"Doctor, What Would You do if You Were Me?" - A Survey of Physician Perspectives Toward Glioblastoma Resection.

OBJECTIVE: How maximal safe resection of glioblastoma (GBM) is implemented in the clinical setting remains understudied. Here, we utilized a survey-based approach to understand physician perspectives on this matter. METHODS: Scenarios involving GBMs were presented to physicians who were asked to select from planned subtotal resection, gross total resection (GTR), medical therapy only, or palliative care. Demographic, experience, and Likert scales of value assessment were collected. RESULTS: In the scenario involving a corpus callosum GBM, 2.33% opted for GTR. For a right frontal GBM, 91.7% opted for GTR. In contrast, only 30.8% chose GTR of a right motor strip GBM (P < 0.001). When presented with a left motor strip GBM, fewer respondents (12.7%, P < 0.001) opted for GTR. Physicians who placed a high value on preserving physical independence were more likely to forgo GTR for right motor GBMs (hazard ratio = 0.068, 95% confidence interval: 0.47-0.97, P = 0.035), and physicians who placed a high value on their faith were more likely to opt for surgical treatments that differ from the general consensus, for instance opting for GTR of the corpus callosum GBM (hazard ratio = 4.18, 95% confidence interval: 1.63-10.74, P = 0.003). No other associations were found between the choice for GTR and other variables collected. CONCLUSIONS: Our results suggest that while maximal safe resection remains a guiding principle for GBM resection, physician preference in terms of the extent of resection varies significantly as a function of tumor location and personal values.

Lumbar Spinal Canal Segmentation in Cases with Lumbar Stenosis Using Deep-U-Net Ensembles.

BACKGROUND: Narrowing of the lumbar spinal canal, or lumbar stenosis (LS), may cause debilitating radicular pain or muscle weakness. It is the most frequent indication for spinal surgery in the elderly population. Modern diagnosis relies on magnetic resonance imaging and its inherently subjective interpretation. Diagnostic rigor, accuracy, and speed may be improved by automation. In this work, we aimed to determine whether a deep-U-Net ensemble trained to segment spinal canals on a heterogeneous mix of clinical data is comparable to radiologists' segmentation of these canals in patients with LS. METHODS: The deep U-nets were trained on spinal canals segmented by physicians on 100 axial T2 lumbar magnetic resonance imaging selected randomly from our institutional database. Test data included a total of 279 elderly patients with LS that were separate from the training set. RESULTS: Machine-generated segmentations (MA) were qualitatively similar to expert-generated segmentations (ME1, ME2). Machine- and expert-generated segmentations were quantitatively similar, as evidenced by Dice scores (MA vs. ME1: 0.88 ± 0.04, MA vs. ME2: 0.89 ± 0.04), the Hausdorff distance (MA vs. ME1: 11.7 mm ± 13.8, MA vs. ME2: 13.1 mm ± 16.3), and average surface distance (MAvs. ME1: 0.18 mm ± 0.13, MA vs. ME2 0.18 mm ± 0.16) metrics. These metrics are comparable to inter-rater variation (ME1 vs. ME2 Dice scores: 0.94 ± 0.02, the Hausdorff distances: 9.3 mm ± 15.6, average surface distances: 0.08 mm ± 0.09). CONCLUSION: We conclude that machine learning algorithms can segment lumbar spinal canals in LS patients, and automatic delineations are both qualitatively and quantitatively comparable to expert-generated segmentations.

Early Postoperative Opioid Requirement Is Associated With Later Pain Control Needs After Supratentorial Craniotomies.

