagogastric surgery. The NICE recommends extending pharmacological VTE prophylaxis to 28 days for patients undergoing major abdominal cancer surgery. While the effectiveness of in-hospital VTE prophylaxis is well-documented, the optimal duration for postoperative VTE prophylaxis remains a subject of debate. This study aims to evaluate the prescribing compliance, effectiveness, and safety of extending VTE prophylaxis to 28 days following hospital discharge (HD), a policy adopted trust-wide since 2014. Method This is an 11-year retrospective study from July 2012-2022, followed by a complete audit cycle conducted between January 2023-2024. The study included all patients who underwent cardio-esophagectomy or gastrectomy for oesophagogastric cancers. Exclusion criteria comprised patients who died during the index admission, those who underwent benign oesophagogastric surgery or local excision of gastrointestinal stromal tumours (GIST), and patients with peripherally inserted central catheter (PICC) line-associated VTE. The primary outcome measured was the prescribing compliance of 28-day VTE prophylaxis post-hospital discharge. Secondary endpoints included the incidence of VTE and bleeding complications necessitating hospital readmission within 28 days of discharge. Results Our study included 582 patients, showing that post-2014, 423 out of 490 patients (86.3%) were discharged with 28-day VTE prophylaxis, compared to 13 out of 92 patients (14.1%) pre-2014, indicating a significant improvement (p&amp;lt;0.05). Only one patient (0.17%) developed VTE more than 28 days post-discharge, and no readmissions due to bleeding complications. In the subsequent audit, 63 out of 68 patients (92.6%) received the prophylaxis, further increasing prescribing compliance. Comparing the two periods, compliance improved from 86.3% to 92.6%, though not statistically significant (p=0.145). Overall, VTE incidence was minimised from 0.17% to 0%, with no readmissions due to bleeding complications. Conclusion Routine extended VTE prophylaxis for 28 days post-hospital discharge should be recommended for cancer patients undergoing oesophagogastric surgery. This practice has significantly improved prescribing compliance rates, reduced post-hospital discharge VTE incidence, and demonstrated safety, with no hospital readmissions due to bleeding complications.

Hyperspectral imaging in neurosurgery: a review of systems, computational methods, and clinical applications.

Accurate identification between pathologic (e.g., tumors) and healthy brain tissue is a critical need in neurosurgery. However, conventional surgical adjuncts have significant limitations toward achieving this goal (e.g., image guidance based on pre-operative imaging becomes inaccurate up to 3cm as surgery proceeds). Hyperspectral imaging (HSI) has emerged as a potential powerful surgical adjunct to enable surgeons to accurately distinguish pathologic from normal tissues. We review HSI techniques in neurosurgery; categorize, explain, and summarize their technical and clinical details; and present some promising directions for future work. We performed a literature search on HSI methods in neurosurgery focusing on their hardware and implementation details; classification, estimation, and band selection methods; publicly available labeled and unlabeled data; image processing and augmented reality visualization systems; and clinical study conclusions. We present a detailed review of HSI results in neurosurgery with a discussion of over 25 imaging systems, 45 clinical studies, and 60 computational methods. We first provide a short overview of HSI and the main branches of neurosurgery. Then, we describe in detail the imaging systems, computational methods, and clinical results for HSI using reflectance or fluorescence. Clinical implementations of HSI yield promising results in estimating perfusion and mapping brain function, classifying tumors and healthy tissues (e.g., in fluorescence-guided tumor surgery, detecting infiltrating margins not visible with conventional systems), and detecting epileptogenic regions. Finally, we discuss the advantages and disadvantages of HSI approaches and interesting research directions as a means to encourage future development. We describe a number of HSI applications across every major branch of neurosurgery. We believe these results demonstrate the potential of HSI as a powerful neurosurgical adjunct as more work continues to enable rapid acquisition with smaller footprints, greater spectral and spatial resolutions, and improved detection.

Foundation models for fast, label-free detection of glioma infiltration.

