Astrocytoma — Know It All!

Editorial

All you need to know about Astrocytoma.

Know your ailment well, so you can manage it better!!

Here we come with Astrocytomatoday!

What is Astrocytoma?

Astrocytoma is a type of cancer in the brain or spinal cord that may develop. Astrocytoma starts in cells that support nerve cells, called astrocytes.

The signs and symptoms of astrocytoma depend on your tumor’s location. Seizures, seizures and nausea may be caused by astrocytomas that arise in the brain. In the region affected by the rising tumour, astrocytomas that develop in the spinal cord may cause weakening and impairment.

Astrocytoma may be a slow-growing tumour or may be a steadily growing, aggressive cancer. Your prognosis and treatment choices are dictated by the aggressiveness(grade) of your astrocytoma.

A type of tumour that develops in the brain and spinal cord is glioma. In the gluey supporting cells (glial cells) that surround nerve cells, gliomas begin and help them work.

Tumours can be formed by three types of glial cells. Gliomas are defined according to the type of glial cell involved in the tumour, as well as the genetic factors of the tumour, and will help determine how the tumour will function over time and the most likely therapies to succeed.

Glioma forms include:

  • Astrocytomas, including astrocytoma, anaplastic astrocytoma and glioblastoma
  • Ependymomas, including anaplastic ependymoma, myxopapillary ependymoma and subependymoma
  • Oligodendrogliomas, including oligodendroglioma, anaplastic oligodendroglioma and anaplastic oligoastrocytoma
  • A glioma can affect your brain function and be life-threatening depending on its location and rate of growth.

One of the most prominent kinds of primary brain tumours is gliomas.

Your condition and your prognosis help assess the type of glioma you have. In addition, surgery, radiation therapy, chemotherapy, targeted therapy and advanced drug trials are alternatives for glioma treatment.

What causes Astrocytoma?

Analytical epidemiological studies have been the subject of the aetiology of diffuse astrocytomas, resulting in associations with different disorders and exposures. The identification of specific causative environmental exposures or agents has been unsuccessful, with the exception of therapeutic irradiation and, perhaps, nitroso compounds (eg, nitrosourea). Although there has been concern about the use of cell phones as a possible risk factor for glioma development, studies have yielded conflicting results.

Children receiving prophylactic irradiation for acute lymphoblastic leukaemia have a 22-fold increased risk of developing CNS neoplasms with an onset interval of 5–10 years, including WHO astrocytoma grades II, III, and IV. In addition, pituitary adenoma irradiation has been shown to carry a 16-fold increased risk of glioma formation.

Evidence exists for genetic susceptibility to glioma development. In inherited neoplastic syndromes, such as Turcot syndrome, neurofibromatosis type 1 (NF1) syndrome and p53 germline mutations, familial clustering of astrocytomas is well described, for example (eg, Li-Fraumeni syndrome). There is evidence in biological research that mutations in specific molecular pathways, such as the p53-MDM2-p21 and p16-p15-CDK4-CDK6-RB pathways, are associated with the development and progression of astrocytoma. There are p53 mutations in two-thirds of low-grade astrocytomas.

In addition, types of human leukocyte antigen (HLA) have been associated with either an increased or decreased risk of brain glioma development.

What are the symptoms of Astrocytoma?

Rather than their biochemical features, the clinical appearance of astrocytomas relies even more on their position within the brain. There are parts in the brain that can tolerate very large tumours until they become symptomatic (such as the areas in the forehead), while there are other sites where even small tumours can cause complications early on, such as weakening in the limbs or difficulties speaking or hearing.

Generally, relative to more aggressive, higher-grade astrocytomas, low-grade astrocytomas appear to be greater in scale until they become symptomatic. This is because, rather than killing it, lower-grade cancers appear to displace the brain, and also because they are associated with less brain swelling than malignant ones.

Common symptoms of astrocytomas are the following:

  • Persistent headaches
  • Headaches which are worse in the morning or cause awakening from sleep ( a sign of increased intracranial pressure)
  • Double or blurred vision
  • Speech problems
  • Decreased cognitive abilities
  • Grasp or limb weakness
  • New seizures

What are the risk factors of Astrocytoma?