BACKGROUND: Despite a renewed focus in recent years on pain management in the inpatient hospital setting, postoperative pain after elective craniotomy remains under investigated. This study aims to identify which perioperative factors associate most strongly with postoperative pain and opioid medication requirements after inpatient craniotomy. MATERIALS AND METHODS: Using an existing dataset, we selected a restricted cohort of patients who underwent elective craniotomy surgery requiring an inpatient postoperative stay during a 7-year period at our institution (n=1832). We examined pain scores and opioid medication usage and analyzed the relative contribution of specific perioperative risk factors to postoperative pain and opioid medication intake (morphine milligram equivalents). RESULTS: Postoperative pain was found to be highest on postoperative day 1 and decreased thereafter (up to day 5). Factors associated with greater postoperative opioid medication requirement were preoperative opioid medication use, duration of anesthesia, degree of pain in the preoperative setting, and patient age. Notably, the most significant factor associated with a higher postoperative pain score and Morphine milligram equivalents requirement was the time elapsed between the end of general anesthesia and a patient's first intravenous opioid medication. CONCLUSION: Postcraniotomy patients are at higher risk for requiring opioid pain medications if they have a history of preoperative opioid use, are of younger age, or undergo a longer surgery. Moreover, early requirement of intravenous opioid medications in the postoperative period should alert treating physicians that a patient's pain may require additional or alternative methods of pain control than routinely administered, to avoid over-reliance on opioid medications.

The 100 Most Highly Cited Publications on Hearing Preservation for Vestibular Schwannomas.

OBJECTIVE: Vestibular schwannomas are benign, slow-growing tumors that often reduce patient quality of life by compressing nearby nerves. Neurological function preservation is one of the indicators of treatment success, with hearing preservation being the most difficult to obtain. This paper provides a bibliometric analysis of hearing preservation in treating acoustic neuromas and a greater understanding of the most highly cited articles, which have enhanced our understanding of this topic. METHODS: Key terms of "acoustic neuroma," "vestibular schwannoma," and "hearing preservation" were queried through Web of Science. Articles were sorted by citation frequency, and the top 100 articles were recorded for title, name of first author, journal title, year of publication, total number of citations (and associated rank), average number of citations per year, country of the first author's associated institution, and type of study. RESULTS: The top 100 cited articles were published from 1980 to 2014. The United States had the highest involvement as a country (55%), the University of Pittsburgh as an institution (13%), and The Journal of Neurosurgery as a publishing source (27%). Fourteen were reviews, and 86 were clinical papers. Of the 86, 73 were retrospective studies. CONCLUSION: Bibliometric analyses summarize and assess potential areas of strength and knowledge gaps within the literature. Studies on hearing preservation in vestibular schwannomas mostly consist of retrospective reviews that assess postoperative outcomes of microsurgery and radiosurgery. Prospective studies and novel treatment options for hearing preservation in vestibular schwannomas are needed to increase current literature diversity.

Use of Tranexamic Acid for Elective Resection of Intracranial Neoplasms: A Systematic Review.

BACKGROUND: As an established antifibrinolytic agent, tranexamic acid (TXA) has garnered widespread use during surgery to limit intraoperative blood loss. In the field of neurosurgery, TXA is often introduced in cases of traumatic brain injury or elective spine surgeries; however, its role during elective cranial surgeries is not well established. We report a systematic review of the use of TXA in elective surgical resection of intracranial neoplasms. METHODS: We performed this systematic review following PRISMA guidelines to identify studies investigating the use of TXA in elective neurosurgical resection of intracranial neoplasms. Variables extracted included patient demographics, surgical indications, type of surgery performed, TXA dose and route of administration, operative duration, blood loss, transfusion rate, postoperative hemoglobin level, and complications. RESULTS: After careful screening, 4 articles (consisting of 682 patients) met our inclusion/exclusion criteria. The studies included 2 prospective cohort studies, 1 retrospective cohort study, and 1 case series. A χ2 test of pooled data demonstrated that patients administered TXA had a significantly decreased need for blood transfusions during surgery (odds ratio, 0.6273; 95% confidence interval, 0.4254-0.9251; P = 0.018). Mean total blood loss was 821.9 mL in the TXA group and 1099.0 mL in the control group across the studies. There was no significant difference in postoperative hemoglobin levels, with a mean of 11.4 g/dL in both the TXA and control groups. CONCLUSIONS: These results support the use of intraoperative TXA in tumor resection. However, its role in tumor resection has been less well investigated compared with its use in other areas of neurosurgery.

Citation analysis of the most influential ependymoma research articles illustrates improved knowledge of the molecular biology of ependymoma.

