Brain tumor

Brain Tumors

The brain, along with the spinal cord, forms the central nervous system (CNS), which controls essential body functions such as thought, speech, and movement. A tumor in the brain can cause various complications due to the brain’s critical role in bodily functions.

Structure of the Brain

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The brain is divided into three main parts:

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1. Cerebrum: The largest part, responsible for thinking, emotions, problem-solving, and voluntary movements. It has four lobes with specific functions:
• Frontal lobe: Controls reasoning, emotions, speech, and movement.
• Parietal lobe: Processes sensory information like touch, temperature, and pain.
• Temporal lobe: Manages memory, hearing, and language comprehension.
• Occipital lobe: Responsible for vision.
2. Cerebellum: Located below the cerebrum, it controls coordination and balance.
3. Brain Stem: Connects the brain to the spinal cord and regulates essential functions like heart rate, breathing, and motor skills.
4. Meninges: Three layers (dura mater, arachnoid, and pia mater) protect the brain and spinal cord. Between the arachnoid and pia mater flows cerebrospinal fluid (CSF), which cushions the brain.

Types of Brain Tumors

1. Primary Brain Tumors: Originate in the brain itself. These tumors are categorized as either low-grade (slow-growing) or high-grade (fast-growing and more aggressive).
2. Secondary Brain Tumors (Metastatic): Tumors that spread to the brain from other parts of the body.

Common Types of Primary Brain Tumors in Adults

1. Gliomas: Tumors that originate in the glial cells, which support the nervous system.
• Astrocytoma: The most common type, originating in astrocytes. It has four grades ranging from slow-growing (Grade 1) to highly aggressive (Grade 4 glioblastoma).
• Oligodendroglioma: Arises from oligodendrocyte cells, which provide support to neurons.
• Ependymoma: Forms in the lining of the brain’s ventricles, where CSF is produced.
• Diffuse midline glioma: Occurs in the brain’s midline structures.
2. Non-Glioma Tumors: These tumors do not arise from glial cells.
• Meningioma: Begins in the meninges and is usually non-cancerous but can cause problems due to its location.
• Pineal and Pituitary Tumors: Originate in the pineal or pituitary glands.
• Medulloblastoma: A cancerous tumor common in children, starting in the cerebellum.
• Schwannoma: A non-cancerous tumor that forms in the nerve sheath.

Statistics

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In India, brain and CNS tumors rank 14th among all cancers, with approximately 31,460 new cases and 26,656 deaths annually.

Survival Rates
In the United States, the five-year survival rate for CNS tumors is approximately 36%.

Risk Factors

• Age: Brain tumors are more common in children and older adults.
• Gender: More common in men.
• Chemical Exposure: Certain chemicals, such as those used in rubber and vinyl manufacturing, may increase the risk, though evidence is not definitive.
• Family History: Genetic conditions can increase the risk.
• Viral Infections: Viruses like Epstein-Barr (EBV) and cytomegalovirus (CMV) may increase the risk of certain brain tumors.

Symptoms

• General symptoms:
• Headaches
• Seizures
• Memory or personality changes
• Nausea and vomiting
• Fatigue
• Dizziness
• Difficulty sleeping or performing daily activities
• Location-specific symptoms:
• Loss of balance or coordination
• Muscle weakness
• Vision problems
• Speech, hearing, or memory impairment
• Partial paralysis

Diagnosis

• Biopsy: A small tissue sample is taken to confirm if the tumor is cancerous.
• MRI/CT Scans: Imaging tests to locate and assess the tumor.
• Lumbar Puncture: CSF is tested for cancer cells.
• EEG: Measures brain activity to detect abnormalities.

Treatment

1. Surgery: The first line of treatment, where the tumor and some surrounding healthy tissue are removed. If the tumor is inoperable, other treatments are used.
2. Radiation Therapy: High-energy radiation is used to kill cancer cells. Various techniques like 3D conformal radiation, intensity-modulated radiation therapy (IMRT), and proton therapy can minimize damage to healthy tissues.
3. Chemotherapy: Drugs like temozolomide and lomustine are used to destroy cancer cells. Chemotherapy is often combined with surgery and radiation.
4. Targeted Therapy: Focuses on specific genes or proteins involved in the tumor’s growth. Drugs like bevacizumab and larotrectinib are commonly used.
5. Supportive Care: Medications like corticosteroids can reduce brain swelling, while anti-seizure drugs help control seizures.

Follow-Up
Regular follow-ups with blood tests, imaging, and neurological assessments are essential to monitor for tumor recurrence and manage side effects.

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