Brain Tumors: Types, Symptoms, Diagnosis, and Treatment

A brain tumor consists of a cluster of abnormal cells in the brain and may be either non-cancerous or cancerous. A malignant tumor can be primary, originating in the brain, or secondary, where cancers spread to the brain from other parts of the body. The size, location, and rate of growth of a tumor will determine the severity of symptoms and the treatment options.

How Brain Tumors Are Classified

Primary and Secondary Tumors

• Primary brain tumors develop inside the brain and rarely spread outside it. Most primary tumors in adults are gliomas, which are named after the type of brain cell they resemble (astrocytomas, oligodendrogliomas, or mixed oligoastrocytomas).
• Secondary (metastatic) brain tumors start in another part of the body and later spread to the brain. They are more common than primary tumors and often occur in people with a history of cancer. Brain metastases most often arise from cancers of the lungs, breast, kidneys, colon, or from melanoma.

Grading of Tumors

Tumors are graded (1–4) based on how abnormal the cells appear under a microscope:

• Grade I: Benign tissue; cells resemble normal brain cells and grow slowly.
• Grade II: Malignant tissue; cells look less like normal cells and grow slowly.
• Grade III: Malignant tissue; cells appear very abnormal and actively grow (anaplastic).
• Grade IV: Malignant tissue; cells look most abnormal and grow rapidly. Glioblastomas fall into this category.

Types

Primary Brain Tumors

• Benign: Do not contain cancer cells, rarely spread, can often be removed, and usually have a defined border. They may still cause serious health issues by pressing on sensitive brain areas and can sometimes become malignant.
• Malignant: Contain cancer cells, grow rapidly, invade nearby tissues, and may spread within the brain or spinal cord.

Common Primary Tumors:

• Astrocytoma: Arises from astrocytes; can be low-grade (I–II) or high-grade (III–IV, including glioblastoma).
• Meningioma: Arises in the meninges; usually benign (Grade I) and slow-growing.
• Oligodendroglioma: Arises from oligodendrocytes; usually occurs in middle-aged adults; Grade II–III.
• Acoustic neuromas (schwannomas): Benign tumors affecting balance and hearing nerves.
• Pituitary adenomas: Mostly benign, affecting hormone production.
• Primitive neuroectodermal tumors (PNETs): Rare malignant tumors from embryonic brain cells.
• Craniopharyngiomas: Rare benign tumors near the pituitary gland that may affect hormonal function.

Secondary (Metastatic) Tumors

• These tumors develop when cancer originating elsewhere in the body reaches and grows in the brain.
• More common than primary tumors.
• Can be the first sign of cancer originating elsewhere.

How Does Brain Function

The brain is divided into several functional areas:

• Cerebrum: Controls sensory perception, motor skills, thinking, learning, speech, and emotions. The left side of the brain governs movements and functions on the right side of the body, while the right side controls the left.
• Cerebellum: Manages balance, coordination, and complex motor actions.
• Brainstem: It links the brain to the spinal cord and manages essential functions such as breathing, blood pressure, and other vital processes.

Lobes of the Cerebrum:

• Frontal lobe: Motor function, planning, judgment, motivation, speech.
• Parietal lobe: Sensation and attention.
• Temporal lobe: Memory, emotions, understanding speech.
• Occipital lobe: Vision.

Brain Mapping: Advanced imaging (fMRI, PET) and electrical mapping help identify critical brain areas to minimize damage during surgery.

Symptoms

Symptoms can differ greatly based on the tumor’s size, growth rate, and location within the brain. Because many of these symptoms respond well to treatment, it is important to report them to your doctor or nurse. Some of the most common issues include:

• Headaches (These are particularly common in patients with large tumors or tumors that interfere with the flow of cerebrospinal fluid inside the brain.)
• Seizures
• Fatigue
• Weakness
• Numbness or tingling
• Difficulty walking
• Change in coordination
• Slurred speech
• Changes in peripheral vision

These symptoms often occur only on one side of the body.

