Astrocytoma

What is Astrocytoma?

Astrocytomas are a type of brain tumor that makes up a significant and complicated part of all brain tumors. These tumors start in star-shaped cells in the brain called astrocytes, which play a key role in helping brain cells function. Among brain tumors, astrocytomas make up 60% and primarily occur in the brain, although they can also appear in the spinal cord.

Treating these tumors is a significant clinical challenge due to their high occurrence and the severe health problems they cause across all ages. The cause of astrocytomas is still largely unknown. Radiation is the only risk factor identified so far. Despite some connections with other possible risk factors like exposure to electromagnetic fields, head injury, or certain jobs, there is no solid evidence yet to back these up.

What Causes Astrocytoma?

Most primary brain tumors don’t have a known cause. The only confirmed risk factor is exposure to a type of radiation called ionizing radiation. For instance, children treated against a type of cancer known as acute lymphocytic leukemia with radiation could be 22 times more likely to develop a brain tumor within 5 to 10 years. Similarly, those who had radiation therapy for a tumor called pituitary adenoma are at 16 times greater risk of developing another type of brain tumor called glioma.

Many people speculate about factors like mobile phone use, head injuries, or job-related exposures, but there’s no solid proof linking these to brain tumors.

A small percentage of patients have family members with brain tumors, which suggests a genetic link. Certain genetic conditions increase the risk of developing a glioma, a type of brain tumor. Some of these inherited conditions include Turcot syndrome, Li-Fraumeni syndrome (related to mutations in a gene called p53), and neurofibromatosis type 1. In fact, p53 mutations are found in about 66% of a type of brain tumor called low-grade astrocytomas.

Risk Factors and Frequency for Astrocytoma

Knowing the patterns of who gets astrocytoma helps us to figure out risk factors and spot the disease earlier in different people and age groups.

• Race doesn’t seem to affect who gets astrocytoma much.
• For a type of astrocytoma called pilocytic astrocytoma, gender doesn’t really play a role.
• In low-grade astrocytomas, the ratio of males to females is 1.18:1.
• In anaplastic astrocytoma, males are more likely to get it, with a male-to-female ratio of 1.87:1.

As for age:

• Pilocytic astrocytoma is more likely to happen during the first 20 years of life.
• Low-grade astrocytomas are most common in people aged 30 to 40, and make up about a quarter of adult cases.
• For low-grade astrocytomas, the age break down is as follows:
  • 10% are younger than 20
  • 60% are between 20 to 45 years old
  • 30% are older than 45 years old
• The average age to be diagnosed with grade 3 astrocytoma is about 40 years old.

Signs and Symptoms of Astrocytoma

An astrocytoma is a type of brain tumor, and understanding a patient’s medical history is a critical part of the diagnosis. This involves unpicking the details of their symptoms, which are typically split into two categories.

• General symptoms: These may include headache (often in the early morning), feeling sick, vomiting, difficulty thinking, changes in personality, and problems with walking.
• Focal symptoms: These can involve seizures, trouble with speech (aphasia), and issues with sight (visual field defects). Half of the patients with certain types of brain tumors might experience seizures. Interestingly, problems with sight might not be noticed by the patient until it leads to something like a car accident.

In addition to the patient’s symptoms, it’s also important to document the duration, frequency, and severity of these symptoms, and any factors that make them better or worse. Health professionals should also find out if the patient has had any previous head injuries, exposure to ionizing radiation, or family history of neurological disorders or cancers. They should also evaluate the patient’s ability to perform daily activities and their quality of life. This comprehensive overview helps establish a timeline of symptom development, recognize potential risk factors, and guide further examinations, ultimately leading to a more accurate diagnosis.

During the physical examination of a patient with astrocytoma, medical professionals carry out a thorough assessment of how the tumor is affecting the central nervous system (CNS). This focuses on the functioning of the cranial nerves, the strength of the patient’s motor responses, their coordination, their sensory perception, and reflexes. They may examine the patient’s field of vision, their ability to walk, and their balance, and test for signs of increased pressure in the skull, such as swelling of the optic disc (papilledema). The resulting findings help to locate the tumor and determine its severity, which in turn guides further imaging studies and the planning of treatment. The results of these examinations, along with imaging studies and analyses of the tissue of the tumor, are vital for making an accurate diagnosis and developing an effective treatment plan.

Testing for Astrocytoma

When doctors check for astrocytomas, a type of brain tumor, they use a combination of physical exams, advanced imaging techniques, and a close look at tissue samples. The most accurate way to confirm the diagnosis is to take a tissue sample through a procedure called a biopsy. This procedure allows experts to examine the cells and perform molecular profiling. These steps are important in determining the severity of the tumor, figuring out the right treatment, and predicting the outlook.

