The symptoms of a brain tumor are numerous and depend mainly on three factors: the location, size and severity (rate of growth) of the neoplasm. A common symptom of many brain malignancies is headache.
The correct diagnosis requires, first of all, a neurological examination and, secondly, some instrumental and laboratory tests, useful for localizing and classifying the tumor.
There are several therapeutic treatments; their choice and also their effectiveness depend on the characteristics (location, severity and size) of the neoplasm.
Brief reference on Concepts of Genetics
Before describing the brain tumor, it is useful to make a brief recall of some key concepts.
What is DNA? It is the genetic heritage of an individual, a sort of biological code in which the somatic traits, predispositions, physical gifts, character, etc. of a living organism are written. DNA is contained in all cells of the body having a nucleus, as it is located inside this.
What are chromosomes? According to the definition, chromosomes are the structural units in which DNA is organized. Human cells contain, in their nucleus, 23 pairs of homologous chromosomes (therefore, 46 chromosomes in all); each pair is different from another in that it has a specific gene sequence.
What are genes? They are short stretches, or sequences, of DNA with a fundamental biological meaning: from them, in fact, proteins, or biological molecules fundamental for life, derive. In the genes, there is "written" part of who we are and who we will become.
What is a genetic mutation? It is a mistake within the DNA sequence that forms a gene. Because of this error, the resulting protein is either defective or completely absent. In both cases, the effects can be deleterious both for the life of the cell, in which the mutation occurs, and for that of the organism as a whole. Congenital diseases and neoplasms (ie tumors) belong to one or more genetic mutations.
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THE DIFFERENT TYPES OF BRAIN CANCER
Brain tumors, or brain tumors, are classified according to various criteria, such as where the tumor begins to grow and how fast it spreads (invasiveness).
- The point of origin of the tumor mass: primary tumor and secondary (or metastatic) tumor.
We speak of primary brain tumor when this arises spontaneously in the "brain or in a neighboring anatomical region (for example, the meninges or the pituitary gland); we speak instead of secondary brain tumor, when the mass of cells derives from a" another neoplasm located in a part of the body distant from the brain (for example, in the lungs). - The growth rate: benign tumor and malignant tumor.
When the growth and spread of the tumor is slow, it is called a benign brain tumor; vice versa, when the growth and formation of the abnormal mass are fast, we speak of a malignant brain tumor (or carcinoma).
A FURTHER DISTINCTION: DEGREES OF A BRAIN CANCER
Figure: a brain tumor (marked by arrows and white asterisks).
Alongside the two previous criteria of distinction, there is a third that classifies brain tumors according to 4 degrees (from I to IV).
The first two grades, I and II, are characterized by slow tumor growth limited to one "area of the brain.
Grades III and IV, on the other hand, are distinguished by a rapidly growing and highly invasive mass.
In light of what has been said so far, it could be argued that grade I and II brain tumors are benign, while grade III and IV brain tumors are malignant. However, the above statement omits a very important aspect that can occur, namely the possibility that a benign tumor, grade I or II, evolves into a malignant tumor. This is what happens, for example, for gliomas.
Benign brain tumors:
- Benign glioma
- Meningioma
- Acoustic neuroma
- Craniopharyngioma
- Hemangioma
- Pituitary adenoma
Malignant brain tumors
- Malignant glioma (the most common is known as glioblastoma multiforme)
EPIDEMIOLOGY
Brain tumors can arise at any age. However, the most affected individuals are the elderly (although it should be noted that there are brain tumors typical of childhood).
According to an English statistic for the United Kingdom, 4,300 benign brain tumors are diagnosed each year, most of which gliomas, and 5,000 malignant tumors, mostly secondary.
Primary cancers are less common than secondary ones.
The second factor is represented by a series of congenital diseases, which predispose to the growth of a tumor mass inside the brain.
Congenital conditions conducive to a brain tumor:
- Neurofibromatosis
- Tuberous sclerosis
- Turcot syndrome
- Li-Fraumeni syndrome
- Von Hippel-Lindau syndrome
- Gorlin syndrome
The third factor is linked to ionizing radiation, especially to their use for the treatment of a previous tumor. In fact, it is unfortunately supported by the statistical data that exposure, for therapeutic reasons, to ionizing radiation favors the onset of other neoplasms.
The fourth factor relates to an individual's family history. If there have been previous cases of brain tumor in the family, then it is more likely that the disorder will also affect close relatives.
PRIMARY TUMORS IN THE BRAIN
Genetic mutations, which cause primary brain tumors, can arise in different types of brain cells. Depending on the site of origin, the following neoplasms develop:
- Astrocytoma
- Ependymoma
- Oligodendroglioma
- Germ cell tumor
- Medulloblastoma
- Meningioma
- Acoustic neuroma
- Pineoblastoma
N.B: astrocytoma, ependymoma and oligodendroglioma belong, more generally, to the category of gliomas.
