Radiation Therapy vs. Chemotherapy for Brain Tumors

By The Preston Robert Tisch Brain Tumor Center

August 26, 2026

Radiation Therapy vs. Chemotherapy: What Brain Tumor Patients Should Know

Originally published Dec. 2023, updated August 2026.

When you or a loved one is diagnosed with a brain tumor, treatment decisions can quickly become overwhelming. Radiation therapy and chemotherapy are two important treatments used in brain tumor care, but they work in different ways and are recommended for different reasons. Depending on the tumor type, grade, molecular characteristics, location, previous treatment, and overall health, a care team may recommend radiation therapy, chemotherapy, both treatments, or another approach entirely.

Understanding the difference between radiation therapy vs. chemotherapy can make conversations with your medical team easier. Radiation generally delivers treatment to a specific area of the brain, while chemotherapy uses medications to target cancer cells. Neither treatment is universally "better" than the other; the appropriate approach depends on the individual diagnosis and treatment goals.

Key Takeaways: Radiation Therapy vs. Chemotherapy

Radiation therapy uses high-energy radiation to damage tumor cells in a targeted area.
Chemotherapy uses anticancer drugs to kill cancer cells or stop them from growing and dividing.
Radiation is a localized treatment, while many chemotherapy drugs are systemic.
Some brain tumors are treated with radiation and chemotherapy together.
Treatment recommendations depend on tumor type, grade, molecular features, location, previous treatments, and overall health.
Side effects differ between treatments and vary from patient to patient.
Surgery, targeted therapy, immunotherapy, clinical trials, and active surveillance may also be part of a brain tumor treatment plan.

What Is the Difference Between Radiation Therapy and Chemotherapy?

Radiation therapy uses focused energy to treat a specific area, while chemotherapy uses medications to target cancer cells. Radiation is delivered directly to the brain tumor or tumor site, whereas chemotherapy may circulate through the bloodstream to reach cancer cells throughout the body. Some brain tumor treatment plans use both therapies because they can work together.

The distinction is important because the two treatments have different delivery methods, treatment schedules, side effects, and roles in brain tumor care.

How Does Radiation Therapy Work for Brain Tumors?

Radiation therapy uses high-energy beams, such as X-rays or other forms of radiation, to damage the DNA of tumor cells. When the damage prevents cancer cells from continuing to grow and divide, the tumor may shrink or its growth may be controlled. Modern radiation techniques use detailed imaging and treatment planning to target the tumor while limiting exposure to surrounding healthy tissue.

Radiation therapy is a localized brain tumor treatment that uses carefully planned doses of radiation to target tumor cells.

Depending on the diagnosis, radiation may be used:

After surgery
When surgery cannot safely remove the tumor
As part of initial treatment for certain malignant brain tumors
To control tumor growth
To treat certain recurrent tumors
To treat brain metastases

Radiation therapy may be delivered using techniques such as external beam radiation therapy, intensity-modulated radiation therapy (IMRT), stereotactic radiosurgery, or other specialized approaches. The appropriate technique depends on factors such as tumor size, location, number of tumors, and treatment goals.

How Does Chemotherapy Work for Brain Tumors?

Chemotherapy uses medications to kill cancer cells or prevent them from growing and dividing. Some chemotherapy drugs can cross the blood-brain barrier, while others may be delivered using specialized approaches designed to reach the tumor or surrounding area.

Chemotherapy is a drug-based treatment that may be used before, during, or after other brain tumor treatments depending on the diagnosis.

Chemotherapy may be administered:

By mouth
Through an IV
Through specialized drug-delivery methods in selected circumstances

One chemotherapy drug commonly used in the treatment of certain adult brain tumors is temozolomide. It is used with radiation therapy for newly diagnosed glioblastoma and may then be continued as maintenance treatment.

However, chemotherapy is not appropriate for every brain tumor. Whether it is recommended depends on the tumor's specific characteristics.

When Is Radiation Therapy Used for Brain Tumors?

Radiation therapy can play an important role in treating both primary brain tumors and tumors that have spread to the brain from another part of the body.

Radiation therapy is often used when doctors need to target tumor cells in a specific area of the brain.

