Brain cancer

Brain cancer is divided into two main groups: primary tumors and cancer, which originate in the brain, and metastatic cancer, which spreads to the brain from other cancers in the body. Approximately one-third of all brain tumors are primary tumors, which are either benign or malignant. The most common type of benign primary brain tumor is the meningioma. This tumor originates from the meninges, the thin tissues that cover the brain, and occurs most commonly during middle adult life and in women. Other very rare benign brain tumors occur mainly in children. These include pituitary adenoma, central neurocytoma, choroid plexus papilloma, colloid cyst, pilocytic astrocytoma, and ganglioglioma. 

The most common type of primary brain cancers are malignant gliomas, which include the glioblastoma multiforme (the most frequently occurring and most malignant of all), the anaplastic astrocytoma, anaplastic oligodendroglioma, and anaplastic mixed oligoastrocytoma. Another malignant brain cancer is the medulloblastoma, which is the most frequent malignant brain tumor in children but rarely occurs in adults. Primary central nervous system lymphoma is a malignant brain tumor that occurs more frequently in patients infected with HIV. 

Cancer that has spread, or metastasized, from other organs is the most frequent cause of malignant brain tumors, causing two-thirds of all cases of brain cancer. The most common source cancers for metastatic brain cancer are lung cancer, breast cancer, kidney cancer, and melanoma. 

Symptoms of brain tumors include epileptic seizures, new-onset headaches that are worse during the night or early morning hours, and unexplained progressive memory and intellectual dysfunction. In young children the most frequent symptoms are nausea, vomiting, headache, and unsteadiness of gait. _Magnetic resonance imaging (MRI) of the brain is almost always used to diagnose the existence of a brain tumor. However, the exact nature of the tumor needs to be confirmed by surgery. 

Treatment for benign brain tumors starts with complete surgical removal of the tumor. If part of the tumor cannot be removed by surgery, radiation therapy can be administered to kill the remainder. Both primary and metastatic malignant brain tumors are treated surgically if the tumor is in an area where it can be removed without much damage to the normal brain, and by radiation therapy. Chemotherapy may also help. However, treatment of adults with malignant brain tumors is only moderately successful, with 50% of patients dying within one to three years, depending on the cancer type, age, and physical condition. Generally, young patients and patients with less malignant tumor types and in good physical condition live longest. Research is currently under way to better understand the mechanisms of brain tumors and help develop new therapeutic strategies directed against the basic growth mechanism.