Other Symptoms

Brain tumors may also cause cognitive, behavioral, and emotional problems. In some cases, these symptoms are severe enough that you may need round-the-clock supervision from a family member, friend, or health care provider:

Language Difficulty (common with tumors on the left side of the brain)

• Trouble with speaking
• Trouble understanding speech
• Trouble with reading or writing

Memory and Problem-Solving Difficulties

• Poor short-term memory
• Trouble with doing tasks
• Changes in judgment

Behavioral Issues

• Personality changes
• Loss of the ability to control urges or impulses
• Agitation and feelings of anger or frustration
• Unpredictable outbursts

Emotional Issues

• Depressed mood
• Anxiety

Modern Diagnostic Tests for Brain Tumors

A neurological exam is the first step in diagnosis. A neurologist will examine your vision, hearing, balance, coordination, reflexes, and strength. This will help identify the areas affected by the tumor.

Imaging Tests

Magnetic resonance imaging (MRI) scans, including functional MRI, perfusion MRI, and magnetic resonance spectroscopy, are used to detect and stage the tumor and plan treatment. CT (Computerized Tomography) and PET (Positron Emission Tomography) scans can help detect cancer elsewhere in the body when a secondary tumor is suspected.

Stereotactic Biopsy

Tissue is removed from the tumor through regular biopsy or a stereotactic biopsy. Stereotactic biopsy may be done for tumors in hard-to-reach or sensitive areas. A small hole is drilled in the skull, and a thin needle is inserted through it. Tissue is removed using the needle. The process is guided by CT or MRI scanning. The tissue sample is analysed to check for the presence of cancer cells.

Molecular diagnostics, sophisticated laboratory tests, and advanced imaging technologies, such as high-powered (7-tesla) MRI scans and magnetic resonance elastography (MRE), enable doctors to plan individualised treatments. This reduces the need for follow-up surgery.

Advanced Treatment Methods for Brain Tumors

Doctors proceed with the treatment based on the type, size, and location of the tumor. Treatment options include:

Surgery

Surgical intervention involves removing the tumor, or part of it, when it is safely accessible. This will provide relief from symptoms. Neuroradiologists, specialists in brain imaging, utilise advanced surgical navigation and mapping equipment to achieve greater accuracy during complex surgeries.

Advanced surgical procedures include

• Awake brain surgery (Awake craniotomy)
• Minimally invasive surgery

Awake Craniotomy – If a brain tumour that causes seizures needs to be removed, awake craniotomy is performed to ensure the safety of the language, speech, and motor centres of the brain. This requires your active participation, so you have to be awake during a portion of the surgery. The anesthesiologist puts you to sleep when a portion of the skull is removed. He then stops administering the sedative and allows you to wake up. The neurosurgeon will conduct brain mapping to determine the control centers of your brain. During surgery, you will be asked questions, shown pictures to identify, and make simple movements. Your responses will further help the surgeon identify the functional areas of your brain.   Based on this and the brain mapping, the surgeon safely removes as much of the tumour as possible while preserving maximum brain function. Once the surgery is complete, the anesthesiologist will put you to sleep, and the surgeon will reattach the skull.

Brain Mapping

The brain is filled with electrical impulses. During brain mapping, these electrical impulses are measured with an Electroencephalogram (EEG). Functional MRI (fMRI) is used to map abnormal blood flow in a specific area of the brain. Positron Emission Tomography (PET) is used to image brain tissue and its activity after administering a radioactive tracer. Brain Mapping is primarily used to identify the main motor, sensory, and visual areas of the brain, thereby minimizing damage during the surgical removal of a brain tumor while maximizing tumor removal.

Radiation Therapy

High-energy beams, such as X-rays or protons, can be used in radiation therapy to kill tumor cells. An external radiation source or a radiation source placed inside the body close to the brain (brachytherapy) may be used.

Radiosurgery

A Gamma knife or linear accelerator is used to deliver radiation therapy. Multiple beams of moderate radiation are focused on a small area to provide a large dose, killing tumor cells.

Chemotherapy

Drugs are given either orally or intravenously to kill tumor cells. The type of brain tumor is determined, and if suitable chemotherapy is used.

Targeted Drug Therapy

Certain drugs can target specific abnormalities present in the cancer cells to kill them. Targeted drug therapy is available for some types of cancers.

Although a brain tumor diagnosis can be daunting, modern medical technologies and thorough rehabilitation provide genuine hope. With timely intervention and continued care, many patients can not only survive but also reclaim a fulfilling and meaningful life beyond cancer.

Frequently Asked Questions