Brain Cancer: The most dreaded cancer
Cancer. The dreaded “
What is Brain Cancer?
Brain cancer is cancer of the central nervous system—the abnormal growth of cells in the brain or the spinal cord. Cells in the human body naturally evolve to repair the damage. However, this process occasionally goes awry when cells are altered and no longer possess their normal characteristics. In it, these abnormal cells multiply out of control. They gather to form clumps called tumors, which grow and spread to impede bodily functions.
Malignant VS. Benign Brain Tumors
Not all brain tumors are cancerous. Benign brain tumors are a mass of slow-growing cells that still have the potential to cause health problems by pressing on nearby brain structures, but they do not invade tissues or spread to other parts of the body. Contrarily, malignant tumors multiply rapidly and invade surrounding brain tissues. If untreated, they advance to organs outside of the nervous system. Only malignant tumors are considered brain cancer.
Risk Factors of Brain Cancer
According to the American Cancer Society, 1% of the population will develop it in their lifetime. While certain malignant brain tumors are more prevalent in women, men comprise the majority of patients at 1 in every 143 people.
There are other risk factors:
- Age—Children and older adults are at a higher risk for brain tumors than middle-aged adults.
- Family history—Researchers have determined that genetic mutations increase one’s susceptibility to brain cancer like hereditary Li-Fraumeni syndrome, tuberous sclerosis, Turcot syndrome, von Hippel-Lindau disease, and more.
- Race—People from northern Europe are twice as likely to have brain cancer than those in Japan. In the United States, Caucasians have
increased incidenceof brain cancer when compared to African Americans.
- Impaired immune system—A weakened immune system, whether congenital or caused by acquired immunodeficiency syndrome (AIDS), anti-rejection drugs, or treatment for other cancers, cannot suppress the ‘out-of-control’ cells occurring in brain cancer.
- Radiation—Brain tumors develop approximately 10 to 15 years after excessive radiation exposure. This includes radiation treatments to manage other cancers or fungal infections.
- Chemical exposure—Chemical exposures linked to it are industrial solvents, pesticides, and oil.
- Head injury—Studies show that severe head trauma is associated with a type of cancer known as meningioma.
Symptoms of Brain Cancer
Although the symptoms vary by type, it shares a set of basic symptoms.
- Headaches—Headaches are new in onset and is exacerbated by activity. They increase in frequency and intensity.
- Fatigue—Trouble sleeping accompanies the tiredness. Normal activities that were once completed with easy require significant energy.
- Seizures—Tumors disrupt the electrical activity in the brain causing seizures.
- Nausea and vomiting—Both nausea and vomiting tend to be worse in the morning.
- Muscle weakness or paralysis—Loss of movement and feeling might be gradual and primarily occur on one side of the body.
- Vision changes—Blurry vision, double vision, or loss of peripheral vision.
- Loss of coordination—Fine motor skills results in problems with balance and depth perception.
- Hearing loss—Pressure on the auditory nerve may lead to progressive hearing loss.
Cognitive Consequences of Brain Cancer
The symptoms inevitably take their toll on the entire physical body. Still,
While the specifics depend on the exact location of the tumor, brain cancer can cause short and long-term memory loss. It is also connected to the inability to concentrate on tasks, confusion in simple matters, and difficulty speaking. Patients may stutter or have problems with word retrieval.
Grades of Brain Cancer
Grade 1 tumors are benign and slow growing. A grade 1 tumor rarely spreads to surrounding tissues. In the best-case scenario, the tumor is removed in its entirety.
A grade 2 tumor is malignant. Although it continues to grow slowly, the chances of reoccurrence with surgical removal are increased. The tumor is likely to spread to surrounding tissues.
The cells of grade 3 brain cancer appear markedly different than healthy cells. Grade 3 brain cancer spreads to surrounding tissues and other areas of the body.
Grade 4 brain cancer is the highest malignancy. The tumor spreads at a rapid rate.