SECONDARY BRAIN CANCERS
As anticipated, secondary brain tumors derive from tumors that have arisen elsewhere in the rest of the body, again due to a genetic mutation. This dissemination process is also known as metastasis or metastasis. The neoplasms that most frequently cause brain metastases are: breast cancer, colon cancer, kidney cancer, lung cancer and, finally, melanoma.
of the brain (ie in the front) causes a sense of weakness, personality changes and loss of smell, while a tumor in the occipital lobe (ie in the back) causes a loss of vision.GENERAL SYMPTOMS FRAMEWORK
Due to the close anatomical proximity of the brain to the skull, a growing brain tumor is unable to expand as well as it could, as a result it simply pushes against the walls of the bony lining and adjacent areas.
This pressure, known as intracranial pressure, is the main cause of headache (the most characteristic symptom of brain cancer) and other manifestations, such as:
- Nausea and vomiting, for no reason
- Vision problems: blurred or double vision and loss of peripheral vision
- Epilepsy attacks
- Confusion during everyday chores
- Difficulty maintaining balance
- Gradual loss of sensation or the ability to move in the legs or arms
- Difficulty expressing themselves in words
- Sudden changes in personality and behavior
- Hearing problems
The above list does not represent what is regularly observed every time a brain tumor appears, but only a general picture of possible symptoms. In fact, an individual tends to lose mainly the brain functions controlled by the area of the brain where the tumor mass grows.
Figure: The brain tumor is characterized by frequent headaches, which arise for no apparent reason.
HEADACHE: WHEN TO SEE THE DOCTOR?
Suspicious headaches are those that arise without any explanation and that become, over time, more and more frequent and severe.
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Nuclear magnetic resonance imaging (MRI) is the "test of choice", but computed tomography (CT) and positron emission tomography (PET) imaging play an equally important diagnostic role.
Knowing where the tumor has formed and whether or not it is the result of metastases helps to plan the therapy correctly.
BRAIN BIOPSY
The brain biopsy takes place after identifying the area affected by the tumor; the examination consists in taking a small portion of the neoplastic mass and observing it under a microscope.
The characteristics of the tumor cells clarify the nature, benign or malignant, of the neoplasm.
Once the treatment is completed, we move on to rehabilitation therapy.
Surgical Removal
The conditions
Surgical removal is a delicate operation, which is performed only when it is possible to access the brain area occupied by the tumor without obstacles. If such conditions exist, the operation is performed under general anesthesia.
The procedure
After having incised the patient's head and skull (craniotomy) at the point corresponding to the site of the neoplasm, the neurosurgeon removes the tumor mass, taking care not to damage the healthy parts of the brain. The success of the operation depends on how large and infiltrated the tumor is: in the most complicated cases, the result is partial, so it is necessary to combine it with one or more of the other treatments mentioned above (radiotherapy, chemotherapy, etc.).
The complications
The risks of the operation consist of: infections, cerebral haemorrhages and lesions of the nerve endings.
Radiotherapy
Radiation therapy consists of subjecting the patient to several cycles of ionizing radiation (high-energy X-rays), in order to destroy the tumor cells.
The procedure can be performed both through an external radiation source, which acts on an "extended area of the head, and through an internal source, located in the immediate vicinity of the area affected by the tumor (brachytherapy).
In general, the external source is chosen in the case of secondary tumors, as, in these situations, the neoplasm is more widespread; on the contrary, an internal source is chosen when the tumor is of the primary type and localized in a specific area.
fatigue, headache, irritation and an increased risk of developing other cancers. The onset of these depends, above all, on the radiation doses received.
Chemotherapy
Chemotherapy is the administration of drugs capable of killing all rapidly growing cells, including cancer cells.
These preparations, the choice of which usually depends on the type of tumor in question, can be taken by mouth or intravenously.
The most widely used chemotherapy drug is temozolomide.
Side effects depend on the drug doses taken and consist of: nausea, vomiting and hair loss.
Chemotherapy and surgery
During the surgical removal procedure, it is possible to place, near where the tumor mass was, a thin bar (called with the English term wafer) containing a chemotherapy drug.In the days following the surgery, this wafer slowly releases its contents, acting directly against cells with tumor characteristics that have not been removed by surgery.
Radiosurgery
Radiosurgery is an operation practiced only in a few hospitals and requires very sophisticated instrumentation.
Briefly, it consists in hitting, with a very intense beam of ionizing radiation, the area occupied by the tumor, when this is located in an inaccessible point for surgical removal.
The treatment usually takes place in a single session.
Targeted Therapy
We talk about targeted therapy when we administer drugs capable of acting exclusively against cancer cells. Unlike chemotherapy (in which even some healthy cells can be destroyed), the target of targeted therapy is a molecule or process characteristic of the cancer cell.
For example, in the case of some malignant gliomas, bevacizumab (or Avastin) is given, which blocks a fundamental neoplastic mechanism, such as the formation of new blood vessels.
Rehabilitation Therapy
Rehabilitation aims to restore lost abilities as a result of a brain tumor. Depending on the area of the brain affected, it may be necessary to:
- Physiotherapy: to restore motor skills.
- Occupational therapy: to make the patient independent again, during daily activities, work, school, etc.
- Speech therapy: to restore spoken language.
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