The history of academic research on ependymoma is expansive. This review summarizes its history with a bibliometric analysis of the 100 most cited articles on ependymoma. In March 2020, we queried the Web of Science database to identify the most cited articles on ependymoma using the terms "ependymoma" or "ependymal tumors," yielding 3145 publications. Results were arranged by the number of times each article was cited in descending order. The top 100 articles spanned across nearly a century; the oldest article was published in 1924, while the most recent was in 2017. These articles were published in 35 unique journals, including a mix of basic science and clinical journals. The three institutions with the most papers in the top 100 were St. Jude Children's Research Hospital (16%), the University of Texas MD Anderson Cancer Center (6%), and the German Cancer Research Center (5%). We analyzed the publications that may be considered the most influential in the understanding and treatment management of ependymoma. Studies focused on the molecular classification of ependymomas were well-represented among the most cited articles, reflecting the field's current area of focus and its future directions. Additionally, this article also offers a reference for further studies in the ependymoma field.

The Role of Vancomycin Powder During Spinal Cord Stimulator Implantation: A Case Series and Review of the Literature.

OBJECTIVE: We examined the role of intrawound vancomycin powder as prophylaxis against postoperative surgical site infection (SSI) after spinal cord stimulator (SCS) implantation. METHODS: We performed a retrospective analysis of 153 consecutive patients who had undergone permanent SCS implantation surgery via open laminectomy between 2014 and 2020. We queried the patients' medical records for patient age, sex, relevant medical history, and whether intrawound vancomycin had been administered. We compared the rates of SSI (primary outcome) and seroma (secondary outcome) within 3 months after surgery between the vancomycin and no-vancomycin groups. Finally, we conducted multivariable logistic regression analyses to identify independent predictors of postoperative SSI or seroma. RESULTS: Of the 153 patients, 59% were women, and the average age was 65.4 years. Overall, 3 patients (2%) had developed an SSI: 2 (methicillin-resistant Staphylococcus aureus, Klebsiella) in the vancomycin group and 1 (methicillin-sensitive Staphylococcus aureus) in the no-vancomycin group. This difference in SSI rate between the 2 groups was insignificant (P = 0.73). Three seromas, all in the no-vancomycin group, accounted for a statistically significant difference in seroma formation between the 2 groups (P = 0.04). Multivariate logistic regression failed to identify any perioperative characteristics as independent predictors of postoperative SSI or seroma. CONCLUSIONS: Our experience suggests open laminectomy for SCS implantation surgery can be performed with a low postoperative SSI rate, with or without the use of powdered vancomycin. We found no evidence suggesting that the use of powdered vancomycin is unsafe or related to postoperative seroma formation. We failed to draw any definitive conclusions regarding its efficacy, despite referencing the largest single case series of SCS implantation to date.

Predicting Spinal Surgery Candidacy From Imaging Data Using Machine Learning.

BACKGROUND: The referral process for consultation with a spine surgeon remains inefficient, given a substantial proportion of referrals to spine surgeons are nonoperative. OBJECTIVE: To develop a machine-learning-based algorithm which accurately identifies patients as candidates for consultation with a spine surgeon, using only magnetic resonance imaging (MRI). METHODS: We trained a deep U-Net machine learning model to delineate spinal canals on axial slices of 100 normal lumbar MRI scans which were previously delineated by expert radiologists and neurosurgeons. We then tested the model against lumbar MRI scans for 140 patients who had undergone lumbar spine MRI at our institution (60 of whom ultimately underwent surgery, and 80 of whom did not). The model generated automated segmentations of the lumbar spinal canals and calculated a maximum degree of spinal stenosis for each patient, which served as our biomarker for surgical pathology warranting expert consultation. RESULTS: The machine learning model correctly predicted surgical candidacy (ie, whether patients ultimately underwent lumbar spinal decompression) with high accuracy (area under the curve = 0.88), using only imaging data from lumbar MRI scans. CONCLUSION: Automated interpretation of lumbar MRI scans was sufficient to correctly determine surgical candidacy in nearly 90% of cases. Given that a significant proportion of referrals placed for spine surgery evaluation fail to meet criteria for surgical intervention, our model could serve as a valuable tool for patient triage and thereby address some of the inefficiencies within the outpatient surgical referral process.

