Radiation therapy cancer treatment can cause fatigue.

Why Am I Tired After Radiation Therapy?

Radiation therapy cancer treatment can cause fatigue.

A cancer diagnosis changes your life. Depending on the type of cancer, treatments may include chemotherapy, bone marrow transplants, surgery, immunotherapy and radiation therapy, or a multidisciplinary approach that includes many of these treatments. In the series of tests and treatments one may produce unpleasant side effects, including excessive fatigue or tiredness. Radiation therapy tends to increase the feeling of fatigue, leaving many to question why, and what can be done about it.

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Causes of Fatigue

While patients often experience fatigue after radiation, it is not necessarily the direct result of your treatment. It can be a symptom of a combination of factors, including: 

  • Your Cancer: Your cancer utilizes nutrients stored in your body in order to grow. In doing so, it takes those nutrients from other functions of the body, leading to fatigue. Depending on the type of cancer and its location, tumors may cause the unexpected release of hormones that contribute to a sense of tiredness. Other cancers lead to an increased energy demand on your body, so energy becomes simply unavailable. As cancer progresses, it may cause damage to your body’s organs, including the liver, kidney, heart, lungs or other organs, which will alter your body’s chemistry. 
  • Your Treatment: Most cancer treatments, including radiation, chemotherapy, immunotherapy, bone marrow transplants, and surgery, often result in fatigue. That’s because while these therapies are intended to kill cancer cells, they can cause damage to the body in the process. You will likely feel fatigued as your body repairs this damage. 
  • Emotional Fatigue: While cancer is a physical disease, it takes a huge emotional toll on most patients. The body responds to stress with the release of cortisol and various hormones. When a major stressor occurs, such as a cancer diagnosis or the ongoing stress during treatment, people run the gambit of emotions. It is a tiring process, so before any treatment begins, the person begins to experience a sense of fatigue.  
  • Anemia: One of the specific ways treatments may cause fatigue is if they result in anemia. Anemia occurs when you don’t have enough healthy red blood cells to carry oxygen throughout the body. If your treatment destroys too many red blood cells, it can cause anemia, a symptom of which is fatigue. 
  • Pain: Pain, a common symptom of both cancer and some treatments, can lead to fatigue. Pain can disrupt sleep, cause depression, and reduce your appetite, all of which result in fatigue. 

Symptoms of Fatigue

For those who have never experienced fatigue, it is easy to assume it is simply tiredness. However, fatigue is not the same as simply feeling sleepy. Everyone feels tired occasionally, but fatigue is often a chronic physical and mental exhaustion. 

While feeling extremely tired is certainly a predominant symptom of fatigue, it often brings with it additional symptoms, such as:

  • Dizziness
  • Physical weakness 
  • Body aches
  • Slow reflexes, both mental and physical
  • Difficulty concentrating or making decisions
  • Headache
  • Mood swings
  • Loss of appetite 
  • Depression

How Does Radiotherapy Contribute to Fatigue?

The cancer itself may contribute to your sense of fatigue as well. While radiotherapy seeks to eradicate cancer by destroying cancer cells with radiation, it also increases the level of fatigue a person feels.

Let’s take a moment to think about how radiation therapy works. A team of experts use technology to provide a lethal dose of radiation to a targeted area of cellular tissue. In those living with cancer, radiation leads to cellular death at the target site. As a result, the immune system responds to “repair” the damage. In this case, the remnants of cancerous tissues are removed from the body.

Unfortunately, some healthy cells near the target area may also receive this dose of radiation. Although technology has advanced light-years in terms of focusing radiation on a specific area, the destruction of healthy cells will naturally lead to an increase in fatigue. For instance, radiotherapy for prostate cancer may result in fewer healthy cells affected than treatment on another area, such as the lungs.

Now, everyone responds to radiation therapy differently, and the exact type of cancer will affect your sense of tiredness as well. For example, if treatment destroys too many red blood cells, a person may develop anemia. Anemia, as a medical condition, is associated with increased fatigue. Meanwhile, larger cancers, requiring a prolonged dose of radiation, will lead to excessive tiredness too.

In addition, the frequency of trips to receive radiotherapy may contribute to fatigue as well. This goes back to the emotional toll of cancer treatment. The constant scheduling of appointments, visiting your oncologist, obtaining radiation treatment, taking chemotherapy and other treatment methods adds to the emotional toll. There will be days when going to the treatment center feels like too much to handle. However, the tiredness is not a permanent aspect of your life.

