Central Nervous System
Pat Price, Karol Sikora in Treatment of Cancer, 2020
The underlying cause of the majority of CNS tumors is unknown. The only environmental factor that is clearly associated with an increased risk of developing a brain tumor is exposure to ionizing radiation, particularly at a young age. Radiation-induced tumors include astrocytomas of all grades, benign and malignant meningiomas, sarcomas, and nerve sheath tumors. A genetic contribution to etiology is also becoming better understood. In addition to a small number of rare syndromes associated with an increased risk of brain tumor (Table 1.2), genome wide association studies (GWAS) have defined at least 10 risk loci for glioblastoma (GBM) and non-GBM tumors.2 These do not increase the risk enough to merit screening approaches (relative risks 1.2–1.4) and are of variable penetrance; nevertheless, identifying them contributes important information in the understanding of gliomagenesis. The immune environment also contributes to tumor promotion, as evidenced by the fact that systemic immunosuppression due to a variety of causes (e.g., immunosuppression following transplant or human immunodeficiency virus [HIV] infection) predisposes to CNS tumors, including primary CNS lymphoma (PCNSL). Current evidence examining lifestyle or environmental exposure has not suggested a specific contribution to etiology.
Introduction
David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack in Brain and Spinal Tumors of Childhood, 2020
Neurosurgery and radiotherapy are the mainstay of effective brain tumor therapy because they are applied directly to the brain. Neuroimaging is extremely sophisticated and can specify the anatomical location of the tumor precisely. In the last decade in many countries the delivery of radiotherapy has been radically transformed by the application of proton therapy with its ability to minimize or avoid radiation dose to non-target tissues, and is described in this book. Furthermore continued advances in the delivery technology for proton therapy have not reached a plateau. Much of the evidence for benefit is still based on dosimetric comparisons and modeling predictions of toxicity reduction. There are increasing numbers of case series, but developing randomized trials comparing proton with photon therapy with respect to long-term toxicity reduction, many years or even decades later, is problematic. Data collection, including “real-world” data, will remain an important priority.
Advances in Portable Neuroimaging and Their Effect on Novel Therapies
Yu Chen, Babak Kateb in Neurophotonics and Brain Mapping, 2017
There are estimated to be approximately 70,000 new cases of primary brain tumors each year in the United States (American Brain Tumor Association, n.d.). This includes tumors in the brain and central nervous system (CNS). It is the second leading cause of death in adolescents under the age of 20. Approximately, one-third of these tumors are malignant. With an average 10-year survival rate, this results in a population of over 700,000 people living in the United States with a brain tumor diagnosis. This does not include secondary metastatic tumors in the brain and CNS that are much more prevalent. Resective surgery is sometimes a great option for a patient, and thus thousands of such surgeries are being done every year. The morbidity and mortality associated with brain tumor resection surgery are high. But one of the great challenges with brain tumor surgery is the ability to visualize and resect the entire tumor during the surgery. Often the surgeon can only rely on visual sight of the tumors with the help of microscopes. Two-dimensional versions of imaging, such as planar x-ray and ultrasound, are entirely inadequate. This results in a large number of surgeries that result in only partial resection. Residual tumor is located by means of postoperative MRI, CT, or PET/CT. This leads to the added expense and danger of repeat surgery.
Recent advances in drug delivery systems for targeting brain tumors
Published in Drug Delivery, 2023
Yi Zhao, Ping Yue, Yao Peng, Yuanyuan Sun, Xing Chen, Ze Zhao, Bingjie Han
Compared with peripheral tumors, the treatment of brain tumors faces many challenges (Figure 1). On the one hand, the physiological barriers (such as blood-brain barrier (BBB), blood-brain tumor barrier (BBTB)) and the over-expressed efflux pumps prevent drugs from entering the central nervous system (CNS) and reaching the tumor site. On the other hand, the inherent characteristics of brain tumors, such as the infiltration, invasion, high heterogeneity, drug resistance and immune escape caused by tumor microenvironment (TME) and cancer stem cells (CSC), further restrict the therapeutic effects, which leading to high failure rate and recurrence rate (Zhao et al., 2020). The median survival of brain tumor patients receiving standard therapy is only about 20 months, and the 2- and 5-year survival rates are only 27% and 10%, respectively (Ashby et al., 2016).
The COVID-19 pandemic altered the modality, but not the frequency, of formal cognitive assessment
Published in Disability and Rehabilitation, 2022
Sam S. Webb, Eirini Kontou, Nele Demeyere
We also investigated the Oxford Cognitive Screen (OCS) specifically, for aim 2, regarding its use before and after March 2020, to explore the uptake of remote assessment using the OCS. Prior to March 2020, 51.75% of all 114 respondents reported using the OCS. Users of the OCS were primarily occupational therapists (68.33%), however, other users included clinical psychologists (8.33%), medical doctors (6.67%), neuropsychologists (6.67%), physiotherapists (3.33%), assistant psychologists (1.67%), speech and language therapists (1.67%), others (3.33%) including a clinical researcher and dietician. The OCS was primarily used in acute stroke units (19.78%) and was also used by community stroke teams (16.48%), community rehabilitation units (15.38%), early supportive discharge (14.29%), neuro out-patient facilities (12.09%), mixed acute and rehab settings (10.99%), memory clinics (2.20%), and others (8.79%) including a cognition clinic, neurological in-patient (n = 2), a community neuro service, neurological rehabilitation (n = 4), a brain injury service, and a geriatric clinic. The 86 respondents reported using the following groups: Stroke = 57, Traumatic brain injury = 17, Mild cognitive impairment = 9, Dementia = 2, and other = 1. Where “other” was for a brain tumor.
Natural substances to potentiate canonical glioblastoma chemotherapy
Published in Journal of Chemotherapy, 2021
Antonietta Arcella, Massimo Sanchez
Inhibition of EGFR has recently been reported to lead to increased secretion of tumor necrosis factor (TNF) and activation of a survival pathway in GBM.102 One of the big problems with the treatment of brain tumors is that not all drugs overcome the blood-brain barrier, so there are few remedies available for brain tumor treatment. In this regard, phytocompounds reduce tumorigenesis, preventing metastasis and/or increasing chemotherapy and radiotherapy efficacy.103 Nanotechnology was used to increase the targeted diffusion of phytochemicals into the brain, which is known to be generally low, due to the presence of the blood brain barrier (BBB). In particular, nanocarriers have recently been created to deliver therapeutic useful loads within the tumor mass. Several polymer nanoparticles that diffuse into the brain (NP) have been used for the treatment of brain tumors. NPs loaded with drugs or natural compounds have shown improved intracranial drug delivery.104,105 In particular, the use of NPs loaded with phytocompounds could represent an effective strategy to block the growth of GBM and other brain tumors, combining the use of relatively non-toxic natural compounds with temozolomide and enhancing their drug delivery with nanotechnologies. NPs can be designed to increase their tropism and specificity toward BBB by conjugating their surface with specific receptors for BBB antigens, receptor ligand, for example lactoferrin can cross the BBB through receptor-mediated transcytosis.106
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