Many types of tumors can involve the brain, from benign, slow-growing tumors, to aggressive rapidly growing cancers.
Malignancies can be primary brain tumors – tumors that started in the brain – or metastatic, meaning cancers that spread to the brain from some other organ or site in the body.
The most common adult primary brain tumors are called gliomas, such as glioblastoma multiforme. Metastatic cancers come to the brain from other sites, such as cancers of the lung or breast, or indeed almost any part of the body where malignancies start.
Radiation therapy is commonly used in the treatment of tumors involving the brain, either as the primary mode of therapy, or in conjunction with surgery, to treat any cancer cells left behind.
Radiation can be used in two ways against brain tumors:
- Focused, to treat a small volume in hopes of eradicating a specific lesion. Focused, or stereotactic, radiation uses multiple beams of radiation tightly targeted to the tumor, which allows for very high doses of radiation in the target but spares the surrounding normal tissue. Intensity Modulated Radiation Therapy (IMRT) is often used in the treatment of brain tumors.
- Directed more broadly to encompass a wider volume of the brain where tumor cells might have spread.