Brain Cancer: What It Is, Symptoms, Diagnosis, and Treatment

Brain cancer is the rapid and uncontrolled multiplication and growth of malignant tumor cells in the brain. The cells responsible for brain cancer have the ability to self-renew. Brain tumors can occur in the pituitary and pineal glands, the membrane on the surface of the brain, and the nerves. Secondary tumors, which originate in other parts of the body and spread to affect the brain, are more common than primary brain tumors that arise directly in the brain. The most commonly observed cases of brain cancer originate from secondary brain tumors. In 2022, it was reported that more than 1,900 people, with an average age of 59, were diagnosed with brain cancer worldwide.

What is Brain Cancer?

Tumors in the brain are abnormal masses of multiplying cells that negatively affect brain functions. Tumors in the shape of a lump can be either benign or malignant. Tumors that do not spread to other parts of the body and grow slowly are benign, and benign tumors are not cancerous. Malignant tumors are cancerous cells, they multiply rapidly, and require urgent treatment. These tend to spread to the brain and other parts of the body.

Brain cancers are not a common occurrence. In particular, brain cancers that originate directly in the brain and do not spread to the body are rare. The more commonly seen brain cancers are those that originate in other parts of the body and spread to the brain. The spread of cancers through metastasis is frequent, and these lead to secondary tumors.

What Causes Brain Cancer?

Various risk factors have been identified for cancers, including brain cancer. While genetic and environmental conditions often trigger cancer development, the impact of these factors on brain cancer is less clear compared to other types of cancer. Major factors that may increase the risk of brain cancer include:

• Gender
• Advancing age
• Genetic links and family history
• Chemical exposure
• Previous radiation therapy

What Are the Symptoms of Brain Cancer?

The symptoms of brain cancer depend on the tumor's location and size. Symptoms are also linked to the rate at which the tumor grows. Benign brain tumors that do not cause cancer develop more slowly, and these symptoms may be so minor or insignificant at first that they go unnoticed. Over time, however, symptoms may worsen over months or even years. Brain tumors that cause cancer are malignant, and these tumors lead to rapidly worsening symptoms. These symptoms often appear suddenly and worsen within days or weeks. The main symptoms of a brain tumor may include:

• Frequent and severe headaches
• A feeling of pressure in the head
• Nausea and vomiting
• Dizziness and balance problems
• Impairments in vision, hearing, smell, or taste
• Memory problems
• Weakness or loss of movement in a part of the body
• Irritability, numbness, fatigue
• Difficulty following simple commands
• Personality and behavior changes
• Seizures

How are Brain Tumors Classified?

Brain tumors are masses of cells that multiply and grow abnormally, unlike normal body cells. According to data, there are more than 150 different types of brain tumors. Brain tumors are divided into two main categories:

• Primary (original) brain tumors: The tumor begins in the brain and tends to stay there.
• Secondary (metastatic) brain tumors: The tumor starts in another part of the body and spreads to the brain. Secondary brain tumors are more common. Kidney and breast cancer, skin and lung cancer are among the common cancers that spread to the brain.

Tumors are graded based on the abnormality level of the cells. The grading provides an idea of how fast the tumor can grow and spread. Treatment planning is done accordingly.

• Grade 1: Tumor cells grow slowly, almost like normal cells. The patient has a high chance of long-term survival.
• Grade 2: Tumor cells appear somewhat abnormal and grow slowly. The tumor may spread to nearby tissue.
• Grade 3: Tumor cells appear abnormal and actively grow toward the brain. These tumors tend to recur.
• Grade 4: Cells appear highly abnormal. They grow rapidly and show signs of spreading.

Rarely, some benign tumors can transform into malignant tumors, and a lower-grade tumor can progress to a higher grade.

Types of Brain Tumors

Brain tumors vary in size. Some brain tumors, even though very small, can be detected because they start showing symptoms early on. Other brain tumors grow to large sizes before being detected. Some of these brain tumors turn cancerous, while others do not. There are basically two types of brain tumors:

• Benign brain tumors generally do not turn into cancer. The tumor cells multiply and grow more slowly. The likelihood of spreading to surrounding tissues is low, and they are usually easy to remove. They rarely spread throughout the entire brain tissue. Depending on the location, they can cause problems due to pressure in certain areas of the brain. Depending on where it is located in the brain, it may be life-threatening.
• Malignant brain tumors are cancerous tissues. Tumor cells often grow and multiply more quickly. Sometimes they can progress slowly as well. Due to the high risk of spreading, they can invade nearby healthy brain tissue. They rarely spread beyond the brain and spinal cord.

Benign and malignant tumors are detailed below.

Types of Benign Brain Tumors
Benign brain tumors, although not cancerous, can cause various symptoms and may require treatment. There is also a possibility of transforming into malignant tumors. Benign brain tumors need to be closely monitored.