A critical challenge in glioma treatment is detecting tumour infiltration during surgery to achieve safe maximal resection1-3. Unfortunately, safely resectable residual tumour is found in the majority of patients with glioma after surgery, causing early recurrence and decreased survival4-6. Here we present FastGlioma, a visual foundation model for fast (<10 s) and accurate detection of glioma infiltration in fresh, unprocessed surgical tissue. FastGlioma was pretrained using large-scale self-supervision (around 4 million images) on rapid, label-free optical microscopy, and fine-tuned to output a normalized score that indicates the degree of tumour infiltration within whole-slide optical images. In a prospective, multicentre, international testing cohort of patients with diffuse glioma (n = 220), FastGlioma was able to detect and quantify the degree of tumour infiltration with an average area under the receiver operating characteristic curve of 92.1 ± 0.9%. FastGlioma outperformed image-guided and fluorescence-guided adjuncts for detecting tumour infiltration during surgery by a wide margin in a head-to-head, prospective study (n = 129). The performance of FastGlioma remained high across diverse patient demographics, medical centres and diffuse glioma molecular subtypes as defined by the World Health Organization. FastGlioma shows zero-shot generalization to other adult and paediatric brain tumour diagnoses, demonstrating the potential for our foundation model to be used as a general-purpose adjunct for guiding brain tumour surgeries. These findings represent the transformative potential of medical foundation models to unlock the role of artificial intelligence in the care of patients with cancer.

Nasoseptal Flap Reuse for Reconstruction in Revision Endoscopic Skull Base Surgery

Abstract Introduction The nasoseptal flap (NSF) is the “workhorse” for reconstruction in endoscopic skull base surgery. It creates a reliable, watertight closure to prevent cerebrospinal fluid (CSF) leaks. The flap's robust vascular pedicle allows for it to be taken down and reused in subsequent reconstructive surgeries if needed. Previous literature has demonstrated successful reuse of the flap up to 24 months after initial surgery. The present study analyzes a cohort of patients with NSFs that were reused up to 12 years following the initial surgery. Methods A retrospective analysis was performed on patients who underwent revision endoscopic skull base surgery for recurrent tumor at a tertiary academic skull base center. Patient demographics, tumor type, length of time between first and second surgery, and outcomes were evaluated. Results A total of 15 patients were identified between 2012 and 2022 who underwent revision endoscopic skull base surgery with previous NSFs that were reused for reconstruction. The time interval between surgeries ranged from 9 months to 12 years. There were 12 pituitary adenomas, 2 Rathke's cleft cysts, and 1 craniopharyngioma. One patient developed a CSF leak 5 days postoperatively, which was repaired with an abdominal fat graft, synthetic dural substitute, and a middle turbinate flap. The operative technique for the take-down and reuse of the NSF will be demonstrated. Conclusion The NSF can be taken down and reused in revision endoscopic skull base cases, even several years after the initial surgery, with excellent coverage of the defect and low incidence of postoperative CSF leak.

NIMG-18. RAPID INTRAOPERATIVE DIFFERENTIATION OF PRIMARY CNS LYMPHOMA FROM COMMON CNS TUMORS USING STIMULATED RAMAN HISTOLOGY AND DEEP LEARNING

Abstract Accurate intraoperative diagnosis is crucial for decision-making during tumor surgery and stereotactic-guided biopsies. Differentiating between primary CNS lymphoma (PCNSL) and non-PCNSL entities such as gliomas and metastatic cancers presents significant challenges due to overlapping histomorphological features, time constraints, and the differing further therapy strategies required. Our study utilized deep learning and stimulated Raman histology (SRH) to address this challenge. We imaged unprocessed, label-free tissue samples intraoperatively using a portable Raman scattering microscope, generating virtual H&amp;E-like images within less than five minutes. Our training set comprised over 54,000 SRH tumor patch images, including various brain tumors. We developed a deep learning pipeline utilizing a ResNet-50 feature extractor and the BYOL (Bootstrap Your Own Latent) self-supervised learning algorithm. We trained a binary linear classifier to distinguish between PCNSL and non-PCNSL entities. Data were collected from New York University (NYU), the University of Cologne (UKK), and the University of Michigan (UM), including 263 SRH whole slide images from 177 patients sourced from surgical resections and stereotactic-guided biopsies. In an international bicentric test cohort (N = 100, NYU and UKK), the model achieved an overall accuracy of 91.1%, an area under the receiver operating characteristic curve (AUROC) of 0.983, a sensitivity of 89.3%, and a specificity of 100% compared to the final formalin-fixed, paraffin-embedded-based diagnosis. Our algorithm can accurately extract typical histomorphological features to help differentiate between PCNSL and non-PCNSL tumors. These results underscore the potential of deep learning models to enhance the accuracy of intraoperative diagnoses for PCNSL and non-PCNSL entities, thereby improving intraoperative decision-making and further treatment strategies by supporting neuropathologists and surgeons.

