By Carol L. Kornmehl, MD 

Radiation therapy is a simple, painless and generally well-tolerated tool for treating and even curing breast cancer. One of the most common side effects of radiation therapy to the breast (after a lumpectomy) or to the chest wall (after a mastectomy) is fatigue. This reaction and its extent is different for every woman. Because radiation therapy is often such an important part of breast cancer treatment, it is important to know how to mitigate its side effects in order to gain the greatest benefit from the therapy.
 
Many breast cancer patients experience fatigue, whether or not they are undergoing radiation treatment. Called cancer fatigue, most people with any kind of cancer go through a period of having low energy.
 
Cancer-related fatigue is not an ordinary sensation of tiredness, but rather a sense of being drained, feeling short of breath with even light activity, experiencing difficulty walking short distances, noting a heaviness of arms and legs, and struggling to perform routine tasks such as showering and cooking. Furthermore, cancer fatigue can make it difficult to concentrate on reading, listening to the radio and watching TV, and can additionally impair a person's ability to think clearly and make decisions. The debility from such cancer-related fatigue can last for days, week or months.
 
In addition to cancer fatigue, some breast cancer patients experience radiation therapy fatigue. Tiredness caused by radiation therapy usually comes in waves and can range from mild to several, but is usually mild or moderate. Rarely does someone need to stop working due to radiation therapy fatigue, but it does tend to become worse as treatment continues. If the fatigue is due solely to radiation therapy, it should gradually resolve after completing treatment.
 
While doctors do not fully understand how radiation fatigue works, they know that during therapy, the body uses a great deal of energy for healing. Traveling to and from daily treatments, Monday through Friday, over the course of seven to eight weeks is a task unto itself. In addition, the stress of breast cancer and the effects of radiation therapy on the normal cells certainly contribute to weariness.
 
More often than not, people who are tired during radiation therapy had experienced some degree of lethargy even before radiation treatment. They were often sleep deprived, either for no particular reason or because of specific factors such as hot flashes, emotional distress or pain. Other reasons for fatigue include use of other medications, metabolic imbalances, dehydration, poor appetite and other nutritional issues, anemia, inactivity and an under-active thyroid gland.
 
The Prescription
 
Women should not hesitate to talk with their radiation oncology team about fatigue. Usually, the team evaluates a patient's fatigue on a weekly basis, rating it on a scale of zero to 10, with zero representing no fatigue whatsoever. Understanding the intensity of the patient's fatigue helps the team decide how to best manage it.
 
Next, the radiation oncology team considers the source of the fatigue, because any treatment should be directed to the root cause of sleep deprivation. For example, if a woman is sleep deprived because she is being awakened regularly by hot flashes, the treating physician should attempt to control the hot flashes. If sleep deprivation stems from anxiety, the patient should take measures to reduce stress. Many breast cancer patients have found that support groups, psychological counseling, music therapy, art therapy, meditation, guided imagery and yoga are useful in stress reduction. When appropriate, antidepressants and antianxiety medications can be beneficial.
 
The radiation oncology team can also correct other medical causes of fatigue, such as an under-active thyroid, anemia or metabolic imbalances. Sometimes a team might provide stimulant medication, especially for people with severe cancer- or radiation-related fatigue.
 
Learning to Take It Easy
 
Even if the oncology team cannot determine a specific cause for fatigue, women can focus on conserving their energy, resting, undertaking physical activity and restoring their energy.
 
Conserving energy means deliberately managing personal energy resources to reduce energy depletion. In other words, women must prioritize the tasks that are most important and delegate less vital responsibilities. For example, the patient can ask friends and relatives to help with shopping, childcare, housework and driving. Conserving energy also means spreading activities throughout the day and taking breaks in between, instead of trying to do everything at once.
 
Too much rest, however, can decrease a person's energy level. Thus, taking several short 20-minute power naps that do not interfere with evening sleep may be more helpful than a long rest period. In fact, scheduling activities throughout the day, including rest periods, is wise.
 
Remaining active is helpful. Light exercise, such as walking, tai chi and yoga, can actually improve a person's energy level. Experts recommend doing physical activity at least three times a week, for at least a half hour each time.
 
Someone with radiation- or cancer-related fatigue should use her leisure time in a restful way. Women can also restore their energy by participating in activities they enjoy, such as listening to music, looking at artwork, gardening or bird watching.
 
Coming Out Ahead
 
Although a number of people who undergo radiation therapy do experience fatigue, most get past this temporary side effect. By working with their radiation oncology teams, people pass the metaphorical finish line of the course of radiation therapy, usually victoriously. Most importantly, they derive substantial benefits from radiation therapy and move on to leading productive, cancer-free lives.

Carol L. Kornmehl, MD, is medical director of Radiation Oncology at Passaic Beth Israel Medical Center, in New Jersey. She is author of the consumer health book, "The Best News About Radiation Therapy" (M. Evans, 2004).  More information on radiation therapy and its effects can be found on her website at www.RTSupportDoc.com.