The exact cause of gliomas, like most primary brain tumours, is not known. But there are some variables that may increase your risk of developing a tumour in the brain. Factors of risk include:

  • Your age. As you age, your risk of a brain tumour increases. Gliomas are most commonly found in adults between the ages of 45 and 65. However, a brain tumour may develop at any age. In children and young adults, certain types of gliomas, such as ependymomas and pilocytic astrocytomas, are more common..
  • Exposure to radiation. People who have been exposed to a type of radiation called ionizing radiation have an increased risk of brain tumour. Examples of ionizing radiation include radiation therapy used to treat cancer and radiation exposure caused by atomic bombs.
    More-common forms of there is an increased risk of brain tumours in people who have been exposed to a type of radiation called ionising radiation. Examples of ionising radiation include radiation therapy used to treat cancer and radiation exposure caused by atomic bombs.
  • It has not been shown that more common forms of radiation, such as electromagnetic fields from power lines and radiofrequency radiation from microwave ovens, increase glioma risk.
  • Whether cellphone use increases the risk of brain cancer is not clear. A possible association between cellphone use and a type of brain cancer called acoustic neuroma has been found in some studies. No association has been found in many other studies. Since cell phones are a relatively new factor, to understand the potential impact on cancer risk, more long-term research is needed. For the time being, experts recommend limiting your exposure by using a speaker or hands-free device, which keeps the cellphone itself away from your head, if you are concerned about the possible link between cellphones and cancer.
  • Family history of glioma. In households, it’s rare for glioma to run. But the chance of getting it can be doubled by possessing a family history of glioma. Some genes have been weakly linked with glioma, but a correlation between these genetic abnormalities and brain tumours needs to be confirmed by further research.

How is Astrocytoma diagnosed?

You may be referred to a specialist who is trained in treating brain and nervous system disorders if your primary care doctor suspects you have a brain tumour (neurologist). A number of tests and procedures may be recommended by your doctor, including:

Consultation with Neurology

A neurological examination. Your doctor may check your vision, hearing, balance, coordination, strength and reflexes during a neurological exam. Problems can provide clues about the part of your brain that might be affected by a brain tumour in one or more of these areas.

Tests for Imaging.

To help diagnose brain tumours, magnetic resonance imaging (MRI) is often used. In some cases, during your MRI study, a dye (contrast material) may be injected through a vein in your arm to help show differences in brain tissue.

Your doctor may be able to evaluate the tumour and plan treatment with a number of specialised MRI scan components, including functional MRI, perfusion MRI and magnetic resonance spectroscopy.

Computerized tomography (CT) scan and positron emission tomography can include other imaging tests (PET).

MRI Scan of the Brain

Brain tumour MRI

In other parts of your body, tests to find cancer. Your doctor may recommend tests and procedures to determine where cancer originated in order to rule out other types of brain tumours that might have spread from other parts of the body. Gliomas originate inside the brain and are not the result of cancer from elsewhere that has spread (metastasized).

Collecting and testing an abnormal tissue sample (biopsy). A biopsy may be done with a needle before treatment or as part of an operation to remove the brain tumour, depending on the location of the glioma.

In hard-to-reach areas or very sensitive areas within your brain that could be damaged by a more extensive operation, a stereotactic needle biopsy may be performed for gliomas. Your neurosurgeon drills a small hole inside your skull during a stereotactic needle biopsy. Through the hole, a thin needle is then inserted. The needle, which is frequently guided by CT or MRI scanning, removes tissue.

To determine if it is cancerous or benign, the biopsy sample is then analysed under a microscope.

The only way to diagnose a brain tumour definitively and give a prognosis to guide treatment decisions is through a biopsy. Based on this information, the grade or stage of a brain tumour can be determined by a doctor who specialises in diagnosing cancer and other tissue abnormalities.

The pathologist will also examine your biopsy sample’s physical appearance and growth rate (molecular diagnosis). Your doctor will explain the findings of the pathologist to you. This data helps guide your treatment plan decision-making.

What is the treatment for Astrocytoma?

Glioma treatment depends on the tumour’s type, size, grade and location, as well as your age, overall health and preferences.

Treatment for glioma may also require the use of drugs to reduce the signs and symptoms of your tumour, in addition to actions to remove the tumour itself.

To reduce swelling and relieve pressure on the affected areas of the brain, your doctor may prescribe steroids. To control seizures, antiepileptic drugs can be used.

Surgery

The first step in treating most types of gliomas is usually surgery to remove as much of the tumour as possible.

Gliomas are small and easy to separate from the surrounding healthy brain tissue in some cases, which allows for complete surgical removal. Tumours can not be separated from surrounding tissue in other cases, or they are located near sensitive areas in your brain and make it risky for surgery. Your doctor removes as much of the tumour as is safe in these situations.

Even the removal of a portion of the tumour can help reduce your symptoms and signs.

Neuropathologists can analyse tissue samples removed by a surgeon in some cases and report the results while surgery is ongoing. This data helps the surgeon determine how much tissue to remove.

In order to help the neurosurgeon protect as much healthy brain tissue as possible while removing the tumour, a variety of surgical technologies and techniques can be used, including computer-assisted brain surgery, intraoperative MRI, awake brain surgery and lasers. For example, you may be asked to perform a task during awake brain surgery with the objective of ensuring that the brain area controlling that function is not damaged.

