Brain Tumors

Side Effects 

When treating a brain tumor, healthy tissues may be affected, resulting in side effects. Some treatments are more likely to cause side effects than others. Side effects vary from person to person, even among those who receive the same treatment.

Some side effects may be prevented, and others may be managed by you and your doctor. Ask your doctor what to expect before beginning treatment. Tell your medical team when a new side effect begins, even if you consider it trivial. The sooner side effects are addressed, the sooner your medical team will be able to help you manage them. Following are some of the common side effects of brain tumors and their treatment and ways to manage them.

Alopecia (Hair Loss)

Some treatments may cause loss of hair on the head, face and other parts of the body. Radiation therapy may cause hair loss in the area being treated. Not every person treated for cancer will lose his or her hair, even when they receive the same treatment.

Be gentle with your hair to reduce the amount of hair loss. Use a soft-bristle brush or wide-toothed comb, and avoid shampoos with strong detergents. Ask your oncologist for a prescription for a wig. Using certain phrasing on the prescription, such as “cranial (or skull) prosthesis due to alopecia caused by treatment for cancer,” may make the wig eligible for insurance coverage.


Certain types of treatment may cause diarrhea. When mild, diarrhea is an inconvenience. If left untreated, it can lead to serious problems, such as dehydration, loss of important nutrients, weight loss and fatigue.

Over-the-counter medicines and supplements are available to control diarrhea, but ask your doctor before taking anything. If diarrhea is severe, your doctor may prescribe other medications or choose to stop your cancer treatment temporarily until it is controlled.


Treatment-related fatigue occurs primarily because the body needs extra energy to repair the healthy tissue damaged by cancer treatment. Additionally, other side effects of treatment, such as pain, nausea and vomiting, can cause or worsen fatigue.

Although most people think more rest will help relieve fatigue, increasing activity and performing regular exercise (such as walking or bike riding) are the best ways to combat it. If your fatigue is severe, your doctor may prescribe a drug to improve alertness.

Fertility Issues

Parenthood is an integral part of life that many individuals envision for themselves. However, certain types of cancer treatments can affect fertility (the ability to start or maintain a pregnancy). For both men and women, fertility options become much more limited after treatments start, so it’s wise to talk to your doctor about safeguarding your fertility before you begin any type of treatment.


Headaches may be a side effect from treatment, as well as a symptom of the pressure caused by the tumor itself. People who have surgery or receive radiation therapy or drug therapy may have headaches.

Try over-the-counter pain relievers and get plenty of rest. If your headache is severe, keep track of the characteristics of your headache. Include the time of day it starts, how often it happens, how long it lasts and where it occurs (forehead, temples, side of head, back of head, etc.). This information may be helpful to your doctor, who may prescribe medication to relieve the pain.

Mouth Sores

Mouth sores may form in the lining of the inside of the mouth and can affect the gums, tongue, roof of mouth or lips. Mouth sores can develop into white patches that may become large red lesions. Pain may range from mild to severe, making it difficult to talk, eat or swallow. Mouth sores are most often related to drug therapy.

If mouth sores develop, try to keep your mouth and lips moist and avoid spicy, acidic or rough-textured foods. Your doctor may suggest rinsing your mouth with special solutions, or may prescribe a medication that coats the lining of your mouth or a pain medication that can be applied topically. Over-the-counter medications may help relieve discomfort.

Nausea and Vomiting

Nausea is feeling sick to your stomach and may be accompanied by vomiting (throwing up). Severe vomiting can lead to dehydration and interrupt treatment. Nausea and vomiting are much easier to prevent than to control once they’ve started. People who have drug therapy or radiation therapy may experience nausea and vomiting.

Talk to your doctor about lowering your medication doses, adding antiemetics (anti-nausea drugs) or other suggestions to help keep you comfortable.


Supportive Care

When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Some treatments may also cause damage or swelling in certain areas of the brain. As a result, you may experience complex cognitive, emotional and physical issues.

Although these are common side effects, managing them is an important aspect of brain tumor treatment. Tell your health care team immediately if you experience any of these conditions so you can take advantage of the supportive care resources that will help you maintain a good quality of life.

Memory and Cognitive Changes

A brain tumor and its treatments may affect your ability to think, reason, concentrate, process and remember information. Fatigue can zap the energy you need for thinking and remembering. These changes may make it difficult for you to focus on tasks or follow conversations, plan or organize your thoughts, learn new things or remember names and dates.

Let friends and family know you’re having trouble remembering things, and ask them to help you by repeating information. A daily planner may help you keep track of events and appointments. Don’t multitask; instead, focus on one thing at a time.

If you experience these types of side effects, talk with your doctor about your concerns. He or she likely will schedule an evaluation to help determine the best ways to train or retrain the cognitive skills that may have been lost or affected during treatment.

Emotional Changes

An interference with brain function may cause unexpected changes in personality and feelings. Your moods may differ, and you may deal with anxiety, anger or stress differently.

A brain tumor diagnosis is often accompanied by depression. It may be caused by the tumor, its treatments or by the diagnosis. Depression is more complex than just feeling sad or hopeless and can result from low hormones, a chemical imbalance in the brain, uncontrolled pain or other unrelieved symptoms.

Spend time with family and friends who can help you cope better with daily life and perhaps reduce the risk of depression. Join an online or in-person cancer support group to meet people who are going through a similar situation. Perform regular physical activity, breathing exercises or meditation.

Consider speaking with a counselor or exploring psychological treatment, which may include individual psychotherapy (counseling to explore emotional issues that contribute to depression) and cognitive-behavioral therapy (counseling to help a person change his or her negative thought patterns and behaviors). If you have thoughts of hurting yourself or others, talk with your doctor immediately.

Physical Challenges

Brain tumor treatment may cause muscle weakness, changes in motor skills and difficulty with speech.

Physical therapy is a form of rehabilitation that aims to improve the ability to move and function. A physical therapist helps identify and correct any issues with mobility that occur as a result of brain tumor treatment.

Speech pathology is a form of rehabilitation that focuses on issues with speech and swallowing. A speech pathologist may offer ways to regain the ability to speak or to improve speech impairment.

Financial Anxiety

Treatment and related items, such as additional care, can be expensive, which can add to the stress you may feel already. Some people may even let the cost prevent them from seeking or continuing treatment. You are encouraged to learn more about the costs related to treating your brain tumor, as well as resources that are available to help reduce or manage the expense. Ask your treatment team or your health insurance provider to refer you to someone who is familiar with your case and can provide more information.


Additional Resources


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