NCMP-08. PRE-OPERATIVE AND INTRA-OPERATIVE RISK FACTORS OF POST-OPERATIVE CEREBELLAR MUTISM SYNDROME IN PEDIATRIC PATIENTS UNDERGOING POSTERIOR FOSSA TUMOR SURGERY: A SYSTEMATIC REVIEW

Abstract INTRODUCTION Post-operative cerebellar mutism syndrome (pCMS) is a complication of surgical removal of posterior fossa tumors. The neurological and linguistic symptoms of pCMS may resolve in approximately 6 months, however, the children are vulnerable to the burden of significant long-term residual deficits. The current literature lacks a review of intraoperative and preoperative risk factors of postoperative pCMS. The authors addressed this issue by conducting a systematic review of studies investigating these risk factors in pediatric patients with posterior fossa tumors. METHODS The authors extracted potential citations from Google Scholar, PubMed, Scopus, and Cochrane. The eligible studies included pediatric patients less than 18 years of age, who were diagnosed with posterior fossa tumors and developed CMS following the posterior fossa tumor surgery. RESULTS A total of 64 studies involving 6,420 patients were included in this systematic review. The preoperative risk factors delineated in this review are oncological, tumor location, tumor extension, structural invasion, radiological predictors, preoperative hydrocephalus, age, gender, and pre-operative language impairment. Of these factors, a substantial number of studies reported histopathological diagnosis of medulloblastoma, high-grade tumor histology, and midline location of posterior fossa tumor as significant risk factors of pCMS. The intraoperative risk factors significantly associated with pCMS included vermis incision, superior cerebellar peduncle involvement, medulloblastoma diagnosis, and gross total tumor resection. Only a few studies identified protective factors that reduced the risk of developing pCMS. CONCLUSION In this systematic review, we have pooled all the available studies with extractable data to identify the intraoperative and preoperative risk factors of postoperative pCMS in pediatric patients undergoing surgery for posterior fossa tumors. This data can be utilized by healthcare professionals including neurosurgeons in identifying factors that compound the risk of postoperative pCMS and factors that have opposite effects on postoperative outcomes.

A primary intracranial neuroepithelial neoplasm with novel TCF3::BEND2 fusion: a case report

Astroblastoma, MN1-altered, is a rare circumscribed glial neoplasm that is composed of round, cuboidal, orcolumnar cells with astroblastic perivascular pseudorosettes, often associated with MN1::BEND2 and MN1::CXXC5 fusions. Atroblastoma-like gliomas harbouring EWSR1::BEND2 have been reported that they defined an epigenetically distinct subtype of astroblastoma. We report a case of a 19-year-old female with an intracranial neuroepithelial tumor featuring a novel TCF3::BEND2 fusion. This tumor, while classified as EWSR1::BEND2 gliomas based on DNA methylation, did not exhibit the MN1 alteration or typical astroblastoma morphology. The patient, initially diagnosed as ependymoma WHO grade 2 following surgery for an intracranial tumor four years prior, presented with a suspected recurrence. Magnetic resonance imaging identified a mixed solid-cystic lesion in the temporal area of the left lateral ventricle. For the recurrent tumor, the histological examination revealed the tumor cells predominantly exhibited a solid arrangement, with the solid areas primarily consisting of oval and short-spindle cells. In certain regions, loosely arranged short-spindle cells was observed. The tumor exhibited high cellular density, nuclear atypia, and frequent mitoses, but lacked the hallmark features typically associated with astroblastoma. Immunohistochemistry revealed patchy positivity for GFAP and OLIG2, diffuse positivity for EMA, and a high MIB-1 labeling index. Genome-wide DNA methylation profiling confirmed the tumor’s classification as EWSR1::BEND2 gliomas with a high-confidence match and revealed focal deletion of chromosome 9q. Targeted next-generation sequencing identified a TCF3::BEND2 fusion, validated by reverse transcription polymerase chain reaction and Sanger sequencing. This case broadens the genetic spectrum of high-grade neuroepithelial tumor and suggests that BEND2 alterations may serve as critical determinants for this EWSR1::BEND2 glioma subgroup within the methylation classifier.