Common Types of Brain Cancer
While not all tumors are malignant, there are more than 120 types of brain tumors. They are classified by type of cell impacted and where in the brain they first originate.
Primary tumors are tumors which grow at the original site of progression. It is where the tumor first grows. Brain cancer caused by a primary tumor originated in the brain rather than starting in another organ and spreading with progression.
Metastatic brain cancer is cancer beginning elsewhere in the body which later spreads to the brain. This can consist of a single tumor or multiple tumors. Cancer of the lungs, breasts, skin, colon, and kidneys frequently spread to the brain.
Metastatic tumors are often discovered by accident. Neurological symptoms drive patients to seek medical attention, which prompts the doctor to order a CT or an MRI scan without a previous history of cancer. The primary site of cancer is generally too small to be detected. The brain metastases contain the same cells from the primary site. Brain cancer that has metastasized is aggressive.
Gliomas stem from glial cells—astrocytes, oligodendrocytes, and ependymal cells. These cells surround the neurons in the brain serving as support and insulation. Gliomas are divided into three types of brain cancer.
Astrocytomas are gliomas that originate in astrocytes. Astrocytes are the star-shaped brain cells in the cerebrum. Astrocytic tumors seldom spread outside of the nervous system. They are classified into four grades. Grade 4 consists of glioblastoma, a particularly aggressive cancer with the highest malignancy for it in adults.
Oligodendrogliomas originate in the glial cells, oligodendrocytes. About 2% of brain tumors are oligodendrogliomas. They grow slowly, but cannot be removed by a neurosurgeon in surgery due to the dense infiltration into nearby brain tissue.
Ependymomas begin in the ependymal cells that line the ventricles of the brain. They do not spread outside of the brain and spinal cord. Hydrocephalus is a common complication, as ependymomas can block the flow of cerebrospinal fluid which causes the ventricles to enlarge. Ependymomas are easily removed during surgery because they do not grow into surrounding brain tissue. If it spreads, ependymomas spread along CSF pathways.
Meningiomas originate in the meninges, the protective membrane around the brain and spinal cord. Prevalent amongst females between 30 and 50 years of age, meningiomas begin as benign tumors and grow slowly—not causing symptoms until their large size interferes with brain function. The small percentage of meningiomas that are malignant grow quickly, spreading to surrounding brain tissues and lungs.
Pediatric Brain Cancer
Pediatric brain cancer describes a number of malignant tumors in children and babies. The American Childhood Cancer Organization states that brain cancer accounts for 15% of pediatric cancers. Leading medical institutions are unsure about its exact cause. The following is true about pediatric brain cancer in comparison to adult brain cancer:
- Location—Children frequently develop tumors in the lower parts of the brain, which affects movement and coordination.
- Type—Medulloblastoma and ependymoma are two forms of cancer more common in children.
- Symptoms—The symptoms are similar to adult onset, varying by size and location of the mass, but babies may have a fuller soft spot (fontanel) on the skull.
- Treatment—Treatment requires higher doses of chemotherapy than given for adult onset brain cancer.
- Prognosis—Children and babies diagnosed with brain cancer have a better outcome. Their tumors are less aggressive and do not grow as rapidly. More than half of children diagnosed survive.
Diagnosing Brain Cancer
If a patient has signs and symptoms of brain cancer, physicians order numerous tests to diagnose the condition. First, they perform a neurological evaluation. The evaluation assesses motor skills like coordination, balance, strength, and reflexes. Vision and hearing tests are included.
A special scan called magnetic resonance imaging (MRI) uses magnetic waves and injected contrast to look for tumors on the brain. An MRI shows the location of the tumor, as well as its size, and it monitors tumor growth. If a tumor is identified, a doctor confirms cancer by surgically obtaining a tissue sample for evaluation under a microscope.
