As a group, gliomas are one of the most common types of brain tumors. While the exact origin of the gliomas is still unknown, it is believed that they are developed by glial cells or precursors of the spinal cord. A glial cell is a type of supporting cell in the brain. The main types of supporting cells in the brain include astrocytes, oligodendrocytes, and ependymal cells.
Gliomas are graded based on how aggressive a tumor is. A higher grade is usually more aggressive and more likely to develop quickly. However, doctors are moving in the direction of using molecular tests to better classification of gliomas.
Astrocytoma. Astrocytoma is the most common type of glioma. Astrocytes are found in the brain or cerebellum. There are 4 types of astrocytoma:
Grade I or pilocytic astrocytoma is a slowly-growing tumor that is usually benign and rarely spreads to nearby tissues. Astrocytoma in children is more common than astrocytoma in adults.
Grade II or low-grade diffuse astrocytoma is a slowly-growing tumor that can often spread to nearby tissues and can develop to a higher degree.
Grade III or regenerative astrocytoma is a cancerous tumor that can quickly grow and spread to nearby tissues.
Grade IV or glioblastoma is a very aggressive form of astrocytoma.
Most brain tumors are not diagnosed until symptoms appear.
The clinician may recommend examination that helps detect the presence and perhaps the type or quality of a tumor in the brain.
In general, the diagnosis of a brain tumor usually begins with an MRI scan. Once the MRI shows that there is a tumor in the brain, the most common way to determine the type of brain tumor is to have a histological examination of a tissue sample after a biopsy or surgery.
Tissue sampling/biopsy / surgical removal of a tumor: A tissue sample of the tumor is usually necessary for the final diagnosis. A biopsy is the removal of a small amount of tissue for microscopic examination and is the only definitive way to diagnose a tumor in the brain. The pathologist analyzes the sample (or samples) of the biopsy.
A biopsy can be done as part of the surgery to remove the entire tumor. Or surgery can be done as a separate procedure if the tumor cannot be removed due to its location or the patient’s health.
The healthcare team might also recommend other tests to help diagnose or find out how well your organism is responding to the treatment (e.g. CT scan, PET scan, myelogram, the molecular examination of the tumor in the biopsy material).
To decide the best treatment of a brain tumor, both type and quality of the tumor must be determined. There are several factors that can help doctors determine the right treatment plan for a brain tumor and a patient’s prognosis:
Histology of the tumor. As it is mentioned in the Diagnosis section, a sample of the tumor (biopsy) is removed for analysis. Tumor histology includes the type of tumor, the grade and additional molecular characteristics that predict how quickly the tumor can develop.
These factors combined may help your doctor understand how the tumor will behave. These factors can also help determine a patient’s treatment options.
Grade describes some of the features of the tumor that are associated with specific effects. For example, doctors may examine whether cancer cells are growing uncontrollably or if there are too many dead cells. Tumors with general features associated with a higher level of growth have a higher Grade. For most tumors, the lower the Grade, the better the prognosis.
Especially for gliomas (astrocytomas), the degree is determined by its characteristics, as shown under the microscope, according to the following criteria:
Grade I. These tumors grow slowly and are unlikely to spread. They can often be treated with surgery.
Grade II. These tumors are less likely to develop and spread, but are more likely to recur after treatment.
Grade III. These tumors are more likely to have rapidly dividing cells but not dead cells. They can grow quickly.
Grade IV. In a grade IV tumor, the cells in the tumor divide and multiply rapidly. In addition, the tumor shows intense growth of blood vessels and areas of dead tissue. These tumors can grow and spread quickly.
Age. In adults, a person’s age and level of function, which is called functional status, is one of the best ways to predict the prognosis. In general, a younger adult has a better prognosis.
Symptoms. The symptoms a patient has and how long they last can also help determine the prognosis. For example, seizures and long term symptoms are associated with better prognosis.
Extension of residual tumor. The surgery is performed to remove the tumor. Residues refer to the size of the tumor that remains in the body after the surgery. A patient’s prognosis is better when the entire tumor can be surgically removed.
Tumor location. A tumor can form in any part of the brain. Some tumor sites cause more damage than others, and some tumors are more difficult to be treated due to their location.
Molecular characteristics. Some genetic mutations in the tumor may help determine the prognosis. These include mutations in the genes: IDH1, IDH2, MGMT and 1p/19q co-deletion.
Metastasis. A tumor that starts in the brain or spinal cord, if it is cancerous, it rarely spreads to other parts of the body in adults, but can develop inside the Central Nervous System. A tumor that spreads to other parts of the brain or spinal cord is associated with a poor prognosis.
Relapse. A relapsed tumor is the one which has reoccurred after treatment. If the tumor returns, another round of test will be performed in order to find out the extent of the relapse.
Treatment options depend on several factors:
- The size of the tumor, the histological type of the tumor and the Grade of the tumor
- If the tumor puts pressure on vital parts of the brain
- If the tumor has spread to other parts of the CNS or body
- Possible side effects
- The patient’s preferences and general state of health
In this section, we focus on targeted therapy.
In addition to conventional chemotherapy, targeted therapy is a treatment which targets:
- specific genes (mutated),
- tumor proteins or
- the tissue environment that contributes to the tumor’s growth and survival
This type of treatment prevents the growth and spread of cancer cells while limiting damage to healthy cells.
Not all tumors have the same goals, and certain tumors may have more than one goal. To find the most effective treatment, your doctor may prescribe molecular tests to identify genes, proteins, and other factors in your tumor. This helps doctors to better choose the most effective treatment for each patient whenever possible (personalized treatment). In addition, research studies continue to reveal more about specific molecular targets and new therapies for them.
If cancer has spread to the brain from another part of the body, it is called brain metastasis. Brain metastases have traditionally undergone surgery or radiotherapy. Chemotherapy is not often used because the blood-brain barrier blocks many drugs from reaching the brain. In the past, chemotherapy was mostly used only if radiotherapy did not work. Current options for treating brain metastases include:
Surgery. Surgery is generally an option only for patients who have a single area of brain cancer. Radiotherapy is often given later.
Targeted treatment. Some types of targeted therapy can easily enter the brain and are able to target specific genetic mutations in the tumor, as in the following cases:
- Non-Small-Cell Lung Carcinoma (NSCLC) in the brain that has a mutation in the EGFR gene
- Non-Small-Cell Lung Carcinoma (NSCLC) in the brain that has a genetic mutation in the ALK gene
- Breast cancer metastasis to the brain that has a positive effect on the HER2 protein
- Metastasis from melanoma to the brain
- Some types of immunotherapy have shown positive results in the treatment of brain metastases from lung cancer and melanoma, wherein this case the expression of certain proteins in the tumor is controlled (e.g. PD-L1, CTLA4, etc.).
Frequently Asked Questions (FAQ)
The examination is performed on the biopsy material or surgical specimen (paraffin block) on which your histological examination was performed as well.
In case your sample is not already in the microDiagnostics’ Ltd archive, contact us to undertake its safe and fast transfer to our laboratory.
You will also need to complete the Consent Form easily and quickly
Contact the molecular diagnostics service department:
Contact Phone: 2310 23 22 72
By cash, credit/debit card or by Online Interbank Deposit.
It usually takes 6 business days.
If more time is needed, you will be notified in time.
One of the primary concerns of microDiagnostics’ Ltd is the protection of your personal data as well as the strict adherence to the conditions protecting your genetic material and medical results.
In full compliance with the General Data Protection Regulation (GDPR) we ensure that you are aware and conscious for any examination will be conducted and we do not announce results via phone calls.