What Is A Brain Tumor?
A Brain tumor, also called an intracranial tumor, is a mass of abnormal tissue in which cells grow and divide out of control, seemingly without being stopped by the mechanisms that control normal cells. Although there are more than 150 distinct types of brain tumors known, primary and metastatic brain tumors are the two major categories.
Primary brain tumors are those that develop from the brain’s tissues or its immediate environs. Primary tumors may be classified as benign or malignant and glial (consisting of glial cells) or non-glial (developing on or in the structures of the brain, including neurons, blood vessels, and glands).
Metastatic brain tumors are those that begin elsewhere in the body (such the breast or lungs) and spread to the brain, often via the circulation. Malignant tumors that have spread to other parts of the body are cancer.
Approximately one in four cancer patients, or about 150,000 individuals each year, have brain metastases. Metastatic brain tumors may form in up to 40% of lung cancer patients. In the past, individuals who were diagnosed with these tumors had extremely terrible prognoses, with median life times of just a few weeks. Innovative surgical and radiation techniques, together with more advanced diagnostic tools, have increased survival rates up to years and improved patients’ quality of life after diagnosis.
Types of Benign Brain Tumors
The majority of patients with chordomas are between the ages of 50 and 60. They are benign, slow-growing tumors. The base of the skull and the lower part of the spine are where they are most often found. Despite being benign, these tumors may penetrate the neighboring bone and impose pressure on the underlying brain tissue. Only 0.2 percent of initial brain tumors are caused by these uncommon malignancies.
Craniopharyngiomas are normally benign tumors, however they are difficult to remove due to their proximity to key structures deep inside the brain. Nearly all patients will need some kind of hormone replacement medication since they typically originate from a pituitary gland section (the organ that controls numerous hormones in the body).
Gangliocytomas, Gangliomas, and Anaplastic Gangliogliomas are uncommon tumors that involve neoplastic nerve cells that are reasonably well-differentiated and occur mostly in young people.
Glomus jugulare tumors are normally benign and are most often seen near the head of the jugular vein, close beneath the base of the skull. They represent the most typical kind of glomus tumor. However, only 0.6 percent of head and neck neoplasms are caused by glomus tumors in general.
Meningiomas are the most frequent benign intracranial tumors, accounting for 10 to 15% of all brain neoplasms, however only a tiny minority are malignant. The meninges, the membrane-like structures that cover the brain and spinal cord, are the source of these malignancies.
Pineocytomas are typically benign tumours that develop from pineal cells and mostly affect adults. Most often, they are slow-growing, homogenous, well-defined, and non-invasive.
Pituitary adenomas are the most frequent intracranial tumors after gliomas, meningiomas, and schwannomas. Pituitary adenomas are benign and generally slow-growing in the vast majority of cases. Even cancerous pituitary tumors seldom metastasize to other organs. The most frequent condition affecting the pituitary is by far adenomas. Though they may be identified in youth, they often afflict persons in their 30s or 40s. The majority of malignant cancers are effectively treatable.
Schwannomas are benign brain tumors that are prevalent in adults. They develop along nerves and are made up of cells that typically act as the nerve cells’ “electrical insulation.” Instead of entering the remaining portion of the healthy nerve, schwannomas often displace it. The eighth cranial nerve, also known as the vestibular cochlear nerve, which connects the brain to the ear, gives rise to acoustic neuromas, which are the most prevalent kind of schwannoma.
Even though these tumors are benign, if they progress and put pressure on nerves and ultimately the brain, they may result in severe consequences and even death. Additionally, the spine and, less often, the nerves that supply the limbs are possible destinations.
Types of Malignant Brain Tumors
Gliomas represent 78 percent of all malignant brain tumors in adults, making them the most common kind. They develop from the brain’s supporting cells, known as glia. These cells are further classified as astrocytes, ependymal cells, and oligodendroglial cells (or oligos). The following are examples of glial tumors:
Astrocytoma is the most prevalent kind of glioma, accounting for over half of all primary brain and spinal cord tumors. Astrocytomas arise from astrocytes, which are star-shaped glial cells that are part of the brain’s supporting tissue. They may arise in any section of the brain, although the cerebrum is the most usually affected. Astrocytomas may affect people of all ages, although they are more common in adults, especially middle-aged males.