Magnetic resonance imaging (MRI), a type of scan that uses magnetic fields and radio waves to produce detailed images of the brain, is the best imaging method for diagnosing astrocytoma. Doctors often use a special dye, called gadolinium, to make the images clearer. If a person cannot have an MRI due to certain medical devices in their body like joint implants or pacemakers, a computed tomography (CT) scan may be performed. Lower-grade brain tumors can be clearly seen on MRI with the help of a particular type of test called a fluid-attenuated inversion recovery sequence.

If a tumor is found, a neurosurgeon will need to take a small sample of it for further examination and grading by an expert in nerve tissue diseases. On the other hand, the CT images of low-grade astrocytomas may not be very clear. They appear as evenly colored, poorly defined, and do not show up clearly after having a contrast dye. In more aggressive types of astrocytomas, there may be some contrast enhancement. As there might be a risk of the disease spreading, doctors might consider doing a whole-body scan to search for other potential tumor sites.

In MRI images, astrocytomas show up as bright areas on T2 imaging, while they appear as areas of the same intensity on T1 imaging. New techniques are being developed to identify how well the tumors are supplied with blood vessels. Some of the recent advancements include arterial spin labeling and dynamic contrast enhancement MRI. Additionally, functional MRI, a new imaging technique that provides information on the functional areas of the brain, is also promising, especially for marking out various brain areas before surgery. Other imaging techniques such as positron emission tomography (PET) scans, magnetic resonance spectroscopy, and perfusion imaging could give insights about the metabolic activity, blood flow patterns, and make-up of the tumor. These could help to check if the tumor is growing or dying after chemotherapy and radiotherapy.

Treatment Options for Astrocytoma

For grade 2 brain tumors, such as gliomas, surgery that safely removes as much of the tumor as possible is recommended. Risk factors that may worsen the prognosis include being over 40 years old, the tumor being larger than 4cm, the tumor crossing the midline of the brain, and the presence of neurological deficits before surgery. Lower risk patients, those under the age of 40, can be closely monitored without immediate treatment. However, high-risk patients may need radiotherapy and chemotherapy. The standard radiotherapy dose for these types of brain tumors ranges between 45 and 54 Gy, given in increments of 1.8 to 2.0 Gy.

Chemotherapy after treatment, known as adjuvant therapy, often includes temozolomide or a combination of procarbazine, lomustine, and vincristine. Radiotherapy might also be used after surgery for tumors that could not be completely removed, remained as leftovers, or recurred. Chemotherapy is often used for a type of low-grade brain tumor known as oligodendrogliomas, especially those that carry specific genetic deletions which make them more susceptible to chemotherapy.

As for grade 3 and 4 brain tumors, the standard treatment includes surgical removal followed by radiotherapy. Afterwards, temozolomide or another chemotherapy regimen may be continued. Be aware that during treatment with both chemotherapy and radiotherapy there can be increased risks related to blood counts, particularly in women. In addition, the reappearance of enhancing lesions on MRI scans may sometimes be seen after radiation as a result of radiation damage rather than actual active tumors.

There are many options for recurrent tumors including surgery, chemotherapy, and novel treatments targeting specific mutations in the tumor. Patients with recurring disease should consider joining clinical trials. Treatment options for these tumors often involve a combination of surgery, medication, and radiotherapy. Experimental treatments are also being investigated, including vaccines and targeted therapies.

Starting patients on antiseizure medications before they’ve had a seizure is controversial. However, those patients who have already had a seizure should start antiepileptic medication. Corticosteroids may be used to decrease inflammation and reduce the effects of the tumor on the brain. Due to the high incidence of blood clotting diseases in patients with high-grade brain tumors, anticoagulants may be used as preventive treatment during hospitalization and in non-mobile patients.

What else can Astrocytoma be?

When a doctor suspects astrocytoma, which is a type of brain tumor, there are other conditions that they need to consider. These conditions can have similar symptoms or may look similar in brain scans. Here is a list of other medical conditions that need to be taken into account:

• Glioblastoma multiforme (another kind of brain tumor)
• Brain metastasis (cancer that has spread to your brain from another part of your body)
• Brain abscess (a pocket of pus in the brain caused by a bacterial or fungal infection)
• Oligodendroglioma (yet another type of brain tumor)
• Encephalitis (inflammation of the brain usually caused by an infection)
• Multiple sclerosis (disease that affects the brain and spinal cord)
• Primary central nervous system lymphoma (a rare form of non-Hodgkin lymphoma that starts in the brain)
• Toxoplasmosis (an infection caused by a parasite, usually contracted from undercooked meat or from contact with cat feces)

The doctor needs to carefully evaluate these possibilities through the necessary tests to ensure a correct diagnosis.