Ethical considerations and patient safety concerns for cancelling non-urgent surgeries during the COVID-19 pandemic: a review.

At the time of writing of this article, there have been over 110 million cases and 2.4 million deaths worldwide since the start of the Coronavirus Disease 2019 (COVID-19) pandemic, postponing millions of non-urgent surgeries. Existing literature explores the complexities of rationing medical care. However, implications of non-urgent surgery postponement during the COVID-19 pandemic have not yet been analyzed within the context of the four pillars of medical ethics. The objective of this review is to discuss the ethics of elective surgery cancellation during the COVID-19 pandemic in relation to beneficence, non-maleficence, justice, and autonomy. This review hypothesizes that a more equitable decision-making algorithm can be formulated by analyzing the ethical dilemmas of elective surgical care during the pandemic through the lens of these four pillars. This paper's analysis shows that non-urgent surgeries treat conditions that can become urgent if left untreated. Postponement of these surgeries can cause cumulative harm downstream. An improved algorithm can address these issues of beneficence by weighing local pandemic stressors within predictive algorithms to appropriately increase surgeries. Additionally, the potential harms of performing non-urgent surgeries extend beyond the patient. Non-maleficence is maintained through using enhanced screening protocols and modifying surgical techniques to reduce risks to patients and clinicians. This model proposes a system to transfer patients from areas of high to low burden, addressing the challenge of justice by considering facility burden rather than value judgments concerning the nature of a particular surgery, such as cosmetic surgeries. Autonomy can be respected by giving patients the option to cancel or postpone non-urgent surgeries. However, in the context of limited resources in a global pandemic, autonomy is not absolute. Non-urgent surgeries can ethically be postponed in opposition to the patient's preference. The proposed algorithm attempts to uphold the four principles of medical ethics in rationing non-urgent surgical care by building upon existing decision models, using additional measures of resource burden and surgical safety to increase health care access and decrease long-term harm as much as possible. The next global health crisis will undoubtedly present its own unique challenges. This model may serve as a comprehensive starting point in determining future guidelines for non-urgent surgical care.

The 100 Most Influential Publications on Medulloblastoma: Areas of Past, Current, and Future Focus.

BACKGROUND: This article is the first to identify the most influential articles on medulloblastoma using the citation analysis methodology. OBJECTIVE: To perform a bibliometric analysis of the 100 most-cited articles on medulloblastoma. METHODS: Using the Web of Science database, search criteria included the title-specific keyword "medulloblastoma" OR "cerebellar primitive neuroectodermal tumor (PNET)" OR "cerebellar PNET." Publications from 1900 to 2020 labeled "article," "review," "data set," or "clinical trial" were chosen and ranked based on total number of citations in descending order. Each article was evaluated based on the following variables: total citations, average citations per year, first author, institution of first author, title, publication year, country of origin, SCImago Journal Rank, and Scopus SNIP (Source Normalized Impact per Paper). RESULTS: Our search yielded 4928 articles on medulloblastoma. The 100 most-cited articles ranged from 192 to 2017 across 42 unique journals; Journal of Clinical Oncology accounted for the most publications (16%). Paul A. Northcott was first author of the most articles on the list (n = 7.7%), and the most widely cited article was "Altered neural cell fates and medulloblastoma in mouse patched mutants" by Goodrich et al., published in Science (1997). CONCLUSIONS: Because medulloblastoma represents the most common form of pediatric cancerous brain tumor, it is important to identify works that have significantly contributed to the body of knowledge regarding this disease. The 100 most-cited medulloblastoma articles comprise a significant collection of data regarding the histopathologic and molecular classification of medulloblastoma as well as clinical outcomes of therapeutics used to treat this disease.

Amygdala Structural Connectivity Is Associated With Impulsive Choice and Difficulty Quitting Smoking.