NCOG-17. THE COMBAT PROJECT - CORE POST OPERATIVE MORBIDITY SET FOR PAEDIATRIC BRAIN TUMOURS

Abstract BACKGROUND Brain tumours are associated with high morbidity both from the tumour and the medical and surgical interventions used to treat them. Post operative morbidity reporting following surgery for paediatric brain tumours is poor due to the lack of a common language when reporting harms. One solution is to develop a core outcome set to stipulate the minimum post operative adverse outcomes that should be reported. The COMBAT (Core Post Operative Morbidity Set for Paediatric Brain Tumours) Project will develop a core outcome set that can be applied to post operative paediatric brain tumour patients to harmonise how adverse outcomes are measured and reported, enabling comparison between different trials, studies and clinical services. We aim to generate interest in The COMBAT Project and invite participation in the project from healthcare professionals and researchers experienced in paediatric neuro-oncology for the consensus process. METHODS AND ANALYSIS We will engage with national and international stakeholders including patients and their carers, healthcare professionals and researchers. A systematic review will identify harms reported in post operative paediatric brain tumour patients and how they are measured. Qualitative interviews with patients and carers will identify any harms of importance to them. A Delphi survey will be created from the harms identified. A consensus meeting will be held to finalise the core outcome set. The final core outcome set will be published and disseminated to encourage uptake. DISCUSSION There is a clear need for a common language to harmonise measurement and reporting of harms following surgery for paediatric brain tumour patients. This project will define post operative adverse outcomes that are of critical importance to key stakeholders. It will be used to standardise surgical morbidity outcome measurement and reporting in trials, studies and clinical practice and will inform future research in this field.

QOL-25. DIGITAL PHENOTYPING OF PERIOPERATIVE MOBILITY METRICS IN PATIENTS UNDERGOING SURGICAL RESECTION OF SKULL BASE TUMORS

Abstract Current methods to assess quality of life and recovery after surgery for skull base tumors are limited and often biased by subjective patient-reported assessments, while objective, in-situ assessments are lacking. Smartphone-based digital phenotyping has been increasingly studied across pathologies, utilizing built-in technologies to measure behavioral patterns pertaining to sleep, physical mobility, social interactions, and cognitive functioning, among others. Here, we report our initial experience with smartphone-based digital phenotyping in patients who underwent resection of skull base lesions. Patients seen at our multi-disciplinary skull base center were enrolled under an institutional board-approved protocol and installed the Beiwe application, which passively collected GPS data 20 days pre- and up to 140 days post-surgery. Variables measured included time spent at home, number of separate significant places visited outside home, daily walking time, and daily number of steps taken. 26 patients were enrolled, comprised of 14 pituitary adenomas, 8 meningiomas, and 4 vestibular schwannomas. All patients demonstrated increased time spent at home, fewer number of significant locations visited, decreased walking time, and decreased total steps in the immediate post-operative period. For pituitaries, mean return to baseline for these variables was 25.7, 24.3, 80.2, and 88.9 days, respectively. For meningiomas, return to baseline was 56.5, 214.4, 45.0, and 45.6 days, respectively. For vestibular schwannomas, return to baseline was 219, 39.9, 35.1, and 36.4 days, respectively. This study demonstrates initial efficacy of digital phenotyping for a cohort of patients undergoing surgical resection of skull base lesions, based on passively collected smartphone GPS data during the peri-operative period. This is part of a larger, ongoing study enrolling surgical patients as well as non-operative controls for comparison. Such peri-operative mobility metrics may potentially be refined to predict postoperative outcomes following surgery such as improvement of neurological symptoms, postoperative CSF leak, infection, dysnatremia, and hospital length of stay.

