Brainstem glioma is an aggressive and dangerous cancer. Without treatment, the life expectancy is typically a few months from the time of diagnosis. With appropriate treatment, 37% survive more than one year, 20% survive 2 years. and 13% survive 3 years.This is not for all brainstem glioma, this statistic reflects DIPG. There are other brainstem gliomas.

Epidemiological studies are required to determine risk factors. Aside from exposure to vinyl chloride or ionizing radiation, there are no known environmental factors associated with brain tumors. Mutations and deletions of so-called tumor suppressor genes, such as P53, are thought to be the cause of some forms of brain tumor. Inherited conditions, such as Von Hippel–Lindau disease, multiple endocrine neoplasia, and neurofibromatosis type 2 carry a high risk for the development of brain tumors. People with celiac disease have a slightly increased risk of developing brain tumors.

Although studies have not shown any link between cell phone or mobile phone radiation and the occurrence of brain tumors, the World Health Organization has classified mobile phone radiation on the IARC scale into Group 2B – possibly carcinogenic. Discounting claims that current cell phone usage may cause brain cancer, modern, third-generation (3G) phones emit, on average, about 1% of the energy emitted by the GSM (2G) phones that were in use when epidemiological studies that observed a slight increase in the risk for glioma – a malignant type of brain cancer – among heavy users of wireless and cordless telephones were conducted.

Brain, other CNS or intracranial tumors are the ninth most common cancer in the UK (around 10,600 people were diagnosed in 2013), and it is the eighth most common cause of cancer death (around 5,200 people died in 2012).

For low-grade tumors, the prognosis is somewhat more optimistic. Patients diagnosed with a low-grade glioma are 17 times as likely to die as matched patients in the general population.

The age-standardized 10-year relative survival rate was 47%. One study reported that low-grade oligodendroglioma patients have a median survival of 11.6 years; another reported a median survival of 16.7 years.

The cause is still unknown. Researchers have not found any direct genetic link.

Gliomas are rarely curable. The prognosis for patients with high-grade gliomas is generally poor, and is especially so for older patients. Of 10,000 Americans diagnosed each year with malignant gliomas, about half are alive one year after diagnosis, and 25% after two years. Those with anaplastic astrocytoma survive about three years. Glioblastoma multiforme has a worse prognosis with less than a 12-month average survival after diagnosis, though this has extended to 14 months with more recent treatments.

About 3 per 100,000 people develop the disease a year. It most often begins around 64 years of age and occurs more commonly in males than females. It is the second most common central nervous system cancer after meningioma.

The cause of oligodendrogliomas is unknown. Some studies have linked oligodendroglioma with a viral cause. A 2009 Oxford Neurosymposium study illustrated a 69% correlation between NJDS gene mutation and the tumor initiation shown by Kevin Smith. A single case report has linked oligodendroglioma to irradiation of pituitary adenoma.

There are no precise guidelines because the exact cause of astrocytoma is not known.

The most common length of survival following diagnosis is 12 to 15 months, with fewer than 3% to 5% of people surviving longer than five years. Without treatment survival is typically 3 months.

Increasing age (> 60 years of age) carries a worse prognostic risk. Death is usually due to widespread tumor infiltration with cerebral edema and increased intracranial pressure.

A good initial Karnofsky Performance Score (KPS) and MGMT methylation are associated with longer survival. A DNA test can be conducted on glioblastomas to determine whether or not the promoter of the "MGMT" gene is methylated. Patients with a methylated MGMT promoter have longer survival than those with an unmethylated MGMT promoter, due in part to increased sensitivity to temozolomide. This DNA characteristic is intrinsic to the patient and currently cannot be altered externally. Another positive prognostic marker for glioblastoma patients is mutation of the "IDH1" gene, which can be tested by DNA-based methods or by immunohistochemistry using an antibody against the most common mutation, namely IDH1-R132H.

More prognostic power can be obtained by combining the mutational status of "IDH1" and the methylation status of "MGMT" into a two-gene predictor. Patients with both "IDH1" mutations and "MGMT" methylation have the longest survival, patients with an "IDH1" mutation or "MGMT" methylation an intermediate survival and patients without either genetic event have the shortest survival.

