Brain cancer

Brain cancer

The brain cancer primary originates in the parenchyma of the brain, spinal cord or nerves. Some tumors that arise from the envelopes of the brain or the marrow (meninges) are also considered primary brain tumors. Metastatic brain tumors have spread from a cancer located in other parts of the body, most often lungs, breast and colon.

The overall risk during the lifetime of suffering from a brain tumor is less than 1% . There are many different types of brain tumors, depending on the cells that are affected and their appearance under a microscope. Tumors can be classified into four general categories:


Gliomas

These tumors are formed in glial cells, which help sustain and protect critical areas of the brain. Gliomas represent the most common type of brain tumor in adults, so they are responsible for approximately 42% of brain tumors in them. The gliomas are subclassified depending on the cell types they affect:

Astrocytomas: star-shaped cells that protect neurons. Tumors of these cells can spread from the primary focus to other areas of the brain, but they rarely spread outside the central nervous system. Astrocytomas are graduated from I to IV according to the speed of progression:

Grade I (pilocytic astrocytoma): slow growth, with little tendency to infiltrate the surrounding brain tissue. More frequent in children and adolescents.

Grade II (diffuse astrocytoma): fairly slow growth, with a tendency to infiltrate the surrounding brain tissue. Observed mostly in young adults.

Grade III (anaplastic / malignant astrocytoma): these tumors grow quite rapidly and infiltrate the surrounding brain tissue.

Grade IV (glioblastoma multiforme, GBM): very aggressive and deadly form of brain cancer . Unfortunately, it is the most common form of brain tumor in adults, accounting for 67% of all astrocytomas.

Oligodendroglioma: estas células producen la mielina, una sustancia grasa que forma una vaina protectora alrededor de las células nerviosas. Los oligodendrogliomas, que constituyen el 4% de los tumores cerebrales, afectan principalmente a personas mayores de 45 años. Algunos subtipos de este tumor son especialmente sensibles al tratamiento con radio y quimioterapia. La mitad de los pacientes con oligodendrogliomas siguen vivos al cabo de cinco años.

Ependymomy : These tumors affect the ependymocytes, which line the pathways that carry the cerebrospinal fluid throughout the brain and spinal cord. Ependymomas are infrequent and represent 2% of all brain tumors; however, they are the most common brain tumors in children. In general, they do not affect healthy brain tissue and do not spread outside the ependyma. Although these tumors respond well to surgery, especially those of the spinal cord, they can not always be completely excised. Five-year survival for patients older than 45 years is close to 70%.


Meningiomas

These tumors affect the meninges, the tissue that forms the protective outer envelope of the brain and spinal cord. A quarter of all brain and spinal tumors are meningiomas, of which up to 85% are benign. Meningiomas can develop at any age, but their incidence increases significantly in people older than 65 years. Women are twice as likely as men to have meningiomas. They usually grow very slowly and usually do not cause symptoms. In fact, many meningiomas are discovered by accident. Meningiomas can be treated successfully by surgery, although some patients, especially the elderly, are candidates for an expectant attitude to monitor the disease.


Acoustic neuroma / schwannomas

The Schwann cells are found in the sheath that lines the nerve cells. Vestibular schwannomas, also called acoustic neurinomas, originate in the 8th cranial nerve, which is responsible for hearing. The specific symptoms of a vestibular schwannoma include ringing in the ears, unilateral hearing loss and balance problems. Schwannomas are usually benign and respond well to surgery.


Medulloblastoma
It is a common brain tumor in children, which is usually diagnosed before 10 years of age. Medulloblastoma appears in the cerebellum, which plays an essential role in the coordination of muscle movements. Some experts think that medulloblastomas come from fetal cells that persist in the cerebellum after birth. These tumors grow rapidly and can invade adjacent parts of the brain, as well as spread out of the central nervous system. Medulloblastomas are somewhat more frequent in boys.


Symptoms of brain cancer and brain tumors
The symptoms that a patient with a brain cancer or brain tumor experiences may vary depending on the location and size of the tumor . Most of the usual symptoms are due to an increase in intracranial pressure as the growing tumor affects the surrounding structures:

• Pain often head (reported by 50% of patients)
• Blurry vision
• Nausea, vomiting, or both
• Personality or cognitive changes

Other symptoms of cancer and brain tumors are specific to their location, such as seizures, speech impairment, weakness or numbness on one side, and problems with coordination, balance, and mobility.