What Are the Side Effects of Radiation Therapy to the Brain?

Brain tumors may be treated with a comprehensive plan that includes radiation therapy, which targets cancer cells and can destroy them effectively. Radiation may be used alone or with other treatments such as surgery and chemotherapy. But can it also cause side effects?

Yes, radiation for primary cancers arising in the brain or secondary cancers that have metastasized to the brain from other organs can cause side effects. These vary with factors including the area treated, radiation dose and individual circumstances.

Side Effects of Radiation Therapy for Brain Tumors

Radiation to the brain can generally cause the following short-term side effects:

• Fatigue
• Hair loss
• Nausea and vomiting
• Headache
• Skin changes
• Cognitive problems, such as memory and speech difficulties
• Seizures

Seizures and headaches may be signs of brain edema (swelling). This is serious and requires urgent medical attention.

Side effects are classified as early or late according to when they occur, such as during or after treatment. 

Early Side Effects: These occur during treatment or within 1 month afterward. They are generally short-lived, mild and manageable:

• Fatigue 
• Skin changes 

Late Side Effects: These may appear from 6 months to several years after treatment ends:

• Memory loss
• Stroke-like symptoms 
• Impaired brain function

Managing Radiation-Related Side Effects

Fatigue

Fatigue is common with many cancer treatments, including radiation therapy. A large majority, around 90% of patients receiving brain radiotherapy, report experiencing fatigue. 

Adequate rest, conserving energy and light physical activity are important during this period. A balanced, healthy diet and sufficient water intake also deserve attention.

Hair Shedding and Hair Loss

Temporary hair loss may develop approximately 2 - 3 weeks after brain radiation begins. Eyebrows and eyelashes may also be affected. 

Preventing hair loss during radiation may not be possible. Hair generally regrows within 3-6 months after treatment. A dermatologist can advise on medication to encourage regrowth. During and after hair loss, people may also:

• Wear a wig or comfortable head covering
• Use sunscreen and wear a hat outdoors
• Use lotion and conditioner if the scalp itches

Skin Changes

Radiotherapy can cause dermatitis, with inflammation, dryness or itching particularly in the treated area. These symptoms generally appear within 1-3 weeks after receiving radiation. 

Doctors or dermatologists can recommend skincare for these changes. People should also use mild, nonirritating soaps and moisturizers, avoid extreme temperatures and protect the treated area from sunlight. For those with symptoms, the American Dermatology Association (ADD) recommends:

• Wash skin very gently with lukewarm water
• Use a gentle, low-pH cleanser when needed
• Avoid sponges, face cloths, exfoliating mitts or loofahs
• Avoid shaving the area
• Moisturize daily (consult a specialist before applying any lotion or cream)

Cognitive Changes

Radiation can damage brain cells, and changes may appear years after treatment. Some people may experience cognitive changes involving memory, attention or problem-solving.

If changes in memory or concentration occur, strategies that may help include: 

• Break tasks into smaller, manageable steps
• Use reminders or organizational tools 
• Do mental exercises or puzzles
• Seek help from occupational therapists or neuropsychologists who offer cognitive rehabilitation techniques

Headaches

Radiotherapy may cause temporary headaches. Over-the-counter painkillers may help simple headaches, but it is important to consult a specialist before taking any medication. 

Headaches may also result from brain edema (swelling), which requires prompt treatment. Patients experiencing headaches during radiation must therefore consult a specialist. 

Nausea and Vomiting

Although nausea and vomiting are common when treatment involves the stomach, gastrointestinal side effects can occur regardless of the area treated. Radiation can cause nausea and vomiting in 50-80% of people, as well as loss of appetite. These generally improve within a few weeks of completing treatment. Small, frequent meals are recommended while symptoms persist. Avoiding fatty or spicy foods may also help, and specialists may prescribe stomach medications.

Nausea may also be a sign of brain edema. People experiencing nausea related to radiation should therefore consult a specialist. 

Seizures

Primary brain tumors, brain metastases and radiation therapy may increase seizure risk. A seizure may indicate brain edema, so anyone having one should consult a specialist without delay. Specialists will generally prescribe medication to manage it. 

Brain Edema

Radiotherapy may cause temporary brain edema (swelling) and increased pressure within the brain, generally within days or weeks after treatment. Symptoms may include:

• Headache
• Nausea
• Seizures

Because these symptoms may indicate brain edema, people should not ignore them or try to manage them with simple medications. They must consult a specialist.

A patient with signs of brain edema is generally monitored in hospital. Anti-edema treatment with drugs such as corticosteroids and mannitol is given for approximately 3-4 days to reduce swelling.

What Are Stereotactic Radiotherapy and Radiosurgery, and Their Side Effects?

Stereotactic radiotherapy and radiosurgery are specialized methods that direct high doses of radiation at specific targets. Their greater precision generally causes fewer side effects than standard radiation. They can nevertheless cause specific side effects depending on the treatment site. For brain tumors, for example, they may cause swelling in surrounding brain tissue.

Side effects can occur at any point during treatment. Most improve within a few weeks afterward, although this may take 2 months. Others may last longer, depending on how long healthy cells need to recover.

Late side effects may improve over time, but some can be permanent. 

To reduce the side effects of radiation to the brain:

• Exercise regularly if possible, but do not start an intense new program without consulting a specialist
• Prioritize adequate rest
• Seek support from family and friends
• Limit alcohol, tobacco and caffeine
• Drink plenty of fluids
• Eat a balanced, healthy diet
• If appetite is a problem, work with a nutrition specialist on a meal plan

Summary: Side Effects of Radiation for Brain Tumors and Their Management

Radiation for primary brain tumors or tumors that have metastasized to the brain may cause side effects depending on the techniques used and individual factors. Late effects can appear months or years afterward, while early effects may occur during or immediately after treatment.

Side effects can be managed. Advances in treatment planning and precise techniques such as stereotactic radiotherapy help minimize them compared with standard radiation. 

Some side effects may signal serious treatment-related conditions, so patients should consult specialists if they experience possible side effects. Specialists can offer optimized options and strategies for managing them.