Surgical Treatment of Astrocytoma

The ideal treatment for a tumor is to remove or reduce its size as much as safely possible through surgery. This also allows for a tissue biopsy to confirm the diagnosis. There are other procedures that can help relieve symptoms, such as procedures to reduce pressure within the skull, like VP shunting or the insertion of an external ventricular drain. Studies have shown that when more than 98% of the tumor is removed, as determined by MRI, there is a notable increase in median survival time when compared to less complete tumor removal. For certain low-level brain tumors, there might be a survival benefit to removing even more tissue than is visible on the MRI.

How urgently a patient needs to see a neurosurgeon depends on several factors. These include the patient’s overall health condition, how severe their symptoms are, and the size and location of the tumor. Before surgery, an MRI and a diffusion tensor imaging test are generally carried out to provide a detailed view of the tumor and the surrounding brain tissue.

In terms of surgical techniques, there are some promising results from a trial involving 314 patients who had a glioblastoma (a type of brain tumor) removed. Within this group, it was found that the rates of total tumor removal were comparable whether they used intraoperative magnetic resonance imaging (iMRI) or 5-aminolevulinic acid, showing success rates of 81% and 78%, respectively. Another trial showed that using iMRI compared to traditional neuronavigation resulted in better patient outcomes.

The timing of surgery will depend on the specifics of the tumor and the patient’s symptoms. For bigger tumors that are causing serious symptoms, immediate surgery is advisable. For smaller tumors causing minimal symptoms, surgery could take place immediately or be delayed, with immediate surgery often preferred.

What to expect with Astrocytoma

Knowing the expected outcomes of astrocytomas is very important for making treatment choices and setting real expectations for patients and their families.

Here is what survival typically looks like for different grades of astrocytomas:

* For grade 2 astrocytomas – typically less than 5 years
* For grade 3 astrocytomas – around 2 to 5 years
* For grade 4 astrocytomas – about 1 year

The outlook is generally better for low-grade tumors, where survival can reach up to 7 to 8 years after surgery. In cases of anaplastic astrocytoma, treatment is aimed at easing symptoms. Using radiotherapy to treat tumors that have been partially removed can improve survival rates after surgery. People usually live almost twice as long after having radiotherapy following surgery (5 years), compared to those who just had the surgical procedure (2.2 years).

A person’s genes also play a role in determining the outlook of a specific tumor. For instance, the type of tumor called oligodendroglioma responds better to a treatment called PCV if it has certain genetic changes (Ch 1p19q). Genes are becoming increasingly important in developing tailored treatments for tumors.

Levels of a substance called kallikrein are also related to a patient’s outlook:

* Higher levels of kallikrein-related peptidases, KLK6 / KLK7-IR, are linked to worse outcomes
* Having an immune response to KLK6/9 is connected to decreased survival.

Possible Complications When Diagnosed with Astrocytoma

Treating astrocytoma, a particular type of brain tumor, can bring a wide range of complications that may affect patient recovery and quality of life. The necessary surgical removal of these tumors can lead to problems like infections, bleeding, and neurological shortcomings from the damage done to nearby brain tissue. Other complications that may arise after the surgery include brain swelling and seizures. Whilst radiotherapy and chemotherapy are necessary for controlling tumor growth, they can cause side effects like fatigue, nausea, decline in cognitive abilities, and a weakened immune system, thereby increasing the risk of infections and anemia.

To properly manage these complications, doctors rely on effective medicines. However, there may be long-term issues like radiation damage to healthy tissue, development of other cancers, and a steady decline in neurological function. Furthermore, the tumor’s position and its ability to infiltrate surrounding tissues can make full removal difficult, which can result in a resurgence and the need for continued treatment. Therefore, handling these problems requires a collaborative approach by a team of specialists, with an aim to simultaneously manage the tumor and side effects. This highlights the need for regular monitoring and supportive care to swiftly address emerging problems.

Complications can include:

• Infections
• Bleeding
• Neurological deficits
• Brain swelling
• Seizures
• Fatigue
• Nausea
• Cognitive decline
• Weakened immune system
• Radiation damage to healthy tissue
• Development of other cancers
• Steady decline in neurological function

Preventing Astrocytoma

The key to managing astrocytoma, a type of brain tumor, lies in prevention, patient education, and empowerment. Even though we don’t know exactly what causes astrocytoma, limiting exposure to certain risk factors, like radiation, is recommended. Educating patients about astrocytoma is crucial; they need to understand everything about the disease – how it manifests its symptoms, the need for early detection, and why regular check-ups are crucial. By being aware of the potential signs of astrocytoma, such as persistent headaches, seizures, and noticeable changes in their nervous system, patients can get diagnosed and start treatment sooner.

Moreover, providing patients with detailed information about the treatments available, the possible side effects, and methods of dealing with symptoms can help them stick to their treatment plan and improve their quality of life. An effective education approach also talks about changes they can make in their lifestyle, nutrition advice, and the kind of social support they can get. These elements can boost their confidence and enable them to handle living with astrocytoma in a more proactive way.