Study of fatigue in cancer patients

Fatigue is one of the most common and distressing symptoms cancer patients experience during chemotherapy and radiation treatment, but it's difficult for health care professionals to accurately assess its severity.

Nurse researchers at the University of Illinois at Chicago are studying fatigue in cancer patients undergoing stem cell transplants using a method successfully used to monitor behaviors such as smoking cessation and alcohol use.

The method is called "ecological momentary assessment" (often referred to as real-time assessment), which provides an instant measurement of patients' fatigue.

Clinicians and researchers usually rely on a patient's memory to collect data on symptoms such as fatigue. But it's difficult for patients to go back in time, says Eileen Hacker, clinical assistant professor and lead researcher of the study, or to average their symptom experiences.

"Their mood may affect their recall. They may have been experiencing pain in addition to fatigue, and that affects how they remember the fatigue experience," she said.

In Hacker's study, patients used a device that is worn like a wristwatch to record the data. The patients entered the intensity of their fatigue by using 10 numbered buttons on the device, one being no fatigue and 10 being the worst.

Patients recorded their fatigue three times a day for three days prior to stem cell transplantation and three days following the procedure. A signal from the device reminded patients when to enter the data.

The Fatigue Guidelines Panel of the National Comprehensive Cancer Network defines cancer-related fatigue as "an unusual, persistent, subjective sense of tiredness related to cancer or cancer treatment that interferes with usual functioning." Fatigue commonly is one of the first symptoms of cancer, and the longest-lasting symptom following cancer in both children and adults, Hacker said.

"For example, an adult diagnosed with acute myelocytic leukemia may seek medical care because of the extreme fatigue," Hacker said. "Cancer can cause fatigue directly or indirectly by spreading to the bone marrow, causing anemia and by forming toxic substances in the body that interfere with normal cell functions.

"People who are having problems breathing -- another symptom of some cancers -- may also experience fatigue."

According to Hacker, this is the first study of real-time collection of fatigue data in acutely ill cancer patients. Ecological momentary assessment holds substantial promise for investigating fatigue and other cancer symptoms, she said.