Brain Cancer : Type, Symptom, Risk Factor, Diagnosis, Grade, Treatment, And Drug

A Brain Tumor (Intracranial neoplasm) occurs when abnormal cells from within the brain.The brain of human is composed of very soft tissue and a gelatin-like texture.Three separate brain areas make up most of the brain's volume, such as telencephalon, mesencephalon, and cerebellum.

The Brain consists of four main parts namely :

• The cerebrum is the largest part of the brain.It contains two cerebral hemispheres on either side of the brain that each control the opposite side of the body.
• The cerebellum is located at the back part of the brain below the cerebrum.
• The brain stem is the portion of the brain that connects to the spinal cord.
• The meninges are the membranes that  surround and protect the brain and spinal cord.

The Characteristics of Tumor :

• Anaplasia or Dedifferentiation is the loss of diffentiation of cells and of their orientation to one another and blood vessels.
• Atypia is an indication of abnormality of a cell.
• Neoplasia is the uncontrolled division of cells.
• Necrosis is the premature or death of cells caused by external factors, such as infection, toxin, and trauma.

There are two main Types of Tumors :

• Malignant or Cancerous Tumors contain cancer cells.These tumors will infiltrate the surrounding tissue.
• Benign Tumors or Non-Cancerous Tumors do not contain cancer cells.These tumors may be present  for some years and be asymptomatic.

The Characteristics of Malignant Tumors

1. Uncontrolled mitosis that is the growth by division beyond the normal limits.
2. Anaplasia is the cells in the neoplasm have an obviously different form in size and shape.
3. Invasion or invasiveness is the spatial expansion of the tumor through uncontrolled mitosis, in the sense that the neoplasm invades the space occupied by adjacent tissue, thereby pushing the other tissues aside and eventually compressing the tissue.
4. Infiltration is the behaviour of the tumor either to grow (microscopic) tentacles that push into the surrounding tissue that often makes the outline of the tumor undefined.It has tumor cells "seeded" into the tissue beyond the circumference of the tumorous mass.
5. Metastasis that spread to other locations in the body via lymph or blood.

Malignant or Cancerous Tumors can be divided into two :

• Primary Tumors begin within the brain.These tumors are generally invasive or they will expand spatially and intrude into the space occupied by other brain tissues and compress those brain tissues.
• Secondary Tumors or Metastasis Tumors start elsewhere in the body sends cells which end up growing in the brain.

The most common of Primary Tumors

1. Gliomas are tumors that grow from the glial cells which are the supportive cell in the brain.Gliomas include :

• Astrocytoma begins in cells called astrocytes in the cerebrum or cerebellum.
• Oligodendroglioma develops from cells called oligodendrocytes.
• Mixed Glioma is made up of more than one of the gliac cell types.
• Ependymoma begins in the passageways in the brain where CSF is made and stored.
• Brain Stem Glioma begins in the glial cells in the brain stem.

2. Non-Gliomas include :

• Meningioma is a tumor that begins in the meninges.
• Pineal gland and Pituitary Adenomas are tumors that begin in the pineal gland and pituitary gland.
• Primary CNS lymphoma is a tumor that begins in the lymphatic system.
• Medulloblastoma is a tumor that begins in granular cells in the cerebellum.It is most common in children.
• Craniopharyngioma is a benign tumor that begins near the pituitary gland located near the base of the brain.
• Acoustic schwannoma is a rare tumor that begins in the vestibular nerve, which is a nerve in the inner ear that helps control balance.

Astrocytoma is a glioma cancer that begins in astrocytes in the cerebrum or cerebellum.

There are four grades of Astrocytoma :

• Grade I (Pilocytic Astrocytoma ) : A slow growing tumor that is most often benign and rarely spreads into nearby tissue.
• Grade II (Low-Grade Diffuse Astrocytoma : A slow growing tumor that can often spread into nearby tissue and can become a higher grade.
• Grade III (Anaplastic Astrocytoma) : a cancerous tumor that can grow quickly and spread into nearby tissues.
• Grade IV (Glioblastoma) is a very agressive form of astrocytoma.

The Symptoms of Brain Tumor

• Vomiting
• Nausea
• Headache
• Dilation of the pupil on the side of the lesion
• Double vision 
• Papilledema
• Memory loss
• Lack of recognition
• Seizures
• Dizziness
• Personality or emotional changes
• Impaired sense of smell
• Impaired hearing
• Facial paralysis
• Visual field impairement
• Difficulty in speaking and with sensation
• Difficulty in walking
• Abnormal fatigue
• Weariness
• Absences and tremors
• Unconsciousness

Risk Factors of Brain Tumor

• Family history of brain tumor
• Inherited conditions or neurofibromatosis
• Age
• Gender
• The Epstein-Barr virus
• Exposure to the industrial chemical, such as vinyl chloride.
• Ionizing radiation.
• N-Nitroso compounds
• Exposure to Nerve agents
• Race or ethnicity
• Home and work exposures
• Electromagnetic fields
• Head injury and seizures

Diagnosis

There is no specific or singular clinical symptom or sign for any brain tumors, the presence of a combination of symptoms and the lack of corresponding clinical indication of infections or other causes can be an indicator to redirect diagnostic investigation towards the possibility of an intracranial neoplasm.

