A brain tumor is a collection of neoplasm (abnormal and excessive growth of tissues) arising in or around the brain. These tumors can disrupt the brain function and cause long-term neurological deficits and even death. Globally, brain tumors make up to 1.8% of all cancer incidence. The International Association of Cancer Registries (IARC) reported that the incidence of brain tumors ranges from 5 to 10 per 100,000 population in India and ranked brain tumor as the 10th most common type of tumor among Indians.
About Brain tumor
The brain is one of the most complex organs in the human body. The brain along with spinal column makes up the central nervous system (CNS), which controls all the vital functions of the body.
A brain tumor is a mass of abnormal cells that grow in the brain. These abnormal cells grow rapidly and invade the healthy areas of the brain. There are different types of brain tumors; some tumors can be benign (non-cancerous) and some can be malignant (cancerous).
Brain tumors can either begin in the brain (primary brain tumors) or may migrate from distant parts of the body to the brain (secondary or metastatic brain tumors).
Signs and Symptoms
The signs and symptoms of a brain tumor depend on the location and size of the tumor. In most cases, brain tumors are asymptomatic during the early stage. However, when the tumor begins to grow and exert pressure on the adjacent brain tissue, the following symptoms may be evident:
- Persistent headaches that worsen with activity or in the morning
- Nausea and vomiting
- Difficulty concentrating or problem-solving
- Memory changes
- Mood or personality changes
- Weakness on one side of the body
- Impaired speech and language (dysarthria)
- Vision problems
- Loss of balance or coordination
Causes and Risk factors
Though the exact cause of brain tumor is unknown, the primary brain tumor develops when the normal cells in the brain undergo any mutation (cellular changes) and start dividing at an uncontrollable rate. The secondary tumor can be the result of a cancer that might have developed in another part of the body and then spread to the brain. The growth rate as well as the location of a tumor determines the severity of the condition.
Factors that might increase the risk of brain tumor include the following:
- Being exposed to ionizing radiations
- Having a family history of brain tumors
- Having a personal history of cancer
- Having a weak immune system
- Being exposed to certain chemicals or carcinogens
- Being exposed to electromagnetic fields
- Being overweight or obese
Diagnostic tests for brain tumor are recommended when a person experiences the symptoms that may signal a brain tumor. The signs and symptoms, along with medical and family history of the patient are assessed to obtain a complete picture.
The following tests are recommended to confirm the diagnosis:
- Neurological examination: This test involves examining the hearing, balance, vision, coordination, and reflexes. Abnormal findings in one or more of these examinations indicate that a specific part of brain may be affected by a brain tumor.
- Imaging: Imaging tests like magnetic resonance imaging (MRI), computerized tomography (CT) scan, and positron emission tomography (PET) scan are used to diagnose brain tumors.
- Biopsy: For the biopsy, a small piece of the tumor is collected through a minimally invasive surgery and is examined in the laboratory to confirm the diagnosis of brain tumor and determine whether it is benign or malignant.
- Skull X-Ray: An X-Ray can show the presence of skull cancers secondary to brain tumors. X-rays can also show the calcium deposits that are found inside some brain tumors.
- Electroencephalography (EEG): This test is used to monitor for possible seizure activity. In this test, several electrodes are attached to the outside of a person's head to measure electrical activity of the brain.
Grading of the Brain Tumor
Brain tumors are graded on a scale developed by the World Health Organization. Grading classifies tumor cells by its features, how they look under the microscope and how quickly they are dividing.
The grades of brain tumors include:
- Grade I: The tumor cells are nearly identical to healthy cells. They are slow growing and unlikely to spread. They can often be treated with surgery.
- Grade II: The tumor cells look slightly different from the healthy cells. These tumors are less likely to grow and spread.
- Grade III: The tumor cells look abnormal and actively divide. They have the potential to transform to grade 4 tumors.
- Grade IV: The tumor cells are actively dividing. In addition, the tumor has both blood vessel growth and areas of dead tissue. These tumors can grow and spread quickly to other body parts.
The treatment modalities for brain tumor aim to remove the tumor as much as possible and to prevent its recurrence. Based on the size and type of the tumor, its growth rate, brain location, and the general health of the patient, the treatment team may recommend any or a combination of following treatment options:
The surgery involves a complete or partial removal of tumors surrounding the brain tissues. It is the first line treatment option for grade-1 brain tumors. Even partial removal of tumors near the sensitive areas of brain may help reduce the signs and symptoms.
The possible side-effects of surgery are bleeding, infections at the incision site, blood clots, etc.
- Radiation therapy:
This involves delivering high-energy beams to destroy the cancer cells. It is usually done prior to the surgery to reduce the size of brain tumors. For brain tumors, the radiation therapy is given either externally by using an external machine or internally by placing a radioactive substance near the tumor. X-rays, gamma rays, electron beams, and photon beam therapy are common energy beams used in radiation therapy. Based on the size, type, and location of the brain tumor, advanced techniques like Intensity-Modulated Radiotherapy (IMRT), Stereotactic Radiosurgery (SRS), and Whole-Brain Radiation therapy are used.
Common side effects of radiation therapy include fatigue, headaches, memory loss and scalp irritation.
Unlike traditional surgery, this method delivers precise, high-dose radiation directly to the tumor, which destroys the tumor cells in that area. Various technologies like linear accelerator and gamma knife are used in radiosurgery.
Chemotherapy is the usage of drugs to destroy rapidly growing cancer cells in the body. These drugs can interfere with the process of cell division and promote cancer cell death. Chemo drugs are injected into a vein (IV) or given orally. Chemotherapy is usually given in cycles and the treatment plan includes a treatment session and a rest period allowing the body to recover. The most common drug used to treat brain tumors is temozolomide.
Common side effects of chemotherapy include nausea, vomiting, fatigue and hair loss.
- Targeted drug therapy:
It uses specific drugs or other substances to identify and destroy the cancer cells without harming the healthy cells. Drugs approved for the treatment of brain tumors are bevacizumab and larotrectinib.
Although there is no way to prevent brain cancers, early diagnosis and proper treatment may reduce the risk of metastatic brain tumors. Routine screening for those with a personal and family history of cancer can help in early diagnosis. Avoiding excessive exposure to radiation and chemicals may also help in reducing the risk of developing a brain tumor.
The outlook after a brain tumor operation depends on the size, type, and location of the tumour, and general health. Children with brain tumors need specialized approaches and care. The survival rate and recurrence rate of cancer varies with the type and grade of brain cancer and the age of the patient. Follow-up care and eating healthy, nutritious food can help in faster healing and in preventing the possible complications.
- Brain tumor. https://www.mayoclinic.org/diseases-conditions/brain-tumor/. Accessed on: 25-08-2020.
- Brain tumor. https://www.cancer.net/cancer-types/brain-tumor/. Accessed on: 25-08-2020.
- Brain tumor. https://braintumor.org/brain-tumor-information/understanding-brain-tumors/. Accessed on: 25-08-2020.
- Brain tumor. https://www.cancer.gov/types/brain. Accessed on: 25-08-2020.
- Brain tumor. https://my.clevelandclinic.org/health/diseases/6149-brain-cancer-brain-tumor. Accessed on: 25-08-2020.