Exercise training has been proposed pre-operatively as a means of improving surgical outcome (prehab) and post-operatively to shorten the recovery period (rehab). Early studies in surgical patients are encouraging and suggest this approach may be effective.
There is an important relationship between physical activity, fitness levels and nutritional well-being.
A recent study estimated that in the UK > 4 million major surgical procedures are performed annually at a cost of ~ £16 billion 1. 12.3% of these are performed on “high-risk” patients (expected mortality >5%). Estimates of postoperative morbidity vary between 7%-50% 2. Recent cohort studies report that the presence of a single post-operative postoperative complication increases the risk of mortality for up to 8 years after surgery, independent of baseline comorbidities. Consequently perioperative morbidity represents a significant public health challenge that with an ageing, increasingly comorbid population is only likely to increase 3.
There is an important relationship between physical activity and fitness levels and nutritional well-being 4. The benefits of exercise-training and nutritional supplementation prior to and following major surgery are unknown. ?The Department of Health recognises the need to improve patient’s fitness and lifestyle prior to surgery, in particular high-risk patients who account for 80% of all deaths following surgery. The impact that post-surgical complications have on an individual’s quality of life is a top priority amongst these patients 5.
Aerobic exercise training augments cardiac, respiratory and musculo- skeletal function.
Regular exercise offers protection against all-cause mortality 7 8 and may represent something of a public health panacea 6. Exercise training especially interval training has been shown to have a long-term anti-inflammatory response 9. It is widely accepted that the systemic inflammatory response associated with major surgery has a profound effect on physiologic function 10. Thus exercise training prior to and following major surgery may modify the inflammatory response and may be of benefit. Exploring the impact of exercise training prior to surgery has recently been identified as one of the research priorities of the Royal College of Anesthetists/James Lind Alliance 5.
Several meta-analyses and systematic reviews have shown aerobic exercise-training is beneficial in improving physical fitness in a variety of clinical populations 11 12 13 even over a short time period. Aerobic exercise training augments cardiac 14, respiratory 15 and musculo- skeletal 16 function. Exercise training can stimulate skeletal muscle adaptations, such as increased mitochondrial content and improved oxygen uptake capacity that may contribute to improving physical fitness.
Preoperative conditioning before a stressful event (i.e. surgical trauma) is termed prehabilitation 17. The goal of prehabilitation is to improve preoperative physical fitness through an exercise intervention programme in an attempt to accelerate postoperative recovery.?Prehabilitation (pre-surgical exercise training) has been shown to be feasible and safe, as well as offering improvements in function and quality of life 18 19 20 21 22 23.?There have been several systematic reviews of exercise-training in patients prior to surgery and during cancer therapy peri-operatively demonstrating some benefit, although further evaluation is required. 24 25 26 27. These reviews report that effective exercise-training programmes increase the anaerobic threshold and peak oxygen uptake within 4-6 week 18 24.
An additional component, which may affect physical fitness, is neoadjuvant and adjuvant cancer treatments (chemo and/or radiotherapy) prior to or following cancer surgery. This has to be taken into account when designing and exercise training programme. Recent data suggests that cancer treatments reduce physical fitness, which in turn relates to adverse clinical outcome 28 29 30.
Cancer treatment has been linked to decreased physical fitness levels.Chemotherapy has been related to skeletal muscle wasting, oxidative stress, mitochondrial death30 and reduced in vivo mitochondrial function31 32. Furthermore, cancer treatment has been linked to decreased physical fitness levels, which appears to be related to the type of treatment, being worse in those receiving surgery and radiotherapy in combination with chemotherapy than in those who receive radiotherapy or surgery alone.
It may therefore be that, in some patients, the tumour regression benefits of such treatments may be outweighed by the harm of diminished physical fitness28. The introduction of neoadjuvant cancer treatment in the surgical pathway may provide a window of opportunity to intervene with exercise training before, during and after cancer treatments to ameliorate or reverse the harmful effects on physical fitness.
The evidence in the neoadjuvant and adjuvant cancer treatment setting is sparse. A synthesis of this literature is published in 2 systematic reviews and indicates that this approach is safe and feasible25 26. However there are insufficient randomised controlled trials in this area to draw reliable conclusions about the efficacy of such an intervention, the optimal characteristics of the intervention, or the impact on clinical or patient reported outcomes. In particular the optimal type of training and its optimal timing require elucidation. Future studies will need to examine the mechanisms of cancer treatment and different exercise programmes as well as translating this to clinically important outcome measures such as disease-free survival and overall survival in different cancer cohorts. Encouragingly, there are ongoing studies investigating the effects of exercise on prevention or mitigation of adverse toxicities and their association to cancer treatment 33 34.
Finally, it is encouraging that people with cancer undergoing the “dual-hit” of surgery and cancer therapy can tolerate exercise training and perhaps global exercise guidelines for people with cancer can be further specified and recommended 35 36 37.