Fatigue: the most common problem your patient has, that you aren’t asking about

For patients with advanced cancer, palliative care patients and pediatric patients with advanced cancer, fatigue is one of the most prevalent and distressing symptoms they experience. It is the most common adverse effect of chemotherapy and radiation therapy.

For cancer survivors, fatigue can continue to be a problem months or years after cancer treatment is completed. Fatigue is frequently multifactorial and affects not only the physical, but the psychological domains. Most patients do not broach the topic with their physician because they assume it is normal. Most clinicians do not ask about it because they do not realize the prevalence of the symptom and the distress it causes. Because of the profound negative impact it has on a patient’s life, addressing fatigue is a crucial component of effective palliative care.

Definition

Christine Zawistowski

Fatigue is a complex symptom that can be described in a multitude of ways. The physical aspect is often described as a perception of muscle weakness or decreased energy. The affective and cognitive aspects include a lack of motivation or interest in activities, and difficulty in concentrating or maintaining attention.

Despite the different ways an individual patient reports their experience of fatigue, almost every patient universally reports that it is not responsive to rest, is not proportional to activity, and it pervades their life and can serve as a significant source of distress.

The National Comprehensive Cancer Network has defined cancer-related fatigue as a “distressing persistent, subjective sense of physical, emotional and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning.”

Mechanisms

There can be multiple causative factors that contribute to fatigue. In advanced cancer, the tumor itself, the treatments and the proinflammatory cytokines produced are known to cause fatigue.

Preexisting comorbidities, pain, anemia, cachexia/malnutrition, deconditioning, psychological factors, sleep disturbances and medication adverse effect profiles are just a few of the additional factors that contribute to fatigue in advanced cancer patients, as well as palliative care patients.

The NCCN guidelines recommend screening every patient for fatigue. If present, a quantitative assessment, such as a numeric zero to 10 scale, should be performed and documented.

There are several assessment tools available for patients with cancer and other conditions to assess for fatigue including the Functional Assessment of Cancer Therapy-Fatigue Subscale, the Brief Fatigue Inventory, the Memorial Symptom Assessment Scale Short Form and the Fatigue Scale-Adolescent.

As with any other symptom, fatigue should be assessed by characterizing the temporal features (onset, course, duration, and daily pattern), exacerbating and relieving factors, associated distress, and impact on daily life. A history and physical exam, as well as laboratory data, can yield additional information.

Management

The treatment of fatigue requires a multimodality approach. Identification and treatment of specific causes such as pain, dehydration, infection, anemia, endocrine and metabolic abnormalities, sleep hygiene and mood disorders should be undertaken.

In all patients, nonpharmacologic measures such as education and counseling are of utmost importance. Helping patients adapt to fatigue by setting realistic goals, modifying activities, prioritizing goals and conserving energy can often be helpful. Studies have demonstrated that exercise actually alleviates fatigue and referral to physical therapy and outpatient rehabilitation programs can be beneficial. If fatigue persists or no treatment- specific causes can be identified, pharmacologic treatment can be considered.

Psychostimulants such as methylphenidate, modafinil and pemoline are some of the best studied medications, but results are often mixed. Additional agents to consider are the cholinesterase inhibitor, donepazil, progestational agents, such as megesterol acetate, and corticosteroids.

Fatigue is the most common symptom advanced cancer patients experience and it causes significant distress and impairs quality of life. Recognition of this symptom is part of good palliative care.

Christine Zawistowski, MD, is a Pediatric Palliative Care and Intensive Care Doctor at the Cancer Institute of New Jersey and Bristol-Myers Squibb Children’s Hospital at Robert Wood Johnson University Hospital, New Brunswick, N.J.

For more information:

• JAMA. 2007;292:295-304.
• J Palliat Med. 2006;9:409-421.