Astrocytomas at the base of the brain are more common in youngsters and account for the bulk of brain tumors in children. The majority of these tumors in children are low-grade, but the majority in adults are high-grade.
Ependymomas, which account for two to three percent of all brain tumors, are caused by a neoplastic transformation of the ependymal cells that line the ventricular system. Some are well-defined, while others are not.
Glioblastoma Multiforme (GBM) is the most aggressive kind of glial tumor. These tumors tend to spread quickly, have a bad prognosis, and develop quickly. They may be made up of a variety of cells, including astrocytes and oligodendrocytes. GBM is more frequent in persons aged 50 to 70, and it affects males more than women.
Medulloblastomas primarily develop in the cerebellum, and they are most common in youngsters. Although they are high-grade tumors, they are frequently treatable with radiation and chemotherapy.
Oligodendrogliomas arise from the cells that produce myelin, which serves as insulation for the brain’s wiring.
Other Types of Brain Tumors
Hemangioblastomas are slow-growing tumors that are most typically seen in the cerebellum. They develop from blood vessels, may be very enormous, and are often accompanied with a cyst. These tumors are more frequent in males than women and are more common in adults aged 40 to 60.
Rhabdoid tumors are very uncommon and severe tumors that develop throughout the central nervous system. They often occur in many locations throughout the body, particularly in the kidneys. They are more common in young children, although they may also occur in adults.
Brain Tumors in Children
Children’s brain tumors often arise from different tissues than those that afflict adults. Treatments that are relatively well tolerated by the adult brain (such as radiation treatment) may hinder normal brain development in children under the age of five.
According to the Pediatric Brain Tumor Foundation, around 4,200 children are diagnosed with a brain tumor in the United States each year, with 72 percent of those diagnosed being under the age of 15.
The majority of these brain tumors develop in the brain’s posterior fossa (or rear). Children often arrive with hydrocephalus (fluid buildup in the brain) or problems with the face or body.
Some forms of brain tumors affect youngsters more than adults. Medulloblastomas, low-grade astrocytomas (pilocytic), ependymomas, craniopharyngiomas, and brainstem gliomas are the most prevalent forms of pediatric cancers.
The World Health Organization (WHO) has devised a grading system based on histological findings under a microscope to determine whether a tumor is malignant or benign.
- Most cancerous
- Rapid expansion and aggressiveness
- Widespread infiltration
- Recurrence is frequent.
- Necrosis prone
Brain Tumors In Adult
According to the National Cancer Institute, 22,910 persons (12,630 men and 10,280 women) will be diagnosed with brain and nervous system malignancies in 2012. It is also estimated that 13,700 of these diagnoses would end in mortality in 2012.
Between 2005 and 2009, the median age for death from brain and other nervous system cancer was 64.
Causes of Brain Tumors
Brain tumors are hypothesized to form when certain genes on a cell’s chromosomes are broken and no longer function correctly. These genes generally govern the pace at which the cell multiplies (if it divides at all), as well as repair genes that mend errors in other genes, and genes that should lead the cell to self-destruct if the damage is beyond repair. An person may be born with partial deficiencies in one or more of these genes in certain instances. Environmental variables may then cause more harm. In other circumstances, environmental damage to the genes might be the only culprit. It’s unclear why some individuals in a “environment” have brain tumors while others don’t.
When a cell divides fast and internal growth-control systems are compromised, the cell may ultimately develop into a tumor. Another line of defense may be the body’s immune system, which would ideally recognize and destroy the aberrant cell. Tumors may create chemicals that prevent the immune system from detecting the aberrant tumor cells, allowing the tumor to finally overcome all internal and external barriers to development.
A quickly developing tumor may need more oxygen and nutrients than the local blood supply designed for normal tissue can deliver. Tumors may generate angiogenesis factors, which encourage the formation of blood vessels. The additional vessels that form boost the flow of nutrients to the tumor, and the tumor ultimately becomes reliant on them. This topic is being researched, but more comprehensive study is required to transfer this information into possible therapeutics.
