Astrocytoma: types, symptoms, causes and treatment

"You have a tumor." It is probably one of the phrases that we are most afraid to hear when we go to the doctor for a check-up or they do tests for a problem for which we do not know the cause. And is that cancer is one of the most feared diseases worldwide, being one of the best known and leading causes of death worldwide and one of the main challenges in medicine along with AIDS and dementia.

Of the many locations in which it can appear, the brain is one of the most dangerous, as even a benign noncancerous mass can cause serious and including death. Among the different types of existing brain tumors, one of the most common are astrocytomas, of which we will talk in this article.

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What are astrocytomas?

We call astrocytoma any neoplasm or tumor formed mainly by astrocytes, one of the main types of glial cells that feed and support neurons. This tumor is therefore a mass of astrocytes that occurs in the face of abnormal, pathological and uncontrolled growth and proliferation of one of the types of glial tissue present in the nervous system, being one of the main types of tumor cerebral.

Astrocytomas are tumors whose symptoms can vary greatly depending on the location or locations in the appear, if they compress other brain areas, their proliferative capacity or if they infiltrate other tissues or become they self-limit. However, at a general level it is common to find the existence of headaches, nausea and vomiting, sleepiness and fatigue, altered consciousness and confusion. It is also relatively frequent that personality and behavior alterations appear. Fever and dizziness are also common, as well as weight changes for no reason, perception and language problems and loss of sensitivity and mobility, and even seizures. It is also possible, especially when they occur in children, that malformations and that the intracranial and extracranial craniofacial anatomy is altered.

This type of tumor can present, as it occurs with other tumors, in a way limited to a specific region or structure or in a diffuse way, the former having a much better prognosis than the second. In general, they do not usually metastasize to other areas of the body beyond the nervous system, although they do spread within that system.

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Diagnosis

The diagnosis of these tumors is complex, being necessary to carry out various procedures. First it is necessary to perform a biopsy of the tumor, which will allow us to take a sample of the brain tumor, currently being performed by stereotaxis. Subsequently, it will be necessary to perform a phenotypic and histological analysis to verify the type of tissue we are talking about, as well as its behavior. Finally, it will be necessary to assess the proliferative capacity, in order to be able to determine its degree and infiltration capacity.

Causes

As with all other brain tumors, the causes of astrocytomas are largely unknown. However, some inherited disorders can facilitate its appearance, such as neurofibromatosis. Also the infection with the Epstein-Barr virus or the previous application of radiotherapy due to another tumor seem to be risk factors for developing them.

Classification according to grades

The term astrocytoma, as we have already indicated above, groups together the set of tumors or neuplasias made up mainly of astrocytes. But within astrocytomas we can find various classifications and divisions, depending among other criteria of its degree of malignancy and proliferation. In this sense, we can observe the existence of four degrees of severity

Grade I

Grade one astrocytomas are all tumors whose main characteristic is benignity. Weight to this they can generate serious problems and even be fatal or generate disability depending on whether they grow and cause the crushing of parts of the brain against the skull. These are rare tumors, predominantly childhood, that have the advantage of having a very high degree of survival and be relatively easy to treat. In many cases, surgical resection is sufficient. An example of tumors of this grade is found in pilocytic astrocytoma.

Grade II

Unlike grade I astrocytomas, grade II ones are themselves cancer, being malignant tumors. Aggressive grade two astrocytomas, much more complex to treat and considered malignant and expansive. They usually cause epileptic seizures, observing diffuse lesions. Generally, this group includes diffuse astrocytomas, among which the most common are fibrillar, gemistocytic and protoplasmic astrocytomas. They are the most common type of low-grade astrocytoma.

Grade III

Grade three astrocytomas result a type of malignant tumor that has a high capacity for proliferation and infiltration towards other structures. The best known is anaplastic astrocytoma. It is frequent that it is the evolution of one of the previous tumors and even that it evolves into a grade four tumor.

