Managing Side Effects of Radiation Therapy

Radiation therapy is often an important component of cancer treatment. Sometimes patients experience little or no side effects from radiation therapy and are able to continue their normal routines. However, radiation therapy can cause mild-to-severe side effects for some patients.

Most side effects that result from radiation therapy are manageable. Before you begin your treatment, your radiation oncologist and their team will prepare you for any potential side effects as part of your treatment plan. As treatment begins, be sure to talk to a member of your radiation oncology treatment team about any problems you may have.

Although effects of radiation therapy on the body can be a cause for concern, the benefits of radiation therapy in the treatment of some cancers outweigh the risks. By developing an understanding of the potential effects and how to manage them in advance of your treatment, you’ll be prepared to weather your radiation therapy alongside your SERO radiation oncology team.

Why Does Radiation Therapy Cause Side Effects?

doctor speaking with patient

Radiation therapy uses X-rays to shrink, damage, or kill the cancer cells. While radiation therapy precisely targets the area affected by cancer, healthy cells near the cancer are sometimes damaged during treatment. When these healthy cells are damaged, it can lead to side effects.

Advances in radiation therapy have increased the accuracy of this treatment option, which has led to fewer side effects for patients. Your radiation oncologist will discuss the potential side effects with you before treatment. Together, you’ll cover the potential pros and cons and decide which treatment approach is best for you.

What Affects the Severity of Radiation Symptoms?

The effects of radiation therapy vary greatly from patient to patient, even those receiving treatment in the same area. Some patients experience no symptoms at all, others experience mild symptoms, and still others find the effects debilitating.

The severity of radiation symptoms is affected by various factors, including:

  • The area of the body receiving radiation treatment
  • The type of radiation therapy being administered
  • The dose of radiation the patient receives with each treatment
  • Any other treatments the patient is receiving as part of their treatment
  • The overall health of the patient

Your radiation oncologist will take these factors into consideration when designing your treatment plan.

What Are the Effects of Radiation Therapy?

Each patient’s experience with radiation therapy is different, and unfortunately it is impossible to predict which side effects you may experience. However, it is important that you understand the potential side effects so that you can report these—and any other symptoms you may experience during treatment—to your oncologist. Your doctor may choose to pause or suspend your radiation therapy or even change your treatment plan based on your symptoms.

Short-Term Effects

Radiation therapy affects the body in several ways, depending on the area of the body being treated and the amount of radiation the body is exposed to. These effects of radiation therapy on the body can appear during or shortly after treatment and can last for several weeks to several months after treatment ends.



The side effect most often reported by patients receiving radiation is fatigue. Fatigue is a general sense of tiredness that may not get better with rest. The fatigue patients experience is usually not very severe, and patients can often continue all or some of their normal daily activities with a reduced schedule. Many patients continue to work full time during radiation therapy.

The underlying cause of fatigue during cancer treatment is not always identifiable, but there are ways to manage fatigue so that it’s effects are not as severe. To manage fatigue, doctors recommend getting plenty of rest, alternating periods of activity with short periods of rest, eating a healthy diet, and reducing stress.


Loss of Appetite & Nausea

Radiation therapy can cause loss of appetite, especially if the head or digestive system are being treated. Patients who receive treatment near their head, neck, abdomen, or pelvic region may experience nausea and vomiting for several hours after treatment. Additionally, those treating head or neck cancer may experience pain when chewing or swallowing, making eating difficult.

When undergoing cancer treatment, a proper diet is very important. To combat the loss of appetite or challenge of eating, eat five or six small meals a day, rather than a few large ones. Try to eat even if you aren’t hungry. Keep snacks handy so you can eat whenever hunger strikes. If you cannot consume enough food to meet your calorie requirements, try adding calories to your meals with butter, milk, and/or cheese.

Liquid supplements or even a feeding tube may be prescribed by a dietitian if you are still unable to consume the calories required to remain healthy and strong through treatment. For more details, download our free Guide to Diet & Nutrition During Radiation Therapy.


Skin Issues

Skin issues are common effects of radiation therapy on the body. Skin problems occur at the site on the body where the radiation is administered. The skin issues caused by radiation therapy can range from mild sensitivity, irritation, dryness, or itching to peeling or blistering. Skin problems usually resolve once treatment ends. For some patients, the skin may remain darker or more sensitive even after treatment.