Questions to Address with Your Doctor

Some people have the fortune of not experiencing severe side effects of radiation therapy. As explained by the American Cancer Society, there is no sure-fire way to determine how extensive your side effects will be before launching treatment. A thorough conversation with your radiotherapy care team can help you prepare for such side effects. 

If your fatigue persists, it’s a good idea to talk about it with your doctor. He or she may be able to identify the primary source of your fatigue and help you find ways to alleviate your exhaustion. 

Before you meet with your doctor, you can prepare by considering these questions, which he or she will likely ask: 

  • When did my fatigue begin? 
  • How has my fatigue changed since diagnosis?
  • How has my fatigue changed during treatment?
  • How often do I experience fatigue? 
  • How long does my fatigue last?
  • How severe is my fatigue?
  • What helps alleviate my fatigue? 
  • What makes my fatigue worse?
  • What other symptoms do I experience alongside my fatigue (like chest pain or trouble breathing)?
  • Am I sleeping well?
  • Am I eating well?
  • Am I getting exercise?
  • How do I feel emotionally? 
  • How is my fatigue affecting my day-to-day life?

How Long Will Tiredness from Radiation Therapy Persist?

People usually see a reduction in tiredness after several weeks of receiving a final treatment. Some people may experience excessive tiredness after the first treatment. Others may gradually develop a sense of growing fatigue over a period of weeks. Of course, the tiredness resulting from radiation therapy alone varies in intensity and duration.

After receiving the final treatment, other factors come into play. The length of time the body takes to repair itself will affect time between final treatment and not feeling so tired. This gives rise to a belief that radiation therapy leads to permanent fatigue.

What Reduces the Severity of Tiredness?

The level of tiredness a person experiences relates closely to other activities during treatment. What a person eats, how much they sleep, their level of pain and mental stress affect the body and result in fatigue. Those with a cancer diagnosis and receiving treatment, including radiotherapy, should follow the advice of their board-certified radiation therapy oncologist to combat fatigue. Some common methods for reducing fatigue include:

  1. Eat a well-balanced diet. All bodily functions rely on the availability of nutrients. Throughout the course of treatment, cancer cells have affected your body’s ability to nourish all cells and tissues. Thus, a well-balanced diet during radiation therapy helps to counteract the adverse effects of cancer and side effects of cancer treatment.
  2. Take medications as prescribed. The multidisciplinary care team may prescribe medications and supplements to reduce the negative impact of cancer and cancer treatment. Medications may be useful for managing pain or even improving appetite. Those living with a cancer diagnosis and undergoing treatment should take all medications as prescribed.
  3. Avoid a sedentary lifestyle. This is a very confusing aspect of preventing fatigue. An active lifestyle will result in tiredness, and if energy is unavailable due to cancer, how can a person be expected to stay active? To answer that question, people need to consider their state of activity prior to the cancer diagnosis. For example, those that maintained an active lifestyle prior to cancer may experience fatigue when they “slow down.” Ultimately, this strategy focuses on getting some movement, but it is important to not overexert oneself during cancer treatment.
  4. Get plenty of rest and sleep. Cancer and cancer treatment are strenuous and tiresome. After receiving treatment, get plenty of rest, and if you experience trouble sleeping, speak with your care team about how may improve your sleeping habits. Balancing rest and work will go a long way in reducing your sense of fatigue.

What About Tiredness That Becomes a Severe Burden?

A final aspect of the cancer fatigue conversation comes up when those receiving treatment begin to experience dramatic changes in the severity and frequency of fatigue. When fatigue becomes persistent and interferes with your ability to perform basic daily function, tell your doctor. More importantly, if fatigue reaches an extreme point and causes confusion, dizziness, loss of balance, severe shortness of breath or leaves you bedridden for more than 24 hours, contact your care team immediately. While it is normal to sleep more than typical after a radiotherapy session, these symptoms greatly increase your risk of injury and could lead to the worsening of your overall health.

Choose an Experienced Radiation Care Team That Will Help You Manage Side Effects.

Radiation therapy will likely result in tiredness that progressively grows worse. However, the tiredness associated with treatment coincides with the positive results of radiotherapy—cancer cell destruction. By knowing more about what causes this tiredness, those living with a cancer diagnosis can make an informed decision about whether to proceed with radiotherapy, and if so, they may also apply the prevention strategies to minimize its impact.

Remember a key part of managing the side effects of cancer treatment will always involve your care team. Therefore, it is important to choose a treatment provider, such as SERO, that understands treatment side effects and how to manage them. Submit your questions and request for a consultation online today.