Brain Tumors

Brain tumors can be seen in all age groups, from the neonatal period (the first month after birth) to advanced age; however, the type, location, frequency and course of the tumor differ greatly according to age group. In childhood, brain tumors are the most common tumors after blood cancers (leukemia). During this period, tumors arising from the cells that make up brain tissue are more frequent; metastases from tumors of other organs and systems are rarely encountered. In childhood, the most common are astrocytomas, medulloblastomas, brainstem gliomas and ependymomas, and these tumors are frequently located in the posterior fossa. In adulthood and with advancing age, the tumor types encountered change, and metastases begin to appear more often alongside tumors arising from brain tissue (most commonly high-grade glial tumors, e.g. glioblastoma multiforme), as well as tumors arising from the meninges, the great majority of which (90%) are benign: meningiomas, adenomas of the pituitary gland, and benign tumors arising from cranial nerves (e.g. acoustic neuromas). It is known that many genetic and environmental factors are effective in the formation of brain tumors. Among the environmental factors considered are ionizing radiation, electromagnetic fields, pesticides, nitrous compounds, viruses and other infectious agents, previous head trauma, and dietary habits.Among brain tumors, meningiomas (they make up approximately 15-20% of all cases) are mostly benign tumors, and when they are completely removed with good surgery, the patient can recover fully; however, the location of the tumor may sometimes make surgery difficult.

Low-grade (grade 1) astrocytomas (e.g. pilocytic astrocytoma), ependymomas and most adenomas of the pituitary gland are cases with a favorable prognosis, in which patients generally recover permanently when they are completely removed. However, in malignant brain tumors with a high degree of malignancy, although surgery is again essential, complete cure is not possible. The reason for this can be explained roughly, by looking at part of the picture, as follows: For example, in glioblastoma multiforme, one of the most aggressive/malignant brain tumors, all cells at the center of the tumor are tumor cells (1:1 ratio); as one moves outward from the center of the tumor in rings, the proportion of tumor cells decreases, but even far from the tumor, e.g. in the opposite cerebral hemisphere, tumor cells are present; even in brain tissue that appears completely normal on advanced imaging methods and during surgery, tumor cells are present, even if at a very low rate (e.g. 1:1000 ratio).

This shows that glioblastoma multiforme is a disease of the entire brain rather than of a local area of it. Therefore, gross/macroscopic total resection of these tumors means removal of the entire tumor that can be seen during surgery or distinguished from brain tissue (using a surgical microscope); unfortunately, however, since tumor cells are also present outside this area, the tumor will recur after some time. The clinical signs and symptoms of brain tumors cover a very broad spectrum. However, if these signs and symptoms are to be grouped under certain categories/headings;

• Signs and symptoms due to increased intracranial pressure (headache, nausea-vomiting, visual disturbances, clouding and loss of consciousness…);
• Impairment/loss of specific neurological functions (focal neurological deficits, e.g. weakness in an arm or leg, speech disorders, behavioral/personality changes…);
• Seizures (epileptic attacks…) are the most frequently occurring signs and symptoms.

Early diagnosis is of great importance in brain tumors. Advanced imaging tools (Magnetic Resonance Imaging…) are available for this purpose. When necessary, it is meaningful for these examinations to be performed on the appropriate patient and performed correctly. Once a diagnosis is made, various further investigations may be carried out to establish the treatment plan and strategy. In the treatment of brain tumors, the main approach is surgical removal of the main tumor (surgical resection). However, when planning treatment, the likely type, size and spread of the tumor, the patient's general and neurological condition, and the patient's preferences should be taken into account. Apart from surgery, radiotherapy, chemotherapy and some treatments at the experimental stage are also applied in brain tumors.