Primary brain tumors originate in the brain itself or in tissues close to it, such as in the brain-covering membranes (meninges), cranial nerves, pituitary gland or pineal gland.
Primary brain tumors begin when normal cells acquire errors (mutations) in their DNA. These mutations allow cells to grow and divide at increased rates and to continue living when healthy cells would die. The result is a mass of abnormal cells, which forms a tumor.
In adults, primary brain tumors are much less common than are secondary brain tumors, in which cancer begins elsewhere and spreads to the brain.
Many different types of primary brain tumors exist. Each gets its name from the type of cells involved. Examples include:
Cancer that begins elsewhere and spreads to the brain
Secondary (metastatic) brain tumors are tumors that result from cancer that starts elsewhere in your body and then spreads (metastasizes) to your brain.
Secondary brain tumors most often occur in people who have a history of cancer. But in rare cases, a metastatic brain tumor may be the first sign of cancer that began elsewhere in your body.
In adults, secondary brain tumors are far more common than are primary brain tumors.
Any cancer can spread to the brain, but common types include:
Risk factors for brain tumors include:
Only about 5 to 10 percent of all cancers are genetically inherited, or hereditary. It’s rare for a brain tumor to be genetically inherited. Talk to your doctor if several people in your family have been diagnosed with a brain tumor. Your doctor can recommend a genetic counselor for you.
Risk for most types of brain tumors increases with age.
Brain tumors in general are more common among Caucasians. However, African-American people are more likely to get meningiomas.
Being exposed to certain chemicals, such as those you might find in a work environment, can increase your risk for brain cancer.
Exposure to radiation
People who have been exposed to ionizing radiation have an increased risk of brain tumors. You can be exposed to ionizing radiation through high-radiation cancer therapies. You can also be exposed to radiation from nuclear fallout. The nuclear power plant incidents in Fukushima and Chernobyl are examples of how people can be exposed to ionizing radiation.
No history of chicken pox
Symptoms of brain tumors depend on the location and size of the tumor. Some tumors cause direct damage by invading brain tissue and some tumors cause pressure on the surrounding brain. You’ll have noticeable symptoms when a growing tumor is putting pressure on your brain tissue.
Headaches are a common symptom of a brain tumor. You may experience headaches that:
You may also experience:
Other common symptoms include:
Symptoms of pituitary tumors
The following symptoms can occur with pituitary tumors:
Diagnosis of a brain tumor begins with a physical exam and a look at your medical history.
The physical exam includes a very detailed neurological examination. Your doctor will conduct a test to see if your cranial nerves are intact. These are the nerves that originate in your brain.
Your doctor will look inside your eyes with an ophthalmoscope, which is an instrument that shines a light through your pupils and onto your retinas. This allows your doctor to check how your pupils react to light. It also allows your doctor to look directly into your eyes to see if there’s any swelling of the optic nerve. When pressure increases inside the skull, changes in the optic nerve can occur.
The doctor may also evaluate your:
Your doctor may order more tests after they finish the physical exam. These could include:
CT scan of the head
CT scans are ways for your doctor get a more detailed scan of your body than they could with an X-ray machine. This can be done with or without contrast.
Contrast is achieved in a CT scan of the head by using a special dye that helps doctors see some structures, like blood vessels, more clearly.
MRI of the head
If you have an MRI of your head, a special dye can be used to help your doctor detect tumors. An MRI is different from a CT scan because it doesn’t use radiation, and it generally provides much more detailed pictures of the structures of the brain itself.
This study uses a dye that’s injected into your artery, usually in the groin area. The dye travels to the arteries in your brain. It allows your doctor to see what the blood supply of the tumors looks like. This information is useful at the time of surgery.
Brain tumors can cause breaks or fractures in the bones of the skull, and specific X-rays can show if this has occurred. These X-rays can also pick up calcium deposits, which are sometimes contained within a tumor. Calcium deposits may be in your bloodstream if your cancer has moved to your bones.
A small piece of the tumor is obtained during a biopsy. A specialist called a neuropathologist will examine it. The biopsy will identify if the tumor cells are benign or malignant. It will also determine whether the cancer originated in your brain or another part of your body.
The treatment of a brain tumor depends on:
The most common treatment for malignant brain tumors is surgery. The goal is to remove as much of the cancer as possible without causing damage to the healthy parts of the brain. While the location of some tumors allows for easy and safe removal, other tumors may be located in an area that limits how much of the tumor can be removed. Even partial removal of brain cancer can be beneficial.
Risks of brain surgery include infection and bleeding. Clinically dangerous benign tumors are also surgically removed. Metastatic brain tumors are treated according to guidelines for the type of original cancer.
Surgery can be combined with other treatments, such as radiation therapy and chemotherapy.
Physical therapy, occupational therapy, and speech therapy can help you to recover after neurosurgery.
There are no specific measures to prevent brain tumors. However, early diagnosis helps in minimizing the complications. Surgical removal of tumors within or around the brain in initial stages can reduce the risk of cancer.
Measures that can aid in preventing the risk of tumors are: