Brain Cancer Risks: Separating Fact From Fiction

Brain cancer is not common. Fewer than 2% of all cancers start in the brain. Today, about 1 million people in the U.S. are living with brain cancer that started in the brain (rather than spread to the brain). Myths about potential brain cancer risks such as cellphone or microwave use often make the rounds in the media, causing panic. While research is still evolving on some brain cancer risks, much is known about what does and doesn't cause brain cancer. Most of the evidence is reassuring. 

Have you had radiation therapy to treat a head or neck cancer when you were younger? If so, that radiation treatment may increase your chances of having a brain cancer down the road, typically around 10 to 15 years later. Ionizing radiation uses high-energy X-rays, gamma rays, or ultraviolet rays to kill cancer cells but can damage the genetic material (DNA) in your cells, potentially setting the stage for brain cancer. Over the years, doctors have developed smarter, safer, and more focused techniques that limit exposure to ionizing radiation during cancer treatment, lessening the risk of brain cancer going forward.

Just 5% to 10% of people with brain tumors have a family history of the cancer. Some rare inherited conditions can increase your chances of getting brain cancer, including neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), Li-Fraumeni syndrome, tuberous sclerosis, and von Hippel-Lindau disease. If you have a condition that places you at a higher risk of brain cancer, your doctor can give you personalized advice on what to do to stay ahead of this risk.

If you've worked with certain chemicals such as vinyl chloride, pesticides, fertilizers, or solvents, you may have a higher risk of brain cancer. The key word is may. Some research points to an increased risk, but other studies do not. The Environmental Protection Agency is looking into many of these chemicals, including vinyl chloride, and plans to place stricter regulations on their use. You can also protect yourself and your family by leaving dirty clothes at work, showering before you leave work, and washing your work clothes separately.

Getting older increases your risk of brain cancer, among other diseases, with 61 being the average age of diagnosis. Men seem to be more likely to get brain cancer than women. Exactly why is not fully understood, but it likely stems from differences in sex chromosomes and sex hormones such as testosterone and estrogen. There are not any brain cancer screening recommendations based on your age or gender. See your doctor if you have any symptoms that could signal brain cancer, such as headaches, vomiting, blurred vision, balance problems, or seizures.

If your immune system is weak because of another condition or because you take drugs to dial down your immune system after an organ transplant, you may be at risk of a specific type of brain cancer. This may be because you're more likely to come down with the Epstein-Barr virus and its complications, including lymphoma of the brain. Still, your overall risk is very low, as these cancers are very rare.

Medical imaging tests that use radiation, such as X-rays or CT scans, deliver much lower levels than what's used during cancer treatments. If there is any increase in brain cancer risk, it is likely to be very small. To be extra safe, most doctors recommend these tests only when absolutely necessary. If you are concerned, ask if ultrasound and magnetic resonance imaging tests, which don’t use ionizing radiation, are options.

The World Health Organization (WHO), the United Nations' global public health group, recently published a sweeping review of more than 60 studies on brain cancer and cellphone use. No connection was found between cellphone use and brain cancer, even among people who use their cellphones for many hours a day and have been doing so for more than a decade. To be extra safe, avoid making calls when the signal is weak, as this causes cellphones to boost radiofrequency transmission power. Also, text rather than talk when you can.

Bluetooth headphones and earbuds may actually reduce radiation exposure, as these devices emit up to 400 times less radiation than cellphones. Exposure from Wi-Fi devices is also considerably lower than from cellphones. Radiofrequency is a type of non-ionizing radiation, which means it is not strong enough to change your DNA or cause cancer. Both Wi-Fi and Bluetooth devices emit levels of radiofrequency radiation that fall far below the guidelines set by of the International Commission on Non-Ionizing Radiation Protection.

It's safe to use your microwave oven. These ovens give off low-energy radiofrequency radiation to heat food and save time. The oven only makes 'microwaves' when the door is shut and the oven is on, keeping the waves contained. In the U.S., government standards limit the amount of radiation that can leak from a microwave oven to a level that's far below what could harm you or your family.

Power lines do emit radiation. Research in the 1970s suggested that living near them may increase the risk of kids developing blood cancers. There is no solid evidence that living near power lines can cause brain cancer at this point. The International Agency for Research on Cancer (IARC) says that the evidence is far from conclusive. The radiation that power lines emit isn't strong enough to damage DNA or cause cancer. Overall brain cancer rates in the U.S. have not increased as power lines have become more prominent, which experts find very reassuring.

Consuming sugar substitutes like aspartame or lots of processed foods, such as packaged cookies and cakes and sugary soft drinks, can take a toll on your health in general, but neither seems to increase your risk of brain cancer. Use artificial sweeteners every once in a while, if it helps to keep your blood sugar in the normal range. Why? A recent study from the IARC shows that people with type 2 diabetes, diseases of the heart and blood vessels, or with both are more likely to die of cancer – including brain cancer – than those who don't have those diseases. Limiting processed foods in favor of whole grains, fruits, and vegetables as part of an overall healthy diet is always a good call.

Brain cancer is rare, and most people's risk is extremely low. After decades of use and study, experts agree that low-level radiation from everyday objects such as cellphones, Wi-Fi, and microwaves doesn't increase your risk of brain cancer. If you're concerned about symptoms, have a history of radiation to your brain, or have an inherited condition linked to brain cancer, work with your doctor to come up with an action plan to stay on top of your health.