Common side effects of radiation therapy


Fatigue is feeling tired physically, mentally, and emotionally. It’s very common with cancer and its treatment, and often happens with radiation therapy. Managing fatigue is an important part of care.

Fatigue means having less energy to do the things you normally do or want to do. It can last a long time and can get in the way of your usual activities. The fatigue caused by cancer and its treatment is different from the fatigue of everyday life, and it may not get better with rest. Cancer-related fatigue is worse, and it’s more distressing. Cancer-related fatigue can:

  • Differ from one day to the next in how bad it is and how much it bothers you
  • Be overwhelming and make it hard for you to feel good
  • Make it hard to be with your friends and family
  • Make you less able to keep up your normal activities, including things like taking care of your home and going to work
  • Make it hard to follow your cancer treatment plan
  • Last different lengths of time, which makes it hard to guess how long you’ll have it

Most people start to feel tired after a few weeks of radiation therapy. Fatigue usually gets worse as treatment goes on. Stress due to your illness and daily trips for treatment may make fatigue worse.

Describing your fatigue

Only you know if you have fatigue and how bad it is. No lab tests or x-rays can diagnose or describe your level of fatigue. The best measure of fatigue comes from your own report to your cancer care team.

You can describe your level of fatigue as none, mild, moderate, or severe. Or you can use a scale of 0 to 10, where a 0 means no fatigue, and a 10 is the worst fatigue you could imagine. Either way you choose, it’s important to describe your fatigue to your cancer care team.

Managing fatigue

The cause of cancer-related fatigue isn’t always clear. But if the cause is known, it often can be treated. For example, if anemia (low red blood cell counts) is causing fatigue, the anemia can be treated. In some patients, treatment may include correcting fluid and mineral imbalances in the blood. Increasing physical activity, treating sleep problems, and eating well might all improve fatigue, too. Education and counseling are often part of the treatment; you can learn how to save energy, reduce stress, and use distraction to focus on things other than the fatigue.

By understanding fatigue, you can cope with it better and reduce your distress. Often, a family member can help you talk to your cancer care team about your fatigue and how it affects you.

Fatigue will usually go away over time after treatment ends. Until then, here are some things that might help you deal with it:

  • Make a list of the things you need to do in order of how important they are to you. Try to do the most important ones first, when you have the most energy.
  • Ask for help from loved ones and friends.
  • Place things that you use often within easy reach.
  • Try to reduce stress. Things like deep breathing, visual imagery, meditation, prayer, talking with others, reading, listening to music, painting, or any other activity that gives you pleasure may help you feel less stressed out.
  • Keep a journal of how you feel each day. Take it with you when you see your cancer care team.
  • Balance rest and activities. Try not to spend too much time in bed, which can make you feel weak. Schedule activities so that you have time for plenty of rest. Most people find that a few short rest periods are better than one long one.
  • Talk to your cancer care team about whether you should exercise, and what types of physical activities may be best for you.
  • Unless you’re given other instructions, eat a healthy diet that includes protein (meat, milk, eggs, and beans), and drink plenty of water each day.

Let your cancer care team know about your fatigue, and be sure to talk with them if:

  • Your fatigue doesn’t get better, keeps coming back, or gets worse.
  • You’re more tired than usual during or after an activity.
  • You’re feeling tired, and it’s not related to something you’ve done.
  • You become confused or can’t focus your thoughts.
  • You can’t get out of bed for more than 24 hours.
  • Your fatigue disrupts your social life or daily routine.

If you need to take time off from work, talk to your employer. You may also have some rights that will help you keep your job. Visit our website to get more information on fatigue. We also have information on work issues and the laws that can help people with cancer.

Skin problems

Your skin in the treatment area may look red, irritated, swollen, blistered, sunburned, or tanned. After a few weeks, your skin may become dry, flaky, or itchy, or it may peel. This may be called radiation dermatitis. It’s important to let your cancer care team know about any skin changes. They can suggest ways to ease the discomfort, maybe lessen further irritation, and try to prevent infection.

Most skin reactions slowly go away after treatment ends. In some cases, though, the treated skin will stay darker and might be more sensitive than it was before.

