If you've ever had a killer headache, you've undoubtedly also had the nagging worry: Could it be a brain tumor?

Headaches may indeed be a symptom of brain cancer, but they’re typically a very late symptom, says Lynne Taylor, MD, director of neuro-oncology at Virginia Mason Medical Center in Seattle, and a member of the American Academy of Neurology. Symptoms such as confusion are much more likely in the early stages of brain cancer, notes Taylor.

SafeBee turned to Taylor, the American Cancer Society and the National Cancer Institute (NCI) to answer other frequently asked questions about brain cancer.

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How common is brain cancer?

Brain cancer is relatively rare compared to other types of cancer, including breast, lung, prostate, colon and bladder cancers, according to the NCI. For example, the NCI estimates that nearly 231,000 new cases of breast cancer will be diagnosed in the U.S. in 2015 versus 23,000 cases of brain and other nervous system cancers.

More than 15,000 people are expected to die of brain cancer in 2015.

What are the types of brain tumors?

Brain cancer can start in nearly any of the many types of tissues and cells in the brain or the spinal cord. The types of brain tumors include:

  • Meningiomas. These slow-growing tumors affect the layers of tissue that surround the outer part of the brain and spinal cord. They account for about one of every three brain and spinal cord cancers and are common in middle-aged and older women. They are often benign. Actresses Elizabeth Taylor and Mary Tyler Moore reportedly had them (and had them successfully removed).
  • Glioblastomas. Usually malignant, these tumors, a type of glioma, are aggressive and often fatal. They start in the brain's glial cells, which surround and support the all-important nerve cells. Former senator Edward "Ted" Kennedy died from a glioma, probably a glioblastoma multiforme.
  • Oligodendrogliomas. These tumors, which also start in the brain’s glial cells, often respond to treatment. One type, anaplastic oligodendrogliomas, can be aggressive and can strike younger people. 

What are the symptoms of brain cancer?

"Personality changes are most common," Taylor says. "Sometimes people are thought to be depressed. There can be confusion and seizures."

Seizures related to brain cancer can be so brief that people do not realize what they are, she says. Sometimes they’re mistaken for a stroke.

Weakness or sensory loss in half the body can be a symptom. So can losing control of a motor function in the hand or foot, visual problems, nausea and vomiting, balance problems and headaches.

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Who gets brain cancer?

Overall, men are more likely than women to develop brain cancer, Taylor says. Meningiomas, however, are more common in women. The lifetime risk of developing brain or other nervous system cancer is 1 in 140 for men and 1 in 180 for women. People ages 55 to 64 are most likely to be diagnosed with brain cancer.

Younger adults can and do get brain cancers. These can be fast growing and aggressive. Most brain cancers are not linked to any known risk factors, according to the American Cancer Society. Most have no obvious cause.

A neurological exam is the first test done if brain cancer is suspected. This will be followed by imaging tests such as MRI and lab tests such as an EEG and lumbar puncture (aka spinal tap). A biopsy can help diagnose the exact type of tumor.

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Why is brain cancer so difficult to treat?

Cancer in the brain is especially tough to treat because ''you have an organ confined within a bony skull," Taylor says. "If you have a tumor in your belly, your belly just gets bigger and bigger." The brain is much more complicated. "When anything grows in the brain, pressure builds up. You have to open the bone to get to the tumor." The tumor may also be in a location that's inoperable, Taylor adds.

How likely is long-term survival?

Survival rates are much lower for brain cancers than for some other cancers and vary depending on the tumor type. However, survival has been increasing slowly. In 1975, the five-year survival rate generally was less than 23 percent, according to the NCI. By 2007, the five-year survival rate was 35 percent.

With newer treatments, patients are living longer, Taylor says. These days, many doctors who treat brain cancer can report they have a patient who beat the odds and lived 10 or 15 years after the diagnosis, Taylor says. "Things are definitely improving for a small percent who are going to be long-term survivors," she adds.

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Kathleen Doheny is a Los Angeles journalist specializing in health, behavior and fitness topics.