In cases where sensitive brain areas could be damaged during the surgical removal of the full tumor, the tissue sample is acquired via a stereotactic needle biopsy. Guided by MRI scanning, a neurosurgeon creates a small hole in the skull near the location of the tumor. A needle is carefully inserted into the hole to remove the tissue. The results of the biopsy aid physicians in treatment.
Brain Cancer Treatment
Treatment depends on the location of the tumor, the type of cancer, and the age and personal health preferences of the patient.
The go-to treatment for brain cancer is the surgical removal of the tumor through a craniotomy—an operation where a neurosurgeon creates an opening in the skull. Surgically removing the tumor reduces the probability of cancer spreading to surrounding tissues and organs. It also relieves symptoms from the tumor pressing on certain parts of the brain.
Sometimes removing the entire tumor is impossible without inflicting life-threatening damage due to the tumor’s location in the brain. Partial removal is ideal in these instances. Removing only a portion of the tumor manages symptoms and lessens the amount of tumor to be treated by chemotherapy and radiation.
Chemotherapy is a term which encompasses numerous widely prescribed medication to treat cancer. The goal of chemotherapy is to kill cancer cells. Patients receive this therapy orally, intravenously through the blood vessels, or injected into the muscle. The exact chemotherapy varies by tumor. Side effects of chemotherapy include nausea, vomiting, and hair loss.
Treatment for high-grade brain cancer demands aggressive treatment. In addition to oral and intravenous therapy, chemotherapy is delivered directly into the brain through the route of an implant. Dime-sized wafers containing chemotherapy drugs are surgically placed in the brain. The wafers dissolve over several weeks to release chemotherapy into the brain. The wafer method is often prescribed as a post-operative treatment to prevent the tumor from returning after surgery.
Along with chemotherapy, radiation is a treatment option for brain cancer. Radiation treatment kills cancer cells through the high-energy beams of x-ray, photons, or gamma rays. Traditionally, external beam radiation is delivered by a machine that aims radiation beams at the site of the patient’s tumor or the brain as a whole. The tumor shrinks as radiation damages the cancer cells for the body to naturally rid of. Radiation therapy is divided between multiple sessions over several weeks to reduce the damage to surrounding healthy cells.
Stereotactic radiosurgery, a newer form of radiation treatment, aims multiple beams of radiation at one site. The beams combine to equal high doses of radiation without damaging healthy tissues. Radiosurgery is done in fewer sessions than external beam radiation.
Can Brain Cancer Be Prevented?
Knowing we possess the power to control our health is comforting. Unfortunately, current research does not lend substantial evidence on brain cancer prevention. What we are aware of focuses on eliminating the risk factors for developing the condition.
Although the airborne exposure to the above chemicals does not have as large of a role in brain cancers as they do in other cancers, adults can lower their chances of developing brain cancer through lifestyle factors like refraining from the consumption of tobacco products, alcohol, and illegal substances, as well as avoiding exposure to radiation, pesticides, and industrial solvents. These chemicals change the genes inside cells that result in cancer in susceptible individuals (Falco, 2017). Staying at a healthy weight and partaking in regular exercise is always helpful to remain healthy. However, sometimes it happens despite our greatest efforts.
Chang, S.M., Mehta, M.P., Vogelbaum, M.A., Taylor, M.D., & Ahluwalia, M.S. (2015). Chapter 97: Neoplasms of the central nervous system. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia, Pa: Lippincott Williams & Wilkins.
American Cancer Society. Types of Brain Tumors and Spinal Cord Tumors In Adults. (2014). Retrieved from https://www.cancer.org/cancer/brain-spinal-cord-tumors-adults/about/types-of-brain-tumors.html#references
Cheyanne is currently studying psychology at North Greenville University. As an avid patient advocate living with Ehlers Danlos Syndrome, she is interested in the biological processes that connect physical illness and mental health. In her spare time, she enjoys immersing herself in a good book, creating for her Etsy shop, or writing for her own blog.