Why should GPs encourage oncology patients to exercise?

Why, I hear you ask, should we suggest exercise to our oncology patients?
 
Why should we add a further burden to our cancer patient’s hectic schedule of appointments, treatments, blood tests, follow-ups, psychological support and cancer council group sessions?
 
The answer, in a nutshell, is because it might just improve their symptoms and their quality of life.
 
Last year, I was privileged to hear Professor Daniel Galvao from the Exercise Medicine Research Institute at Edith Cowan University speak about exercise oncology and exercise as a synergistic cancer treatment. I had the sense this was something we should be taking onboard.
 
Just last month, 25 oncology organisations called for exercise to be prescribed to all cancer patients.
 
Exercise during cancer treatment has been shown to reduce fatigue, nausea and improve body weight, and has a role in treatment, rehabilitation and recovery, disease prevention, palliation and survival prolongation. Most research to date has focused on exercise in breast, colon and prostate cancer.
 
In Stage one or two breast cancer, Professor Galvao’s research has shown exercise blunts the reduction in physical functioning in breast cancer survivors with increases in quality of life and peak oxygen consumption.
 
Similarly, prostate cancer patients who exercise while undergoing androgen-deprivation therapy have less fatigue, improved quality of life, feel more empowered and, importantly, demonstrate no adverse effects as a result of exercise.
 
Resistance training may actually improve chemotherapy tolerance and while this has been demonstrated to a lesser extent with aerobic exercise, aerobic training prevents reductions in VO₂ maximum seen with some treatments.
 
There is high-level evidence that exercise in cancer patients is safe, good for aerobic fitness and muscle strength and improves fatigue levels. There is moderate-level evidence that exercise improves body size, anxiety and level of physical functioning.
 
So, what exercise should we be recommending?
 
Combined resistance and aerobic exercise prescription, and soccer training, have been shown to reduce muscle loss and improve fatigue in cancer patients.
 
Studies suggest that an early supervised program with later transition to a home program improves exercise uptake and compliance. Regular physical activity is recommended, with 150 minutes per week of aerobic exercise plus two sessions of strength training exercises the initial target level. If patients cannot manage this, we should make sure we are encouraging them to avoid inactivity and return to their normal activities of daily living as soon as possible.
 
Can exercise lower risk of cancer recurrence, delay progression and improve survival?  
 
Studies demonstrate a 37% reduction in risk of dying from cancer if patients are physically active following treatment and a 35% risk reduction of cancer progression with 360 minutes of physical activity per week. Preliminary evidence from active surveillance in prostate cancer suggests that exercise may delay progression and transition to active therapy.
 
How can this be? It may be related to telomere length. Telomere shortness in humans is a prognostic marker of ageing, disease and premature mortality and it has been demonstrated that telomeres lengthen in lifestyle intervention groups. This is thought to be a biological mechanism, but research continues. Phase three trials continue researching the impact of exercise on cancer outcomes.
 
Physical activity has far-reaching value for cancer prevention with 10–40% reductions cited depending on which cancer is being investigated. There is a protective association in breast cancer between increased exercise after diagnosis and prognosis/recurrence, and the associated protective effect of exercise in breast cancer has been demonstrated in estrogen-receptor-positive (ER-positive) patients. Malignant recurrent glioma has a greater survival length associated with activity of greater than 150 minutes per week.
 
In summary, exercise will at a minimum do no harm and for many cancer subgroups shows an association with better outcomes with regards to quality of life, prognosis and prevention. Clearly, not all patients will demonstrate the same response and this will depend upon cancer subgroups, as well as individuals.
 
Overall, though, the broad message is clear: Exercise should be encouraged because exercise is a form of medicine.

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