You need to be gentle with your skin. Here are some ways to do this:

  • Do not wear tight, rough-textured, or stiff clothes over the treatment area. This includes anything tight or elastic that squeezes the area. Instead, wear loose clothing made from soft, smooth fabrics. Do not starch your clothes.
  • Do not rub, scrub, scratch, or use adhesive tape on treated skin. If your skin must be covered or bandaged, use paper tape or other tape for sensitive skin. Try to put the tape outside the treatment area, and don’t put the tape in the same place each time.
  • Do not put heat or cold (such as a heating pad, heat lamp, or ice pack) on the treatment area without talking to your cancer care team first. Even hot water may hurt your skin, so use only lukewarm water for washing the treated area.
  • Protect the treated area from the sun. Your skin may be extra sensitive to sunlight. If possible, cover the treated skin with dark-colored or UV-protective clothing before going outside. Ask your cancer care team if you should use sunscreen. If so, use a broad spectrum sunscreen with a sun protection factor (SPF) of at least 30. Reapply the sunscreen often. Continue to give your skin extra protection from sunlight, even after radiation therapy ends.
  • Use only lukewarm water and mild soap. Just let water run over the treated area. Do not rub. Also be careful not to rub away the ink marks needed for your radiation therapy until it’s done.
  • Check with your cancer care team before shaving the treated area. They might recommend that you use an electric shaver if you must shave the area.
  • Ask your cancer care team before using anything on the skin in the treatment area. This includes powders, creams, perfumes, deodorants, body oils, ointments, lotions, hair-removal products, or home remedies while you’re being treated and for several weeks afterward. Many skin products can leave a coating on the skin that can cause irritation, and some may even change the dose of radiation that enters the body.

Hair loss

Radiation therapy can cause hair loss (alopecia). But hair is only lost in the area being treated. For instance, radiation to your head may cause you to lose some or all of the hair on your head (even eyebrows and lashes), but if you get treatment to your hip, you won’t lose the hair on your head.

Most people find that their hair grows back after treatment ends, but it can be hard to deal with hair loss. When it does grow back, your hair may be thinner or a different texture than it was before. Ask your cancer care team if you have any questions or concerns about hair loss.

If you do lose your hair, your scalp may be tender and you may want to cover your head. Wear a hat or scarf to protect your head when you’re in the sun. If you prefer to wear a hairpiece or wig, be sure the lining doesn’t irritate your scalp. Your local American Cancer Society office may be able to help you get wigs or hats. You may also want to check to see if head coverings are tax deductible or if they’re covered by your health insurance.

Low blood counts

Rarely, radiation therapy can lower white blood cell or platelet counts. These blood cells help your body fight infection and prevent bleeding. If your blood tests show lower blood counts, your treatment might be delayed for a week or so to allow your blood counts to return to normal. This side effect is more likely if you are also getting chemotherapy.

See Understanding Your Lab Test Results to learn more about blood cells and what changes in the numbers of these cells means.

Eating problems

Radiation to the head and neck or parts of the digestive system (like the stomach or intestines) might cause eating and digestion problems. For instance, you might have sores in your mouth or throat, nausea, vomiting, or loss of appetite. But even if you have trouble eating or lose interest in food during treatment, try to eat protein and some high-calorie foods. Doctors have found that patients who eat well can better handle their cancer treatments and side effects.

Coping with short-term diet problems may be easier than you think. There are a number of guides and recipe booklets for people who need help with eating problems. See Nutrition for the Person With Cancer During Treatment for advice on managing eating problems and some easy recipes to try.

The list below suggests things you can do when you don’t feel like eating, and how to make the most of it when you do feel like eating.

  • Eat when you’re hungry, even if it’s not mealtime.
  • Eat 5 or 6 small meals during the day rather than 2 or 3 large ones.
  • Vary your diet, and try new recipes.
  • If you enjoy company while eating, try to eat with family or friends, or turn on the radio or TV.
  • Keep healthy snacks close by for nibbling when you get the urge.
  • If other people offer to cook for you, let them. Don’t be shy about telling them what you’d like to eat.
  • If you live alone, you might want to arrange for a program like Meals on Wheels to bring food to you. Ask your cancer care team or local American Cancer Society office about programs in your area.

If you’re able to eat only small amounts of food, you can increase the calories per serving by trying the following:

  • Add butter or olive oil.
  • Mix canned cream soups with milk or half-and-half rather than water.
  • Drink milk shakes, instant breakfast mixes, or liquid supplements (in cans or bottles) between meals.
  • Add cream sauce or melted cheese to your favorite vegetables.

Some people find they can handle large amounts of liquids even when they don’t feel like eating solid foods. If this is the case for you, try to get the most from each glassful by adding powdered milk, yogurt, juice, or liquid nutrition drinks.

Talk to your cancer care team if you have any eating problems. They can help you find ways to feel better and get the nutrients your body needs.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: June 30, 2015 Last Revised: June 30, 2015

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.