Symptoms Of Brain Tumors
The following symptoms may accompany various forms of brain tumors, depending on where the tumor is located:
- Headaches that may be worse in the morning or keep the patient up at night
- Convulsions or seizures
- Problems thinking, speaking, or communicating
- Personality shifts
- Weakness or paralysis in one area or side of the body Dizziness or loss of balance
- Vision shifts
- Hearing alterations
- Numbness or tingling in the face
- Nausea or vomiting, difficulty swallowing
- Perplexity and disorientation
Diagnosis Of Brain Tumors
Brain cancers may be identified using sophisticated imaging methods. Computed tomography (CT or CAT scan) and magnetic resonance imaging are two diagnostic techniques (MRI). Other MRI sequences may assist the surgeon in planning the removal of the tumor depending on the location of the brain’s normal nerve networks. Intraoperative MRI is also utilized to guide tissue samples and tumor removal during surgery. Magnetic resonance spectroscopy (MRS) is used to investigate the chemical composition of the tumor and to evaluate the type of the lesions visible on the MRI. PET scanning may aid in the detection of recurrent brain cancers.
A biopsy is often the only method to obtain a definite diagnosis of a brain tumor. The biopsy is performed by the neurosurgeon, and the pathologist provides the final diagnosis, identifying whether the tumor is benign or malignant and grading it appropriately.
Treatment For Brain Tumors
Brain tumors (whether primary or metastatic, benign or malignant) are often treated with surgery, radiation, and/or chemotherapy – individually or in different combinations. While radiation and chemotherapy are more often utilized for malignant, residual, or recurring tumors, treatment choices are determined on a case-by-case basis and rely on a variety of criteria. Each form of treatment comes with its own set of dangers and side effects.
Surgery
It is widely believed that surgically removing a brain tumor completely or almost completely is advantageous to the patient. The task for the neurosurgeon is to remove as much tumor as feasible while preserving brain tissue critical to the patient’s neurological function (such as the ability to speak, walk, etc.). Neurosurgeons have traditionally opened the skull with a craniotomy to get access to the tumor and remove as much of it as feasible. During surgery, an EVD may be placed in the brain fluid cavities to drain normal brain fluid while the brain heals from the procedure.
A stereotactic biopsy is another popular treatment that is occasionally done before a craniotomy. This less invasive procedure enables clinicians to acquire tissue in order to make an accurate diagnosis. A frame is often affixed to the patient’s head, a scan is produced, and the patient is then transferred to the operating room, where a tiny hole in the skull is drilled to provide access to the aberrant region. Some hospitals may do this treatment without the need of a frame, depending on the location of the lesion. A tiny sample is collected for microscopic inspection.
Surgical navigation systems, which are computerized equipment, were launched in the early 1990s. These technologies helped the neurosurgeon with tumor guiding, localization, and orientation. This knowledge decreased the dangers and increased the scope of tumor excision. Surgical navigation technologies enabled previously inoperable tumors to be removed with tolerable risks in many circumstances. Some of these devices may also be utilized for biopsies without the need for a frame to be attached to the skull. One disadvantage of these systems is that they need a pre-surgery scan (CT or MRI) to instruct the neurosurgeon. As a result, they are unable to account for intraoperative brain movements. Researchers are researching approaches that use ultrasound and surgery in MRI scanners to better update navigation system data during surgery.
Some believe intraoperative language mapping to be an essential approach for patients with malignancies that impact language function, such as big, dominant-hemisphere gliomas. During the surgery, a conscious patient is operated on and the anatomy of their language function is mapped. The doctor then assesses which parts of the tumor may be safely removed. Cortical language mapping may be employed as a safe and effective supplement to maximize glioma resection while conserving critical language areas, according to recent research.
Some individuals with brain malignancies may need ventriculoperitoneal shunting. Cerebrospinal fluid (CSF) is constantly flowing inside the brain and spine of everyone. If this flow is interrupted, the fluid-containing sacs (the ventricles) may swell, causing increasing pressure inside the brain and leading in hydrocephalus.