Introduction: The amygdala is known to play a role in mediating emotion and possibly addiction. We used probabilistic tractography (PT) to evaluate whether structural connectivity of the amygdala to the brain reward network is associated with impulsive choice and tobacco smoking. Methods: Diffusion and structural MRI scans were obtained from 197 healthy subjects (45 with a history of tobacco smoking) randomly sampled from the Human Connectome database. PT was performed to assess amygdala connectivity with several brain regions. Seed masks were generated, and statistical maps of amygdala connectivity were derived. Connectivity results were correlated with a subject performance both on a delayed discounting task and whether they met specified criteria for difficulty quitting smoking. Results: Amygdala connectivity was spatially segregated, with the strongest connectivity to the hippocampus, orbitofrontal cortex (OFC), and brainstem. Connectivity with the hippocampus was associated with preference for larger delayed rewards, whereas connectivity with the OFC, rostral anterior cingulate cortex (rACC), and insula were associated with preference for smaller immediate rewards. Greater nicotine dependence with difficulty quitting was associated with less hippocampal and greater brainstem connectivity. Scores on the Fagerstrom Test for Nicotine Dependence (FTND) correlated with rACC connectivity. Discussion: These findings highlight the importance of the amygdala-hippocampal-ACC network in the valuation of future rewards and substance dependence. These results will help to identify potential targets for neuromodulatory therapies for addiction and related disorders.

Visual Outcomes After Pituitary Surgery.

Visual signs and symptoms are a common manifestation of pituitary adenomas from compression or ischemia of the optic nerves and optic chiasm. Although bitemporal hemianopsia is a classic presenting visual field deficit, additional visual disturbances can result from these tumors. After endoscopic endonasal pituitary surgery, most patients have improvement in visual symptoms. Preoperative factors including retinal nerve fiber layer thickness, severity of preoperative deficit, duration of visual symptoms, tumor size, extent of resection, and patient age serve as possible predictors of postoperative visual outcomes.

Prediction of post-operative delayed hyponatremia after endoscopic transsphenoidal surgery.

OBJECTIVES: Delayed symptomatic hyponatremia is a known phenomenon occurring > 3 days after transsphenoidal surgery. This is a significant cause of post-operative emergency room visits and re-admissions. We describe and characterize post-operative hyponatremia in patients undergoing endoscopic transsphenoidal surgery, identify predictive factors, and create a clinical tool for predicting high risk patients. PATIENTS & METHODS: We retrospectively reviewed a series of over 300 consecutive patients undergoing endoscopic transsphenoidal surgery and identified patients with delayed hyponatremia as well as patient, tumor, and surgical characteristics. In addition, we recorded inpatient post-operative sodium and specific gravity values as well as treatment upond discharge. Univariate and multivariate analyses were carried out to identify predictors of delayed hyponatremia and stratify patients into risk groups. RESULTS: We found that 15% of patients developed delayed hyponatremia and that this occurred most commonly on post-operative day 7. This accounted for more than half of re-admissions after this type of surgery. Female patients and patients needing fluid restriction or fludrocortisone upon discharge were more likely to develop delayed hyponatremia. Patients with post-operative diabetes insipidus were less likely to develop delayed hyponatremia. Using ROC analysis we developed a score which reliably could stratify patients at risk for delayed hyponatremia. CONCLUSIONS: We confirm the risk of delayed hyponatremia after transphenoidal surgery and identify factors that are revealed before discharge to identify patients at higher risk of delayed hyponatremia. These data may help identify patients who require treatment upon discharge and short interval follow up to avoid significant costs of re-admission.

Dose Hypofractionated Stereotactic Radiotherapy for Intracranial Arteriovenous Malformations: A Case Series and Review of the Literature.

