June 10, 2007
Science Daily/University of Rochester Medical Center
Scientists offer an in-depth examination of cancer-related fatigue, with hope that a better understanding of the topic will prompt new research and treatment.
In a special publication sent to thousands of oncologists nationwide this month, University of Rochester Medical Center scientists offer an in-depth examination of cancer-related fatigue, with hope that a better understanding of the topic will prompt new research and treatment.
Virtually all cancer patients complain of some degree of persistent fatigue. Coping with this challenging side effect is critical to surviving cancer, especially since many people desire to work, raise children, run a household, or engage in recreation throughout their treatments, said Joseph Roscoe, Ph.D., a co-author and research associate professor of Oncology at the University's James P. Wilmot Cancer Center.
"It used to be that fatigue was viewed as an inevitable part of sickness," said Roscoe, a cancer survivor. "Now we know better, and there's a great deal of ongoing research about what causes fatigue and how it can be managed. For some people, fatigue is so debilitating that they want to stop their cancer treatments, which is why it is particularly important to find ways to address this problem."
During his own bout with cancer fatigue, Roscoe recalled feeling "jet lagged all the time." But rest or sleep does not alleviate cancer fatigue, and it often persists for months. In some studies, patients report more stress from fatigue than from pain, depression or nausea.
Unfortunately, no one has turned up a quick fix. "Exercise is looking very promising and one psychostimulant drug, modafinil, is being studied as a potential new treatment," Roscoe said. "But nothing yet has clearly demonstrated the ability to relieve cancer-related fatigue."
The following is a snapshot of what is reviewed in the journal:
-- Scale of the problem. Of the 1.3 million Americans diagnosed with cancer in 2005, 95 percent of the people scheduled to receive chemotherapy or radiation expected to experience fatigue. Studies show the frequency of actual fatigue during chemo ranges from 70 to 100 percent; likewise, 90 percent of patients who receive radiation therapy report fatigue. Also, up to 40 percent of patients report unusual fatigue upon diagnosis, a sign that fatigue is an early symptom of malignancy as well as a consequence of treatment.
-- Underlying causes. Cancer fatigue disrupts several interrelated systems: physiological, biochemical, psychological. The effect varies among individuals and also during different phases of treatment. It likely involves changes in the endocrine system, circadian rhythms, metabolism, cytokines and seratonin production. Predisposing factors must be understood before researchers can develop useful prevention or treatment strategies.
-- Measurement of a subjective symptom. More than 20 different assessments are used to diagnose fatigue, from single-question scales to multidimensional measurements of a patient's physical, emotional and cognitive functioning. Most patients can easily rate their fatigue on a scale from 0 to 10, researchers said. However, it is important for physicians to distinguish cancer fatigue from other ailments such as depression, and treat accordingly.
-- Fatigue and cancer-related sleep disorders. Approximately 25 to 50 percent of all prescriptions that doctors write for cancer patients are for hypnotics. Studies show that sleep disturbances are more severe in the most fatigued patients, suggesting a reciprocal relationship between these two distinct conditions.
-- Drug remedies. The first step to managing cancer fatigue is to treat conditions that may contribute to it, such as anemia, pain or depression. Studies show that anemia medications alleviate cancer fatigue to some degree. Other classes of drugs called psychostimulants have shown promise in open-label trials. Further research is needed.
-- Non-drug remedies. A growing body of evidence shows that exercise and support groups help people with cancer fatigue the most. Additional studies into nutrition therapy, yoga, mindfulness stress reduction, and polarity therapy also show promise. Many people with cancer already use non-drug behavioral therapies on their own, researchers said, but it's important that the scientific community continue to fund and study these interventions.