It may be recommended:

Following surgery
When a tumor cannot be completely removed
When surgery is not considered safe or appropriate
For certain high-grade tumors
For certain brain metastases
To control symptoms associated with tumor growth
For some recurrent tumors

The timing and type of radiation depend heavily on the diagnosis. For example, radiation plays a major role in treating many high-grade gliomas, while some lower-grade tumors may be monitored or treated with other approaches depending on their characteristics.

When Is Chemotherapy Used for Brain Tumors?

Chemotherapy is used for specific brain tumor types and situations rather than as a universal treatment for every patient.

Chemotherapy may be recommended when a tumor is known to be responsive to a particular drug and when the potential benefits outweigh the risks and side effects.

Chemotherapy may be considered:

After surgery
During and after radiation therapy
For certain high-grade gliomas
For some recurrent brain tumors
When specific molecular or pathological features support its use
As part of a clinical trial

For example, NCI identifies surgery followed by radiation therapy and chemotherapy as a treatment option for newly diagnosed glioblastoma.

Treatment decisions can also change if a tumor returns. Recurrent brain tumors do not necessarily have the same treatment plan as newly diagnosed tumors, and options may include surgery, radiation, chemotherapy, targeted therapy, or clinical trials depending on the individual case.

Can Radiation Therapy and Chemotherapy Be Used Together?

Yes. Radiation therapy and chemotherapy are sometimes used together as part of a coordinated brain tumor treatment plan.

Combining radiation and chemotherapy may allow physicians to target tumor cells using two different treatment approaches.

One well-established example is newly diagnosed glioblastoma. NCI identifies surgery followed by radiation therapy with concurrent chemotherapy, followed by additional chemotherapy, as a standard treatment approach for many patients with newly diagnosed glioblastoma.

The exact treatment schedule varies based on:

Tumor type
Tumor grade
Molecular characteristics
Patient age
Overall health
Previous treatment
Treatment goals

Using both treatments does not mean that every patient will receive the same combination or schedule.

Radiation Therapy vs. Chemotherapy: Which Is Better?

There is no single treatment that is better for every brain tumor patient.

The best treatment depends on the tumor, the patient, and the goals of treatment—not simply whether radiation or chemotherapy is more powerful.

A treatment team may consider:

Tumor type: Different brain tumors respond differently to treatment.
Tumor grade: More aggressive tumors may require more intensive treatment.
Molecular characteristics: Molecular testing can provide information that influences treatment decisions.
Tumor location: The location can affect whether surgery or radiation is appropriate.
Previous treatment: Treatment plans may change when a tumor recurs.
Overall health: Age, other medical conditions, and functional status can influence treatment recommendations.
Patient preferences: Quality of life and individual goals are important parts of treatment planning.

This personalized approach is why two people with brain tumors may receive very different treatment plans.

Radiation Therapy vs. Chemotherapy Side Effects

Both treatments can cause side effects, but the type and severity vary considerably.

Side effects depend on the treatment, dose, schedule, tumor location, and individual patient. Your care team can help anticipate and manage them.

Possible Radiation Therapy Side Effects

Patients receiving radiation to the brain may experience:

Fatigue
Headaches
Scalp irritation
Hair loss in the treated area
Nausea
Brain swelling
Cognitive or memory changes in some circumstances

The likelihood and severity of side effects depend on the area being treated, radiation dose, treatment duration, and individual factors.

Possible Chemotherapy Side Effects

Depending on the medication, chemotherapy may cause:

Fatigue
Nausea
Changes in appetite
Changes in blood counts
Increased infection risk
Constipation or diarrhea
Other medication-specific effects

Not every patient experiences the same side effects, and supportive medications can help manage many treatment-related symptoms.

How Long Do Radiation Therapy and Chemotherapy Take?

Treatment schedules vary significantly depending on the tumor and treatment plan.

Radiation Therapy

Conventional external beam radiation therapy is often delivered in multiple sessions over several weeks. Other approaches, such as stereotactic radiosurgery, may be delivered in a single session or a small number of sessions.

Chemotherapy

Chemotherapy is frequently administered in cycles, with treatment periods followed by breaks that allow the body to recover. The number and length of cycles depend on the medication and diagnosis.

For some patients, chemotherapy and radiation are administered concurrently. For others, one treatment may follow another.

What Other Treatments May Be Used for Brain Tumors?

Radiation and chemotherapy are only two components of modern brain tumor care.

