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News Archive: Michigan Oncology Journal Spring 99

Breast Cancer and Fatigue: Advances in Solving the Puzzle

-Bernadine Cimprich, Ph.D., R.N.,
Assistant Professor of Nursing
Program Director, Quality of Life Research

Fatigue, manifested as a global sense of loss of energy, is the most frequently reported source of distress associated with breast cancer, regardless of treatment modality (1). Fatigue has been reported in 58% to 95% of women treated for breast cancer. Numerous studies of symptom distress have indicated a high prevalence of fatigue during and following adjuvant chemotherapy for breast cancer with few observed differences in the clinical pattern of fatigue among standard chemotherapeutic regimens (2). Prospective studies also have consistently shown that fatigue is a distressing symptom during radiation therapy following breast-conserving surgery, increasing in severity over the course of treatment (3). Increased use of multiple treatment modalities for breast cancer, including high-dose chemotherapeutic regimens and biotherapeutic agents, may compound the problem of fatigue in breast cancer patients. Few prospective studies, however, have compared possible differences in incidence and severity of fatigue among various breast cancer treatment modalities. Finally, fatigue often becomes a chronic, unexplained post-treatment problem in long-term survivors of breast cancer that persists even years after completion of treatment (4).

Impact of Fatigue
A patient's descriptive report of the sensation of fatigue, such as being tired, weary or worn out, belies the complexity and impact of the problem (1). Cancer-related fatigue should not be confused with the normal, adaptive sensation of tiredness that one experiences after a day's hard work and is relieved by rest. Rather, the problem of fatigue is characterized by decreased ability to do mental and physical work that persists and worsens in a manner that is disproportionate to any work done.

Fatigue presents significant obstacles to effective functioning during and following breast cancer treatment. Persistent fatigue has been commonly associated with impairment in mental functioning including decreased attention, impaired perception and thinking, and reduced ability to function effectively (1). Reported consequences of fatigue are decreased ability to manage everyday tasks, disruption of employment, and difficulty maintaining personal and social relationships (1). Clinical reports indicate that severe fatigue can lead to premature withdrawal from or curtailment of potentially curative cancer treatments; however, no research has been done that systematically documents the true costs of fatigue on quality of life and clinical outcomes.

Issues in Therapeutic Management
Despite the significant nature of the problem of fatigue in women treated for breast cancer, definitive therapeutic solutions are yet to be determined, probably because there are multiple contributing factors and the underlying mechanisms are poorly understood (1) (see Table 1 for a summary of supportive management strategies for fatigue). Importantly, in many instances, fatigue is symptomatic of conditions directly related to breast cancer or its treatment, such as anemia, dehydration, chronic pain, depression and sleep problems. To the extent that these conditions can be treated, fatigue can be relieved, at least in part.

One proposed mechanism of unexplained fatigue involves changes in skeletal muscle structure and function related to disease and treatment. The tendency that commonly accompanies cancer treatment to reduce physical activity can lead to decreased muscle strength and endurance. Early signs of such muscle disuse are manifested in patient reports of poor activity tolerance and fatigue. Recent studies of the effects of moderate physical exercise in patients undergoing radiation treatment for breast cancer have shown promising results with demonstrated benefits of improved physical functional status and reduced sensation of fatigue (5).

Another area of study focuses on the cognitive component of cancer-related fatigue. The brain mechanism underlying the ability to attend has been implicated in producing fatigue because its function requires exertion of neural inhibitory (mental) effort to sustain focus (6). In general, this attentional mechanism provides the mental effort needed for effective functioning in daily life. When dealing with a life-threatening illness such as breast cancer, multiple psychological demands may be experienced with little respite for prolonged periods of time, which both compromise and place exceptional strain on normal attentional capacity. Not surprisingly, women have consistently described the diagnosis of breast cancer as a point of major discontinuity in their lives resulting in a need for adjustment in every life domain. In this demanding life situation, mental effort is needed to help a person think clearly, make treatment decisions, problem solve, maintain personal relationships and carry out necessary tasks such as treatment-related activities or self-care. Mental effort is normally limited and fatigue can easily ensue, particularly under conditions of psychological distress commonly present in the diagnosis and treatment of breast cancer. On a functional level, a person experiencing such mental or "attentional" fatigue would have difficulty performing both mental and physical activities such as following a train of thought, acquiring new information, making a decision, or carrying out life tasks, such as planning a meal or balancing a checkbook.

Current Research Initiatives
Given that multiple factors may contribute to fatigue in women treated for breast cancer, targeted interventions are required to effectively address the source of the problem. Investigators at the University of Michigan Cancer Center currently are studying the problem of attentional fatigue in women newly diagnosed with breast cancer. Preliminary data have shown that breast cancer patients manifest attentional fatigue with a reduced capacity to direct attention during the three months following mastectomy or breast conservation surgery and that such fatigue could be ameliorated by an intervention involving regular exposure to natural restorative environments (7,8). Participants who were randomly assigned to take part in attention-restoring activities showed a significant improvement in attentional fatigue parameters over time, as well as a fuller resumption of pre-treatment employment activities (8). In addition, the findings indicated that attentional fatigue might be differentiated from psychological distress, such as depressed mood state or changes in physical functional state. A randomized, longitudinal study is being conducted to further evaluate the efficacy of natural restorative environments for attentional and functional restoration in 200 women newly diagnosed with breast cancer. The study also will examine the possible detrimental effects of attentional fatigue on physical functioning, emotional distress and ability to carry out life roles.


Supportive Management Strategies for Fatigue

• Determine and manage any medical causes, e.g., anemia, dehydration, pain, sleep disorder, nutritional deficiency
• Differentiate between fatigue and depression
• Educate patients and families that fatigue is frequently an expected side effect of breast cancer treatment
• Encourage self-care strategies at the start of treatment: - muscle strengthening and exercise programs, e.g., light to moderate- intensity walking - attention-restoring activities, e.g., experiences in natural settings such as walking, sitting, watching birds, tending plants or gardening
• Teach energy-conservation techniques, e.g., pacing activities; focusing on priorities; accepting help; delegating tasks; creating structure in daily activities
• Monitor level of fatigue and effectiveness of selected strategies

References

1. Winningham ML, Nail LM, Burke MB, et al. Fatigue and the cancer experience: The state of the knowledge. Oncol Nurs Forum. 21: 23-36, 1994.
   
2. Berger AM. Patterns of fatigue and activity and rest during adjuvant breast cancer chemotherapy. Oncol Nurs Forum. 25: 51-62, 1998.
   
3. Irvine DM, Vincent L, Graydon JE, et al. Fatigue in women with breast cancer receiving radiation therapy. Cancer Nurs. 21: 127-135, 1998.
   
4. Ferrell B, Dow K, Leigh S, et al. Quality of life in long-term cancer survivors. Oncol Nurs Forum. 22: 915-922, 1995.
   
5. Mock V, Hassey Dow K, Meares C, et al. Effects of exercise on fatigue, physical functioning, and emotional distress during radiation therapy for breast cancer. Oncol Nurs Forum. 24: 991-1000, 1997.
   
6. Cimprich B. Symptom management: Loss of concentration. Sem Oncol Nurs. 11: 279-288, 1995.
   
7. Cimprich B. Attentional fatigue following breast cancer surgery. Res Nurs Health. 15: 199-207, 1992.
   
8. Cimprich B. Developing an intervention to restore attention in cancer patients, Cancer Nurs. 16: 83-92, 1993.

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