Brain tumors develop from cells in the brain or its lining (called meninges). Brain tumors cover tens of different diseases. Some are benign, and this this case we will often propose a surgical removal. Others are much more aggressive diseases, often difficult to treat despite unquestionable therapeutic advances. In this case, a multidisciplinary care in a specialized center is indispensable. The choice and sequence of treatments (surgery, radiation therapy, chemotherapy) will then be defined on the basis of a precise diagnosis, the characteristics of the tumors and of course the medical history of the patient.
What are the manifestations of brain tumors?
The clinical manifestations of brain tumors are extremely variable. Schematically, we distinguish three large categories of symptoms and signs.
1) Intracranial hypertension: When a brain tumor develops in the brain, it takes up space. As the brain is surrounded by skulls bones that are non-deformable, the growth of the tumor causes an increase in pressure in the brain. In increase in pressure manifests itself through headaches, which are sometimes very strong, vomiting, often projectile, and sometimes disturbance in vision.
2) Epilepsies: A tumor that develops within the brain cells disturbs the communication network between these cells. A sort of “short-circuit” may ensue, triggering an epileptic seizure. The most well-known and impressive epileptic seizures occur through a sudden loss of consciousness, accompanied by uncontrollable jerking movements, most of the time in half of the body. The patient may also lose control of his urine and feces, bite his tongue or breathe very loudly. Following this seizure, the patient must recover and thus enters a very deep sleep. The seizures are very impressive but exceptionally dangerous.
The tumors may develop in any area of the brain and therefore trigger short-circuits in different locations. Depending on the area where the tumor develops, the epileptic manifestations may vary greatly. They could entail uncontrollable movements limited to one part of the body, without loss of consciousness, temporary sensations of numbness in half the body, panic attacks or abdominal pains.
3) Functional disorders: The brain directs our functions as a whole, be they motor, intellectual or behavioral. Depending on the area where it develops, the brain tumor may cause dysfunctions that may take extremely varied forms: difficulty walking, difficulty using an arm or a hand, facial deformation, sensitivity disorders, walking disorders, but also difficulties expressing oneself, calculating, writing, or even depression or behavioral and memory disorders.
The areas of research or the avenues of hope
The current treatments rely mostly on surgery, radiation therapy or chemotherapy, mainly in tablet form. Nevertheless, intense research efforts are ongoing throughout the world, in order to better understand how a brain tumor can develop and hence try to develop new treatment strategies.
Here are a few examples:
- Anti-angiogenesis: starting from a certain size, probably only a few millimeters, the tumor must create its own blood vessels in order to ensure its nutrition and growth. The mechanisms that allow the creation of these new vessels are being increasingly better comprehended, allowing for the development of new medicines. An anti-angiogenic medicine is already used regularly, mainly in the case of relapse. Various other medicines are in development and some should become available in the years to come.
- Immunotherapy: there is no longer any doubt that our defense system, called immune system, tries to protect us against the development and growth of tumors. Recent studies show that these mechanisms are also active against tumors that develop in the brain. Therefore, immunotherapies consist in exploiting these natural properties for therapeutic purposes. Various strategies are in development, either in the form of so-called therapeutic vaccines (that is to say targeting patients suffering from these brain tumors), or in the form of cell therapy that involves injecting patients with lymphocytes (white blood cells) capable of identifying the tumor cells and destroying them.
- Limit the invasion of the brain: one of the biological particularities of the brain tumor cells is their ability to invade the normal structures of the brain, they are able to crawl along the neurons and migrate several centimeters from their origin. This phenomenon has two important consequences: it limits the effectiveness of so-called local treatments, such as surgery and radiation therapy, and it explains the functional disturbances related to brain tumors. Research carried out in the last 15 years has allowed the identification of numerous mechanisms responsible for this invasion phenomenon. This raises the development of several medicines that limit these migration phenomena. Some are in an advanced stage of development.