Brain Tumor Symptoms, Causes & Risk Factors
Posted on June 10, 2026 in Brain Tumors
When it comes to brain tumors, understanding the warning signs can make a critical difference in getting timely medical care. While brain tumors are relatively rare, accounting for less than 2% of all cancers, knowing what to watch for helps you recognize when something needs medical attention.
Understanding Brain Tumors
A brain tumor is an abnormal growth of cells in or around the brain. According to the National Brain Tumor Society, there are more than 120 different types of brain tumors, which vary significantly in how they behave and what symptoms they cause.
Not all brain tumors are cancerous. Approximately 80% of brain tumors are benign (noncancerous), meaning they grow slowly and do not spread to other parts of the body. However, even benign tumors can cause serious problems depending on their location and size. The remaining 20% are malignant (cancerous) and tend to grow more quickly.
Brain tumors affect people differently based on several factors including the tumor’s size, its location in the brain, how fast it grows, and whether it’s benign or malignant. This is why symptoms can vary so widely from person to person.
Common Brain Tumor Symptoms
Brain tumor symptoms fall into two main categories, according to MD Anderson Cancer Center. Global symptoms indicate that something is growing in the brain and causing pressure buildup, while focal symptoms point to where the tumor is located.
General Symptoms That Affect the Whole Brain
These symptoms occur when a tumor grows large enough to increase pressure inside the skull or disrupt overall brain function.
Headaches
The most common symptom, affecting about half of all brain tumor patients. However, having headaches does not mean you have a brain tumor, as headaches are extremely common and usually caused by other conditions.
Brain tumor headaches have distinctive features. According to Scripps Health, these headaches tend to be worse when lying down, especially during sleep, and less severe when you’re up and active. They often feel worse in the morning and may intensify with activities that increase pressure in the head, such as coughing, bending over, or straining during a bowel movement.
Nausea and Vomiting
Persistent nausea and vomiting can indicate increased pressure within the skull. These symptoms often accompany headaches, particularly in the morning.
Seizures
New seizures in an adult are one of the most common signs of certain types of brain tumors, according to Scripps Health. Seizures occur when a tumor disrupts the normal electrical activity in the brain. They don’t always involve full-body convulsions. Some seizures appear as brief lapses in awareness, confusion, unusual sensations like tingling or déjà vu, or even smelling odors that aren’t really there.
Fatigue and Cognitive Changes
Brain tumors can cause persistent tiredness, confusion in everyday matters, memory problems, difficulty following simple commands, and trouble concentrating. These changes often develop gradually and may be subtle at first.
Vision and Hearing Changes
Blurred vision, double vision, loss of peripheral vision, or hearing problems can all signal a brain tumor. The National Brain Tumor Society notes that these symptoms depend heavily on where the tumor is located.
Location-Specific Symptoms
The brain is divided into different regions that control specific functions. Where a tumor grows determines which symptoms appear.
Frontal Lobe Tumors
Located in the front of the brain, the frontal lobe controls personality, decision-making, and movement. Tumors here can cause personality changes, behavioral shifts, mood swings, difficulty speaking, impaired judgment, and weakness on one side of the body. Family members often notice that something seems different about the person but can’t quite pinpoint what.
Temporal Lobe Tumors
The temporal lobes, located on the sides of the brain near the ears, process memories and sound. Tumors in this area commonly cause memory problems, especially difficulty remembering recent events, speech and language difficulties, hearing problems, and unexplained feelings of fear or anger.
Parietal Lobe Tumors
These tumors affect the area behind the frontal lobe that processes sensory information. Symptoms include decreased sensation on one side of the body, difficulty recognizing body position or body parts (called neglect), problems with hand-eye coordination, and confusion distinguishing left from right.
Occipital Lobe Tumors
Located at the back of the brain, the occipital lobe controls vision. Tumors here cause various vision problems: blurred vision, loss of parts of the visual field, visual hallucinations, difficulty recognizing familiar objects or faces, and trouble reading.
Cerebellum Tumors
The cerebellum sits at the back of the head below the occipital lobe and controls balance and coordination. Tumors here cause difficulty walking, problems with balance, trouble with coordinated movements like reaching for objects, and unsteadiness.
Brainstem Tumors
The brainstem controls vital functions like breathing and heart rate. Tumors in this critical area can cause difficulty swallowing, weakness on one side of the face (such as a crooked smile), hearing loss, drowsiness, and behavioral changes.
When Symptoms Require Immediate Attention
According to the Mayo Clinic, you should call 911 or seek emergency care if you experience sudden, severe symptoms that might indicate stroke-like complications from a brain tumor. The University of Utah Health notes that many brain tumors are initially mistaken for strokes because they can cause sudden weakness, numbness on one side of the body, difficulty speaking, or vision changes.