The diagnosis will start by taking :

• A medical history notes medical antecedents and symptoms.
• Cinical and laboratory investigations serve to exclude infections as the cause of symptoms.
• Gene Testing is a laboratory test in which a sample of blood or tissue is tested for changes in a chromosome that has been linked with a certain type of brain tumor.It is done to diagnose inherited syndrome.
• Examinations in the stage include the eyes, otolaryngological (ENT), and electrophysiological exams.
• The use of Electroencephalography.
• Magnetic Resonance Imaging (MRI) with gadolinium is a procedure that uses magnet, radio, waves, and a computer to make a series of detailed pictures of the brain and spinal cord.It is as indicator for malignant gliomas, meningiomas, and brain metastases.
• Computed Tomography (CT) scan is the procedure that make a series of detailed picture of areas inside the body.
• Positron Emission Tomography (PET) scan is a procedure to find malignant tumor cells in the body.
• Histoligical examination of tumor tissue sample obtained either by means of brain biopsy or open surgery.It is to determine the appropriate treatment and the correct prognosis.A Stereotactic biopsy is done when imaging tests show there may be a tumor deep in the brain and it is hard to reach.An Open biopsy is done when imaging tests show that there may be a tumor that can be removed by surgery.

Tumor Grading System based on WHO

• Grade I (Low Grade) : The tumor cells look more like normal cells under a microscope and grow and spread slower than grade II, III, and IV tumor cells.They rarely spread into nearby tissues.The grade I can be treated by surgery.
• Grade II : The tumor cells  grow and spread slower than grade III and IV tumor cells.They may spread into nearby tissues and may recur.Some tumors may become a higher-grade tumor.
• Grade III : The tumor cells look different from normal cells under a microscope and grow quicklier than grade I and II tumor cells.cells.They are likely to spread into nearby tissues .
• Grade IV (High Grade) : The tumor cells do not look like normal cells under a microscope and grow and spread very quickly.There may be areas of dead cells in the tumor.The Grade IV cannot be treated.

Treatment of Brain Tumor

The treatments of brain tumor depend on the type , grade, and the location of neoplasm. The treatnents can be done by ways :

1. Active Surveillance is closely watching a patient's condition but not giving  any treatment unless there are changes in test results that show condition is getting worse.
2. Surgery is  to remove tumor  tissue  in order that it decreases pressure of the tumor on nearby parts of the brain.
3. Radiation Therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing.The way of radiation therapy is given depending on the type, grade, and location of the tumor.The ways of giving radiation therapy as follow :

• 3-Dimensional Conformal Radiation Therapy is a procedure that uses a computer to create a 3-dimensional (3-D) picture of the brain or spinal cord tumor.
• Intensity-modulated Radiation Therapy is a type of 3-D radiation therapy that uses a computer to make picturesof the size and shape of the brain or spinal cord tumor.
• Stereotactic Radiosurgery is a type of radiation therapy that uses a head frame attached to the skull to aim a single large dose of radiation directly to a brain tumor

4. Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells either by killing the cells or by stopping them from dividing.

5. Targeted Therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells.

• Monoclonal Antibody Therapy is a type of targeted therapy that uses antibodies made in the laboratory from a single type of immune system cell.Bevacizumab is monoclonal antibody that binds to a protein called vascular endothelial growth factor (VEGF) and may prevent the growth of new blood vessels that tumors need to grow.

6. Proton Beam Radiation Therapy is a type of high - energy, external radiation therapy that uses streams of protons (small, positively-charged pieces of matter) to make radiation.

7. Biologic Therapy is a treatment that uses the patient's immune system to fight cancer.

Drugs approved by FDA (Food and Drug Administration) for Brain Tumor.

• Afinitor (Everolimus)
• Afinitor Disperz (Everolimus)
• Avastin (Bevacizumab)
• Becenum (Carmustine)
• Bevacizumab
• BiCMU (Carmustine)
• Carmubris (Carmustine)
• Carmustine
• Carmustine Implant
• CeeNu (Lomustine)
• Everolimus
• Gliadel (Carmustine Implant)
• Gliadel Wafer (Carmustine Implant)
• Lomustine
• Methazolastone (Temozolomide)
• Temodar (Temozolomide)
• Temozolomide

Drugs Combinations used in Brain Tumor

• PVC