Grade IV

Astrocytomas that are more invasive, aggressive, and infiltrating are considered grade four, spreading rapidly to other areas of the brain. The most typical and well-known astrocytoma with this degree of malignancy is glioblastoma multiforme, being in fact the most common type of brain neoplasm. The prognosis is usually fatal and life expectancy is greatly reduced.

The two most frequent

Some of the most common characteristics of some of the two most common and well-known types of astrocytoma are explained below.

Glioblastoma multiforme

The most common of all astrocytomas and one of the most common brain tumors (about a fourth of the brain tumors diagnosed are glioblastomas) is also the most aggressive and the worst forecast. It is a tumor in which cells are poorly differentiated, which reproduces at high speed and proliferates at the vascular level generating the death and degeneration of other structures due to necrosis. Life expectancy does not usually exceed one year and three months. It can be primary, appearing by itself, but it is generally an evolution of some of the lesser malignancy tumors.

Anaplastic astrocytoma

The second of the most well-known and malignant types, we are facing a grade III astrocytoma that tends to infiltrate the surrounding tissue without destroying it, appearing a thickening of these. It usually generates edema around the affected area, although it does not usually generate necrosis. Survival is greater than in glioblastoma, although only about 20% survive more than five years. It has been debated whether there is a hereditary genetic predisposition in some subjects because some hereditary syndromes predispose their appearance.

Treatments

The treatment of a brain tumor such as astrocytomas is something that must be carefully planned, bearing in mind that we are facing an intervention that can generate alterations in different brain regions beyond that directly affected by the tumor. However, even if secondary disturbances occur, the priority must be integrity

Surgery to resect the tumor is one of the main treatment modalities for astrocytomas, the treatment being initial to be applied in practically all things and after which other therapies will be applied that eliminate the remains of the tumor or prevent its expansion. However, sometimes complete resection will not be possible, as occurs in cases where the tumor is located in the brain stem (since its resection could cause the death of the subject by controlling vital functions in this area).

This resection is carried out in both low-grade and high-grade tumors, despite that in the latter it is frequent that there are recurrences and infiltrations in other areas cerebral. This is because even in these cases, resection can improve the mental capacities of the patient that were diminished by the pressure of the tumor. Once the maximum possible amount of tumor has been removed, they are usually used radiation therapy and chemotherapy to fight cancer cell debris.

In the case of radiotherapy, we are facing the application of high doses of radiation on cancerous tissues in order to destroy cells and shrink or finish killing tumors, and has been found to be very effective in high-grade tumors malignancy. The need to focus the radiation only on the cancerous area must be taken into account, since if used in a generalized way, a large number of healthy cells would be destroyed excessively.

Chemotherapy is the application of powerful chemicals and drugs used to fight the tumor, generally by inhibiting the proliferation of the tumor by applying substances that prevent cell division and DNA repair. Among these substances we can find temozolomide, ifosfamide, etoposide, carboplatin or lomustine.

On a psychological level, intervention is also recommended, especially when symptoms and disturbances of anxiety and mood occur. Psychoeducation is essential, especially in those cases in which the only possible treatment is solely palliative and / or they are in the terminal phase. It is also essential to have a safe and reliable space in which to be able to solve doubts and express feelings and fears without fear of being judged, something common in this type of disease. Likewise, there are therapies such as adjuvant psychological therapy, creative innovation therapy or therapy of visualization that can be applied in order to help the subject to have a greater perception of control over their disease.

Bibliographic references:

• Buckner, J.C.; Brown, P.D.; O'Neill, B.P.; Meyer, F.B.; Wetmore, C.J. & Uhm, J.H. (2007). Central Nervous System Tumors. Mayo Clinic Proceedings, 82: 1271-86.
• Kleihues, P.; Burger, P.C. & Scheithauer, B.W. (1993). The new WHO classification of brain tumors. Brain Pathol 3 (3): 255-68.
• Michaud, D.S. (2016). Epidemiology of brain tumors. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SK, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier.
• Pérez, L.; Galarraga, J.; Gomez, H. & Tamayo, J.D. (2000). Classification of astrocytic gliomas. Brief considerations. Rev. Neurol., 31: 1180-1183.