Understanding Brain Cancer

What Are the Risk Factors for Brain Cancer?

Last updated and reviewed on June 16, 2026.

A risk factor is anything that raises the likelihood that a person will develop a certain disease. It is important to understand that having a risk factor does not mean you will definitely get brain cancer, and not having any known risk factors does not mean you are immune to it. Most people diagnosed with brain cancer have no identifiable risk factors at all. Still, knowing what raises the risk helps doctors identify people who may benefit from closer monitoring and helps researchers continue working toward prevention.

Brain cancer is actually one of the cancers with the fewest well-established, modifiable (changeable) risk factors. Unlike lung cancer or skin cancer, where lifestyle choices like smoking or sun exposure play a major role, brain cancer does not have a long list of proven environmental or behavioral risk factors. This can feel frustrating for patients and families who want to know "why," but understanding that most brain cancers arise without any identifiable cause is part of understanding this disease.

What Raises Your Risk for Developing Brain Cancer?

• Ionizing Radiation Exposure: The most clearly established environmental risk factor for brain tumors is exposure to ionizing radiation, the kind used in medical treatments like radiation therapy to the head and neck. People who received radiation therapy to the brain or skull for another condition (such as childhood leukemia or a prior brain tumor) have an elevated risk of developing a new brain tumor years or even decades later. This is an important long-term consideration for cancer survivors who received cranial radiation, especially as children.
• Radiation: CT scans or X-rays used in medical diagnosis involve much lower doses, and the risk from routine diagnostic imaging is considered very small. Radiation from natural background sources (like radon in the ground) or from non-ionizing radiation sources (like cell phones, Wi-Fi, or power lines) has not been proven to cause brain tumors, despite many years of research specifically looking at these questions.
• Inherited Genetic Conditions: A small percentage of brain tumors, estimated at around 5 to 10 percent, are linked to inherited genetic syndromes. The most well-known are:
  • Neurofibromatosis type 1 (NF1) is caused by mutations in the NF1 gene and raises the risk of developing gliomas, particularly low-grade gliomas of the optic nerve and other brain areas.
  • Neurofibromatosis type 2 (NF2) is caused by mutations in the NF2 gene and raises the risk of meningiomas, ependymomas, and schwannomas (including acoustic neuromas/vestibular schwannomas).
  • Li-Fraumeni syndrome is caused by mutations in the TP53 gene and significantly raises lifetime risk for multiple cancers, including brain tumors, bone tumors, breast cancer, and leukemia.
  • Turcot syndrome is a rare inherited condition linked to colorectal polyps and also raises the risk of medulloblastoma or glioblastoma.
  • Von Hippel-Lindau (VHL) syndrome raises the risk of hemangioblastomas, benign but serious tumors of blood vessels, in the brain, spinal cord, and other organs.
  • Gorlin syndrome (Basal Cell Nevus Syndrome) raises the risk of medulloblastoma, particularly the desmoplastic subtype.

• Family History close family member (parent, sibling, or child) with a brain tumor has a slightly higher risk of developing one themselves. In most cases, this is not because of a single known inherited gene mutation; it may reflect shared environmental exposures, gene variants that have not been fully studied yet, or simply chance. A clear family history of brain tumors, especially in multiple relatives or at young ages, is worth discussing with your doctor.
• Immune System Suppression Primary central nervous system (CNS) lymphoma is a type of brain cancer that is significantly more common in people with weakened immune systems, particularly those living with HIV/AIDS or those taking immunosuppressant medications after an organ transplant. As effective antiretroviral therapy for HIV has become widespread, rates of CNS lymphoma in people with HIV have dropped considerably.
• Age increases the risk of most types of brain cancer. Glioblastoma, the most common and aggressive malignant brain tumor, is most often diagnosed in people over 65. However, brain tumors can and do occur at any age, and some types, like medulloblastoma and ependymoma, are more common in children and young adults. The brain tumor landscape is genuinely different between children and adults, with different tumor types, behaviors, and treatment responses.
• Sex Gliomas, including glioblastoma, are slightly more common in men than in women. Meningiomas, on the other hand, are significantly more common in women, occurring at roughly twice the rate as in men. Researchers believe hormonal factors may play a role in the sex differences seen in meningioma risk.
• Race and Ethnicity white Americans have a higher incidence of glioblastoma than Black, Hispanic, or Asian Americans. Meningiomas, however, are more common in Black Americans. The reasons for these differences are not fully understood.

Important reminder: Most people diagnosed with brain cancer have none of the risk factors listed here. If you have been diagnosed, it is not your fault. In the vast majority of cases, there is nothing you did or did not do that caused this to happen.

Factors That May Lower Your Risk Of Brain Cancer

Unlike some other cancers, brain cancer does not have many proven lifestyle-based risk reduction strategies, largely because so little is known about its root causes. However, some findings from research are encouraging.

Allergy and immune activity: Several large studies have found that people who have a history of allergies or a higher level of immune activity actually appear to have a lower risk of developing glioma. Researchers believe this may be because an active immune system helps identify and remove abnormal cells before they become tumors, though this is still being studied.

Avoiding unnecessary radiation to the head: While medical radiation used in diagnosis is generally safe, minimizing unnecessary radiation exposure is always a good idea. This means avoiding unnecessary CT scans or X-rays of the head unless medically needed.

Healthy lifestyle habits: While no specific diet or exercise routine has been proven to prevent brain cancer, maintaining an overall healthy lifestyle, not smoking, eating a balanced diet, staying at a healthy weight, and limiting alcohol consumption support your general health and immune system, which may play a role in cancer prevention.

Awareness of genetic risk: If you have a family history of brain tumors or a known genetic syndrome, speaking with a genetic counselor can help you understand your risk and decide whether genetic testing or closer monitoring is right for you. Early awareness gives you and your doctor more options.

References

1. American Cancer Society. Brain and Spinal Cord Tumor Risk Factors. https://www.cancer.org/cancer/types/brain-spinal-cord-tumors-adults/causes-risks-prevention/risk-factors.html

2. National Cancer Institute. Adult Central Nervous System Tumors Treatment (PDQ) – Patient Version. https://www.cancer.gov/types/brain/patient/adult-brain-treatment-pdq

3. Ostrom QT, et al. CBTRUS Statistical Report: Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2015–2019. Neuro-Oncology. 2022. https://pubmed.ncbi.nlm.nih.gov/36196752/

4. Gunner Johansson, et al. Recent developments in brain tumor predisposing syndromes. Taylor and Frances Online. 2015. https://www.tandfonline.com/doi/full/10.3109/0284186X.2015.1107190#abstract

5. National Cancer Institute. Adult Brain Tumors: Risk Factors. https://www.cancer.gov/types/brain/patient/adult-brain-treatment-pdq

6. American Cancer Society. What Causes Brain and Spinal Cord Tumors in Adults? https://www.cancer.org/cancer/types/brain-spinal-cord-tumors-adults/causes-risks-prevention/what-causes.html