You should be gentle with the affected skin. Use lukewarm water and mild soap to cleanse it and avoid applying lotion, perfumes, etc. without consulting your care team first. You should also shield skin from the sun and avoid abrading the area by wearing soft, loose clothing.


Hair Loss

Hair loss or thinning is another common side effect of radiation therapy when radiation is directed towards a hair-bearing area of the body. Radiation therapy will only cause hair loss at the treatment site, rather than all over the body. The hair will typically regrow once treatment is over, although it may be a different texture or thinner than it was before.

If your treatment occurs near your scalp and you experience hair loss, the skin underneath may be sensitive. It may help to keep the skin covered with a loose hat, scarf, or wig.

Long-term Effects of Radiation Therapy

Because it can sometimes damage normal cells, radiation therapy can cause lingering problems in the treated areas. Many patients receiving radiation therapy will experience some short-term side effects. However, the long-term side effects are much less common and not every cancer patient will experience them. A small percentage of patients may develop symptoms after their treatment.


Mouth & Throat Issues

Patients receiving treatment for cancer in the mouth, throat, neck, or upper chest may experience long-term symptoms that affect their mouth, teeth, or throat.

  • Teeth: If you receive radiation to your mouth, it can increase the likelihood of tooth decay or other problems. Patients should receive a thorough oral check-up before treatment, and any decaying teeth should be removed.
  • Mouth Dryness: Radiation therapy in the mouth can affect salivary glands. If this happens, your glands may not be able to produce enough saliva, which makes your mouth dry. This effect may last for months or even permanently after treatment.
  • Change of Taste: After and during treatment, food may taste different. That’s because radiation can affect your taste buds. Some patients’ sense of taste is permanently altered.
  • Swallowing: Radiation therapy can cause the feeling of a lump in your throat for some patients. This may impact the patient’s ability to swallow. A speech pathologist can help these patients recover.


Bladder, Bowel, & Digestion Problems

Patients who receive treatment to their abdomen or pelvic area may experience problems with their bladder or bowels even after their radiation therapy has finished. Some patients may lose some control of their bladder. This may lead them to urinate more often or leak a few drops of urine when they laugh or sneeze.

If the lining of the stomach or bowels becomes irritated during radiation, it could have long-term consequences. Some patients experience diarrhea, cramping, or excess gas. Others may experience radiation proctitis, or swelling caused by damage to the rectum. Symptoms of radiation proctitis may include blood or mucus in the stool, painful bowel movements, or a constant need to empty the bowels.


Infertility & Intimacy Issues

Patients treating cancer in their abdomen, pelvic region, or reproductive organs may experience long-term effects on their fertility and sexual health.

For women, radiation can affect the vagina, causing inflammation that makes intercourse painful. They may experience vaginal stenosis, which makes the vagina shorter and narrower, also causing pain during intercourse. Additionally, radiation in these areas may trigger early menopause for some women. This happens when radiation causes the ovaries to stop producing normal hormones. This affects the patients’ ability to get pregnant in the future.

For men, radiation near the pelvis or testicles may temporarily or permanently reduce sperm production. If it is permanent, this will affect his fertility. Some patients also experience difficulties in getting or maintaining erections.


Secondary Cancer

Although rare, the damage that radiation can cause to healthy tissues could potentially lead to the development of a second cancer several years after treatment.. The risk of developing a second tumor because of radiation therapy is very low. For many patients, radiation therapy can cure their cancer and thus the benefit of treatment far outweighs the very small risk of secondary malignancy

Site-specific Effects of Radiation Therapy

Radiation therapy is a local treatment. This means it is applied directly to the affected area, rather than the entire body. The side effects, both short-term and long-term, usually only impact the area of the body that is being treated.

For example, a breast cancer patient may notice skin irritation, like a mild to moderate sunburn. A patient with cancer in the mouth may have soreness when swallowing. These side effects are usually temporary and can be treated by your doctor or other members of the treatment team.


