glioblastoma

Glioblastoma: description

Glioblastoma belongs to the brain as a brain tumor. The World Health Organization (WHO) assigns grade 4 glioblastoma to brain tumors. It is the highest severity a brain tumor can reach.

Most often, the tumor forms in one cerebral hemisphere and quickly grows across the beam into the other cerebral hemisphere. Its shape resembles that of a butterfly, which is why it is sometimes referred to as “butterfly glioma”.

If one examines the tumor tissue under the microscope, one can recognize small cavities (cysts), dead tissue (necroses) and hemorrhages. This colorful and often variable appearance has given the tumor the name glioblastoma multiforme or also colorful glioma.

Primary and secondary glioblastoma

Since its tumor cells are derived from the astrocytes in the brain (a special cell type), the glioblastoma is also referred to as astrocytoma (grade IV). Depending on the exact origin, one differentiates between a primary and a secondary tumor form:

A primary glioblastoma arises directly from healthy astrocytes and is much more common than a secondary tumor. It can develop within a few weeks and mainly affects older people in the sixth to seventeenth decade.

A secondary glioblastoma develops from an astrocytoma of lower WHO grade, ie an already existing tumor from astrocytes. In this case, the glioblastoma is the end stage of a prolonged tumor disease. The age peak of the patients is between the 50th and 60th year of life.

Glioblastoma: frequency

Men are more likely to be affected by glioblastoma than women. Every year, around three people in a small city with 100,000 inhabitants, such as Trier or Cottbus, develop such a brain tumor. Not only is it the most common glioma, it is also the most common primary malignant brain tumor in adults.

Special variant: gliosarcoma

Gliosarcoma is a variant of classic glioblastoma, which differs from it in certain tissue properties. Diagnosis, therapy and prognosis are the same for both.

Glioblastoma: symptoms

As with almost all diseases of the brain, the symptoms of glioblastoma mainly depend on the exact location of the proliferating tissue. Depending on the brain region, completely different symptoms can occur. Glioblastoma causes symptoms, which usually appear much more suddenly and increase more rapidly than other brain tumors. This is because this tumor can develop within a few weeks and grows very fast. The brain has no way to adapt so quickly to other pressure conditions.

Common glioblastoma symptoms are headache. They typically occur during the night or in the early morning hours and improve during the day. Unlike ordinary headaches, they return regularly and become more violent. Medications are often ineffective.

Other possible symptoms include seizures and personality changes. If the glioblastoma is growing in the speech center or in control centers of individual muscles, sufferers have difficulty speaking or moving. Since these symptoms can occur suddenly, it is not uncommon for a misdiagnosis stroke.

In the glioblastoma end stage, the tumor is usually so large that it causes increased intracranial pressure. Patients are often sick in the morning. Some have to vomit. If the pressure continues to increase, the patients often feel tired or drowsy. In extreme cases, a glioblastoma can even cause comatose conditions.

Glioblastoma – symptoms

For more information on individual symptoms in brain tumors such as glioblastoma, see the article Brain Tumor Symptoms.

Glioblastoma: causes and risk factors

A glioblastoma comes from so-called astrocytes. These cells make up the largest proportion of the supporting cells (glial cells) in the central nervous system. They separate the nerve tissue from the brain surface and the blood vessels. Just like other cells in the body, astrocytes are regularly renewed. This can lead to errors that lead to uncontrolled cell growth and ultimately to a tumor.

In addition, a glioblastoma can also emerge from an already existing tumor: in a second- or third-grade astrocytoma classified by the WHO, the tumor cells can change malignantly, resulting in a grade 4 glioblastoma. This glioblastoma course is rarer. In most cases, the tumor forms directly (primary), ie from healthy cells.

Risk factors for a glioblastoma

Why a glioblastoma develops, has so far been insufficiently clarified. The only assured risk factor is ionizing radiation. People are usually only exposed to harmful radiation doses within the scope of a radiotherapy, so the irradiation of another tumor can cause such a brain tumor.

In addition, it is known that people with certain underlying diseases more often develop glioblastoma than those without these diseases. These include on the one hand the Turcot syndrome and on the other hand disorders that are generally associated with a tendency to the formation of gliomas (such as glioblastoma): neurofibromatosis type I (Recklinghausen’s disease) and II, tuberous sclerosis (Bournville-Pringle disease) and the Li-Fraumeni syndrome. These very rare diseases are usually associated with typical skin changes.

Glioblastoma: examinations and diagnosis

The most common symptoms of this brain tumor, such as headache, speech problems, or epileptic seizures, cause most patients to visit a neurologist. To collect the medical history (anamnesis), this first inquires in detail about the symptoms and their time course as well as any underlying or previous diseases. To gain a better overview, the doctor then performs a neurological examination. If there is a suspicion of a brain tumor, he initiates further investigations.

Magnetic resonance and computed tomography

The most important diagnostic procedure for a glioblastoma is the magnetic resonance imaging (MRI) of the skull. If this is not possible for certain reasons (for example with carriers of a pacemaker), computer tomography (CT) is used as an alternative as an imaging method. In most cases, the patient is injected with a contrast agent before the examination, which is absorbed by the tumor. As a result, in imaging it typically appears as a bright, annular structure. Although this appearance is already very characteristic of a glioblastoma, usually a tissue sample is taken (biopsy).

biopsy

The removal and examination of a tissue sample of the tumor serves on the one hand to ensure the diagnosis and on the other hand to determine exact tissue properties. These can influence the subsequent glioblastoma therapy. If the tumor cells have lost some of the genetic material (1p / 19q) or are chemically altered (MGMT) in a particular gene region, they can be better treated with chemotherapeutic agents. Tumors with these changes can therefore be targeted.

Glioblastoma: treatment

In a glioblastoma, the treatment of choice is as radical a surgery as possible. Subsequently, the tumor region is irradiated to kill any residual cells of the tumor. At the same time, most patients receive chemotherapy with temozolomide. It will continue for another six months after the irradiation. Elderly patients whose tumors meet certain MGMT characteristics can also be treated by radiation or chemotherapy alone.

If the tumor returns after a successful therapy, a decision is made individually on another operation, radiotherapy or chemotherapy. In addition to temozolomide, drugs such as CCNU or the antibody bevacizumab are available as medicines.

Relief of the disease symptoms

In addition to the above-mentioned therapies that directly combat the tumor, measures are often used to alleviate the symptoms of the disease. Since the glioblastoma has a very poor prognosis, the disease is difficult to process for many sufferers and relatives. Some may be assisted by psychotherapy or pastoral care.

Examination and treatment

For more information on examination and treatment of brain tumors, see the article Brain Tumor.

Glioblastoma: disease course and prognosis

Even with maximum therapy, glioblastoma healing can not usually be achieved. Patients undergoing surgery, radiation and chemotherapy have a median survival of approximately 15 months. Nearly ten percent of patients survive five years. Without therapy, the median survival time is about two months. It is about five months for surgery alone, about 12 months for surgery plus radiotherapy.

Life expectancy and quality are also subject to individual factors. The tumor cells do not have the same characteristics in every individual. Some treat better than others. If the tumor shrinks rapidly under therapy, glioblastoma prognosis is usually better than in other cases.

In addition, chemotherapeutics and radiotherapy are tolerated differently by patients. If the side effects are too strong, glioblastoma therapy harms the sufferer more than it helps them. Then it should be weighed individually whether the treatment will continue less intensively. As a result, affected persons influence the glioblastoma process themselves to a certain extent: they accept a shorter lifetime, as a result of which their quality of life with the glioblastoma improved.