This document discusses primary brain tumors (PBT). It notes that while the incidence of PBT has remained stable in some age groups, it has increased in children under 14 and adults over 70. PBT account for about 2.4% of cancer deaths each year in the US. The median survival time for glioblastoma multiforme (GBM), the most common and aggressive type of PBT, is 12-16 months. The document then discusses tumor classification, epidemiology, management through surgery, radiation therapy, and chemotherapy. It focuses on gliomas like GBM and anaplastic astrocytoma as the most common and aggressive PBT.

1. PRIMARY BRAIN TUMOR OR PBT
Alireza Arabestanino, DO, Ed.D, B.S.
Research Fellow Brain Tumor and Skull Base Surgery at Harvard Medical
School

2.  EPIDEMIOLOGY AND PRECURSORS OF BRAIN TUMORS
 TREATMENT TECHNIQUES AND METHODS
 TYPE OF BRAIN TUMOR

3. EPIDOMIOLOGY
For people in the 15- to 44-year-old age group , the overall incidence rates have remained fairly stable in
recent years. The cause of the increased incidence of PBT in some age groups remains unclear, but may be due
to improvements in diagnostic neuro-imaging such as magnetic resonance imaging (MRI). In other words,
the increase in PBT incidence may be more apparent than real due to ascertainment bias.
Although uncommon neoplasms, they rank among the top 10 causes of cancer-related deaths in the United
States and account for a disproportionate 2.4% of all yearly cancer-related deaths. The median survival for a
patient with GBM is approximately 12-16 months, a figure that hasn’t improved substantially over the past 30
years.

4. Primary brain tumors are relatively infrequent and are classifieds malignant or benign, according to the
World Health Organization classification. About 238,000 patients are annually diagnosed with malign brain
tumor worldwide. Contemporary epidemiological studies suggest an increasing incidence rate for the
development of PBT in children less than 14 years of age and in patients 70 years or older. PBT remain a
significant health problem in the United States and worldwide. Overall, they account for some of the most
malignant tumors known to affect human beings and are often refractory to all modalities of treatment. PBT
will be diagnosed in approximately 30,000-35,000 patients in the United States this year and are associated
with significant morbidity and mortality. Of the estimated 14 patients per 100,000 population that will
develop a PBT this year, 6-8 per 100,000 will have a high-grade neoplasm, usually some form of glioma such
as glioblastoma multiforme (GBM) or anaplastic astrocytoma (AA).

5. MANAGEMENT
 Primary pathology of brain tumors
The use of appropriate treatment strategies depends on knowing the type of tumor affecting a particular patient.
Tumor classification and grade, in addition to helping with treatment decisions, provide important information about
the prognosis. This chapter follows the World Health Organization (WHO) classification that separates tumors of the
nervous system into different nasal organisms and assigns each lesion a grade from I to IV, with grade I being
biologically incapacitated and grade IV is the most biologically malignant and has the worst prognosis.
In the WHO classification, tumors of neuronal and meningeal origin contain two large and clinically related groups of
neoplasms. Gliomas (e.g. GBM, AA, oligodendroglioma, medulloblastoma) are the largest subtype in the
neuroepithelial class of neoplasms and are also the most common type of PBT. Tumors of epithelial origin, and in
particular gliomas, can grow sporadically in the brain or become more limited. Disseminated tumors are the most
common and include astrocytoma, oligodendroglioma, and mixed oligoastrocytoma. Each of these subtypes can
undergo malignant metamorphosis and become the most aggressive form of glioma, GBM.

6.  Radiation therapy of the Primary of brain tumors
Fragmented radiotherapy with external beam is a suitable form of treatment for almost all patients with high-grade
gliomas (such as GBM, AA, AO, medulloblastoma), as well as for low-grade PBTs that are surgically inaccessible or after
Have progressed since the initial removal. Numerous randomized controlled trials compared with resection alone
(approximately 38-34 weeks vs. 18-14 weeks) have shown survival benefits for patients with high-grade glioma
undergoing surgery and radiation. Respectively, it seems that the mechanism of cell death is the production of DNA
strand damage by ionizing radiation and the production of highly reactive oxygen radicals, which causes further DNA
damage and disruption of cellular processes. Fatal or fatal damage to endothelial cells in tumor vessels may also be
significant.
The standard approach is applied in the early postoperative phase and initially uses cohesive radiation ports that enclose
the T2-weighted target with a margin of 1 to 3 cm, using a dose of approximately 4500-4700 cGy in daily fractions of
180-200 cGy. After completing this section, a "low cone" is performed, which increases the tumor volume by weight T1
with contrast with a margin of 1 to 3 cm, and brings the total dose to about 6000 cGy.