Types of brain tumors

Types of Brain Tumors in Adults:
Primary & Metastatic Tumors

Understanding the different types of brain tumors in adults is crucial for patients and their loved ones. Whether you or your loved ones is newly diagnosed, experiencing a recurrence or regrowth, or seeking more information, knowing the specific type of tumor can help guide treatment decisions.

Primary Brain Tumors

Primary brain tumors in adults start in the brain or its surrounding tissues. These tumors can range from benign (non-cancerous) to malignant (cancerous), and each type behaves differently.

• Gliomas – These are the most common type of primary brain tumors in adults, arising from glial cells, which support and protect nerve cells. Gliomas include:
  • Astrocytomas – Develop from astrocytes, which is a type of glial cell.
    • Glioblastoma (GBM) – A type of astrocytoma. GBM is considered to be the most aggressive type of brain tumor in adults.
  • Oligodendrogliomas – Originate in oligodendrocytes, which are cells that create the protective myelin sheath around nerves.
  • Ependymomas – Form in the lining of the ventricles (fluid-filled spaces) in the brain or the spinal cord.
• Meningiomas – These primary brain tumors in adults develop from the meninges, the layers of tissue covering the brain and spinal cord. Meningiomas are typically benign but can still cause debilitating side effects if they grow and press on surrounding structures.
• Pituitary Tumors – These primary brain tumors in adults form in the pituitary gland, which controls various hormones in the body. Most pituitary brain tumors are benign adenomas.
• Schwannomas – These primary brain tumors in adults arise from Schwann cells, which help insulate nerves. The most common type is vestibular schwannoma (also called acoustic neuroma), which affects the nerve responsible for balance and hearing.

Metastatic Brain Tumors

Metastatic brain tumors, also known as secondary brain tumors, occur when cancer cells from other parts of the body spread to the brain. These are much more common than primary brain tumors in adults. Cancers that commonly metastasize to the brain include:

• Lung cancer
• Breast cancer
• Melanoma (skin cancer)
• Kidney cancer
• Colon cancer

Because metastatic brain tumors in adults start in another part of the body, treatment focuses on both the brain tumor and the original cancer. Treatments may include surgery, radiation, targeted therapy, or a combination of options.

Benign vs. Malignant Brain Tumors

Brain tumors in adults can be classified based on how they grow and behave:

• Benign brain tumors – Non-cancerous, generally slow-growing, and less likely to spread. However, even benign tumors can cause symptoms by pressing on areas of the brain.
• Malignant brain tumors – Cancerous and often more aggressive. These tumors tend to grow quickly and can invade nearby brain tissue.

Understanding Tumor Regrowth and the Importance of Timely Treatment

After a brain tumor is removed or treated, it’s possible for the tumor to grow back. This is called tumor recurrence or tumor regrowth. Some tumors, especially aggressive or malignant ones like glioblastoma, can start to grow again quickly – even between treatments.

In some cases, there may be a delay between surgery and the start of radiation or other therapies. During this time, tumor cells that were not fully removed can begin to multiply again and grow back, which may impact the success of future treatments.

That’s why it’s so important to have a treatment plan that starts working as soon as possible after surgery. Talk to your care team about treatment options designed to reduce the risk of tumor regrowth and protect healthy brain tissue.

GammaTile^®* for brain tumors in adults is one example of a radiation treatment placed during surgery, so it starts fighting tumor cells right away—without delay.¹

Learn more about GammaTile and how it may help reduce the risk of tumor recurrence.

Understanding Brain Tumors in Adults

If you, a family member, or a friend has been diagnosed with a brain tumor, you are not alone. Learning about your condition can help you feel more in control and make informed decisions about your care.

The information on this page is intended to be a helpful resource for understanding brain tumors in adults. However, it is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with your doctor or healthcare provider to determine the best treatment plan for your specific condition.

Download our Patient Discussion Guide to help you ask the right questions, understand your diagnosis, and explore your treatment options with your care team. We encourage you to use this during appointments to feel more confident, prepared, and in control of your care.

Next: Learn more about recurrent brain tumors.