EXERCISE AND CANCER

Cancers form a very large group of conditions which are extremely common causes of disease, disability, suffering and death. Nearly 40% of people will be diagnosed with one or another type of cancer in their lifetime and cancer causes nearly 30% of all deaths in the UK. Cancers are also very disparate, varying from minor skin excrescences to devastatingly fast spreading and fatal malignancies. The place of exercise in the prevention and management of such a wide spread of conditions is likewise very variable.

Exercise and cancer prevention

A large meta-analysis of 1.44 million individuals found that regular physical activity reduced the risk of 13 different cancers – by 10% for the breast up to 42% for the gullet. Other cancers which were prevented by physical activity included liver, lung, kidney, stomach, womb, bone marrow (ie leukaemia), colon, rectum and bladder.  Overweight and obesity, the close relatives of lack of exercise, are among the commonest contributory causes of cancer. Exercise clearly has a preventive role here too.  Avoidance of weight gain has been shown to reduce the risk of cancers of the colon, gullet, kidney, breast and womb.

Exercise in the treatment of cancer patients

When it comes to the treatment of cancers, exercise is attracting increasing attention. Evidence is emerging to show that regular exercise can reduce recurrence of treated cancers after medical and surgical treatment and also prolong life. In one study of breast cancer, exercise treatment was associated with double the chance of survival over eight years. The chance of recurrence was reduced by a third.^.

Quality of life as well as survival is a further important advantage of exercise for cancer patients. A number of centres use exercise in the treatment of prostate cancer with encouraging results. Benefits include reduced rates of progression. A trial of football playing in prostate cancer patients showed increased bone density, better mental health scores and lower rates of hospital admission in the players. One success was that more than half of the footballing participants continued even when they had to pay their own membership fees after the trial ended!

Lung cancer provides another example. A recent article has promoted the use of exercise to treat patients with lung cancer ¹. These patients usually  present insufficient levels of physical activity and exercise, which contributes to quality of life impairment, reduction in functional capacity with skeletal muscle atrophy or weakness, and worsening of symptoms, particularly breathlessness. Exercise programmes have been shown to improve fatigue, quality of life, cardiorespiratory fitness, lung function, muscle mass and strength, and psychological status in patients with lung cancer. Moreover, physical fitness levels, especially cardiorespiratory endurance and muscular strength, are independent predictors of survival.

Prehabilitation ²

This neologism describes the use of fitness programmes to prepare patients for the forthcoming rigours of surgery, radiotherapy, chemotherapy etc. The fitter you are before treatment the better you will withstand the assaults of the medical profession and the better your outcomes, including mortality and resistance to all the complications of treatment. Poor physical fitness predicts adverse outcomes, particularly after surgery. Physical training has been shown to reduce postoperative complications and speed discharge. This applies also to all major surgery, particularly in older patients.

Finally

So, being at risk of or diagnosed with cancer are real indications for exercise – and remember, we are all a bit at risk.

1. doi: 10.1634/theoncologist.2019-0463
2. Clinical Medicine 2019;19:458-6