Long-term benefits have also been associated with those patients who receive surgery, radiotherapy, and temozolomide chemotherapy. However, much remains unknown about why some patients survive longer with glioblastoma. Age of under 50 is linked to longer survival in glioblastoma multiforme, as is 98%+ resection and use of temozolomide chemotherapy and better Karnofsky performance scores. A recent study confirms that younger age is associated with a much better prognosis, with a small fraction of patients under 40 years of age achieving a population-based cure. The population-based cure is thought to occur when a population's risk of death returns to that of the normal population, and in GBM, this is thought to occur after 10 years.

UCLA Neuro-Oncology publishes real-time survival data for patients with this diagnosis. They are the only institution in the United States that shows how their patients are performing. They also show a listing of chemotherapy agents used to treat GBM tumors. Despite a poor prognosis, there is a small number of survivors who have been GBM free for more than 10–20 years.

According to a 2003 study, glioblastoma multiforme prognosis can be divided into three subgroups dependent on KPS, the age of the patient, and treatment.

Astrocytoma causes regional effects by compression, invasion, and destruction of brain parenchyma, arterial and venous hypoxia, competition for nutrients, release of metabolic end products (e.g., free radicals, altered electrolytes, neurotransmitters), and release and recruitment of cellular mediators (e.g., cytokines) that disrupt normal parenchymal function. Secondary clinical sequelae may be caused by elevated intracranial pressure (ICP) attributable to direct mass effect, increased blood volume, or increased cerebrospinal fluid (CSF) volume.

Treatment typically consists of radiotherapy and steroids for palliation of symptoms. Radiotherapy may result in minimally extended survival time. Prognosis is very poor, with only 37% of treated patients surviving one year or more. Topotecan has been studied in the treatment of brainstem glioma, otherwise, chemotherapy is probably ineffective, though further study is needed.

In anywhere from fifty to eighty percent of cases, the first symptom of an oligodendroglioma is the onset of seizure activity. They occur mainly in the frontal lobe.

Headaches combined with increased intracranial pressure are also a common symptom of oligodendroglioma. Depending on the location of the tumor, any neurological deficit can be induced, from visual loss, motor weakness and cognitive decline. A computed tomography (CT) or magnetic resonance imaging (MRI) scan is necessary to characterize the anatomy of this tumor (size, location, heter/homogeneity). However, final diagnosis of this tumor, like most tumors, relies on histopathologic examination (biopsy examination).

Gliosarcoma is a rare type of glioma, a cancer of the brain that comes from glial, or supportive, brain cells, as opposed to the neural brain cells. Gliosarcoma is a malignant cancer, and is defined as a glioblastoma consisting of gliomatous and sarcomatous components.

It is estimated that approximately 2.1% of all glioblastomas are gliosarcomas. Although most gliomas rarely show metastases outside the cerebrum, gliosarcomas have a propensity to do so, most commonly spreading through the blood to the lungs, and also liver and lymph nodes.

Gliosarcomas have an epidemiology similar to that of glioblastomas, with the average age of onset being 54 years, and males being affected twice as often as females. They are most commonly present in the temporal lobe.

Oligoastrocytomas are a subset of brain tumors that present with an appearance of mixed glial cell origin, astrocytoma and oligodendroglioma. These types of glial cells that become cancerous are involved with insulating and regulating the activity of neuron cells in the central nervous system. Often called a "mixed glioma", about 2.3% of all reported brain tumors are diagnosed as oligoastrocytoma. The median age of diagnosis is 42.5.

Oligoastrocytomas, like astrocytomas and oligodendrogliomas, can be divided into low-grade and anaplastic variant, the latter characterized by high , conspicuous cytologic , mitotic activity and, in some cases, microvascular proliferation and necrosis.

However, lower grades can have less aggressive biology.

These are largely supratentorial tumors of adulthood that favor the frontal and temporal lobes.

A brain stem tumor is a tumor in the part of the brain that connects to the spinal cord (the brain stem).