Depending on the diagnosis, treatment may also include surgery, targeted therapy, immunotherapy, active surveillance, supportive care, or clinical trials.

A treatment plan may include:

Surgery: To remove as much tumor as safely possible or obtain tissue for diagnosis
Radiation therapy: To target tumor cells in a specific area
Chemotherapy: To treat tumors that respond to anticancer drugs
Targeted therapy: To target specific molecular characteristics in certain tumors
Immunotherapy: To harness or modify the immune system against cancer
Clinical trials: To evaluate promising new approaches
Active surveillance: To monitor selected tumors that do not immediately require treatment
Supportive care: To manage symptoms and treatment side effects

How Doctors Decide Between Radiation and Chemotherapy

Treatment selection is a collaborative process. Rather than asking whether radiation or chemotherapy is inherently better, patients can ask which treatment, or combination of treatments, is most appropriate for their specific tumor.

Your treatment team considers the complete clinical picture before recommending radiation, chemotherapy, both, or another approach.

Doctors may evaluate:

Pathology results
Tumor grade
Molecular test results
Tumor location and size
MRI findings
Whether surgery was performed
Amount of tumor remaining after surgery
Previous treatments
Current symptoms
Overall health
Potential benefits and side effects
Available clinical trials

This individualized approach is particularly important because brain tumors represent many different diseases with different biological behaviors and treatment responses.

Understanding Your Brain Tumor Treatment Options

Radiation therapy and chemotherapy each play important but different roles in brain tumor treatment. Radiation focuses treatment on a specific area, while chemotherapy uses medications to target cancer cells; in some cases, using both together provides the most appropriate approach.

There is no one-size-fits-all treatment plan for brain tumors. Your diagnosis, tumor characteristics, imaging, previous treatments, overall health, and personal goals all contribute to the recommendations made by your care team.

Advanced Imaging Options at Duke

At the Preston Robert Tisch Brain Tumor Center at Duke, our team of multidisciplinary specialists work together to evaluate each patient's diagnosis and develop an individualized treatment strategy. Patients may have access to advanced treatment approaches, supportive services, and clinical research as part of comprehensive brain tumor care.

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FAQs: Radiation Therapy vs. Chemotherapy for Brain Tumors

Is radiation or chemotherapy better for brain tumors?

Neither treatment is universally better. Radiation therapy is designed to target a specific area, while chemotherapy uses drugs to treat susceptible cancer cells. The appropriate treatment depends on the tumor type, grade, molecular characteristics, location, previous treatment, and overall health.

Can you have chemotherapy and radiation at the same time?

Yes. Certain brain tumor treatment plans use chemotherapy and radiation concurrently because the combination can provide benefits that either treatment alone may not provide. A well-known example is the use of temozolomide during radiation therapy for many patients with newly diagnosed glioblastoma.

Does chemotherapy cross the blood-brain barrier?

Some chemotherapy drugs can cross the blood-brain barrier, while many others cannot reach the brain in sufficient amounts through standard systemic administration. Drug selection and delivery therefore matter when treating brain tumors. Your neuro-oncology team can explain whether a particular chemotherapy drug is expected to reach your tumor.

Does radiation therapy cause hair loss?

Radiation therapy can cause hair loss in the area receiving radiation. The amount of hair loss depends on the radiation dose, treatment field, and individual factors, and hair may regrow after treatment in some patients. Your radiation oncology team can explain what to expect based on your specific treatment plan.

How are radiation and chemotherapy different from surgery?

Surgery physically removes as much of a tumor as can be safely removed or obtains tissue for diagnosis, while radiation and chemotherapy treat tumor cells through different mechanisms. Surgery is often an important first step for tumors that can be safely accessed, but it may be followed by radiation, chemotherapy, or other treatments. The appropriate combination depends on the individual tumor.

Can radiation therapy be used without chemotherapy?

Yes. Some patients receive radiation without chemotherapy depending on the tumor type, age, health, molecular characteristics, previous treatment, and treatment goals. Other patients may benefit from a combination of radiation and chemotherapy. Your care team determines the appropriate approach based on your diagnosis.

Can chemotherapy be used without radiation?

Yes. Chemotherapy may be used without radiation in certain circumstances, including some tumor types or recurrent disease. Treatment options depend on the specific tumor and what therapies have already been used. Clinical trials may also provide additional options for eligible patients.