Primary brain tumors can be benign or malignant. Benign brain tumors do not contain cancer cells, and once they are removed, they rarely grow back. Although they are benign, they can grow near sensitive areas of the brain and cause symptoms and even be life-threatening. That is why they need to be removed. Occasionally benign brain tumors can become malignant. Malignant brain tumors (referred to as ‘brain cancer’) on the other hand, do contain cancer cells and as such are often life-threatening. The grade of the tumor tells if it is benign or malignant; slow-growing or fast-growing. Over time, a low-grade tumor may become a high-grade tumor.
Grade I: The cells are benign and grow slowly.
Grade II: The cells are malignant and grow slowly.
Grade III: The cells are malignant and grow more rapidly than Grade II. These tumors are called anaplastic.
Grade IV: The cells are abnormal and tend to grow quickly.
TYPES OF PRIMARY BRAIN TUMORS
There are many types of primary brain tumors. Primary brain tumors are named according to the type of cells or the part of the brain in which they begin. The most common types are:
- Astrocytoma: Tumor that arises from astrocytes. Grade I or II astrocytoma may also be called a low-grade glioma. A grade III astrocytoma is also called a high-grade or an anaplastic astrocytoma (AA). Grade IV astrocytoma is also called a high-grade astrocytoma or a glioblastoma multiforme (GBM).
- Meningioma: Tumor that arises from the meninges. It is usually benign (Grade I) but can be grade I, II, or III.
- Oligodendroglioma: Tumor that arises from cells that make the fatty substance that covers and protects nerves. It can be grade II or III.
These depend on tumor size, type, and location. Symptoms may be caused when a tumor presses on a sensitive area of the brain or when the brain swells in response to the tumor.
The most common symptoms of brain tumors are:
- Headaches (usually worse in the morning)
- Nausea and vomiting
- Changes in speech, vision, or hearing
- Problems balancing or walking
- Changes in mood, personality, or ability to concentrate
- Problems with memory
- Muscle jerking or twitching (seizures or convulsions)
- Numbness or tingling in the arms or legs
Most brain tumors just happen spontaneously. Very few patients have risk factors that put them at a higher chance of getting them.
- History of exposure (to the brain) to ionizing radiation from high dose x-rays and other sources can cause cell damage that leads to a tumor. People exposed to ionizing radiation may have an increased risk of a brain tumor, such as meningioma or glioma.
- Researchers are studying whether using cell phones, having had a head injury, or having been exposed to certain chemicals at work or to magnetic fields are risk factors. Studies have not shown consistent links between these possible risk factors and brain tumors, but additional research is needed.
- Neurologic exam: Your doctor checks your vision, hearing, alertness, muscle strength, coordination, and reflexes. Your doctor also examines your eyes to look for swelling caused by a tumor pressing on the nerve that connects the eye and the brain.
- MRI: If a brain tumor is suspected based on the symptoms and neurological exam, this is the best scan to look for it. An MRI uses a strong magnet to make detailed pictures of areas inside your head. Sometimes contrast is used; it is injected into a blood vessel in your arm or hand to and makes abnormal areas easier to see.
- CT scan: If a patient can’t get an MRI or if a brain tumor wasn’t suspected as the cause of symptoms, sometimes a CT scan of the head will be done. A CT is an x-ray machine linked to a computer that takes a series of detailed pictures of your head. Sometimes contrast is used; it is injected into a blood vessel in your arm or hand and makes abnormal areas easier to see.
- Surgery/Biopsy: Once a brain tumor is suspected on an MRI (or CT scan), the surgeon will decide if it is safe to remove. If it is, then surgical removal of the entire tumor serves as the diagnostic test (so the pathologist can look at it under the microscope and report the kind of tumor it is) as well as the first line of treatment (called a “gross total resection”). If a maximal safe gross total resection is not possible, then either part of the tumor is removed for diagnosis and treatment (called a “subtotal resection”) or a biopsy is done.
Brain tumors are not staged like other cancers. They are categorized by type, grade, and location as detailed above under “What is Brain Cancer?”
Maximal safe resection serves both as diagnosis and as the primary first treatment. Other treatment such as chemotherapy and radiation therapy depend on the following things:
External beam radiation therapy: involves focusing a beam of ionizing radiation to the tumor while sparing the surrounding tissue. It is delivered by a series of painless outpatient treatments over several weeks. Treatments are given Monday through Friday and last less than 30 minutes.
- Type and grade of brain tumor
- Size and location in the brain
- Extent of resection (gross total vs. subtotal vs. biopsy only)
- Patient’s age and health status
3-Dimensional Conformal Radiotherapy (3D-CRT): is a method of treatment delivery that combines multiple radiation treatment fields using 3-dimensional computer planning to produce a high-dose area of radiation that conforms to the shape of the area to be treated. This technique allows the tailoring of delivery of precise doses of radiation to the targeted area while sparing surrounding normal healthy tissue.
Intensity modulated radiation therapy (IMRT): is an advanced form of 3D-CRT that modifies the intensity or strength of each radiation beam. It utilizes a sophisticated system of treatment delivery that allows a precise adjustment of the radiation beam intensity to the tissue within the target area while minimizing effects on surrounding tissue. This may allow for a higher dose of radiation to be delivered to the tumor from multiple angles.
Image Guided Radiation Therapy (IGRT): is another technology that can also be used to ensure better targeting of daily radiation treatments.
Temozolomide is the most common agent used after surgery often in combination with radiation therapy. Several agents have been used for both low-grade and high-grade tumors if the tumor is recurrent.
Possible Treatment Side Effects
Dr. Farber, Dr. Spierer, and their staff at The Farber Center for Radiation Oncology will discuss potential side effects with you before, during, and after treatment, and ensure that your experience is personalized.