DISP-10. RACIAL AND SOCIOECONOMIC DIFFERENCES IN CLINICAL AND ACCESS TO CARE OUTCOMES IN NEUROSURGICAL-ONCOLOGY PATIENTS

Abstract BACKGROUND Large database studies have identified racial and socioeconomic differences in neurosurgical-oncologic outcomes. For clearer insights and understanding, more detailed and prospective evaluation is needed. METHODS We retrospectively analyzed a database of 1475 patients undergoing surgery for CNS tumors over 5 years. Multivariate analysis, specific to various pathologies, was conducted to identify demographic and socioeconomic factors (including age, sex, racial identity, primary language, insurance status, and income estimate) associated with access to care and clinical outcomes. Additionally, prospective patient-centered interviews were conducted on neuro- oncology patients to qualitatively explore reasons for disparities in healthcare. RESULTS Significant associations were found between racial identities (White n=911; Hispanic n=285; Asian n=206; Black n=74) and sex (ANOVA p 0.0043), age (p&amp;lt;0.0001), income estimate (p&amp;lt;0.0001), primary language (p&amp;lt;0.0001), and insurance status (p&amp;lt;0.0001). Among different pathologies, presentation to the ED, rather than outpatient setting, was consistently associated with a non- English primary language (p=0.0312) and Medi-Cal insurance (p=0.0029). Time from imaging diagnosis to neurosurgical consultation was associated with non- English primary language (p=0.0262) and Medi-Cal (p=0.0030). Delay between recommendation for surgery and date of surgery was significant in Black patients (p=0.0112). A non- English primary language was negatively associated with having a gross total resection (p=0.0087). Notably, adjuvant treatments were less likely for those with non-English primary language (p=0.0203), Black race (p=0.0049), and Medi-Cal coverage (p=0.0014). Cox regression analysis identified only age (p&amp;lt;0.0001) as a predictor of poorer overall survival in oncologic cases. Prospective interviews identified cultural, economic (work- related), and healthcare navigation issues as reasons for differences in access to care. CONCLUSIONS Across the spectrum of neurosurgical oncology diagnoses, racial and socioeconomic factors independently associate with access to care but not clinical outcome variables. Further investigation is needed, particularly in patients with non- English primary languages and cultural attitudes towards chemotherapy and radiation therapy.

QLTI-12. COST ANALYSIS OF EMERGENCY PROCEDURES FOR BRAIN TUMORS – WHEN YOU CAN WAIT

Abstract BACKGROUND Neurosurgery is expensive and requires advanced technology to achieve the best outcomes, especially for brain tumors. Generally patients are prepared during consultations for a brain tumor surgery, with anesthesiology, cardiology, neuropsychology and other specialties evaluations. Ideally, the hospitalization is planned before and patient is admitted only when is in good conditions. However some patients with brain tumors are evaluated in emergency department and sometimes require urgent procedures. OBJECTIVE This study aimed to estimate the direct cost of specialized care for adult neuro-oncological patients considering previous scheduled procedures versus urgent surgeries and another factors that may impact decision about nonelective procedures. METHODS This observational economic analysis describes the direct cost of care of neuro-oncological patients in Santa Casa de São Paulo, Brazil. Only adult patients with a common primary brain tumor were included. RESULTS The global mortality rate considering all patients were 12.7% and 92.3% of them occurred in nonelective procedures. Also these patients had a greater infection rate and period of hospitalization. Because of this we reviewed when a patient with brain tumor really need an urgent procedure. Despite several patients are initially diagnosed through ER investigation, probably the majority could be compensated through ambulatory consultations and after admitted with better conditions. Situations in which emergency surgery are required include acute hydrocephalus and non-compensated intracranial hypertension. CONCLUSIONS These patients usually have difficulty access to neurosurgical evaluation and so, only look for health assistance when the disease cause severe disability. Emergency surgeries were associated with an increased rate of infections and mortality. The findings of this study could be used by policymakers for resource allocation and to perform economic analyses to establish the value of neurosurgery in achieving global health goals. severe disability. KEY WORDS: costs; brain tumor; emergency; infections

SURG-01. INTRAOPERATIVE FLUORESCENCE ACTIVITY OF 5-AMINOLEVULINIC ACID IN BRAIN METASTASIS OF LUNG CANCER IS ASSOCIATED WITH THE GENETIC ALTERATION OF CELL CYCLE REGULATION

Abstract With advancement of technology in brain tumor surgery, fluorescence image, such as 5-Aminolevulinic Acid (5-ALA), can help detect the residual tumor during surgery. Recently, genetic alteration of cancer is additionally considered as prognostic factor with being added into traditional prognostic system, such as Graded Prognostic Assessment (GPA) scoring system. The primary objective of this study was to investigate the association of certain genetic alterations and intraoperative fluorescent activity of 5-ALA in brain metastasis (BM) of lung adenocarcinoma. A retrospective cohort study was conducted among 72 patients who underwent surgical resection of BM of lung adenocarcinoma at our institute for five years. Cancer cell infiltration was estimated by the intraoperative fluorescent activity of 5-ALA, and genetic alterations were analyzed by next-generation sequencing (NGS). Total 72 patients were eligible for analysis. Strong fluorescence was obtained in 56 (77.8%) patient during surgery. The sensitivity and specificity for detecting cancer cell infiltration using 5-ALA were 87.5% and 96.4%, respectively. In the NGS data of BM, genetic alteration of cell cycle regulation, DNA repair, tumorigenesis, proliferation, epigenetic regulation, and cancer immunology were detected in 73.6%, 44.4%, 56.9%, 66.7%, 30.6%, and 2.8%, respectively. Genes associated with cell cycle regulation (p = 0.003) and cell proliferation (p = 0.044) were significantly associated with positive fluorescence activity of 5-ALA in the adjacent brain tissue. Genetic alterations in cell cycle regulation and cell proliferation were also associated with shorter recurrence-free survival (p = 0.013 and p = 0.042, respectively) and overall survival (p = 0.026 and p = 0.042, respectively) in the multivariate analysis. Additionally, age, KPS, status of NSCLC, RPA class, GPA score, modality of adjuvant treatment were associated with PFS and OS.The results suggest that genetic alterations in cell cycle regulation and cell proliferation are associated with positive fluorescence activity of 5-ALA in the adjacent infiltrative brain tissue and influence the clinical outcome of BM of lung adenocarcinoma.

INNV-10. ULTRA-RAPID INTRAOPERATIVE GLIOMA TUMOR CELL QUANTIFICATION

Abstract The diagnosis and treatment of brain tumors often depends on molecular-genetic data. To date, however, there has been no intraoperative method to rapidly and iteratively utilize tumor-specific genetic alterations to guide brain tumor surgical resections, complicating intraoperative diagnosis and precluding measurement of tumor cell burdens at surgical margins. To address this gap, we developed Ultra-Rapid droplet digital PCR (UR-ddPCR), which can be completed in 15 minutes from tissue to result with an accuracy and sensitivity comparable to standard ddPCR. We demonstrate an UR-ddPCR assay for the IDH1 R132H clonal mutation that is present in many low-grade gliomas. We illustrate the clinical feasibility of UR-ddPCR by performing it intraoperatively for 49 samples from 13 glioma cases, achieving intraoperative quantification in an average of 14 minutes and 54 seconds spanning a wide dynamic range from 0.1% to 94% tumor cell percentages. We further combine UR-ddPCR measurements with UR-stimulated Raman histology intraoperatively to estimate tumor cell densities in addition to tumor cell percentages, across a wide range from &amp;lt; 1 to 1332 cells/mm2. We anticipate that UR-ddPCR, along with future refinements in assay instrumentation, will enable novel point-of-care diagnostics and the development of molecularly-guided brain tumor surgeries that improve clinical outcomes.