Intraoperative MRI

Surgery, such as infection and bleeding, to remove a glioma carries risks. Other risks may depend on the part of the brain your tumour is in. Surgery on a tumour near nerves that connect to your eyes, for example, may carry a risk of loss of vision.

Radiation therapy

Gamma Knife targeting

In the treatment of glioma, particularly high-grade glioma, radiation therapy generally follows surgery. Radiation utilises high-energy beams to kill tumour cells, such as X-rays or protons. Glioma radiation therapy comes from a machine outside of your body (external beam radiation).

For the treatment of glioma, there are several types of external beam radiation currently being used and understudy. In determining the timing and type of radiation therapy you may receive, the type of glioma you have, its grade, and other prognostic factors are considered. A doctor who specialises in radiation therapy for cancer (radiation oncologist) will work closely with your other doctors to plan and coordinate the most appropriate radiation treatment for you.

Choices for radiation therapy include:

  • Using computers to pinpoint delivery of radiation treatment to the exact location of the brain tumor. Techniques include intensity-modulated radiation therapy and 3D conformal radiation therapy.
  • Using protons — the positive parts of atoms — rather than X-rays as the source of radiation. This technique, called conformal proton beam therapy, delivers radiation only once proton beams reach the tumor, causing less damage than X-rays to surrounding tissue.
  • Using multiple beams of radiation to give a highly focused form of radiation treatment. While this technique is called stereotactic radiation therapy (radiosurgery), it doesn’t actually involve surgery in the traditional sense. Each beam of radiation isn’t particularly powerful, but the point where all the beams meet — at the brain tumor — receives a very large dose of radiation to kill the tumor cells in a very small area.

There are different types of technology used in radiosurgery to deliver radiation to treat brain tumors, such as a Gamma Knife or linear accelerator (LINAC).

Side effects of radiation therapy depend on the type and dose of radiation you receive. Common side effects during or immediately following radiation include fatigue, headaches and scalp irritation.

Chemotherapy

Chemotherapy uses tumour cells to kill drugs. It is possible to take chemotherapy drugs in pill form (orally) or inject them into a vein (intravenously).

To treat gliomas, chemotherapy is usually used in combination with radiation therapy.

Temozolomide (Temodar), which is taken as a pill, is the chemotherapy drug used most often to treat gliomas.

Chemotherapy side effects depend on the type and dose of drugs you are receiving. Common side effects include vomiting and nausea, headache, loss of hair, fever, and weakness. With medication, some side effects may be managed.

Targeted therapy with drugs

Targeted drug treatments concentrate on specific abnormalities within cancer cells that are present. By blocking these abnormalities, targeted drug treatments can cause cancer cells to die.

Bevacizumab is one of the targeted drug treatments used to treat a type of brain cancer called glioblastoma (Avastin). This medication, given through a vein (intravenously), stops the formation of new blood vessels, cuts the tumour’s blood supply and kills the cells of the tumour.

Innovations in treatment

A very active field of study is brain cancer research. Researchers are investigating new ways of delivering drugs to brain tumours, including pumps that release chemotherapy or targeted drug therapy to a tumour in a continuous, slow flow. The convection-enhanced delivery of this type of treatment is called (CED).

In order to deliver electric fields to the brain, another type of therapy uses a technology called tumour treating fields (Optune), which can help stop the proliferation of cancer cells. Optune is a wearable, portable device and is used for the treatment of newly diagnosed glioblastoma in adults in combination with temozolomide.

In order to release chemotherapy to tumour tissue that remains after surgery, implanted, biodegradable wafer therapy (Gliadel) relies on the implanted disc. And particles with an unusually high surface area carry chemotherapy directly to a tumour across the blood-brain barrier in nanoparticle therapy.

After-treatment rehabilitation

A session with physical therapy

  • Because brain tumours that control motor skills, speech, vision and thinking can develop in parts of the brain, rehabilitation may be a necessary part of recovery. You may be referred by your doctor to services that may help, such as:
  • Physical therapy can help you regain motor skills or muscle strength that have been lost.
  • Occupational therapy, which can help you get back to your normal daily activities after a brain tumour or other disease, including work.
  • Speech therapy with speech disorder specialists (speech pathologists), which can help if you have trouble talking.
  • Tutoring for children of school age, which can help children cope with memory and thinking changes after a brain tumour

References:

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https://www.mayoclinic.org/diseases-conditions/glioma/diagnosis-treatment/drc-20350255

https://www.thebraintumourcharity.org/brain-tumour-diagnosis-treatment/types-of-brain-tumour-adult/astrocytoma/

https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Astrocytoma-Tumors

https://www.webmd.com/cancer/brain-cancer/what-is-astrocytoma#1

https://emedicine.medscape.com/article/283453-overview#a7

https://rarediseases.org/rare-diseases/astrocytoma/