Even after surgery, an oligoastrocytoma will often recur. The treatment for a recurring brain tumor may include surgical resection, chemo and radiation therapy. Survival time of this brain tumor varies - younger age and low-grade initial diagnosis are factors in improved survival time.

Ganglioglioma is a rare, slow-growing primary central nervous system (CNS) tumor which most frequently occurs in the temporal lobes of children and young adults.

Definitive treatment for ganglioglioma requires gross total surgical resection, and a good prognosis is generally expected when this is achieved. However, indistinct tumor margins and the desire to preserve normal spinal cord tissue, motor and sensory function may preclude complete resection of tumor. According to a series by Lang et al., reviewing several patients with resected spinal cord ganglioglioma, the 5- and 10-year survival rates after total resection were 89% and 83%, respectively. In that study, patients with spinal cord ganglioglioma had a 3.5-fold higher relative risk of tumor recurrence compared to patients with supratentorial ganglioglioma. It has been recognized that postoperative results correlate closely with preoperative neurological status as well as the ability to achieve complete resection.

With the exception of WHO grade III anaplastic ganglioglioma, radiation therapy is generally regarded to have no role in the treatment of ganglioglioma. In fact, radiation therapy may induce malignant transformation of a recurrent ganglioglioma several years later. Adjuvant chemotherapy is also typically reserved for anaplastic ganglioglioma, but has been used anecdotally in partially resected low grade spinal cord gangliogliomas which show evidence of disease progression.

DIPG has a 5-year survival rate of <1%. The median overall survival of children diagnosed with DIPG is approximately 9 months. The 1- and 2-year survival rates are approximately 30% and less than 10%, respectively. These statistics make DIPG one of the most devastating pediatric cancers. Although 75–85% of patients show some improvement in their symptoms after radiation therapy, DIPGs almost always begin to grow again (called recurrence, relapse, or progression). Clinical trials have reported that the median time between radiation therapy and progression is 5–8.8 months. Patients whose tumors begin to grow again may be eligible for experimental treatment through clinical trials to try to slow or stop the growth of the tumor. However, clinical trials have not shown any significant benefit from experimental DIPG therapies so far.

DIPGs that progress usually grow quickly and affect important parts of the brain. The median time from tumor progression to death is usually very short, between 1 and 4.5 months. During this time, doctors focus on palliative care: controlling symptoms and making the patient as comfortable as possible.

The standard treatment for DIPG is 6 weeks of radiation therapy, which often dramatically improves symptoms. However, symptoms usually recur after 6 to 9 months and progress rapidly.

A nervous system neoplasm is a tumor affecting the nervous system. Types include:

- Nerve sheath tumor

- Brain tumor

- Arachnoid cyst

- Optic nerve glioma

The chances of intracranial epidermoids is about 1% of all brain tumors. This benign tumor of the brain is made up of normal skin cells (stratified epithelial lining) on the outside, and fatty acids and keratin are on the inside of the tumor or sac. Only the sticky outer membrane is alive thus sticking to brain tissues and nerves.

Epidermoid tumors strongly adhere to the brain stem or cranial nerves. Often the lining of the tumor connected to the brain stem or parts difficult to "peel" away are left behind leaving residual tumor after surgery, this can contribute to the risk of regrowth.

Pituicytoma is a rare brain tumor. It grows at the base of the brain from the pituitary gland. This tumor is thought to be derived from the parenchymal cells of the posterior lobe of the pituitary gland, called pituicytes. Some researchers believe that they arise from the folliculostellate cells in the anterior lobe of the pituitary. As such, it is a low-grade glioma. It occurs in adults and symptoms include visual disturbance and endocrine dysfunction. They are often mistaken for pituitary adenomas which have a similar presentation and occur in the same location. The treatment consists of surgical resection, which is curative in most cases.

The 5-year disease-free survival for age >5 years is 50-60%. Another report found a similar 5-year survival at about 65% with 51% progression-free survival. The 10-year disease-free survival is 40-50%. Younger ages showed lower 5 and 10-year survival rates. A 2006 study that observed 133 patients found 31 (23.3%) had a recurrence of the disease within a five-year period.