What is a Brain Tumor?
A brain tumor is a growth of abnormal cells that have formed in the brain. Some brain tumors are cancerous (malignant), while others are not (non-malignant). Either way, tumors in the brain or central nervous system. The central nervous system is made up of the brain as well as the spinal cord. It can affect the brain’s ability to work normally.
What is the difference between malignant and benign brain tumors?
Whether a tumor is benign or malignant depends on the level of cell abnormality. If the tumor is made up of normal looking cells, then it is benign; however, if the cells are abnormal, then the tumor is malignant.
“Benign” brain tumors are not cancer, although they often cause symptoms and will sometimes require treatment. Although many people are familiar with the term “benign,” it’s not always an accurate description. Even a so-called “benign” tumor is a serious medical condition. For that reason, we prefer to use the term “non-malignant” to describe brain tumors made up of noncancerous cells.
Malignant brain tumors are cancer. They generally grow faster and more aggressively than non-malignant tumors, invade other areas of the brain and spinal cord, and can be deadly.
Are All Brain Tumors Brain Cancer?
What is Tumor Grading?
A tumor grade is a way to classify a tumor and will help members of the healthcare team communicate more clearly about the tumor, determine treatment options, and predict outcomes.
Tumors are assigned Grade I, II, III, or IV based on abnormalities of the cells they contain. A tumor can have more than one grade of cell. The highest, or most malignant, grade of cell determines the tumor’s grade, even if most of the tumor is made up of lower-grade cells.
World Health Organization (WHO) Tumor Grade Descriptions
Grade I: These are the least malignant tumors and are usually associated with long-term survival. They grow slowly and have an almost normal appearance when viewed through a microscope.
Grade II: These tumors are slow growing and look slightly abnormal under a microscope. Some can spread into nearby normal tissue and recur, sometimes as a higher grade tumor.
Grade III: These tumors are malignant, although there is not always a significant difference between grade II and grade III tumors. The cells of a grade III tumor are actively reproducing abnormal cells, which grow into nearby normal brain tissue. These tumors tend to recur, often as a grade IV.
Grade IV: These are the most malignant tumors. They reproduce rapidly, can have a bizarre appearance when viewed under the microscope, and easily grow into nearby normal brain tissue. These tumors form new blood vessels so they can maintain their rapid growth.
Overview of the Brain’s Anatomy
The central nervous system (CNS) is made up of the brain and spinal cord. The brain is the most critical organ in the body. It directs and regulates all body functions.
The brain is made up of multiple parts, and each part of the brain is responsible for a different body function. Therefore, brain tumor symptoms, and potential treatment options, depend a great deal on where the tumor is located.
Brain Tumor Statistics
Brain tumors do not discriminate. They affect all ages, genders, and ethnicities.
- Over 700,000 Americans are living with a brain tumor today.
- Nearly 80,000 people will be diagnosed with a primary brain tumor this year.
- There are more than 120 different types of primary brain and CNS tumors.
- Approximately one-third (32 percent) of brain and central nervous system (CNS) tumors are malignant.
- About 28,000 kids in the United States are fighting brain tumors right now.
- This year, nearly 16,000 people will die as a result of a brain tumor.
- Survival after diagnosis with a primary brain tumor varies significantly by age, tumor type, location, and molecular markers.
Brain Tumor Statistics by Age
- The median age at diagnosis for all primary brain tumors is 60 years
- Brain tumors are the second most common cancer among children 0-14. They are the leading cause of cancer-related deaths in this age group, outpacing even leukemia according to a 2016 report.
- More than 4,600 children and adolescents between the ages of 0-19 will be diagnosed with a primary brain tumor this year
- Brain and CNS tumors are the third most common cancer among adolescents and young adults (ages 15-39) and the third most common cause of cancer death in this age group
Risk Factors for Brain Tumors
Risk factors are things that may increase a person’s chance of getting a disease. Some risk factors, like age, genetics, and family history, are out of our control. Other risk factors, like smoking, are within our power to change.
Most of the time, we don’t know what causes a given person to develop a brain tumor. Having one or more risk factors does not automatically mean that you’ll develop a brain tumor, just as the lack of risk factors doesn’t guarantee that you’ll never develop one. Talk with your doctor about what you can do to reduce your risk.
Environmental Risk Factors
Of the many potential risk factors scientists have studied, only one – exposure to ionizing radiation – has been clearly shown to increase the risk of developing brain tumors. Ionizing radiation is frequently found in X-rays, which is why human bodies are protected by lead shields when some X-rays are performed.
Genetic Risk Factors
Anything that refers to the genes can be called “genetic.” However, only about 5 to 10 percent of brain tumors are passed down from one generation to another in a family (heredity).
In cases of hereditary brain tumors, a mutation change in the DNA sequence that makes up a specific gene is passed from parent to child. Most genetic risk factors are not present at birth, but actually develop as we age. While most of our genes do their jobs as expected, a small number develop a mutation or other error that causes them stop working the way they should. This malfunctioning can change the way cells grow, which may eventually lead to the development of cancer.
If multiple members of your family have been diagnosed with brain tumors, or you have concerns about starting a family, a genetic counselor may be able to help. Contact the National Cancer Institute’s Cancer Information Service (1-800-422-6237) to find a genetic counselor in your area.