What is Cancer-related Fatigue?

Cancer-related Fatigue : an introduction

    Fatigue is one of the major issues in survival of many cancer patients and yet has been given very little attention. Fatigue is the most common side effect of cancer as a disease and its treatments  in the form of chemotherapy, radiotherapy or selective biological response medication,etc.
    This introductory article will address the issue of fatigue and answer the preliminary questions like 'what is fatigue', 'is there a difference between healthy fatigue and fatigue experienced by cancer patients', etc.

•   What is fatigue?

Fatigue is the feeling of tiredness or weariness experienced by a person. It does not have a huge impact on the functional ability of a healthy person. This is because the fatigue experienced by healthy individuals is generally due to physical exertion like working more than usual or taking a gym class after a long day's work.After which, the body signals that it's tired or fatigued, and after adequate rest, there remains no sign of it whatsoever. But, the exhaustion or fatigue that develops due to malignant tissues in cancer and the action of the therapeutic agents used against it is unique in intensity and character.

•    Is there a difference between healthy fatigue and fatigue that cancer patients experience?

Yes, there is.Healthy fatigue is described as acute or short term fatigue generated because of exertion, that is relieved by sleep and rest .Whereas the fatigue that cancer patients experience is not generated because of exertion  and is never completely relieved by sleep or rest. Cancer related fatigue is generally seen with associated problems like anemia, respiratory obstruction, hormonal imbalance, depression, and poor quality of life, etc.

Healthy fatigue is in proportion to the extent of physical exertion, but cancer related fatigue is disproportionate to the same.
For example, a healthy individual will experience fatigue after a long day's work and there's no sign of it the next morning. Whereas, a cancer patient will experience fatigue even without any sort of activity done, this fatigue might stay throughout the day, and may remain the same even after sleep.

• What is cancer treatment related fatigue/cancer-related fatigue?

This fatigue is developed because of cancer and its treatments.It may  be observed in patients with advanced cancer who are not under any medication for cancer.This fatigue is seen during the chemotherapy regime and after the radiotherapy cycle is completed.And also after surgeries. This is generated because of the drugs and their side effects on the body.

Cancer treatment related fatigue can be categorized as chronic fatigue because it is present over a long period of time and interferes with the normal functioning and results into poor quality of life .This may improve after therapy or treatment is completed but a certain level of fatigue persists for months or years following the treatment making this a significant issue in survivorship. The fatigue generated due to cancer and its treatments together is known as 'Cancer-related fatigue' or( CRF). This was recently accepted as a diagnosis in the International Classification of Diseases 10th Revision-Clinical Modification.

Causes of fatigue are discussed in the next post Causes of Cancer-related fatigue.

Also read
Cancer-related Fatigue symptoms
How to diagnose Cancer-related fatigue?
How to evaluate Cancer-related fatigue using simple tools?
How to evaluate fatigue using multi-dimensional tools?
What are the causes of Cancer?