Brain Tumor Awareness Month: Understanding a Complex Diagnosis

A month without a call to action

Most awareness campaigns end with an instruction. Get screened. Quit smoking. Check yourself.

May cannot offer any of those. There is no screening test for brain tumors, and NCI has no evidence-based prevention advice for them either. That absence is honest, and it is the starting point rather than a gap to be filled with something reassuring.

What is left is understanding, and support for people carrying a diagnosis that is unusually hard to explain.

One name, dozens of diseases

Brain tumors make up 85% to 90% of all primary central nervous system tumors, meaning tumors that begin in the brain or spinal cord.

NCI lists them by frequency:

• Anaplastic astrocytomas and glioblastomas, about 38%.
• Meningiomas and related tumors, about 27%.
• Pituitary tumors.
• Schwannomas.
• CNS lymphomas.
• Oligodendrogliomas.
• Ependymomas.
• Low-grade astrocytomas and medulloblastomas.

In the spine the order is different again. Schwannomas, meningiomas and ependymomas account for about 79% of primary spinal tumors.

These are not variations on a theme. A meningioma and a glioblastoma differ in growth rate, treatment and outlook as much as two cancers in different organs do. Our page on brain tumors separates the main groups.

The causes are mostly unknown, and NCI says so

Few definitive observations have been made about environmental or occupational causes. NCI lists only a short set of possibilities.

Exposure to vinyl chloride may raise the risk of glioma. Epstein-Barr virus has been implicated in primary CNS lymphoma. Transplant recipients and people with AIDS have a substantially increased risk of that same lymphoma.

Inherited syndromes account for a small share. NCI names these:

• Neurofibromatosis type 1.
• Neurofibromatosis type 2.
• Von Hippel-Lindau disease.
• Tuberous sclerosis.
• Li-Fraumeni syndrome.
• Turcot syndrome.
• Nevoid basal cell carcinoma syndrome.

For most people diagnosed, none of this applies. There is no exposure to point at and nothing that could have been done differently.

What molecular testing changed

The most important development in this field is not a drug. It is that the tumor's genetics now guide care.

NCI names three alterations as powerful prognostic factors in diffuse glioma, and notes they may guide management:

• MGMT promoter methylation. A chemical tag that switches off a DNA repair gene. Tumors with it tend to respond better to certain chemotherapy.
• IDH1 or IDH2 variants. Changes in genes controlling cell metabolism. They mark a distinct and generally slower-behaving group of gliomas.
• 1p/19q codeletion. Loss of segments from two chromosomes at once, which defines oligodendroglioma.

NCI links other factors to a worse outlook:

• Age over 40.
• Disease that is already growing.
• A tumor larger than 5 cm.
• A tumor crossing the midline.
• Contrast uptake on MRI.
• Reduced performance status.
• Neurological symptoms.
• Surgery that left visible tumor behind.

That list explains why two people with the "same" diagnosis can be given very different information.

What treatment is built from

NCI lists five components for primary CNS tumors: surgery, radiation therapy, chemotherapy, active surveillance, and supportive therapy.

For glioblastoma, combined treatment with surgery, radiation and chemotherapy is standard. Temozolomide is taken by mouth. It has replaced the older drug carmustine as the standard chemotherapy for malignant gliomas. A large trial showed a survival gain when it was added to radiation.

Some low-grade gliomas are treated differently. So are anaplastic oligodendroglial tumors. For both, long-term randomized trials support adding three drugs: procarbazine, lomustine and vincristine.

Not every tumor is treated straight away. Active surveillance means regular scans and exams, with no treatment. It suits slow tumors where acting carries more risk than waiting. Our page on radiation therapy covers what that part involves.

Treating the pressure, not only the tumor

This is the part most people have never heard of, and it often matters more day to day than the cancer treatment itself.

Tumors cause swelling in the brain tissue around them, called peritumoral edema. The skull is rigid. That swelling raises pressure inside it. The result is headaches, drowsiness, vomiting and worsening brain function.

NCI lists dexamethasone, a steroid, along with mannitol and furosemide, as the drugs used to treat it. Anticonvulsants are described as mandatory for anyone who has had a seizure.

Much of the improvement people notice in the first days comes from these medicines. It does not come from anything aimed at the tumor.

When to get checked

With no screening test, symptoms are the only route in. See a doctor about:

• A headache that is new in character, worse on waking, or comes with vomiting.
• A first seizure, at any age.
• New weakness, numbness or clumsiness affecting one side.
• New difficulty with speech, vision, hearing or balance.
• A change in memory, concentration, mood or personality that other people notice.

Most of these have other explanations. A first seizure in an adult is the exception. It always needs urgent assessment. NCI notes seizures can come months or years before diagnosis in slow tumors.

The scale of it

The 2026 projection of about 24,740 new brain and other nervous system cancers in the United States, with about 18,350 deaths, is the American Cancer Society's; SEER publishes it on its Stat Facts page. NCI's own measured figures are a combined incidence of 6.1 cases per 100,000 people per year and a mortality rate of 4.4 per 100,000.

Worldwide, about 321,476 new cases were diagnosed in 2022, with an estimated 248,305 deaths. Five-year relative survival in the United States for 2016 to 2022 was 32.9%, and the median age at diagnosis is 61.

Incidence is higher in White people than Black people, and mortality is higher in men than women.

What this does not mean

That survival figure averages tumors that behave in wildly different ways. Our page on glioblastoma shows how far one type can sit from the mean.

It also leaves out benign brain tumors, and tumors that spread to the brain from elsewhere. It is not a number for everyone with a mass in the head.

And "no screening, no prevention" is not the same as "nothing can be done". It means the useful actions are recognizing symptoms early, getting the tumor typed properly, and supporting the households that carry the load.

Sources

• NCI PDQ, Adult Central Nervous System Tumors Treatment (Health Professional Version) — https://www.cancer.gov/types/brain/hp/adult-brain-treatment-pdq
• NCI PDQ, Adult Central Nervous System Tumors Treatment (Patient Version) — https://www.cancer.gov/types/brain/patient/adult-brain-treatment-pdq
• SEER Cancer Stat Facts, Brain and Other Nervous System Cancer — https://seer.cancer.gov/statfacts/html/brain.html
• American Cancer Society, Cancer Facts & Statistics — https://www.cancer.org/research/cancer-facts-statistics.html

How this article was prepared

An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.

The National Cancer Information Foundation publishes Cancer Explained. This page is for learning. It is not medical advice and does not suggest a test or treatment.

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