Brain cancer refers to a growth of abnormal cells in the brain. These tumors can start in the brain (primary brain tumors) or spread to the brain from cancers elsewhere in the body (metastatic tumors). Some brain tumors are non-cancerous (benign) while others are malignant “brain cancers” that grow quickly and invade tissue. Even benign tumors can cause serious symptoms by pressing on brain structures. This article provides an overview of brain cancer, including the main types, early warning signs, how it’s diagnosed, key statistics, and new developments in detection.
Brain tumors are classified by the cells they originate from. Below are some of the most common types in older adults:
Glioblastoma (GBM): An aggressive cancer arising from glial (supportive brain) cells, and the most common malignant brain tumor in adults. GBM accounts for about 16% of adult primary brain tumors. It grows rapidly and is difficult to cure; five-year survival rates are very low (around 6–9% for patients in their mid-40s to mid-50s). GBM often affects adults over 45 and can cause headaches, personality changes, or seizures as it progresses.
Meningioma: A tumor of the meninges, the membranes covering the brain and spinal cord. Meningiomas are usually benign (non-cancerous) and slow-growing. They are the single most common brain tumor type, making up roughly 46% of adult brain tumors. Meningiomas often occur in people over 60 (more frequently in women) and can grow for years before causing symptoms like headaches or focal neurological deficits. Because they are often treatable (usually with surgery and/or radiation), survival rates are high – about 79% five-year survival for patients in their late 40s and 50s.
Astrocytoma: A tumor originating from astrocytes, the star-shaped glial cells. This category includes a range of gliomas from lower-grade (grade II) astrocytomas to grade III (anaplastic) astrocytomas. These tumors tend to grow slower than GBM (which is actually considered a grade IV astrocytoma) and often affect middle-aged adults. While they are malignant, they generally have better outcomes than GBM; for example, a diffuse low-grade astrocytoma has around a 46% five-year survival in people age 45–54. Astrocytomas can cause seizures, cognitive changes, or weakness, and sometimes progress into more aggressive forms over time.
Metastatic Brain Tumors: Cancer that has spread to the brain from another organ (such as the lung, breast, colon, or skin). Metastatic tumors (also called secondary brain tumors) are actually more common than primary brain cancers. Approximately 200,000 new cases of brain metastases are diagnosed in the U.S. each year – several times the number of primary brain tumors. Virtually any cancer can spread to the brain, but lung cancer, breast cancer, melanoma, and kidney cancer are among the most likely to do so. These tumors often present with symptoms similar to primary brain tumors. Treatment typically focuses on controlling the spread (through therapies like radiation or surgery) and managing symptoms.
Brain tumors can produce a wide range of symptoms. In adults over 45, it’s especially important to recognize new or unusual symptoms and not simply attribute them to “normal aging.” Early detection of a brain tumor can greatly improve outcomes. Common early signs include:
Frequent headaches: Especially headaches that are new, persistent, and worse in the morning or wake one from sleep. These may be accompanied by nausea or vomiting. While many adults get headaches, a pattern of headaches that steadily worsens over time or is coupled with other neurological symptoms should be evaluated by a doctor.
Seizures: A seizure in someone with no prior history of epilepsy is a red flag for a brain tumor until proven otherwise. About one-third of brain tumor patients experience seizures as an initial symptom. Any sudden convulsion, unusual spell of confusion, or loss of consciousness warrants prompt medical attention.
Cognitive or personality changes: Brain tumors can subtly affect memory, thinking, and mood. Family members might notice the person becoming more confused, forgetful, or having trouble following conversations and simple commands. Some tumors cause personality changes – for example, a formerly calm person may become easily irritable or apathetic. Such changes, especially if they worsen over weeks or months, should be investigated.
Weakness or balance problems: Unexplained weakness or numbness in an arm or leg, or clumsiness and balance difficulty (stumbling, swaying while walking), can indicate a tumor affecting the motor areas or cerebellum. Sometimes this is mistaken for stroke; unlike a stroke, tumor symptoms often develop gradually. If you notice progressive loss of coordination or one-sided weakness, consult a physician.
Vision or speech disturbances: Tumors in certain brain regions can cause blurred or double vision, loss of peripheral vision, or other visual changes. Likewise, a growth affecting language centers may lead to speech problems – difficulty finding words, slurred speech, or trouble understanding others. These symptoms, particularly if they are new and getting worse, should be promptly evaluated.
Keep in mind that the symptoms depend on the tumor’s location and growth rate. A slow-growing meningioma might cause very subtle issues for years, whereas an aggressive glioblastoma can produce symptoms that escalate over a short time. In any case, new neurological symptoms in midlife or later age should not be ignored.