• Astrocytomas: Caused by the uncontrolled multiplication of cells called astrocytes. They typically form in the cerebrum, the largest part of the brain. Astrocytomas often spread throughout the brain and can occur in different grades. They can cause behavioral changes and seizures.
• Germ Cell Tumors: Germ cells are reproductive cells that develop into sperm and egg cells. Tumors that form in germ cells are called germ cell tumors. These cells are mostly found in the ovaries and testes, but they can occasionally appear in other parts of the body, including the brain. When a germ cell tumor occurs in the brain, it is typically located near the pituitary or pineal gland.
• Meningiomas: Meningiomas are tumors that form in the membranes (meninges) surrounding the brain and spinal cord. They are the most common type of primary brain tumor in adults. They are usually benign and tend to grow slowly.
• Pituitary Tumors: These tumors form inside or around the pituitary gland, located at the base of the brain. Pituitary tumors are generally benign.
• Nerve Tumors: These tumors form within or around the nerves. The most common type that forms in the head is called “Schwannoma,” which is an acoustic neuroma. This benign tumor is found at the main nerve connection between the inner ear and the brain.

Types of Malignant Brain Tumors
Malignant tumors are more aggressive than benign ones. They generally spread throughout the brain and spinal cord and damage surrounding tissues, requiring treatment as soon as possible.

• Gliomas: Glial cells surround and support the neurons in the nervous system. Gliomas are tumors that form in these glial cells.
• Embryonal Tumors: These tumors occur in cells left over from fetal development. Embryonal cells remain in the brain after birth. Therefore, they are commonly seen in babies and young children. The most common type of embryonal tumor is medulloblastoma.
• Pineal Tumors: These tumors form inside or around the pineal gland in the brain. The pineal gland is located in the center of the brain and produces melatonin, a hormone that regulates the sleep-wake cycle. Pineal tumors can be benign or malignant.
• Ependymomas: These tumors form in the fluid-filled spaces in the brain and the channels that carry cerebrospinal fluid (CSF). They tend to spread along the CSF but do not spread into normal brain tissue. About half of ependymomas are seen in children under the age of three, although they can also affect adults.

Brain Cancer Diagnostic Methods

If there is a suspicion of a brain tumor causing cancer, several physical examination techniques are used for diagnosis. The reflexes, muscle strength, balance and coordination, temperature sensation, and the ability to feel a pinprick are checked to examine the functions of different parts of the brain. In addition, some cancer screening techniques are available for diagnosing brain cancer:

• CT (Computed Tomography): Uses X-rays to take images of the inside of the body.
• MRI (Magnetic Resonance Imaging): Uses a computer to take images of cross-sections of the body.
• MRS (Magnetic Resonance Spectroscopy): Studies changes in the brain's chemical composition and the chemical profile of the tumor.
• PET Scan: A radioactive solution is injected to track the faster absorption of cancer cells compared to normal cells and visualize them.
• SPECT: A three-dimensional image of the blood flow affected by the tumor in the brain.
• Lumbar Puncture: Involves extracting cerebrospinal fluid from the lower back with a needle to detect cancer.
• Biopsy: Involves taking a sample of cells, fluid, or tissue from the affected area.

Brain Cancer Treatment

Brain tumor treatment is determined based on the type, location, and size of the tumor. Common treatments for brain cancer include surgery and radiation therapy. Additionally, the degree of cancer, the patient’s overall health, and age are factors that affect treatment.

• Surgery: Aims to remove the tumor without damaging brain tissue essential for neurological functions. Complete removal of cancerous tissue is possible. In cases where this is not feasible, symptoms may be alleviated, and the size of the surgery may be reduced.
• Radiation Therapy: A treatment that uses high-energy X-rays to kill cancer cells and shrink tumors. If tumor cells remain in the area after surgery, radiation therapy is applied to eliminate the remaining tumor cells. If surgery is not an option, radiation therapy may be the sole treatment.
• Chemotherapy: Aims to damage the genes inside cancerous cells and kill them. Combining multiple chemotherapy drugs increases the chance of killing more cancer cells. Some chemotherapy drugs are used to prevent tumor cells from growing rather than killing them. Chemotherapy is typically administered orally or intravenously. Resistance to chemotherapy occurs when the tumor does not respond to the drug or the drug cannot reach the brain through the bloodstream. In some cases, resistance to chemotherapy may be observed.
• Laser Interstitial Thermal Therapy (LITT): A new technique used to treat smaller tumors in hard-to-reach areas. It uses a catheter to insert a laser into the lesion and destroy it thermally. Since this technique is new, long-term effects have not been proven.
• Combined Therapy: Depending on the tumor's condition, your doctor may recommend combined therapies.

If you suspect brain cancer or have been diagnosed, it is crucial to consult with specialists and follow your treatment plan. Early detection in cancer is critically important and should not be overlooked. Always keep your scheduled appointments and adhere to your treatment plan.