F

atigue generally refers to tiredness and lack of energy. A person who is not eating properly or has poor physical conditioning may experience fatigue '€“ which means that the body is letting a person know that there is not enough nutrition or that a person is overdoing exercise. The tiredness is usually short term and recovers rapidly with adequate nutrition or rest.

However, fatigue for people with cancer can be very different. Cancer or its treatment may make one feel very tired. There are multiple possible obvious - or not obvious - causes and the tiredness may not go away, even with rest. Fatigue is very common in people with cancer. It can be the most troubling symptom for some patients.

In general, cancer related fatigue (CRF) is subjective. Patients may have a persistent sense of tiredness or exhaustion. It may involve physical, emotional and cognitive aspects and is not proportional to a patient'€™s activity and may substantially affect daily functioning. Many patients will experience CRF to a certain extent throughout their treatment, and sometimes even after treatment is over. CRF can be difficult to identify, although the common complaints are low energy, low motivation, tiring easily and difficulty sleeping.

Many things can contribute to CRF, including factors unrelated to the cancer, those that are cancer treatment-related or those related to a recurrence of the cancer.

Some patients develop non-cancer related conditions, such as diabetes or hypothyroidism, during their follow ups. These conditions can present with fatigue and low energy if undetected.

Patients will generally feel tired after chemotherapy, and treatment-related anaemia is a cause of fatigue that can be corrected by medication or blood transfusions. Hormonal therapy used to treat cancer can also cause CRF and medications that lower male or female hormones such as for treating prostate or breast cancer can also have an effect on energy levels. In these situations, medication may need to be adjusted.

Detection of the underlying cause of fatigue is important for specific treatment to combat CRF. For general prevention, some chemotherapy patients benefit from a light symptom-limited workout. It is best to check with the treating doctor in each case.

For some, short exercise can be done during the week after chemotherapy when they are not too tired. Exercise strengthens bones and maintains overall physical well being. Light exercise of at least up to 15 minutes is recommended to improve heart and lung function and to strengthen joints and muscles. Fluids and good nutrition are equally important. A balanced diet is best.

If a patient is unusually fatigued, we will need to investigate for sinister causes, such as the side effects of cancer drugs, such as diarrhoea. In these cases, a patient will need to replenish fluids and electrolytes. Checking to make sure these are adequately replaced is easily done with a blood test. In other cases, cancer recurrences need to be excluded by further tests and treated if necessary.

Stress may not contribute to CRF. Most patients are on medical leave and away from work during cancer treatment and some worry that stress might contribute to cancer recurrence. However, this has not proven to be true. In cases of prolonged stress, some people feel discouraged and may not want to return to work. These are emotional and social issues which need to be managed. A little stress can have some motivational effects. Anxiety and depression, on the other hand, can contribute to CRF. Managing these emotions is important and occasionally professional help is needed.

Patients should be on regular follow up with oncologists after a cancer diagnosis, informing doctor if they experience persistent disturbance in normal activities or sleep. A patient who feels fatigued despite adequate sleep or rest may warrant further evaluation. Although patients may be fearful that CRF is related to a cancer relapse, very often it is not. We always start by evaluating the common, simple, treatable causes first. Patients may be relieved to know that their suffering may be something easily managed.

Peter Ang, a physician and visiting consultant to the National Cancer Center, was previously the senior consultant medical oncologist and director of the Cancer Education Service.