Tumors of the central nervous system (CNS) are generally divided into primary tumors, which develop from brain tissue cells or surrounding structures (i.e., meninges – meningiomas), and a much larger group of tumors, secondary tumors, that have spread (metastasised), whose original tumor may be anywhere in the body (for example, in a breast, lung, kidney).
Primary brain tumors represent roughly 1–2% of all malignant tumors. In the Czech Republic, brain tumors affect some 800 people each year, with the number of males being slightly higher. The incidence of this disease is more frequent in two age groups: children up to five years of age, and adults over 60 years of age.
Primary brain tumors are a highly varied group. Most commonly, they form from the cells of supportive brain tissue (neuroglia), and these tumors are called gliomas, making up over 50% of all CNS tumors. Simply put, according to certain histological markers and behaviour, gliomas are divided into those with a low level of malignancy (low-grade gliomas), and those with a high level of malignancy (high-grade gliomas).
Low-grade gliomas grow slowly, sometimes even over the course of several years. They are more common in younger age groups (20–40 years of age). The growth of these types of tumors are not clearly demarcated from the surrounding healthy brain tissue, which is why it is difficult to remove them completely using surgery. Over the course of years, they can gradually grow in size or change into malignant gliomas.
High-grade gliomas most often originate in two different ways – either through natural development based on genetic disorders from a low-grade glioma or directly from healthy brain tissue. Rapid, aggressive growth (weeks to months) is typical for these malignant gliomas. They most often affect people over the age of 50. The borders of these tumors are not distinct or clearly defined, which is why complete removal is not possible. Recurrence is common, as is renewed growth at the site or surrounding area after surgery.
Other Types Of Brain Tumors
When addressing common brain tumors, it is important to mention meningiomas, which are typically benign tumors that form from the membranous layers surrounding the brain, and are more common in women and persons over the age of 50. Other types of tumours include cranial nerve tumours (neurinomas), which are typically benign, as well as pituitary adenomas, which manifest in hormonal disorders or visual disorders (visual field defects due to pressure on the optic nerve). Predominantly pediatric tumors generally include medulloblastomas and ependymomas.
Brain Cancer Treatment
The treatment of CNS carcinomas requires a multidisciplinary approach. A comprehensive treatment strategy must be determined by a team of specialists, including a neurosurgeon, radiation or clinical oncologist, pathologist, and radiologist.
In most CNS tumors, their surgical removal is of paramount importance. Surgery, or radiotherapy alone, is sufficient for some patients. For other patients, combined surgery, radiotherapy, and chemotherapy treatment must be used. Radiotherapy plays an irreplaceable role in the comprehensive treatment of CNS cancer.