BACKGROUND: Brain arteriovenous malformations (AVMs) are pathologic tangles of intracerebral vessels. The treatment of AVMs aims to reduce the risk of devastating intracranial hemorrhage (ICH). Hypofractionated stereotactic radiotherapy (HSRT) can be used to treat large lesions and reduce the risk of radiation toxicity to the surrounding structures. We analyzed the data from our institutional experience of the past 15 years in treating large AVMs with both 5- and 6-fraction HSRT and evaluated the pretreatment characteristics that are most predictive of the radiographic response. METHODS: We included 37 patients and 42 treatments of intracranial AVMs measuring >3 cm in their largest dimension. Data were collected retrospectively by reviewing the electronic health records. The AVM volume was measured before HSRT and at the most recent follow-up appointment. Symptomatic outcomes, including treatment-related inflammation, were measured and defined categorically. RESULTS: Complete obliteration was achieved in 11.9% of the patients. The mean AVM volume had decreased significantly after HSRT (P = 8.7e-8). The percentage of volume reduction differed significantly between patients receiving 30-Gy fractions, (∂V = -48.7%) and those receiving 25-Gy fractions (∂V = -29.1%; P = 0.035). Patients with partial or complete obliteration were more likely to have received a total dose of 30 Gy rather than 25 Gy (P = 0.056) and showed a trend toward being treatment naive (P = 0.053). CONCLUSION: HSRT can be used as a method to manage large AVMs, with obliteration in some cases and sufficient volume reduction in most others for adjuvant treatment with other modalities. The 30-Gy total dose was generally superior to 25 Gy in achieving obliteration or volume reduction. Further studies focused on longer follow-up periods are warranted.

Tentorial sling for microvascular decompression in patients with trigeminal neuralgia: a description of operative technique and clinical outcomes.

OBJECTIVE: Trigeminal neuralgia is a debilitating pain disorder most often caused by arterial compression of the trigeminal nerve, although there are other etiologies. Microvascular decompression (MVD) remains the most definitive treatment for this disorder, with cure rates reported between 60% and 80%. Traditional MVD techniques involve a retrosigmoid craniotomy with placement of an inert foreign material, such as Teflon, between the nerve and compressive vessel. Recurrence of trigeminal neuralgia after MVD has been associated with vessel migration, adhesion formation, and arterial pulsation against the Teflon abutting the nerve. Additionally, foreign materials such as Teflon have been reported to trigger inflammatory responses, resulting in recurrence of trigeminal pain. An alternative method for decompression involves the use of a sling to transpose the compressive vessel away from the nerve. Results of various sling techniques as a decompressive strategy are limited to small series and case reports. In this study, the authors present their experience utilizing a tentorial sling for MVD in patients with trigeminal neuralgia. METHODS: Institutional review board approval was obtained in order to contact patients who underwent MVD for trigeminal neuralgia via the tentorial sling technique. Clinical outcomes were assessed utilizing the Barrow Neurological Institute (BNI) pain intensity score immediately after surgery and at the time of the study. RESULTS: The tentorial sling technique was performed in 45 patients undergoing MVD for trigeminal neuralgia. In 41 of these patients, this procedure was their first decompressive surgery. Immediate postoperative relief of pain (BNI score I) was achieved in 80% of patients undergoing their first decompressive procedure. At last follow-up, 73% of these patients remained pain free. Three patients experienced recurrent trigeminal pain, with surgical exploration demonstrating an intact tentorial sling. The complication rate was 6.6%. CONCLUSIONS: Transposition techniques for MVD have been described previously in small series and case reports. This study represents the largest experience in which the utilization of a tentorial sling for MVD in patients with trigeminal neuralgia is described. The technique represents a novel method for decompression of the trigeminal nerve by transposition of the offending vessel without the use of foreign material. Although the authors' preliminary results parallel the historical cure rate, further outcome data are required to assess long-term durability of this method.

MR-guided delivery of AAV2-BDNF into the entorhinal cortex of non-human primates.

