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Glioma Childhood Cerebral Astrocytoma Cure - Glioma Childhood
Cerebral Astrocytoma Medicine Drug
Astrocytomas are primary central nervous system tumors that arise primarily in and rarely spread away from the CNS parenchyma contained within the cranial vault. Astrocytomas are so named because of their histologic resemblance to astrocytes and account for ~75% of neuroepithelial tumors. In 1993 the World Health Organization (WHO) established a four-tiered histologic grading guideline for astrocytomas in an effort to eliminate confusion regarding diagnoses. The low grade astrocytomas (I & II) are among the least common of all reported brain tumors, less than 6%, while the highest grade (IV), also known as glioblastoma multiforme (GBM), is the most common primary CNS malignancy and second most frequent brain tumor. Despite the comparatively low incidence of astrocytomas to other human cancers, the higher grades (III & IV) represent disparate mortality rates. Median survival of GBM victims who forgo treatment is approximately 90 days, and even with aggressive surgical, radio- and chemo- therapies is only extended to about twelve months, while long term survival (at least five years) falls under 3%.[1][2]
Contents [hide] 1 Grading 2 Diagnosis 3 Treatment 4 References 5 See also
[edit] Grading The aforementioned WHO grading system is delineated by histopathologic features and are characterized by[1][2]:
Grade 1 — pilocytic astrocytoma - A well circumscribed and generally considered benign growth. Median age at diagnosis is 12 years however these tumors are uncommon (2.3% of brain tumors). Grade 2 — diffuse astrocytoma - are tumors that begin to show invasive characteristics and greater cellularity. Median age at diagnosis is 46 years and relatively rare (<1% of brain tumors). Grade 3 — anaplastic astrocytoma - A pathology separated from the lower grades because of disproportionate increases of mitotic figure presence (indicative of proliferation), more diffuse invasion of brain parenchyma and primitive cellular characteristics or apparent de-differentiation (anaplastic transformation). Median age at diagnosis is 45 years and is also uncommon (3.2% of brain tumors) Grade 4 — glioblastoma multiforme - Approximately 80% of astrocytomas and greater than 20% of all brain tumors are classified as GBM; this if often confused with gliomas altogether: 40% of primary CNS tumors and 78% of brain malignancies. Nearly all lower grade astrocytomas will progress to grade IV, particularly the anaplastic astrocytomas. These tumors are further characterized by rampant tumor and endothelial cell proliferation, nuclear pleomorphisms, areas of pseudopalisading necrosis and intimate close association of invaded host tissue. The remainder of astrocytomas are unclassified unique variants. Futhermore, some tumors may show histologic similarities to multiple glia, e.g. oligoastrocytomas. The existence of such tumors brings debate as to the proper origin of gliomas: possibly cancer stem cells, not the glia themselves. Appropriate care should be taken to note histologic similarities, not assumption of origin.
[edit] Diagnosis A Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scan is necessary to characterize the extent of these tumors (size, location, consistency). CT will usually show distortion of third and lateral ventricles with displacement of anterior and middle cerebral arteries. Histologic analysis is necessary for grading diagnosis.
[edit] Treatment For low grade astrocytomas, removal of the tumor will generally allow functional survival for many years. In some reports, the 5 year survival has been over 90% with well resected tumors. Indeed, broad intervention of low grade conditions is a contested matter. In particular, pilocytic astrocytomas are commonly indolent bodies that may permit normal neurologic function. However, left unattended these tumors may eventually undergo neoplastic transformation. To date, complete resection of high grade astrocytomas is impossible because of the diffuse infiltration of tumor cells into normal parenchyma. Thus, high grade astrocytomas inevitably recur after initial surgery/therapy and are usually treated similarly as the initial tumor. Despite decades of therapeutic research, curative intervention is still nonexistent for high grade astrocytomas; patient care ultimately focuses on palliative management.
[edit] References ^ a b Buckner JC, Brown PD, O'Neill BP, Meyer FB, Wetmore CJ and Uhm JH (2007). "Central Nervous System Tumors". Mayo Clinic Proceedings 82: 1271-86. PMID 17908533. ^ a b Central Brain Tumor Registry of the United States, http://www.cbtrus.org/
[edit] See also glioma brain tumor pilocytic astrocytoma glioblastoma multiforme intracranial pressure Histopathologic video of low grade astrocytoma
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