Radiation Therapy For Glioma: Weighing Risks & Benefits
- Radiation therapy is one of the most effective treatments available for people with gliomas. It uses targeted, high-energy beams to slow tumor growth and help improve symptoms such as headaches, seizures, or neurological changes.
- However, it can cause both short-term and long-term side effects.
- Fortunately, advances in surgery, medications, and understanding of tumor biology mean that some patients — especially those with lower-grade gliomas — may be able to delay radiation for years or, in some cases, avoid it entirely.
- Common short-term side effects can include things like fatigue, hair loss in the treatment area, and headaches, while long-term side effects might include cognitive changes like memory and processing speed.
“Radiation is a very effective treatment for glioma. We historically have used it for both IDH mutant gliomas and IDH wild type gliomas such as glioblastoma,” Dr. Nicolas Gonzalez Castro, a neuro-oncologist at Dana-Farber Cancer Institute, tells SurvivorNet. “But it’s a treatment that is associated with neurotoxicity, with injury to the cells of the brain that are not tumor cells, but still receive relatively high doses of radiation.”
Read MoreHow Is Radiation Treatment Delivered?
Radiation therapy for glioma is typically given for five days, from Monday through Friday, over several weeks. Each treatment session is brief — often just 10 to 20 minutes — and feels similar to getting an X-ray. Here is a breakdown of what to expect:- Planning Scan (Simulation): Before radiation begins, you will have a special CT scan used to design your treatment plan. A custom mask is made to keep your head still. The masks are lightweight and molded to your face, but do not block breathing or vision. This ensures radiation is delivered safely and precisely every day.
- Treatment Planning: Your radiation oncologist, along with medical physicists and dosimetrists, uses advanced computer programs to map the exact location of your tumor, avoid healthy brain tissue as much as possible, and choose the safest and most effective dose.
- Daily Treatments: During each session, you will lie comfortably on the treatment table with your mask on. The machine (called a linear accelerator) adjusts around you. You do not feel the radiation — there is no heat, pain, or burning sensation. Most people can drive themselves to and from treatment.
Depending on the type and grade of the tumor, your doctor may use different types of radiation, including:
- IMRT (Intensity-Modulated Radiation Therapy): The most common, allows precise targeting
- Proton Therapy: May reduce radiation dose to healthy brain tissue in select patients
- Stereotactic Radiosurgery (SRS): Used rarely for gliomas but may be used for small, well-defined areas or recurrences
What Are The Side Effects?
Radiation is generally well tolerated, but some side effects can occur. These depend on the tumor’s location, the total dose, and your individual sensitivity.
Short-term side effects, which may occur during treatment or shortly after but are usually temporary, may include:
- Fatigue (very common)
- Hair loss in the treatment area
- Scalp irritation or dryness
- Headaches or pressure sensations
- Nausea, especially with tumors near certain brain regions
- Temporary worsening of symptoms due to swelling
Your doctor may prescribe steroids or other medications to help reduce swelling and symptoms.
Long-term side effects, which present or continue long after treatment has stopped, can include:
- Cognitive changes (memory, processing speed)
- Radiation necrosis, an area of inflammation that can mimic tumor regrowth
- Hormone changes if treatment affects the pituitary gland
- Stroke-like symptoms or very late secondary tumors (rare)
Your radiation team will monitor you carefully for any signs of these issues and treat them promptly if they arise.
Can Radiation Be Avoided Or Delayed?
In many cases, radiation can be postponed without harming outcomes. This depends on tumor type and patient factors.
Your care team might recommend waiting if you have:
- IDH-mutant, low-grade glioma
- A tumor that was mostly or completely removed with surgery
- Minimal symptoms
- Slow tumor growth on MRI
- Favorable molecular markers, such as 1p/19q codeletion
In these situations, your doctors may follow a strategy called “active surveillance,” where you have regular MRI scans and clinical check-ins but do not immediately receive radiation.
Why Delay Radiation?
“Despite the fact that we have made a lot of progress in terms of how we target radiation, there is still collateral damage to other cells,” Dr. Castro explains.
“And over time … oftentimes several decades, we see the cumulative effect of radiation in their thinking and their ability to remember things [and] to make decisions,” he adds.
Your team may recommend avoiding radiation (when it is safe to do so) to reduce exposure to potential long-term side effects, preserve cognitive function for as long as possible, allow younger patients to continue working, studying, or caring for family, maintain quality of life before more intensive therapy is needed, or in favor of trying newer treatment approaches.
Questions To Ask Your Doctor
- Is it safe to delay radiation in my case?
- If radiation is recommended, what can we do to reduce the likelihood of side effects?
- How will I be monitored during treatment?
- Who can I contact if I experience long-term side effects?
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