Other warning signs requiring immediate medical attention include:
- The worst headache of your life that comes on suddenly
- Seizures, especially if you’ve never had them before
- Sudden vision loss or severe vision changes
- Difficulty breathing or swallowing
- Loss of consciousness or extreme drowsiness
For non-emergency symptoms, you should still see your doctor promptly if you experience persistent or worsening headaches, new seizures, gradual vision or hearing changes, progressive weakness or numbness, memory problems or personality changes, or any combination of symptoms that concern you.
What Causes Brain Tumors?
The honest answer is that for most brain tumors, doctors don’t know the exact cause. According to the American Cancer Society, brain tumors happen when cells in or near the brain develop changes in their DNA. These changes cause cells to grow uncontrollably and live longer than they should, forming a tumor.
In some cases, a person may be born with changes in certain genes that increase their risk. In other cases, environmental factors like radiation exposure may damage genes. Often, though, the DNA changes appear to happen randomly during a person’s lifetime without any clear cause.
The brain is relatively well-protected from most cancer-causing chemicals found in food or air, which is why environmental factors don’t seem to play a major role in most brain tumors. The gene changes that lead to brain tumors might simply be random events that occur inside cells.
Known Risk Factors of Brain Tumors
While most brain tumors have no clear cause, researchers have identified several factors that can increase risk.
Age
Brain tumors can develop at any age, but they’re most common in two groups: children under 15 and adults over 65. Cancer Research UK notes that risk increases with age, with the highest rates in people between 85 and 89 years old.
Radiation Exposure
The only well-established environmental risk factor is exposure to ionizing radiation, particularly radiation therapy used to treat other cancers. The American Cancer Society explains that this most often occurs in people who received radiation to the head as children for leukemia or other cancers. These radiation-induced brain tumors typically appear 10 to 15 years after treatment, though sometimes not for decades.
It’s important to note that the low-level radiation from routine medical imaging like X-rays and CT scans, while not risk-free, causes far fewer brain tumors than therapeutic radiation doses.
Inherited Genetic Conditions
A small percentage (less than 5%) of brain tumors are linked to inherited conditions. Johns Hopkins Medicine identifies several rare syndromes that increase risk:
- Neurofibromatosis types 1 and 2
- Li-Fraumeni syndrome
- Von Hippel-Lindau disease
- Tuberous sclerosis
- Lynch syndrome
- Turcot syndrome
People born with these conditions have genetic changes that make them more susceptible to developing brain tumors.
Family History
While most people with brain tumors have no family history of the disease, having a close relative (parent, sibling, or child) with a brain tumor does slightly increase your risk.
Weakened Immune System
People with compromised immune systems, such as those with AIDS or who take immune-suppressing drugs after organ transplants, have a higher risk of developing central nervous system lymphoma, a type of brain tumor.
Body Weight
Being overweight or obese increases the risk of meningioma, a usually benign type of brain tumor. Cancer Research UK reports that approximately 2% of brain tumors diagnosed in the UK are linked to excess weight.
Do Cell Phones Cause Brain Tumors?
The possible connection between cell phone use and brain tumors has received significant research attention. The American Cancer Society notes that while some studies have suggested a possible increased risk of certain tumors with heavy cell phone use, most larger studies have not found an increased risk overall. The radiofrequency energy from cell phones is different from ionizing radiation and does not damage DNA in the way that X-rays do. Research continues to monitor this question, but current evidence does not show a convincing link.
When to See Your Doctor
If you’re experiencing symptoms that concern you, especially if they’re new, persistent, or worsening, make an appointment with your doctor. Keep in mind that brain tumors are relatively rare. Many conditions can cause similar symptoms, and most of the time, symptoms like headaches, dizziness, or memory problems have other explanations.
Your doctor will conduct a thorough evaluation, which may include a neurological exam to test your vision, hearing, balance, coordination, reflexes, and strength. If a brain tumor is suspected, imaging studies like MRI or CT scans can help identify abnormalities.
The most important thing is not to ignore persistent symptoms or chalk them up to stress or aging without getting them checked. Early detection of brain tumors, when possible, allows for more treatment options and better outcomes. While we can’t prevent most brain tumors, we can take symptoms seriously and seek prompt medical evaluation when something doesn’t feel right.
At SERO, our radiation oncology specialists work closely with neurosurgeons and other cancer care providers to develop personalized treatment plans for brain tumors. If you or a loved one has been diagnosed with a brain tumor and wants to understand your radiation therapy options, our team is here to help guide you through your treatment journey.
