Cancer associated fatigue

Fatigue is the most common symptom of patients during cancer from diagnosis to end of life and is defined as distressing, persistent, subjective sensitive physical, emotional and or cognitive tiredness or exhaustion related to cancer or cancer treatment.

The fatigue related to cancer is not proportional to recent physical activity and that it interferes with usual functioning

Among the most common complaints associated with cancer.

Up to 40% of patients report fatigue with the diagnosis of cancer, and 80–90% experienced it during chemotherapy and radiotherapy, 17–21% during chemotherapy alone.

Cancer related fatigue is one of the most pervasive toxicities experienced by survivors.

Up to 40% of survivors continue experiencing debilitating fatigue after completion of treatment.

Survivors often report lack of energy, tiredness, need to slow down and rest, all of which interferes with ability to work, resume daily routines, and engage in physical activity.

Hormonal and immunotherapy, and targeted therapy can be responsible for fatigue.

Cancer related fatigue is probably related to physiological and biochemical systems which vary according to the type of tumor, stage of disease, and treatment.

The proposed mechanisms of cancer related fatigue is multifactorial: proinflammatory cytokines, neuroinflammation, hypothalamic-pituitary-adrenal axis dysregulation, circadian rhythm desynchronization, disrupted energy metabolism, skeletal muscle wasting, neural transmitter dysregulation, and vagal activation.

Can occur during or after treatment, during long-term survivorship, and in patients with extensive and or metastatic disease.

Cancer associated fatigue probably initiating in the skeletal muscles due to progressive reduction of physical activity, but the brain is critical as a essential regulator of fatigue perception.

Defined 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 activites and interferes with functioning (NCCN Guidelines).

Not relieved by rest or sleep.

One of the most common symptoms with chemotherapy, with a prevalence of 65-99%.

For proper diagnosis other significant medical illnesses such as anemia, depression, obstructive sleep apnea, other sleep disorders, poor nutrition, hypothyroidism, hypogonadism, chronic use of opioids, or hypopituitary state must be ruled out.

Has subjective and objective components and include physical symptoms such as physical weakness and tiredness, depression, lack of motivation, impaired cognition and reduces ability to sustain social relationships.

Negatively affects quality of life, emotional well-being, and ability to tolerate treatment.

Cancer related fatigue highly prevalent in cancer patients and impairs quality of life with more distress and impact than pain, depression and nausea.

Can persist for months or years.

May be perceived as the most distressing symptom associated with cancer, even worse than pain or nausea and vomiting.

Persistent fatigue may last months or years after completion of therapy.

Often part of a cluster of symptoms including: depression, sleep disorder, and pain.

Underlying pathophysiology has not been elucidated.

Suggested mechanisms of ideology include serotonin dysregulation, muscle and ATP metabolism abnormalities, hypothalamus-pituitary-adrenal axis dysfunction, abnormal circadian rhythms and increased cytokine production.

Tryptophan degradation and cytokines, and pro inflammatory mediators are produced in response to cancer and have been associated with fatigue: their direct role in pathogenesis however is controversial.

Cytokines have been implicated in cancer associated fatigue by possibly acting on mood, muscle mass, strength, and the metabolism.

There is a positive correlation between fatigue and circulating levels of

 inflammatory markers including interleukin-6, IL-1 and neopterin values.

Factors contributing include the direct effects of cancer, adverse effects of treatments, psychological factors including personality traits, comorbid illnesses, comorbid physical symptoms, and lifestyle factors.

Comorbid processes may contribute to the overall degree of fatigue and include anemia, cachexia, depression, sleep deprivation, cancer treatments, myelosuppression, and hypothyroidism.

Commonly graded by the National Cancer Institute Common Toxicity Criteria and ranges from grade 1, with mild fatigue but no impact on daily living, to grade 4 with the patient experiences severe fatigue related disabilities.

No proven pharmacologic treatment.

A study of a combination of physical activity with dexamethasone showed improvement in cardio respiratory fitness, but the improvement was seen for up to three weeks after the discontinuation of dexamethasone (Yennurajalingam S).

Yoga improves fatigue among cancer survivors with improvements in walking, physical activity, and quality of life.