Hydrocephalus, if left untreated, may cause brain damage and even death. The neurosurgeon may elect to employ a shunt to drain spinal fluid away from the brain, lowering pressure. The peritoneal cavity is the most common bodily cavity into which CSF is redirected (the area surrounding the abdominal organs). The shunt is often permanent. If it gets clogged, the symptoms are similar to those of hydrocephalus and may include headaches, vomiting, vision issues, disorientation, or lethargy, among other things. An Endoscopic Third Ventriculostomy is another procedure that may be performed to manage congestion of the brain fluid channels. This allows cerebral fluid to be redirected around the blockage without requiring a shunt.
Radiation Treatment
Radiation treatment kills cancer cells and aberrant brain cells while shrinking tumors by using high-energy X-rays. If the tumor cannot be properly treated with surgery, radiation treatment may be a possibility.
Standard External Beam Radiotherapy employs a range of radiation beams to provide conformal coverage of the tumor while reducing the dosage to normal structures in the surrounding area. With contemporary delivery systems, the danger of long-term radiation harm is quite minimal. In addition to 3-dimensional conformal radiation (3DCRT), newer delivery methods include intensity-modulated radiotherapy (IMRT) (IMRT).
Proton Beam Treatment is a kind of radiation in which protons, a type of radioactivity, are selectively directed at the tumor. The benefit is that less tissue around the tumor is damaged.
Stereotactic radiosurgery (such as Gamma Knife, Novalis, and Cyberknife) is a procedure that concentrates radiation on the target tissue using several beams. This therapy causes less harm to the tissues around the tumor. There is currently no evidence that one delivery strategy is better to another in terms of clinical outcome, and each has merits and downsides.
Chemotherapy
Chemotherapy is usually thought to be beneficial in treating some pediatric cancers, lymphomas, and certain oligodendrogliomas. While chemotherapy has been shown to enhance overall survival in patients with the most aggressive primary brain tumors, it only benefits around 20% of all patients, and clinicians are unable to anticipate which patients may benefit prior to treatment. As a result of the possible negative effects, some doctors prefer not to utilize chemotherapy (lung scarring, suppression of the immune system, nausea, etc.).
Chemotherapy works by causing cell damage that normal tissue can mend better than malignant tissue. Resistance to chemotherapy may entail the survival of tumor tissue that is unable to react to the medicine or the drug’s failure to pass from the circulation into the brain. The blood-brain barrier is a particular barrier that occurs between the circulation and brain tissue. Some researchers have attempted to increase the efficacy of chemotherapy by weakening this barrier or injecting the medicine directly into the tumor or brain. Another class of medications’ purpose is to prevent tumor development rather than to destroy tumor cells. Development modifiers (such as the breast cancer therapy, medication Tamoxifen) have been used in certain circumstances to try to inhibit the growth of cancers that are resistant to other therapies.
The use of chemotherapy-impregnated wafers, which may be administered by the neurosurgeon during surgery, was authorized by the US Food and Drug Administration in 1996. The wafers gradually release the medicine into the tumor, and the patient undergoes chemotherapy with systemic side effects.
Interstitial Thermal Therapy with Laser (LITT)
Laser Thermal Ablation is a recent method being used by certain facilities to treat tiny tumors, especially in locations that were previously difficult to access with open surgical techniques. This entails inserting a small catheter into the lesion, potentially performing a biopsy, and then utilizing a laser to thermally ablate the lesion. Because this approach has just recently been employed in the treatment of brain tumors, its long-term effectiveness has not been demonstrated.
Experimental Therapies
Many novel medicines are now being investigated, particularly for malignancies for whom the prognosis is often poor with existing conventional therapy. It is uncertain if these treatments will be effective. These treatments are administered according to a protocol and include immunotherapy, targeted toxin therapy, anti-angiogenesis therapy, gene therapy, and differentiation therapy. Combinations of therapies may also be able to enhance patients’ outcomes while reducing negative side effects.
Source >> www.aans.org