If a brain tumor is suspected, doctors will perform a series of evaluations and tests to confirm the diagnosis and identify the tumor type. The typical steps include:
Neurological exam: The first step is usually a thorough exam of the nervous system. The doctor will check your reflexes, muscle strength, vision, hearing, balance, coordination, and cognitive function. Specific deficits (for example, weakness in the left arm or trouble with peripheral vision) can provide clues about where in the brain a tumor might be located.
Imaging tests: If exam findings suggest a possible brain issue, imaging is done to look inside the skull. A CT scan (computed tomography) is a quick X-ray based scan that may be done initially, especially in emergency situations or to rule out other problems. However, the preferred imaging for brain tumors is MRI (magnetic resonance imaging). An MRI provides a more detailed view of brain tissue and tumors. Often, a contrast dye is injected to make any tumor show up more clearly on the MRI. MRI can not only detect a tumor but also give an idea of its size, location, and possibly its nature. In some cases, specialized MRI techniques (such as MR spectroscopy or perfusion MRI) or a PET scan (positron emission tomography) are used to further characterize the lesion. These advanced imaging tools can help distinguish tumor tissue from normal brain or scar tissue and assess how active or aggressive the tumor might be.
Biopsy and pathology: Imaging alone can strongly suggest a tumor, but the definitive diagnosis comes from examining tumor cells under a microscope. To obtain cells, a biopsy is performed. In many cases, if the tumor is accessible and operable, a neurosurgeon will remove as much of it as safe during surgery and send samples to the lab. If the tumor is in a tricky location not easily removable, a smaller stereotactic needle biopsy can be done. A pathologist then analyzes the tissue to determine the tumor type and its grade. Modern molecular tests may also be done on the biopsy sample to look for genetic markers that can guide treatment.
Additional tests may include blood work or a spinal fluid exam in certain cases, but the neurological exam, imaging, and biopsy are the cornerstone of diagnosis.
Brain cancer is relatively uncommon, but its impact is significant, especially in older adults. Here are some key statistics and facts for the United States:
How common is it? In 2025, an estimated 24,820 new malignant brain or spinal cord tumors will be diagnosed in the U.S. This figure includes all ages. However, if one counts benign tumors as well, the total number is much higher. Approximately 79,000 adults over age 40 were expected to be diagnosed with a primary brain tumor in 2023.
Age distribution: The risk of brain tumors increases with age. The median age at diagnosis is around 60 years. Brain and other central nervous system cancers are most frequently diagnosed in people between 65 and 74. Over two-thirds of brain tumor cases occur in those above 40. In older adults, brain tumors rank among the more common cancers – they are the seventh most common type of tumor and the sixth leading cause of cancer-related death in people over 40.
Prevalence: Thanks to advances in treatment, many patients live with brain tumors for years. As of 2021, about 182,000 people in the U.S. were living with a diagnosis of brain or other nervous system cancer.
Survival rates: Overall, considering all primary brain tumors (including benign), the five-year survival rate for adults is around 72%. For malignant brain tumors in older adults, survival is much lower. Among adults aged 40 and over, only about 21% survive five years. Glioblastoma has especially poor outcomes – around 9% for ages 45–54, and around 6% for ages 55–64. For benign tumors, survival is much better: about 90% in those over 40. For example, meningioma patients typically see five-year survival rates of 80% or higher. Grade II/III astrocytomas fall in between, with survival rates from 29% to 46% in middle-aged adults, depending on grade.
It’s important to remember that survival statistics are averages. Individual outcomes vary based on tumor type, location, genetics, treatment options, and overall health.
Most brain cancers do not have a clear cause, but certain factors can increase the risk:
Advancing age is one of the strongest risk factors. Risk increases significantly after age 45 and peaks in the elderly.
Sex: Women are more likely to develop benign brain tumors, while men are more likely to develop malignant ones like glioblastoma.
Radiation exposure: High-dose ionizing radiation to the head increases the risk, especially when received for previous cancer treatments.
Genetic conditions: Rare syndromes like NF1, NF2, Li-Fraumeni syndrome, and tuberous sclerosis can increase risk, though they are uncommon.
Metastasis from other cancers: Lung, breast, kidney, and skin cancers are most likely to spread to the brain.
Factors like cell phone use, wireless networks, or prior head injuries have not been shown to meaningfully increase risk.
Early detection is key, and recent advances show promise:
Advanced imaging: Modern MRI techniques such as MR spectroscopy, perfusion MRI, and PET scans help distinguish tumors from healthy tissue or scarring.
Liquid biopsy: New blood tests are being developed that detect tumor DNA fragments in the blood, offering a less invasive way to diagnose brain tumors. These are still under research but show high accuracy.
Artificial intelligence: AI is being trained to spot brain tumors on MRI scans, improving early detection and possibly even identifying tumor types non-invasively.