Head, Neck, & Brain

After receiving radiation therapy to the head or neck, patients may experience:

  • Headaches
  • Fatigue
  • Loss of appetite and nausea
  • Sores on the mouth or gums
  • Trouble swallowing
  • Dry mouth
  • Tooth decay
  • Hearing loss and earaches
  • Jaw stiffness
  • Hair loss on the scalp
  • Hypothyroidism
  • Lymphedema (swelling in the neck or chin)
  • Difficulty with speech or memory
  • Seizures



Patients who receive radiation therapy to their chest may experience short- and long-term symptoms, including:

  • Shortness of breath
  • Coughing
  • Trouble swallowing
  • Sensitivity or soreness of the breast or nipples
  • Stiffness in the shoulders
  • Radiation pneumonitis, which may cause cough, fever, and thickness in the chest. This usually occurs between two weeks and six months after radiation therapy.
  • Radiation fibrosis, or permanent lung scars. This occurs when radiation pneumonitis goes untreated.
  • Cardiac problems



When radiation therapy is applied to the abdomen or stomach, patient may experience the following side effects:

  • Nausea and vomiting
  • Loss of appetite
  • Difficulty with bladder control
  • Bowel cramping and pain
  • Diarrhea
  • Constipation


Pelvic Area

Following radiation therapy aimed at the pelvic area, patients may experience:

  • Diarrhea
  • Bleeding of the rectum or blood in the stool
  • Difficulty with bladder control or bladder irritation
  • Sexual or intimacy problems, like erectile dysfunction
  • Reduced sperm counts and sperm activity
  • Menstruation changes
  • Early onset menopause and its symptoms, including vaginal itching, burning, dryness, or other issues around sexual health
  • Infertility

When Do Patients Start to Feel the Side Effects of Radiation?

Side effects usually begin by the second or third week of treatment, and they may last for several weeks after the final radiation treatment. In rare instances, serious side effects develop after radiation therapy is finished.

Your radiation oncologist and radiation oncology nurse are the best people to advise you about the side effects you may experience. Talk with them about any side effects you are having. They can give you information about how to manage them and may prescribe medicines that can help relieve your symptoms.

How Long Radiation Do Side Effects Last?

It’s important to remember that the severity and duration of your side effects depends on your specific treatment. As your healthy cells recover from radiation, your symptoms will begin to lessen. For many patients, side effects clear up within one to two months of finishing treatment. Sometimes it takes longer for those healthy cells to recover.

Tips for Dealing with Radiation Therapy Side Effects

If you find that the effects of your radiation therapy are affecting the quality of your daily life, speak with your doctor and team. They may be able to change your radiation therapy treatment plan in order to lessen your symptoms and help you get back to work or leisure activities sooner.

There are other changes you can make in your day-to-day life that may help you manage the symptoms of your radiation therapy. Some ways to reduce these side effects include:

  1. Maintain a well-balanced diet. While radiation may cause you to lose your appetite or may even make eating difficult, maintaining a well-balanced diet is of utmost importance. Your body needs plenty of nutrients to fight your cancer and stay strong through radiation.
  2. Get plenty of rest. Many patients experience fatigue throughout the course of their radiation therapy. You may find that you need to rest or sleep more than normal, and that’s a good thing. Listen to your body and get as much rest as possible.
  3. Find a cancer support groupA cancer diagnosis can feel isolating for many, and it can be difficult to share your experience with radiation therapy with friends or family. Finding a group of peers who are also navigating cancer and radiation can offer a helpful support system in this difficult time.
  4. Try medications. If you are experiencing pain as a result of your cancer or radiation therapy, your doctor may prescribe over-the-counter pain pills or stronger medications. Depending on your treatment area, your doctor may also prescribe radioprotective drugs. These drugs protect the areas around your treatment site from being affected by radiation.
  5. Remain physically active. When you’re contending with fatigue, pain, or other side effects, it can be difficult to get motivated. However, maintaining physical activity throughout your radiation offers a host of benefits. In fact, being active can even help lessen symptoms like fatigue and help with anxiety.

Your Side Effects Treatment Plan

If your doctor has prescribed radiation therapy as part of your cancer treatment plan, the potential side effects may seem daunting. However, these side effects do not affect everyone. No matter the symptoms of your radiation therapy, they are almost always worth the benefit of such a targeted, effective treatment option.

As you continue through your radiation therapy, it’s important that you communicate openly with your care team about your symptoms. They will be able to help you manage any side effects. Your radiation oncologist may even be able to change your radiation therapy or offer you medications to help. Together, you’ll come up with a treatment plan not only for your cancer, but for the side effects of radiation.

Do you have any additional questions about radiation and its side effects? Contact SERO, and our team will do their best to answer any questions you may have about the effects of radiation therapy.

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