Brain-derived neurotrophic factor (BDNF) gene delivery to the entorhinal cortex is a candidate for treatment of Alzheimer's disease (AD) to reduce neurodegeneration that is associated with memory loss. Accurate targeting of the entorhinal cortex in AD is complex due to the deep and atrophic state of this brain region. Using MRI-guided methods with convection-enhanced delivery, we were able to accurately and consistently target AAV2-BDNF delivery to the entorhinal cortex of non-human primates; 86 ± 3% of transduced cells in the targeted regions co-localized with the neuronal marker NeuN. The volume of AAV2-BDNF (3 × 108 vg/µl) infusion linearly correlated with the number of BDNF labeled cells and the volume (mm3) of BDNF immunoreactivity in the entorhinal cortex. BDNF is normally trafficked to the hippocampus from the entorhinal cortex; in these experiments, we also found that BDNF immunoreactivity was elevated in the hippocampus following therapeutic BDNF vector delivery to the entorhinal cortex, achieving growth factor distribution through key memory circuits. These findings indicate that MRI-guided infusion of AAV2-BDNF to the entorhinal cortex of the non-human primate results in safe and accurate targeting and distribution of BDNF to both the entorhinal cortex and the hippocampus. These methods are adaptable to human clinical trials.

Superior Prognostic Value of Cumulative Intracranial Tumor Volume Relative to Largest Intracranial Tumor Volume for Stereotactic Radiosurgery-Treated Brain Metastasis Patients.

BACKGROUND: Two intracranial tumor volume variables have been shown to prognosticate survival of stereotactic-radiosurgery-treated brain metastasis patients: the largest intracranial tumor volume (LITV) and the cumulative intracranial tumor volume (CITV). OBJECTIVE: To determine whether the prognostic value of the Scored Index for Radiosurgery (SIR) model can be improved by replacing one of its components-LITV-with CITV. METHODS: We compared LITV and CITV in terms of their survival prognostication using a series of multivariable models that included known components of the SIR: age, Karnofsky Performance Score, status of extracranial disease, and the number of brain metastases. Models were compared using established statistical measures, including the net reclassification improvement (NRI > 0) and integrated discrimination improvement (IDI). The analysis was performed in 2 independent cohorts, each consisting of ∼3000 patients. RESULTS: In both cohorts, CITV was shown to be independently predictive of patient survival. Replacement of LITV with CITV in the SIR model improved the model's ability to predict 1-yr survival. In the first cohort, the CITV model showed an NRI > 0 improvement of 0.2574 (95% confidence interval [CI] 0.1890-0.3257) and IDI of 0.0088 (95% CI 0.0057-0.0119) relative to the LITV model. In the second cohort, the CITV model showed a NRI > 0 of 0.2604 (95% CI 0.1796-0.3411) and IDI of 0.0051 (95% CI 0.0029-0.0073) relative to the LITV model. CONCLUSION: After accounting for covariates within the SIR model, CITV offers superior prognostic value relative to LITV for stereotactic radiosurgery-treated brain metastasis patients.

Cumulative Intracranial Tumor Volume Augments the Prognostic Value of Diagnosis-Specific Graded Prognostic Assessment Model for Survival in Patients with Melanoma Cerebral Metastases.

BACKGROUND: The diagnosis-specific graded prognostic assessment scale (ds-GPA) for patients with melanoma brain metastasis (BM) utilizes only 2 key prognostic variables: Karnofsky performance status and the number of intracranial metastases. We wished to determine whether inclusion of cumulative intracranial tumor volume (CITV) into the ds-GPA model for melanoma augmented its prognostic value. OBJECTIVE: To determine whether or not CITV augments the ds-GPA prognostic scale for melanoma. METHODS: We analyzed the survival pattern of 344 melanoma patients with BM treated with stereotactic radiosurgery (SRS) at separate institutions and validated our findings in an independent cohort of 201 patients. The prognostic value of ds-GPA for melanoma was quantitatively compared with and without the addition of CITV using the net reclassification index (NRI > 0) and integrated discrimination improvement (IDI) metrics. RESULTS: The incorporation of CITV into the melanoma-specific ds-GPA model enhanced its prognostic accuracy. Addition of CITV to the ds-GPA model significantly improved its prognostic value, with NRI > 0 of 0.366 (95% CI: 0.125-0.607, P = .002) and IDI of 0.024 (95% CI: 0.008-0.040, P = .004). We validated these findings that CITV improves the prognostic utility of melanoma ds-GPA in an independent cohort of 201 melanoma cohort. CONCLUSION: The prognostic value of the ds-GPA scale for melanoma BM is enhanced by the incorporation of CITV.